New evidence for block and thrust sheet rotations in the central …gilder/Re... · 2016-03-08 · New evidence for block and thrust sheet rotations in the central northern Calcareous

New evidence for block and thrust sheet rotations in the central

northern Calcareous Alps deduced from two pervasive

remagnetization events

E. L. Pueyo,1,2 H. J. Mauritsch,1 H.-J. Gawlick,3 R. Scholger,1 and W. Frisch4

Received 9 March 2006; revised 30 September 2006; accepted 27 April 2007; published 6 October 2007.

[1] We present 81 paleomagnetic sites (Early Triassicto Early Cretaceous) from the central sector of thenorthern Calcareous Alps (NCA, Eastern Alps, Austriaand Germany). Stepwise thermal demagnetizationdefines three magnetic directions mostly carried bylow unblocking temperature and low-coercivityminerals: J3, 350�; J2, 500�; J1, 575� and 680�.J3 and J2 show positive inclinations, whereas J1 (veryseldom) is of dual polarity. The fold tests showthat a J3 can be interpreted as a postfolding andposttilting remagnetization and J2 as a postfolding andpre(syn)tilting. J1 can be considered as primarybecause of the occurrence of two polarities andevidence presented by other authors in the area. Allthree components show a systematic and significantclockwise rotation after comparing with the expectedEuropean references. J2 or J1 are marked by higherrotation values than J3. J2 shows different inclinationsdepending on the structural position (north orsouthward dips). Considering the structural evolutionand the observed inclinations, the first postfolding andpretilting remagnetization event (J2) could have takenplace between Late Cretaceous and Eocene times butcertainly before the thrusting of the NCA over theRhenodanubian Flysch and northward tilting causedby the stacking of the lower Austroalpine nappes. Thesecond postfolding and posttilting remagnetization(J3) would have been acquired after the final thrustingof the NCA over Penninic units. From then, the NCAbehaved as a set of rigid blocks recording the mainstage of vertical axis clockwise rotation (65� inaverage) associated with the continental collision.The variable degree of rotation in the differentpositions (from 40� to 134�) can be explained byindividual vertical axis rotation in a block systemtrying to adjust to space problems. The constant

declination differences between J2 and J3 (25� inaverage) would reflect the rotation related with thelateral differences of shortening during the obliquethrust of the Austroalpine units over the Penninicunits. Citation: Pueyo, E. L., H. J. Mauritsch, H.-J. Gawlick,

R. Scholger, and W. Frisch (2007), New evidence for block and

thrust sheet rotations in the central northern Calcareous Alps

deduced from two pervasive remagnetization events, Tectonics,

26, TC5011, doi:10.1029/2006TC001965.

1. Introduction

[2] Paleomagnetism in orogenic zones is commonlyapplied for the definition of vertical axis rotations, whichare mostly related to differential shortening or displacementat different scales [McCaig and McClelland, 1992; Allerton,1998; Pueyo et al., 2004; Soto et al., 2006] and may escapeidentification if classical structural methods are applied.Large-scale orogenic processes like rotations related toescape tectonics or oroclinal bending can also be deducedfrom the geographical distribution of paleomagnetic vectors[Eldredge et al., 1985].[3] On the other hand remagnetizations are common in

orogenic areas and were not generally considered fortectonic interpretation before the 1980s [Hannah andVerosub, 1980; Cisowski, 1984; McCabe and Elmore,1989]. Normally, they are associated with different orogenicprocesses like thermal metamorphism or fluid circulation,such as basinal fluids associated with thrusting, Morerecently, the maturation of organic matter [Banerjee andElmore, 1997] or the burial diagenesis of clay minerals[Katz et al., 1998] are proposed as other possible mecha-nisms of widespread remagnetization. Despite being themost common explanation for most magnetic overprints‘‘the fluids effect’’ remains elusive in the majority ofexamples [Elmore et al., 2001]. Independent of the respon-sible process, the remagnetization directions would yieldadditional and very valuable information to reconstruct thekinematics and geometry of orogenic areas since theyrepresent intermediate snapshots of the deformation history.[4] The northern Calcareous Alps (NCA) belong to the

upper Austroalpine megaunit (AU) of the Eastern Alps andrepresent one of the largest tectonostratigraphic units of theAlps. The application of paleomagnetism in this part of theorogen started very early [Hargraves and Fischer, 1959],and continues until today [Soffel, 1975; Mauritsch andFrisch, 1978, 1980; Heer, 1982; Becke and Mauritsch,1985; Soffel and Wohl, 1986; Mauritsch and Becke, 1987;

TECTONICS, VOL. 26, TC5011, doi:10.1029/2006TC001965, 2007

1Paleomagnetic Laboratory, University of Leoben, Gams, Austria.2Now at Instituto Geologico y Minero de Espana, Unidad de Geologıa y

Geofısica, Zaragoza, Spain.3Institute of Geosciences, University of Leoben, Leoben, Austria.4Institut fur Geologie und Palaontologie, Universitat Tubingen, Tubingen,

Germany.

Copyright 2007 by the American Geophysical Union.0278-7407/07/2006TC001965

TC5011 1 of 25

Channell et al., 1990, 1992; Channell and Stoner, 1994;Gallet et al., 1993, 1994, 1996, 1998; Haubold et al., 1999;Thony et al., 2006]. These studies had different goals, suchas the reconstruction of the nappe system evolution (char-acterization of rotations) or the platform configuration ofthis margin of the Tethys Ocean (Triassic and Jurassicmagnetostratigraphy and paleogeographical reconstruc-tions). Some of these works [Heller et al., 1989] werefocused on compilations, large-scale interpretations andoverviews partially [Mauritsch and Marton, 1995] underthe light of the lateral extrusion hypothesis [Ratschbacher etal., 1991]. On the other hand, remagnetizations were earlydescribed by Kligfield and Channell [1981] in the Alpineorogen. Despite of the large amount of paleomagnetic workcarried out in this mountain belt and except for a few cases[Channell et al., 1992; Muttoni and Kent, 1994; Pueyo etal., 2001], magnetic overprints have been described mostlyin the western areas [e.g., Rochette and Lamarche, 1986;Thomas et al., 1999; Collombet et al., 2002; Cairanne et al.,2002; Kechra et al., 2003; Thony et al., 2006]. However,remagnetizations have not been seriously considered so farin the NCA as kinematic indicators. The size of the 600 kmand its complex geological evolution contrasts with theamount and distribution of paleomagnetic data available(133 sites) and the diversity of interpretations. This largeand important Alpine unit needs a more careful analysis andnew data. A first stage in the interpretation of paleomagneticdata began with the critical reinterpretation of previousworks [Haubold et al., 1999] under the reliability criteriaproposed for paleomagnetic data [Van der Voo, 1990].Consistent data based on a better age control of themagnetization (proved by stability tests) are essential inany single block, thrust sheet, and nappe. Structural unitsmust be considered independently to isolate the vertical axisrotation related to the thrust system arrangement (relativerotation among units) from large-scale movements or dif-ferent initial paleogeographical configurations. On top ofthis, paleomagnetic results are crucial to control ‘‘out ofplane’’ movements in structural cross sections or three-dimensional (3-D) models if reliable shortening estimateswant to be obtained. To shed some light on these problems,the central part of the NCA (south of Salzburg) has beenexamined in detail by studying 77 new sites and fourmagnetostratigraphic profiles. Previous data in the area(45 sites from Mauritsch and Frisch [1978], Heer [1982],Becke and Mauritsch [1985], Mauritsch and Becke [1987],Channell et al. [1990, 1992], and Gallet et al. [1993]) werealso included in the interpretation.

2. Geological Setting

[5] The NCA represents the upper structural level of theAustroalpine units (AU). In its central sector it is thrustingto the north over the Rhenodanubian flysch (Penninic),which thrusts over the Molasse basin and the Europeanbasement. The Graywacke Zone and the lower crystallineAU rest below the NCA at its southern border (Figures 1aand 1b). The NCA represents a thin-skinned fold and thrustbelt [Plochinger, 1995] and the final geometry and the

facies distribution seen today reflects the opening andclosure of two oceans (Meliata and Penninic) and thesubsequent collision caused by the oblique and rotationalconvergence between the Adriatic (African) and Europeanplates since Triassic times [Frisch, 1979; Neubauer et al.,2000]. The magnitude of the accommodated frontal short-ening (present N–S direction) deduced from balanced andrestored cross sections in the NCA structures [Linzer et al.,1995; Auer and Eisbacher, 2003] spans between 45 and80 km and is similar to those estimated from 3-D retrode-formation [Behrmann and Tanner, 2006]. The NCA consistsof a mostly Mesozoic pile of carbonates up to 5 km thick, inwhich three different detachment levels can be identifiedalong the sedimentary sequence (Figure 1c). It reflects thelarge carbonate platforms in this part of the Tethys fromMiddle Triassic up to Late Triassic [Zankl, 1971; Tollmann,1985; Mandl, 2000, and references therein]. This platformshows an increase in depositional depth toward the east(present south), and the different geological environments(with different rheological properties) played an importantrole in the further thrust system configuration [Tollmann,1985]. The opening of the Penninic Ocean since EarlyJurassic separated the NCA from the European plate, andthe first contractional phase of thrusting and block tiltingstarted (including sliding and olistolites) in a general deep-water setting with relatively low sedimentation rates [Bohmet al., 1995]. In late Middle to Late Jurassic times, deep andsometimes very thick siliceous sediments were deposited[Gawlick et al., 1999, and references therein] due to theclosure of parts of the Tethys (Meliata-Hallstatt) Ocean. Atthis time, the Tirolic nappes, including the HallstattMelange, formed. This tectonic event was sealed by shallowwater carbonate platform sediments between the Late Ju-rassic and Early Cretaceous (Plassen Formation, OberalmFormation [Gawlick and Frisch, 2003]). During EarlyCretaceous times (Hauterivian onward), the system wascharacterized by the final contractional deformation (dueto the onset of subduction of the Penninic ocean) affectingmainly the former Late Triassic platform (lagoonal faciessequences in the northern parts). At this time the Bavaricand Tirolic nappes were formed. The Gosau Group repre-sents the basin infill of basins postdating the Mesozoicdeformation, including initial stages of thrusting in the NCA[Wagreich, 1993, 1995; Faupl and Wagreich, 2000;Wagreich and Decker, 2001]. During the Eocene, earliernappe and fault structures were reactivated in an overallcompressional regime and parts of the NCA experiencedtheir final detachment from their basement and werethrusted onto the Rhenodanubian Flysch. Early to middleMiocene lateral tectonic extrusion caused considerable E–W stretching of the Eastern Alps and thus also of the NCA[Linzer et al., 1997; Frisch et al., 1998, and referencestherein]. The brittle Austroalpine megaunit experiencedblock segmentation and rearrangement of the created blockpuzzle during this event [Linzer et al., 2002; Frisch andGawlick, 2003].[6] The present-day structure in the studied area (Figure 2;

the central NCA) can be described as follows [e.g.,Schweigl and Neubauer, 1997; Frisch and Gawlick,

TC5011 PUEYO ET AL.: REMAGNETIZATIONS IN THE CENTRAL NCA

2 of 25

TC5011

Figure

1.

(a)Geologicalsketch

map

oftheAlpsdisplayingthemajorstructuralelem

entsandthelocationofthestudied

area

(modifiedfrom

Bigiet

al.[1983],Egger

etal.[1999],Neubauer

etal.[2000],Collombet

etal.[2002],andothers).

(b)TRANSALP‘‘crocodile’’model

throughtheEastern

Alps[from

TRANSALPWorkingGroup,2002;Luschen

etal.,

2004].

(c)Sim

plified

stratigraphic

columnforthecentral

unitsoftheNCA

(mostly

Tirolicunits,

form

erStauffen-

Hollengebirge,Goll-Lam

mer,andBerchtesgaden

nappes)in

whichthesampledform

ationshavebeenmarked

withastar.


3 of 25

TC5011

Figure 2. Geological map of the Central NCA, based on the structural map of Italy [Bigi et al., 1983](compiled by B. Plochinger for the NCA). Major changes in the stratigraphy are shown as well asstructural features. Paleomagnetic sites from this work along with former data are also shown (fordetailed information, see Tables 1 and 2).


4 of 25

TC5011

2003]: The northern sector of the Stauffen-Hollengebirge(SH) nappe (lower Tirolic nappes) is limited to the north byan important thrust over the Bavaric nappes and the Rhe-nodanubian Flysch. The northern hanging wall unit displaysa shallow dip to the south (probably indicating the angle ofthe basal thrust plane). Southward in the Osternhorn block,the beds remain horizontal (e.g., Tauglboden), and the upperpart (Schrambach Formation in eastern Weitenauboden) isthrust by Triassic carbonates (the Lammer unit; Hallstattmelange). The southernmost part of this thrust sheet hasbeen tilted to the north (northern slope of the Tennenge-birge) reflecting the geometry of the underlying stackedbasement units. Below this thrust, in the Salzach canyon,the Dachstein beds dip moderately toward the north (upperTirolic unit of the former Stauffen-Hollengebirge nappe).Most part of the data set belongs to the former Stauffen-Hollengebirge and Berchtesgaden nappes (lower and upperTirolic units, respectively, in the new classification byFrisch and Gawlick [2003]) and part to the Goll-Lammerunit [Tollmann, 1973, 1985, 1987; Plochinger, 1995],redefined as Juvavic-Hallstatt Melange [Frisch andGawlick, 2003]. Previous paleomagnetic data were mostlyobtained in the north central part of the NCA [Mauritschand Frisch, 1978; Smathers, 1987; Channell et al., 1992;Heer, 1982; Gallet et al., 1993], mainly in the Liassicformations because of their well-know magnetic signal(Table 1 and Figure 2); primary components of magnetiza-tion, which are characterized by dual polarities and carriedby hematite were identified. Secondary directions were onlypoorly described or ignored. Fold tests were not shownbecause of the monotonous bed orientations in the northernsector of the NCA. In general systematic clockwise rota-tions ranging from 45� to 90� were observed.

3. Sampling and Laboratory Methods

[7] Seventy-seven new sites were sampled with conven-tional drilling machines (Figures 1 and 2), 7 to 10 coresdistributed in three to four beds (2–3 m of stratigraphicprofile) were taken per site. Three of them (KB01, KB03and WG01) consist of microfolds on outcrop scale (Ober-alm Group). Sites were evenly distributed in differentstructural units; the differences in bedding attitude enablingthe application of the fold test in almost all sampled units/nappes. Supplementary measurements were taken in thefield (bedding planes, cleavage, faults, sliken-sides, micro-fold axis, etc.) to characterize the geometry of the structures(fold axes, faults, etc.) and correctly restore the paleomag-netic data to the undeformed stage. The sampled strati-graphic levels span from the early Middle Triassic(Gutenstein Formation) to the Cretaceous-Tertiary deposits;the Gosau Group (see stratigraphic details in Figure 1c). Inaddition 4 magnetostratigraphic profiles were sampled try-ing to keep a regular and continuous spacing of data (one totwo cores per level). NR01 (40 samples) and NR02 (90)span the Norian/Rhaetian boundary, GA01 (20) spans theHettangian to Toarcian and TB01 (53) covers from Liassicto Malmian (Figure 1).[8] Isothermal remanent magnetization (IRM) acquisition

curves and backfield experiments were performed to qual-

itatively estimate the magnetic carriers in the rocks. A 2-Gpulse magnetizer allowed us to apply fields up to 2.5 T. Theremanences were measured with a 2-G super conductingthree-axis magnetometer (AC and DC sensors). The thermaldemagnetization of three-component IRM indicated theunblocking temperature spectrum [Lowrie, 1990] was usedto design the demagnetization procedure. Stepwise thermaldemagnetization was better to isolate the different paleo-magnetic components and was performed with a MagneticMeasurements Ltd. oven every 30� and 50� from 20�C to575�C and occasionally higher steps. Simultaneous meas-urements of bulk susceptibility were taken during progres-sive demagnetization to control possible changes inmagnetic mineralogy. In total more than 670 samples werethermally demagnetized in the Gams paleomagnetic labo-ratory (Montanuniversitat Leoben, Austria).[9] At the sample scale paleomagnetic directions were

fitted by means of the principal component analysis[Kirschvink, 1980] and the software package Paldir 7.0(Utrecht Paleomagnetic Laboratory). Only directions withmaximum angular deviations (MAD) lower than 15� wereconsidered in further calculations. Fisher [1953] statisticswere applied to average out the characteristic directions atevery site. Demagnetization circles (DC) and the stackingroutine (SR) [Scheepers and Zijderveld, 1992; Pueyo et al.,2007] were auxiliary used to improve site means (a95 <15�). The DC intersections were implemented together withdirect observations (directions) to achieve the site mean anderror. Since the number of circles (n) per site is usuallylower than 4, the number of intersections ([n2 � n]/2) issimilar to the number of direct observations (conventionaldirections) and does not condition the site mean. The SRwas mostly applied in pilot sites (v.g. Berchtesgaden); theMADcharacterized themean direction obtained from the site-stacked sample. Several fold tests were run using the 1995SuperIAPD package by T. H. Torsvik, J. C. Briden, andM. A.Smethurst.

4. Results

[10] Magnetic carriers seem to be very monotonousdespite the large variety of rocks in the NCA. A rockmagnetism study based on IRM curves and thermal demag-netization of three components IRM (see the auxiliarymaterial) and carried out in all rock types allows recogniz-ing low-coercivity minerals (dominantly magnetite andsome traces of sulphides) as main paleomagnetic carriers,other minerals as hematite can be scarcely found in a fewlithologies (e.g., Adnet Formation, Radiolarites).1

[11] Orthogonal demagnetization diagrams (Figure 3)reveal three distinct paleomagnetic components. They aremostly independent of the rock types and, as a rule; two ofthem are present in many of the processed sites (see alsoTables 2 and 3): For J1 a high-temperature component hasbeen isolated in a few samples. This component has higherunblocking records (sometimes above 600�C). For J2 anintermediate direction unblocks from 350�C to 450�–

1Auxiliary materials are available in the HTML. doi:10.1029/2006TC001965.


5 of 25

TC5011

Table

1.PreviousPaleomagnetic

Sites

intheTirolicNappeSystem

(Form

erStauffen-H

ollengebirgeNappe)

a

Site

Ref.

Long

Lat

Map

Locality

Form

ation

Stratigraphic

Age

Age

Strike

Dip

DD

Obs

nN

BAC

Pola95

K

ABC

a95

KD

ID

I

1W06

Heer1982

13.243

47.569

94

W06Schonalm

Adnet

limestone

Liassic

200

299

42

NSam

p6

695

67

N4

323

55

35

4323

2W07

Heer1982

13.243

47.569

94

W07Schonalm

Adnet

limestone

Liassic

200

300

38

NSam

p8

872

62

N3

404

51

29

3404

3W03

Heer1982

13.195

47.582

94

W03Zim

merau

Adnet

limestone

Liassic

200

298

31

NSam

p7

760

47

N6

109

51

19

6109

4W04

Heer1982

13.195

47.582

94

W04Zim

merau

Adnet

limestone

Liassic

200

298

31

NSam

p6

664

51

N2

1335

52

24

21335

5W05

Heer1982

13.195

47.582

94

W05Zim

merau

Adnet

limestone

Liassic

200

299

28

NSam

p6

669

49

N4

230

57

25

4230

6W01

Heer1982

13.187

47.583

94

W01Golling

Adnet

limestone

Liassic

200

248

42

NSam

p6

679

42

N6

129

43

36

6129

7W02

Heer1982

13.187

47.583

94

W02Golling

Adnet

limestone

Liassic

200

250

44

NSam

p10

10

83

41

N28

446

36

28

48

W08

Heer1982

13.187

47.583

94

W08Golling

Adnet

limestone

Liassic

200

302

39

NSam

p6

6275

�41

R13

28

257

�17

13

28

9W12

Heer1982

13.092

47.600

94

W12RossfeldstrasseN

lRoßfeldschichten

Hauterivian

130

106

36

SSam

p10

10

54

50

N4

119

112

67

4119

10

W13

Heer1982

13.092

47.600

94

W13RossfeldstrasseN

lRoßfeldschichten

Hauterivian

130

353

17

ESam

p8

842

66

N11

26

58

52

11

26

11W14

Heer1982

13.091

47.625

94

W14Rossfeldstrasse

uRoßfeldschichten

Hauterivian

130

108

8S

Sam

p6

692

47

N34

5101

49

34

512

W15

Heer1982

13.091

47.625

94

W15Rossfeldstrasse

lRoßfeldschichten

Hauterivian

130

113

6S

Sam

p8

860

74

N11

28

77

78

11

28

13

W16

Heer1982

13.091

47.625

94

W16Rossfeldstrasse

lRoßfeldschichten

Hauterivian

130

--

-Sam

p8

830

76

N51

227

85

51

214

W17

Heer1982

13.091

47.625

94

W17Rossfeldstrasse

lRoßfeldschichten

Hauterivian

130

112

10

SSam

p7

768

34

N16

15

74

41

16

15

15

MF-M

oos

M&F1978

13.438

47.632

95

OHG

Moosbergalm

Adnet

limestone

Liassic

200

--

-Sam

p2

2?

?N

17

228

55

30

17

228

16

Ch-A

dCh1990

13.164

47.634

94

Adnet

Adnet

limestone

Liassic

200

--

-Sites

33

79

48

N10

149

81

57

16

64

17

MF-A

us

M&F1978

13.411

47.638

95

OHG

Ausserliem

bach

Adnet

limestone

Liassic

200

--

-Sam

p2

2?

?N

10

689

76

49

10

689

18

PR

Ch.1992

13.395

47.675

95

WSG

Promeckbach

Adnet

limestone

Liassic

200

--

-Sam

p21

21

35

45

N3

92

57

63

392

19

G-A

d-1

Gall.1993

13.155

47.680

94

Adnet-Langmoos

Adnet

limestone

Liassic

200

222

12

WSam

pb

b190

�60

R3

182

176

�52

3182

20

G-A

d-2

Gall.1993

13.155

47.680

94

Adnet-Langmoos

Adnet

limestone

Liassic

200

216

11

WSam

pb

b76

45

N4

98

66

51

498

21

G-A

d-3

Gall.1993

13.155

47.680

94

Adnet-Langmoos

Adnet

limestone

Liassic

200

216

11

WSam

pb

b51

56

N3

199

35

57

3199

22

G-A

d-4

Gall.1993

13.155

47.680

94

Adnet-Langmoos

Adnet

limestone

Liassic

200

219

11

WSam

pb

b79

46

N3

147

68

52

3147

23

WE1

Ch.1992

13.342

47.683

95

WSG

Wetzstein

1Adnet

limestone

Liassic

200

216

17

WSam

p8

10

270

�49

R4

211

253

�61

4211

24

WE2

Ch.1992

13.342

47.683

95

WSG

Wetzstein

2Adnet

limestone

Liassic

200

--

-Sam

p10

14

84

52

N4

188

42

64

4188

25

WE3

Ch.1992

13.342

47.683

95

WSG

Wetzstein

3Adnet

limestone

Liassic

200

140

18

SSam

p7

843

43

N4

210

39

61

4210

26

MF-K

on

M&F1978

13.355

47.693

95

OHG

Konigsbachtal

Adnet

limestone

Liassic

200

--

-Sam

p2

2?

?N

417

12

58

64

417

12

27

W09

Heer1982

13.145

47.698

94

W09Adnet

Adnet

limestone

Liassic

200

203

12

WSam

p6

6259

�48

R15

21

249

�57

15

21

28

W10

Heer1982

13.145

47.698

94

W10Adnet

Adnet

limestone

Liassic

200

--

-Sam

p6

631

61

N55

214

61

55

229

W11

Heer1982

13.145

47.698

94

W11

Adnet

Adnet

limestone

Liassic

200

96

22

SSam

p5

566

46

N7

119

91

53

7119

30

KB

Ch1992

13.400

47.700

95

WSG

Kendlbach

Adnet

limestone

Liassic

200

130

12

SSam

p19

19

60

54

N5

47

68

65

547

31

MF-A

dM&F1978

13.134

47.710

94

OHG

Adnet

Adnet

limestone

Liassic

200

--

-Sam

p6

6?

?N

13

27

64

56

13

27

32

MF-Bre

M&F1978

13.399

47.721

95

OHG

Breitenberg

Adnet

limestone

Liassic

200

--

-Sam

p6

6?

?N

4256

59

24

4256

33

HA

Ch1992

13.380

47.728

95

WSG

Hofw

andalm

Adnet

limestone

Liassic

200

323

38

NSam

p8

823

�71

R19

11

257

�67

19

11

34

HS1

Ch1992

13.250

47.750

95

WSG

Hintersee

1Adnet

limestone

Liassic

200

301

8N

Sam

p12

13

82

62

N6

58

72

56

658

35

HS2

Ch1992

13.250

47.750

95

WSG

Hintersee

2Adnet

limestone

Liassic

200

917

ESam

p20

21

47

61

N4

87

64

49

487

36

MF-Sau

M&F1978

13.334

47.758

94

OHG

Saubachgraben

mostly

carbonates

Jurassic

175

--

-Sam

p8

8?

?N

10

34

71

42

10

34

37

MF-Sch

M&F1978

13.318

47.761

94

OHG

Schafbachgraben

mostly

carbonates

Jurassic

175

--

-Sam

p6

6?

?N

18

15

56

49

18

15


6 of 25

TC5011

550�C; it is present inmost rock types and is sometimes difficultto separate from J3. For J3 a low-temperature componentunblocks between 200�C and 350�C which is not alwayspresent. Finally, a very viscous and unstable low-temperaturecomponent appears below 200�C was not considered.[12] In situ J3 and J2 directions display positive inclinations

(about 95% see Table 2) on contrary J1 shows normal andreverse polarities (e.g., GA01) but ismissing inmost of the sites.Site averages are well defined for the low- and intermediatetemperature components (J3 and J2) and only a few of themwere rejected because of insufficient definition (a95 > 15�). Thedata set show the following:[13] 1. J3 and J2 normal polarity components simulta-

neously occur in many sites. J2 is always present.[14] 2. In most cases (about 80%) and before any tectonic

correction, J3 and J2 components display NE-E declinationsand positive inclinations (Figures 4a and 5 and Table 2), inagreement with previous data [Mauritsch and Frisch, 1978;Channell et al., 1990, 1992; Heer, 1982; Gallet et al., 1993].[15] 3. After tectonic correction there is a large scatter of

magnetic inclination for every rock age (Figure 4b), but thescatter is much less in geographic coordinates (Figure 4a).These observations together with the monotonous normalpolarity of J3 and J2 suggest the occurrence of widespreadremagnetizations.[16] 4. In addition, it is noteworthy that the highest

temperature component (J1) appears only in a few sites inthe northernmost positions (only in the lower Tirolic unit).[17] 5. The rotation value is always higher for the

intermediate temperature component (J2) than for the lowerone (J3). This happens within a single sample (Figure 3;VS01.06a, KB03.01a, KA11.02a, KA12.06a) and at the sitescale (KA11 Figures 4c and 5). In most cases the great circlematched by the two components does not cross the present-day geomagnetic field direction and therefore a partialoverlapping with a viscous direction can be excluded.[18] 6. J3 and J2 show different inclinations at both the

specimen and site-mean levels (Figure 4c). For example insite KA11 the lower temperature component (J3) is 54� ininclination and 72� for the intermediate (J2). The separateapplication of the fold test in all structural units is needed toavoid misinterpretations, to validate the hypothesis ofremagnetization and to establish a relative age of themagnetization with respect to the deformation events. Thearea studied has been divided in two major nappes [Frischand Gawlick, 2003] and the paleomagnetic sites have beengrouped and processed following this structural classifica-tion: (1) The lower Tirolic nappe (previously known as theStauffen-Hollengebirge nappe (SH)) represents the largestone, and the Berchtesgaden sector, within this unit, has beenprocessed independently, and (2) the upper Tirolic nappeincludes the Hallstatt Melange (previously known as theLammer nappe) and thrusts the SH in its middle outcrop-ping position (Lammer valley). The northern part of the SHis considered as the Tauglboden nappe (lower Tirolic unit),the old Lammer nappe includes the Lammer-Sillenkopfnappe (upper Tirolic), which overthrusts (Trattberg) theTauglboden nappe and finally, the former southern part ofthe SH nappe is considered to be an Ultra-Tirolic nappe.

Site

Ref.

Long

Lat

Map

Locality

Form

ation

Stratigraphic

Age

Age

Strike

Dip

DD

Obs

nN

BAC

Pola95

K

ABC

a95

KD

ID

I

38

M&BG2-1

M&B1987

47.590

13.500

95

Elendgraben

GosauGroup

‘‘±K/T’’

80

--

-Sam

pb

b?

?N

10

851

34

10

839

M&BG2-2

M&B1987

47.590

13.500

95

Elendgraben

GosauGroup

‘‘±K/T’’

80

--

-Sam

pb

b?

?R

20

4191

�52

20

440

M&BG2-3

M&B1987

47.590

13.500

95

Elendgraben

GosauGroup

‘‘±K/T’’

80

--

-Sam

pb

b?

?R

10

8222

�44

10

841

M&BG2-4

B&M

1985

47.590

13.500

95

Gosau(PassGschutt)

GosauGroup

‘‘±K/T’’

80

232

25

NSam

pb

b57

56

N8

37

23

51

837

42

W19

Heer1982

47.604

12.871

93

Hintersee

Hierlatzlimestone

Liaasic

200

245

28

NSam

p7

771

28

N16

16

56

27

16

16

43

W20

Heer1982

47.604

12.871

93

Hintersee

Hierlatzlimestone

Liaasic

200

245

28

NSam

p8

853

36

N8

47

37

26

847

44

W21

Heer1982

47.604

12.871

93

Hintersee

Hierlatzlimestone

Liaasic

200

228

24

NSam

p9

960

16

N5

129

52

19

545

W22

Heer1982

47.604

12.871

93

Hintersee

Hierlatzlimestone

Liaasic

200

242

19

NSam

p6

659

32

N6

114

48

28

6

aFirstcolumnisnumberofsiteonFigure1;Site,nam

eoftheoriginalsite;Ref,references(M

&F,Mauritsch

andFrisch[1978];Ch,Channelletal.[1992],Heer[1982],andGall,Galletetal.[1993]);Long,

longitude;Lat,latitude;

Locality,geographicnam

es;Strike(right-handrule),dip;DD,dip

direction;Obs,samplesorsites;n/N,number

ofsamplesconsidered/number

ofsamplesanalyzed;D,I,declination

andinclinationofthepaleomagnetic

vector(BAC,before

anycorrection(insitu);ABC,afterbeddingcorrection);questionmarksindicatenonsense

results;Pol,polarity;a95,K,Fisher

[1953]statistical

param

eters.

bNumberingofsites.

Table

1.(continued)


7 of 25

TC5011

Figure 3


8 of 25

TC5011

Most fold tests show statistically significant postfoldingdirections (J3 and J2), except for three cases due to thesmall number of sites (J3 in Berchtesgaden) or to insuffi-cient bedding differences (J2 and J3 at Lammer). Neverthe-less, the postfolding character of the remagnetization can beassumed in these cases (e.g., Lammer) due to the directionalsimilarity with the well-reported postfolding components inthe closer units (see Table 2). Taking into considerationthese results, the low-temperature component (J3) and theintermediate one (J2) must be interpreted before any cor-rection (in situ). Data described by other authors (Table 1and Figure 6b) seems to display a negative fold test as well.Some further facts should be pointed out.[19] 7. These remagnetizations can be observed in previ-

ous works [Channell et al., 1992; Gallet et al., 1993].Channell et al. [1992] showed demagnetization diagramsdisplaying the J2 and J1 components described here. Mostdata from Heer [1982], and perhaps from other authors,were previously interpreted as primary, but they fit verywell with the remagnetization directions.[20] 8. Recent paleomagnetic investigations [Schatz et al.,

2002] in the graywacke zone (structurally below the NCA),near the Salzach and south of the studied area, show apostfolding direction. This ‘‘component B’’ (065,46 a95

17� and K 12) has been interpreted as an ‘‘Alpine’’ overprintand it is very similar to the detected directions in the NCA.[21] 9. Relative rotations among sites also exist; J2 ranges

between 40� (at GA01) and 134� (VS04).[22] 10. Although unusual, the occurrence of reverse

polarities seen here (J3 component) and in previous data[Channell et al., 1990, 1992; Gallet et al., 1993, 1994,1996, 1998; Mauritsch and Marton, 1995] may support theprimary character of the high-temperature component (J1).However, significant fold tests are hard to obtain in the areadue to the small dip changes and therefore the primarycharacter it is difficult to prove unambiguously.[23] 11. In the central NCA, J1 is confined exclusively in

the northernmost sector of the NCA. Therefore a S-Ngradient in the remagnetization mechanism may be alsoconsidered in the discussion.

5. Discussion

5.1. Constraints on the Timing of the Remagnetizations

[24] J1 can be considered older than J2 and J2 older thanJ3 as founded on fold test data, the increasing value ofclockwise (CW) rotation and the progressively lowerunblocking temperatures. Unfortunately the age of theremagnetizations cannot be inferred from the inclinationvalues by comparison with the expected inclinations fromthe African and European plates [Besse and Courtillot,2002] (Figure 7) because of the absolute lack of resolution.However, the different inclination values of J2 and J3components, together with the geological knowledge in

the sector (structural evolution and major deformationstages) may enable better constraints on the age of thetwo paleomagnetic directions (J2 and J3).[25] The northern Calcareous Alps, as a part of the

Eastern Alpine system, have undergone a complex, poly-phase deformational history that is related to the closure ofthe Triassic/Jurassic Tethys ocean (Meliata-Hallstatt) duringLate Jurassic to Early Cretaceous times, and the closure ofthe Penninic Ocean between Middle Cretaceous to EarlyTertiary [e.g., Lein, 1987; Wagreich, 1993, 1995; Gawlick etal., 1999, Faupl and Wagreich, 2000; Neubauer et al.,2000]. There is not a total agreement about the relativetiming and importance of these tectonic processes but wehave tried to synthesize them to constraint the age of ourmagnetizations (Figure 7):[26] 1. The closure of the Tethys Ocean was responsible

for the emplacement of the Hallstatt Melange (Juvavicnappes) between late Middle and early Late Jurassic times[Gawlick et al., 1999; Gawlick and Bohm, 2000].[27] 2. The major metamorphic event during Early Cre-

taceous times was related to the first nappe stacking.However, other minor events have been recognized duringthe middle/early Late Jurassic and the early Late Cretaceous[Frisch and Gawlick, 2003]. The Early Cretaceous peakreached very low to low-grade metamorphism in the NCA[Hoinkes et al., 1999; Spotl et al., 1998], and it is well datedin the south central part around 115–120 Ma [Frank andSchlager, 2006, and references therein]. Finally, eclogitefacies in the crystalline AU has been dated as Aptian-Albian(90–95 Ma) by Thoni and Miller [1996] and may beaffecting structurally higher units. South-north gradientsacross the NCA has been identified by means of theconodont color alteration index [Gawlick et al., 1994].[28] 3. The Penninic Ocean oblique subduction began

during Early Cretaceous (Turonian/Santonian as proposedby Wagreich [1995]) or a bit later, during Early Campaniantimes (as proposed by Liu et al. [2001]) according to40Ar/39Ar data. The Bavaric and Tirolic nappes wereemplaced within the NCA at this time.[29] 4. The Gosau basins were formed [Pober and Faupl,

1988] immediately after. They were filled with exoticdetritus from the Penninic-Austroalpine accretionary wedge(north of the NCA) and represent the last significantsedimentary record in the NCA.[30] 5. The Gosau period also depicts a relatively quiet

intermediate stage before the very last episode of thrustingover the Penninic flysch and the formation of the Molasse(European) Basin, along with the reactivation and rear-rangement of previous structures, as deduced from meso-scopic brittle data [Schweigl and Neubauer, 1997]. Thisevent was linked with the beginning of the basement (lowerand middle Austroalpine units) stacking in the south.[31] 6. Subduction of the Penninic Ocean was accom-

plished and continental collision started during Eocene

Figure 3. Paleomagnetic directions. Orthogonal diagrams and equal-area stereographic projection of progressive stepwisedemagnetization of selected samples from the different rock types (geographic coordinate system).


9 of 25

TC5011

Table

2a.Geographical

andGeological

LocationsofNew

Paleomagnetic

Sites

intheLower

andUpper

TirolicUnitsFrom

theCentral

SectoroftheNCAa

No.

Site

Geographical

andGeological

Location

Age

Cores

RHR

Strike

Dip

DD

Obs

Long

Lat

Map

Geographic

Inform

ation

Form

ation(Rock

Type)

1MK01

13.045

47.693

93

Marktschellenberg(Bayern)

SchrambachForm

ation

(Jurassic/Cretaceous)

135

6270

41

NSev

2WB01

12.918

47.596

93

Wim

mbachklamm

(Berchtesgaden)

DachsteinkalkForm

ation(U

pper

Triassic)

210

4267

35

N3

WB02

12.918

47.596

93

Wim

mbachklamm

(Berchtesgaden)

Kossen

Form

ation(N

orian-Rhaetian)

212

4243

39

N4

WB03

12.918

47.596

93

Wim

mbachklamm

(Berchtesgaden)

ScheibelbergForm

ation

4262

50

N5

WB04

12.918

47.596

93

Wim

mbachklamm

(Berchtesgaden)

Triassic-Jurassic

Boundary

3250

58

N6

WB05

12.918

47.596

93

Wim

mbachklamm

(Berchtesgaden)

Adnet

form

ations(Liassic)

200

3246

45

N7

WB06

12.918

47.596

93

Wim

mbachklamm(Berchtesgaden)

Adnet

Form

ation-top(Lias)

200

4246

45

N8

WB07

12.918

47.596

93

Wim

mbachklamm

(Berchtesgaden)

KlausForm

ation

175

3304

25

N9

WB08

12.918

47.596

93

Wim

mbachklamm

(Berchtesgaden)

StrubergForm

ationRed

Radiolarite

166

2323

34

N10

WB09

12.918

47.596

93

Wim

mbachklamm

(Berchtesgaden)

StrubergForm

ationBlack

Radiolarite

166

1323

34

N11

JE03

13.02

47.576

93

Jenner

(Berchtesgaden)

Dachsteinreef

slope-Gosauseelimestone

4166

80

W12

JE04

13.02

47.576

93

Jenner

(Berchtesgaden)

Dachsteinreef


4162

68

W13

JE05

13.021

47.576

93

Jenner

(Berchtesgaden)

Dachsteinreef


4160

75

W14

JE06

13.021

47.576

93

Jenner

(Berchtesgaden)

Dachsteinreef


4159

72

W15

JE07

13.022

47.576

93

Jenner

(Berchtesgaden)

Dachsteinreef


2163

84

W16

JE08

13.022

47.576

93

Jenner

(Berchtesgaden)

Dachsteinreef


6156

82

W17

JE09

13.023

47.576

93

Jenner

(Berchtesgaden)

Dachsteinreef


4168

76

W18

JE01

13.02

47.575

93

Jenner

(Berchtesgaden)

Dachsteinreef


3128

103

E(o)

19

HA08

13.006

47.57

93

Buchsenkopf(Berchtesgaden)

DachsteinForm

ation(U

pper

Triassic)

210

2187

42

W20

HA09

13.006

47.57

93


StrubbergForm

ation

4187

42

W21

HA06

13.003

47.567

93


DachsteinForm

ation(U

pper

Triassic)

210

3268

16

N22

HA05

12.996

47.551

93

Seeaukopf(Berchtesgaden)

DachsteinForm

ation(U

pper

Triassic)

210

2216

45

W23

HA04

12.999

47.546

93

Seeaukopf(Berchtesgaden)

DachsteinForm

ation(U

pper

Triassic)

210

4290

21

N

24

HD01

13.17

47.731

94

Gaissau

(Mortlbach)

HaupdolomiteForm

ation(N

orian)

212

9190

24

W25

HD02

13.181

47.727

94

Gaissau

(Mortlbach)

HaupdolomiteForm

ation(N

or)

212

986

17

S26

GA01

13.189

47.723

94

Gaissau

(Mortlbach)

StrubbergForm

ationRadiolarite

(Malm)

166

20

15

22

E27

GA03

13.212

47.723

94

Gaissau

(Mortlbach)

Kossen

Form

ation(Rhaetian)

212

7122

17

S28

GA02

13.205

47.722

94

Gaissau

(Mortlbach)

Adnet

Form

ation(Lias)

200

62

29

E29

NR02

13.191

47.721

94

Mortlbach(G

aissau)

Kossen

Form

ationNorian-Rhaetian

212

90

48

15

S30

DU01

13.094

47.675

94

Durrenberg(H

allein)

SchrambachForm

ation(Jurassic/Cretaceous)

135

944

82

E31

DU02

13.094

47.675

94

Durrenberg(H

allein)

SchrambachForm

ation(Jurassic/Cretaceous)

135

815

68

E32

TB01

13.271

47.668

94

Tauglbodenbach

Tauglb

RadiolKlauss,+I79Adnet

form

ations

204-145

90

26

1E

Sev

33

LB01

13.236

47.655

94

Tauglbodenbach

Oberalm

Form

ation(M

alm)

149

10

OutcropFold

Test

Sev

34

KB03-A

13.239

47.641

94

Kerzerbrunnstrasse(St.Koloman)

Oberalm

Form

ation(M

alm)

149

5270

125

S(o)

35

KB03-B

13.239

47.641

94


Oberalm

Form

ation(M

alm)

149

5264

66

N36

KB02

13.234

47.639

94


Oberalm

Form

ation(M

alm)

149

11254

56

N37

KB01-A

13.238

47.638

94


Oberalm

Form

ation(M

alm)

149

6269

121

S(o)

38

KB01-B

13.238

47.638

94


Oberalm

Form

ation(M

alm)

149

6253

60

N39

KB01-C

13.238

47.638

94


Oberalm

Form

ation(M

alm)

149

6231

21

NSev

40

WG01-A

13.204

47.636

94

Wegscheid(St.Koloman)

Oberalm

Form

ation(M

alm)

149

7335

73

NSev

41

WG01-B

13.204

47.636

94

Wegscheid(St.Koloman)

Oberalm

Form

ation(M

alm)

149

7299

26

NSev

42

SW02

13.273

47.628

94

Seewaldsee(St.Koloman)

Oberalm

Form

ation(M

alm)

149

6120

36

S43

SW01

13.278

47.626

94

Seewaldsee(St.Koloman)

Oberalm

Form

ation(M

alm)

149

8256

26

N44

KH02

13.252

47.619

94

Weitenaubach(Voglau-St.Kol)

SchrambachForm

ation

135

9233

38

W45

RF02

13.197

47.613

94

Strubau-Egger

Rossfeld

Form

ation(Cretaceous)

124

8125

35

S46

RF01

13.198

47.606

94

Strubau-Egger

Rossfeld

Form

ation(Cretaceous)

124

9191

32

W


10 of 25

TC5011

Table

2a.(continued)

No.

Site

Geographical

andGeological

Location

Age

Cores

RHR

Strike

Dip

DD

Obs

Long

Lat

Map

Geographic

Inform

ation

Form

ation(Rock

Type)

47

KH03

13.268

47.606

94


SchrambachForm

ation

135

8240

22

W48

KH04

13.282

47.602

94


DachsteinForm

ation(U

pper

Triassic)

210

60

30

E49

KH01

13.286

47.601

94


DachsteinForm

ation(U

pper

Triassic)

210

7216

27

W50

GL01

13.172

47.596

94

Golling(Salzach)

Oberalm

Form

ation(M

alm)

149

7217

30

W51

WS0x

13.293

47.593

94

Lam

merbachklamm

GutensteinForm

ation(A

nis)

6314

57

N52

KA18

13.312

47.59

94

Grillberg(Lam

erbach)

Flysch

6321

46

N53

GS02

13.297

47.589

94

Rettenbach-Flichtlhotberg

GutensteinForm

ation(A

nis)

8310

55

N54

GS01

13.298

47.587

94


GutensteinForm

ation(A

nis)

9296

44

N55

KA07

13.189

47.584

94

Pichler-PassLueg

(Salzach)

DachsteinForm

ation(U

pper

Triassic)

212

6253

47

N56

KA08

13.196

47.581

94

Zim

merau-PassLueg

(Salzach)

DachsteinForm

ation(U

pper

Triassic)

212

3282

43

N57

KA09

13.196

47.581

94

Zim

merau-PassLueg

(Salzach)

DachsteinForm

ation(U

pper

Triassic)

212

6279

15

N58

RT01

13.3

47.58

94


Skytian

(Lower

Triassic)

10

313

39

E59

KA06

13.188

47.579

94

PassLueg

(Salzach)

DachsteinForm

ation(U

pper

Triassic)

212

6283

32

N60

NR01

13.192

47.579

94

Pass-Lueg

(Salzachklam)

Kossen

Form

ationNorian-Rhaetian

212

34

291

21

N61

KA04

13.195

47.574

94

PassLueg

(Salzach)

DachsteinForm

ation(U

pper

Triassic)

212

6322

32

N62

KA05

13.195

47.574

94

PassLueg

(Salzach)

DachsteinForm

ation(U

pper

Triassic)

212

6322

32

N63

KA12

13.244

47.57

94

Sattlberg-Schonalm

(Tennengbg)

StrubbergForm

ationRadiolarites(Call-Oxf)

166

6275

50

N64

PL02

13.188

47.569

94

PassLueg

(Salzach)

DachsteinForm

ation(U

pper

Triassic)

212

8316

33

N65

KA10

13.248

47.568

94

Sattlberg-Schonalm

(Tennengbg)

StrubbergForm


166

6296

50

N66

KA11

13.248

47.568

94

Sattlberg-Schonalm

(Tennengbg)

StrubbergForm


166

6294

40

NSev

67

PL01

13.184

47.567

94

Paß

Lueg

(Salzach)

DachsteinForm

ation(U

pper

Triassic)

212

8315

31

N

Gosau

68

VS04

13.112

47.561

94

Vordercschlumsee(H

agengbg.)

DachsteinForm

ation(U

pper

Triassic)

212

7309

29

N69

VS03

13.108

47.559

94

Vordercschlumsee(H

agengbg.)

Kossen

beds(N

orian-Rhaetian)

212

7313

17

N70

VS01

13.108

47.557

94

Vordercschlumsee(H

agengbg.)

Adnet

facies

(Lias)

200

7308

20

N71

VS02

13.108

47.557

94

Vordercschlumsee(H

agengbg.)

Adnet

facies

(Lias)

200

8293

32

N72

KS01

13.233

47.549

94

Knallstein

(Tennengebirge)

Dachstein(M

egalodonts)Form

ation

212

4279

34

N73

HC01

13.163

47.504

94

Horndlgraben

(Salzach)

GutensteinForm

ation(A

nis)

10

249

38

N74

PA05

13.421

47.634

95

Huttenkogel

(Postalmstrasse)

Adnetkalk(Lias)

200

7143

55

S75

PA06

13.414

47.626

95

Huttenkogel

(Postalmstrasse)

DachsteinForm

ation(N

orian-Rhaetian)

212

7217

10

W76

PA03

13.386

47.612

95

Huttenkogel

(Postalmstrasse)

Gosau(U

pper

Cretaceous)

100

10

263

49

N77

PA01&2

13.367

47.604

95

Huttenkogel

(Postalmstrasse)

Gosau(U

pper

Cretaceous)

100

8262

71

N78

RB01

13.469

47.594

95

Randobach

(Rußbach)

Gosau(U

pper

Cretaceous)

100

11

274

53

N79

GO01

13.516

47.55

95

Hintertal

(Gosaubach)

Gosau(U

pper

Cretaceous)

100

939

26

E80

GO02

13.516

47.55

95

Hintertal

(Gosaubach)

Gosau(U

pper

Cretaceous)

100

9345

20

E81

GO03

13.503

47.588

95

Gosau(PassGschutt)

Gosau(H

ochmoosschichten)

100

9101

25

S

aSite,

site

nam

e;Long,longitude;

Lat,latitude;

map,Austrian

map

reference

fram

e;locality,geographic

nam

es;strike(RHR,right-handrule);

dip

andDD,dip

direction.Abbreviations:

Taugl,

Tauglbodenbach;Radiol,Radiolarite;Lias,Liassic;Malm,Malmian;Call-Oxf,CallovianOrfordian;Obs,observations;Sev,several

beedingattitudes;(o),overturned

bedding.


11 of 25

TC5011

Table

2b.Geopgraphic

Coordinates

ofNew

Paleomagnetic

Sites

intheLower

andUpper

TirolicUnitsFrom

theCentral

SectoroftheNCAa

No.

Site

J3(300�C

–350�C

)J2

(450�C

–500�C

)J2

–J3

InSitu(G

eographic

Coordinates)

Pol

a95

KMAD

D/I

(ABC)

InSitu(G

eographic

Coordinates)

Pol

a95

KMAD

D/I

(ABC)

DI

Tub,�C

Met

nN

D/I

(bac)

Tub,�C

Met

nN

D/I

(BAC)

1MK01

500

SR

510

67/39

N15

48/16

2WB01

330

SR

66

84/69

N6

30/48

500

SR

66

95/69

N3

32/52

11

03

WB02

500

SR

66

59/71

N2

0/46

4WB03

330

SR

24

57/26

N11

46/0

500

SR

24

78/48

N5

40/26

21

22

5WB04

330

SR

55

178/50

N6

308/67

500

SR

55

164/38

N3

312/83

�14

�12

6WB05

500

SR

23

98/62

N4

17/53

7WB06

500

SR

45

152/62

N10

342/72

8WB07

500

SR

66

152/�

30

R?

2161/�

16

9WB08

500

SR

22

46/66

N4

49/32

10

WB09

500

SR

22

348/31

N3

0/13

11

JE03

500

SR

44

303/28

6304/�

30

12

JE04

460

SR

44

115/84

4105/23

13

JE05

500

SR

44

40/59

10

269/40

14

JE06

430

SR

44

300/37

12

289/�

17

15

JE07

460

SR

22

32/37

18

297/41

16

JE08

460

SR

66

165/87

5243/7

17

JE09

460

SR

44

56/88

5258/15

18

JE01

500

SR

33

60/�

33

?3

35/40

19

HA08

500

SR

22

307/28

N4

303/�

920

HA09

360

SR

44

68/39

N2

19/67

500

SR

44

93/55

N7

295/82

25

16

21

HA06

500

SR

33

150/22

N9

145/35

22

HA05

500

SR

22

64/27

N5

34/38

23

HA04

400

SR

44

359/48

N6

4/28

24

HD01

250

PCA

66

72/43

N21

952/62

500

PCA

58

87/19

N9

64

83/42

15

�24

25

HD02

330–500

PCA

66

58/47

N17

17

77/52

26

GA01

430

PCA

17

17

40/57

N3

168

61/43

27

GA03

330

PCA

34

39/55

N14

54

44/71

430

PCA

34

60/48

N14

50

74/62

21

�7

28

GA02

360

PCA

66

357/53

N3

372

31/46

500

PCA

66

353/42

N12

28

18/39

�4

�11

29

NR02

300

PCA

31

32

51/51

N5

26

68/47

500

PCA

67

73

86/46

N3

26

73/5

35

�5

30

DU01

330

PCA

11

63/69

N-

-114/0

430

PCA

45

97/66

N10

59

119/�

1134

�3

31

DU02

300

PCA

55

75/78

N11

37

98/11

430

PCA

55

113/51

N7

89

110/�

16

38

�27

32

TB01

360

PCA

25

25

51/57

N8

13

51/57

500

PCA

46

53

65/56

N4

32

65/56

14

�1

33

LB01

300

PCA

44

46/52

N40

752/57

460

PCA

910

54/44

N14

13

50/46

8�8

34

KB03-A

300

PCA

22

82/39

N70

7124/21

500

SR

45

109/35

N10

129/0

27

�4

35

KB03-B

300

SR

66

62/45

N10

35/2

460

PCA

66

96/54

N11

31

33/26

34

936

KB02

300

PCA

55

41/33

N14

25

28/�

4460

PCA

12

15

62/43

N6

47

31/14

21

10

37

KB01-A

460

PCA

77

113/27

N11

25

95/45

38

KB01-B

400

PCA

66

62/42

N9

50

31/12

460

PCA

56

83/35

N12

32

45/24

21

�7

39

KB01-C

460

PCA

36

47/28

N29

13

37/25

40

WG01-A

360

PCA

10

10

178/15

N15

10

146/26

500

CD

99

106/66

N14

481/�

641

WG01-B

400

PCA

10

10

128/52

N8

54

96/48

500

CD

910

246/�

52

R11

5234/�

30

42

SW02

500

PCA

10

10

48/51

N3

333

116/79

43

SW01

360

SR

10

10

36/44

N15

23/24

500

SR

10

10

60/53

N1

186/�

53

24

944

KH02

500

SR

99

84/35

NŒ

689/7

45

RF02

330¡

PCA

55

320/47

N29

7282/44

450

PCA

55

19/69

N28

7236/74


12 of 25

TC5011

Table

2b.(continued)

No.

Site

J3(300�C

–350�C

)J2

(450�C

–500�C

)J2

–J3

InSitu(G

eographic

Coordinates)

Pol

a95

KMAD

D/I

(ABC)

InSitu(G

eographic

Coordinates)

Pol

a95

KMAD

D/I

(ABC)

DI

Tub,�C

Met

nN

D/I

(bac)

Tub,�C

Met

nN

D/I

(BAC)

1MK01

500

SR

510

67/39

N15

48/16

2WB01

330

SR

66

84/69

N6

30/48

500

SR

66

95/69

N3

32/52

11

03

WB02

500

SR

66

59/71

N2

0/46

4WB03

330

SR

24

57/26

N11

46/0

500

SR

24

78/48

N5

40/26

21

22

46

RF01

330¡

PCA

44

287/70

N33

7283/38

450

PCA

68

306/39

N16

16

300/9

19

�31

47

KH03

460

PCA+CD

10

12

121/�

54

16

9129/�

33

48

KH04

360

SR

66

31/49

N6

50/29

500

SR

66

169/�

81

R11

251/�

60

49

KH01

500

SR

88

60/3

N7

56/13

50

GL01

360

PCA

77

310/36

N12

22

309/6

51

WS0x

400

SR

77

88/50

N15

21

70/2

500

SR

23

24

123/45

N5

90/15

35

�5

52

KA18

450

PCA

57

359/80

N11

40

41/37

53

GS02

500

PCA

99

80/53

N2

415

62/4

54

GS01

300

PCA

99

50/58

N6

58

38/15

500

PCA

99

86/32

N5

109

95/35

36

�26

55

KA07

350

PCA

77

61/51

N12

48

26/25

450

PCA

77

86/49

N3

436

37/38

25

�2

56

KA08

450

PCA

33

103/53

N21

24

48/43

57

KA09

350

PCA

66

66/47

N4

239

55/37

450

PCA

77

85/58

N5

112

65/51

19

11

58

RT01

500

PCA

78

70/35

N15

18

64/0

59

KA06

350

PCA

66

68/46

N5

154

51/23

450

PCA

66

89/53

N7

81

59/36

21

760

NR01

330

PCA

34

34

51/49

N3

52

43/30

500

PCA

35

35

69/61

N3

52

51/44

18

12

61

KA04

350

PCA

33

52/50

N9

134

52/18

450

PCA

57

76/64

N10

53

64/33

24

14

62

KA05

350

PCA

66

69/44

N8

54

64/13

450

PCA

66

85/61

N6

104

57/17

16

17

63

KA12

350

PCA

66

75/54

N6

122

41/21

450

PCA

66

104/65

N3

622

37/39

29

11

64

PL02

330

PCA

66

68/47

N18

12

61/15

500

PCA

66

85/55

N13

23

69/26

17

865

KA10

350

PCA

66

66/53

N7

85

49/9

450

PCA

77

85/55

N5

138

70/31

19

266

KA11

350

PCA

66

70/55

N4

253

50/21

450

PCA

66

103/72

N4

289

60/36

33

17

67

PL01

330

PCA

88

65/53

N9

38

57/23

500

PCA

11

11

88/61

N3

171

68/34

23

868

VS04

500

PCA

11

11

134/48

N6

66

104/42

69

VS03

360

SR

79

91/46

N12

29

81/33

500

PCA

10

10

113/54

N10

23

123/�

10

22

870

VS01

330

SR

10

10

95/44

N8

82/31

500

SR

10

10

115/30

N2

247/26

20

�14

71

VS02

500

SR

10

10

77/41

N1

63/18

72

KS01

360

SR

68

52/48

N9

38/20

460

PCA

58

66/65

N15

50

36/38

14

17

73

HC01

500

PCA

88

81/57

N4

142

30/46

74

PA05

500

PCA

99

0/19

N4

327/40

75

PA06

500

PCA

10

10

251/36

N5

256/30

76

PA03

500

PCA

15

15

315/68

N18

338/22

77

PA01&2

500

PCA

99

38/20

N18

43/�

30

78

RB01

500

PCA

710

83/51

N27

645/21

79

GO01

430

PCA

44

328/38

N10

38

341/61

80

GO02

430

PCA

77

342/42

N13

27

359/39

81

GO03

PCA

66

31/27

N13

39/50

aSite,site

nam

e;Tub,unblockingtemperature;Met,directionsfittingmethod(PCA,principal

componentanalysis;CD,dem

agnetizationcircles;SR,stackingroutine);n/N,number

ofsamplesconsidered/

number

ofsamplesanalyzed;D,I,declinationandinclinationofthepaleomagnetic

vector(BAC,before

anycorrection(insitu)andABC,afterbeddingcorrection);Pol,polarity

observed

(N,norm

al;

R,reverse);a95,K,Fisher

[1953]statisticalparam

eters.MAD,maxim

um

angulardeviation(PCA)oftheChRM

deducedfrom

thestacked

sample(SR).J2-J3(D

andI),declinationandinclinationdifference

betweenJ2

andJ3.


13 of 25

TC5011

times, as deduced from the age of thrusting of lowerAustroalpine over Penninic [Liu et al., 2001]. Severe spaceproblems appeared during the Miocene after the quickTauern window exhumation (between 30 and 10 Ma ago[e.g., Lammerer and Weger, 1998; Frisch et al., 1998,2000]) and the Eastern Alpine system underwent a lateralextrusion toward the east [Ratschbacher et al., 1991]. Thesouth Alpine indentor geometry along the Periadriatic faultis a key piece to understand the final tectonic rearrange-ment. In this context of lateral strike-slip faulting, manyprevious NCA structures are overprinted and the nappestructure underwent extreme reorganization [Linzer et al.,2002; Frisch and Gawlick, 2003]. In view of these geolog-ical processes two different ages are considered to date themore pervasive remagnetization event (J2):[32] 1. During the major metamorphic peak during Late

Cretaceous. The Gosau Group paleomagnetic data couldprove or disprove this hypothesis since they should notshow the J2 direction if this proposed age is valid. Unfor-tunately very few sites were studied in this work (Figure 2and Table 2). Half of them, together with some previousdata (Table 1) display a similar characteristic in situ direc-

tion as the Triassic rocks located in the vicinity (Figure 8a).However, the absence of total parallelism with the otherGosau Group sites as well as some evidences of primaryinformation found in other sectors of the NCA [Mauritschand Frisch, 1980; Haubold et al., 1999] does not clarify theinitial hypothesis. Moreover this possibility has other dis-advantages because it is hard to assume that later stages ofdeformation (e.g., Bavaric and Tirolic thrusting) have notmodified the bedding orientation. Structural evidence[Schweigl and Neubauer, 1997] indicates the formation of

Figure 4. (a) Stereographic projection of J3 and J2 before and after tectonic correction. (b) Stratigraphicage versus magnetic inclination (after bedding correction). (c) Magnetic mean directions in site KA11.The two components (J3 and J2) have different inclinations; 54� and 72�, respectively, and a declinationvalue almost 30� different. This site is located in the southern part of the Tirolic unit and displays a northdipping attitude.

Table 3. Primary Directions in the Northern Calcareous Alpsa

Site Tub Met n N

BAC

Pol. a95 K

ABC

D I D I

GA01-N 575 PCA 4 4 5 59 N 11 53 40 56GA01-R 575 PCA 11 11 168 �72 R 8 30 234 �69GA01 575 PCA 15 15 354 69 N + R 7 29 49 66TB01 >550� CD(i) 106 153 219 �45 R 4 15 219 �45

aSame symbols as in Table 2.


14 of 25

TC5011

new structures or even the reactivation of old ones duringsubsequent deformation episodes.[33] 2. An Early Tertiary (in the broad sense) age, after

the end of Gosau Group deposit, may be also considered forthe main magnetic overprint (J2). This second possibilityexplains better the postfolding character of the remagneti-zation, which would have been acquired after the finalconfiguration of the NCA front (including the final thrustingof the Bavaric and Tirolic units and possible reactivations ofthe Hallstatt Melange nappes) but the cause of the remag-netization is unclear.[34] To constrain the age of the second remagnetization

event (J3), the subsequent tectonic history of the NCA hasto be considered: the thrusting and nappe stacking of theAustroalpine units over the Penninic domain (circa lateEocene to early Oligocene) and the complex rearrangementof the NCA during the complex collision (Miocene times).It is widely accepted that except for some map-scale andgentle structures in some Miocene basins, no major foldingor thrusting took place during the extrusion, but large block

movements, e.g., translations and vertical axis rotations bylarge directional fault systems [Linzer et al., 1997; Frisch etal., 1998, 2000; Frisch and Gawlick, 2003]. This factimplies that within a given block, no major changes in thepaleomagnetic inclination can be expected after this period.Consequently, the age of the J3 remagnetization should bebounded between Eocene and Oligocene times (before anylarge rotational movement).[35] As in the case of J2, the cause responsible for the

remagnetization remains elusive since both componentswere presumably acquired significantly after any metamor-phic event. Recent works suggest that pressure solutionstructures (cleavage, stylolites) may be an efficient mecha-nism responsible for widespread and pervasive remagneti-zations [Elmore et al., 2006; Oliva et al., 2007]. Penetrativedeformation structures (stylolites) are noticeable every-where in the NCA, therefore additional rock magnetism,paleomagnetic and microstructural evidences are needed tocheck this hypothesis.

Figure 5. Maps showing the degree of rotation at the different sites for the two principal components(a) J3 and (b) J2. The local paleomagnetic reference (D 002, I 60; a95 1.2�, and K 704) was interpolatedfrom the European apparent pole wander path (APWP) [Besse and Courtillot, 2002] calculated for theSalzburg location for the period between 100 and 30 Ma.

Figure 6. (a) Fold test (macro). Evolution of concentration parameters (K) during progressive restoration (percentage ofunfolding) of beds and paleomagnetic vectors (J3 and J2) for the four major tectonic domains; Berchtesgaden (west),Stauffen-Hollengebirge and Lammer (central), and Postalm and adjacent areas (east). Note that both components display asignificant best grouping before the restoration process starts (K value is higher or significantly better) denoting a negativefold test after McElhinny [1964] (postfolding magnetization). (b) Most data from previous studies (see Table 1), which alsodisplay a negative fold test (see Table 1). Bedding planes have been deduced from published information or have beentaken in the field when possible. A possible overlapping between J3 and J2 is not rejected in data from other authors. (c)Fold test (micro). Despite the large interlimb angle (165�) of the mesofolds (outcrop scale) sampled in the Oberalm Group,the fold test was not significant due to the pseudoparallel orientation among the vectors and the fold axis in some of theoutcrops. Nevertheless, the combination of different microfolds in the Oberalm Group has given a negative (almostsynfolding) fold test.


15 of 25

TC5011

Figure 6


16 of 25

TC5011

Figure

7.

Ageofremagnetization,comparingthelocalinclinationswiththeexpectedinclinationsattheSalzburg

location

(latitude47�500 N

andlongitude13�050 E)deducedfrom

theapparentpolarwander

pathforEurasiaandAfrica[Besse

and

Courtillot,2002].Additional

inform

ationregardingthestratigraphyandmajoroceanic,metam

orphic,andtectonic

events

arealso

shownas

afunctionoftime.


17 of 25

TC5011

5.2. Geometrical Clues

[36] Further evidence on the age the remagnetizations canbe derived from the relation between the paleomagneticcomponents and the geometry of the geological structures.Although both directions display a large scatter in declina-tion (e.g., between 40� to 134� in J2, Figure 8c), theconsistency (Table 2) of the difference between J2 and J3components is statistically significant and remarkable,mostly between 15 and 35� (Table 2). These values havebeen calculated subtracting the J3 declination from the J2one and keeping the J2 inclination for the difference vector.The averages are more conspicuous (Figures 8b and 8c); J3and J2 means are 064, 51 (a95 5� and K 36) and 086,51 (a95

6� and K 17) respectively, since J2–J3 direction is 022,51(a95 5� and K 31). This vector (J2–J3) represents the degreeof rotation of J2 just before the second remagnetizationevent (i.e., acquisition of the J3).

[37] Another key observation is the relationship betweenthe J2 and J3 inclinations and the north-south position of thesites (Figure 9). On average, the J2 directions exhibitinclinations lower than 50� in the northern sector (theLammer basin being the boundary) and higher than 50� inthe southern area. In contrast, J3 seems to be reasonablyconstant (�50�) independently of its location. In those siteshaving both magnetic components, their inclinations havebeen subtracted and plotted into the map to remark morethis feature (Figure 9a and Table 2): Negative values arefrequent in the northern sector while positive values arecommon in the southern side. This pattern can be explainedif before the acquisition of the second and younger remag-netization component (J3), the J2 component underwent atilting to the north in the southernmost positions while thenorthern sector suffered an opposite tilt to the south.[38] This fact is well proven along the overprinted

magnetostratigraphic Norian-Rhaetian sections (NR1 and

Figure 8. (a) Gosau plot, in situ site means for Tennengebirge and Lammer units. (b) Central NCA mapdisplaying the rotations deduced after subtracting the J2 and J3 declinations. This image represents themoment right before the second remagnetization event (J3). (c) Stereographic plots (equal-areaprojection) of the J2–J3, J3, and J2 vectors.


18 of 25

TC5011

NR2 see location at Figure 9 and stereoplots at Figure 10)where the averages are based on 130 samples and areexcellent (a95 < 5� and k > 25). In the southern part (PassLueg area) the NR01 section is dipping 21� to the north;J3 plunges with 49� while J2 with 61�. On the contrary thenorthern profile NR02 (Mortlbach) in the northern part ofthe unit is dipping slightly to the south and shows oppositeinclinations; J3 at 51� and J2 at 46�. The hardest component(J1) could only be adequately defined in a few samples inNR02 (northern section), while; in contrast, NR01 (in thesouthern part) did not show any evidences of high-temperature directions. The fold tests from both profiles(Figure 10a) reveal key information; J3 is postfolding (0%

unfolding for the best fitting) since J2 seems to be closer toa synfolding direction (non significant; 20% for the best fit).[39] We have performed a fold test at the time of the J3

overprint to clarify this point. In the first check, the J2–J3declination has been calculated keeping the original J2inclination (bedding planes have been also restored properlyfrom the effect of the J3 vertical axis rotation). As in theNorian-Rhaethian profiles the evolution of the concentrationparameter during stepwise restoration (Figure 10a) implies apostfolding acquisition. However, if the fold test is observedin detail, it is clear that the J2 direction pass through amaximum of grouping between the in situ (0%) and thefully restored (100%) positions. This value (20% restora-

Figure 9. (a) Map displaying the difference in inclination between J2 and J3 components. Since J3 ispretty constant, the black points represent inclined values and the white points shallow inclinations. (b)Stereographic projection (equal-area) of site means for both components in those sites in which appeartogether. (c) Simplified structural cross section through the central Calcareous Alps showing the neededtilts to explain the J2 inclination paradox (cartoon based on the overview mapping of Austria by Egger etal. [1999]). See Figure 1a for exact location.


19 of 25

TC5011

tion) is the best grouping for the set of vectors. Although thefold test is nonsignificant, the structural control on theinclinations is consistent and gives reliability to the tiltingassumption (Figure 9b). In conclusion, the J2 componentcan be identified as a postfolding, pretilting and prerotationand the J3 remagnetization as a postfolding, posttilting andprerotation.

5.3. Tectonic Implications

[40] The proposed ages for the J2 and J3 remagnetiza-tions, the geometric and kinematic constraints deduced fromthe paleomagnetic analysis, along with the geological his-tory of the central NCA, may combine in the followingmodel (Figure 11):[41] 1. Sedimentation and primary acquisition of the

Mesozoic paleomagnetic field. This process may havepersisted during most of the sedimentary history of theNCA, from Triassic to Cretaceous. The first pervasiveremagnetization event (J2) will have erased most of thisinformation.[42] 2. The J2 remagnetization event was very pervasive

and affected all rock types. Only a few remnants of primaryinformation are preserved in the northernmost sector. Thisprocess probably happened after the configuration of theNCA thrust system (J2 is postfolding), but before anyimportant tilting of the NCA edifice (J2 is pretilting). Theremagnetization age cannot be given precisely (Late Creta-ceous–Early Tertiary, in the broad sense). After the perva-sive overprint, the J2 component recorded a fairly constantclockwise rotation (20–25�) that may be related with thelateral gradient of shortening (vertical axis rotations) asso-

ciated with the emplacement of the Austroalpine nappesover the Penninic units. On top of this, the J2 componentrecorded a differential tilting (Figure 9); a northward tiltingof the southernmost portions of the NCA, related with thebeginning of stacking of basement units (Greywacke zone),and a slight southward tilting of the northernmost positionsnear the NCA boundary probably due to the low-anglethrust over the Eocene Rheno-Danubian flysch. The pretilt-ing character of J2 marks the upper boundary of theremagnetization age, which must be definitely before Eo-cene times. On the other hand, the rare preservation of theprimary directions (J1) considerably restricts any accuratepaleogeographical deduction (at least in this sector). Theparallelism between J1 and J2 could imply the lack ofrotations before the Tirolic thrusting, but the absence ofintermediate information in this long time gap makes thehypothesis very speculative.[43] 3. J3 remagnetization is a younger remagnetization

associated with a less pervasive overprinting event thatallowed the preservation of J2. This overprint took placeafter the final thrusting of the NCA over the Penninic flyschand after the southern stacking of Austroalpine basement(J3 is postfolding and posttilting) but before any importantrotation (J3 records an average of 65� CW rotation).Therefore its age can be constrained, in most probability,around Oligocene times before the Miocene extrusion.[44] 4. From this moment onward the NCA behaved in a

different style; a complex system of block domains sepa-rated by faults underwent large lateral movements butnonsignificant internal deformation (folding) within theseblocks can be expected. Recent palinspastic reconstructions

Figure 10. (a) Fold test using robust data (more than 100 samples) from NR01 and NR02 profiles. J2–J3 fold test is for the whole data set. South has been also corrected for the rotation recorded by the J3component.


20 of 25

TC5011

[Frisch and Gawlick, 2003] support this model. Hence J3would record the main stage of rotation (60� in average)associated with the collision. If the average value of J3 (60�)is assumed to reflect the large-scale rotation associated withthe collision, which in turn would affect the whole centralNCA, then the J3 declination minus the average 60� (escaperelated rotation) will represent the block rotation valueassociated with the different domains. This value is rela-tively variable but it is limited between +30� and �30�,implying both clockwise and counterclockwise relativerotation among the different blocks. Differences of rotationvalues among different blocks reflect different ways accom-modating local space problems.[45] A 20� Miocene counter clockwise (CCW) rotation

has been recently described in the western part of the NCA(Tyrol) [Thony et al., 2006] and in the Pannonian andStyrian basins [Marton et al., 2000; Scholger et al., 2003]as well as in the Vienna Basin [Scholger and Stingl, 2004].This event has not been observed in the central NCA sincethere are not Miocene sediments to be checked, therefore a20� underestimation in the bulk clockwise rotation couldaffect our interpretation.

6. Conclusions

[46] The paleomagnetic analysis (77 sites and 4 profiles)of two remagnetization components in the central sector ofthe northern Calcareous Alps, together with the evaluationof geological processes in the area, have given the followingtectonic and geodynamic implications:

[47] 1. Most of the original paleomagnetic record (J1) hasbeen erased because of two pervasive remagnetizationevents (J2 and J3). The northern parts have been partiallypreserved, confirming the south-north gradient previouslyreported by other methods [Gawlick et al., 1994; Hoinkes etal., 1999]. The lateral extension of the overprints is partiallyproven in the western [Thony et al., 2006] and easternsectors [Schneider, 2002; Pueyo et al., 2002] but must beaccurately delineated in future work.[48] 2. The central NCA behaved as a large unit during

the thrusting over the flysch trough during Eocene times, asdenoted by the absence of folding of the first remagnetiza-tion (J2). This thrusting underwent at least 22� clockwiserotation and indicates a local gradient of shortening. TheEocene thrusting was synchronous or prior to the basementstacking in the south as deduced by the large-scale tilting ofJ2. Therefore no important stacking of basement unitsoccurred before this time.[49] 3. A second event of remagnetization (J3) took place

after the Eocene thrusting and the basement stacking (mostprobably during Oligocene times as regard of its postfoldingand posttilting character). This paleomagnetic direction didrecord the most important event of clockwise rotation (60�in average), which most likely took place during thecollision of the Eastern Alps.[50] 4. However, block rearrangements include relative

clockwise and counterclockwise rotations (up to 30� inmagnitude) during this time as denoted by the differentialdegree of rotation recorded by the second remagnetization(J3).

Figure 11. Cartoon of the central northern Calcareous Alps evolution as deduced from paleomagneticdata.


21 of 25

TC5011

Figure A1. Magnetic mineralogy in different rock types of the NCA. Normalized IRM acquisitioncurves and the thermal demagnetization of three-component IRM plus the back field experiment. Blackdots, hard component (2.5 T); gray dots, intermediate one (0.4 T); and white dots, soft components(0.1 T).


22 of 25

TC5011

[51] The vast paleomagnetic data set indicates an ex-tremely complex Neogene evolution of the Eastern Alpsduring the collision that seems to be controlled by thecoupling with the rotational history of the southern plate[Thony et al., 2006] and possibly induced by the plateboundaries geometry. Further systematic paleomagneticanalyses (paying especial attention to remagnetizations)focus in the acquisition of robust and reliable Tertiaryrotation data must be performed in future studies to shedlight and to unravel this complex collisional system and torefine the geodynamic interpretation.

Appendix A: Magnetic Mineralogy

[52] Previous research in the NCA was mostly concen-trated on the Liassic (Adnet Formation) [e.g.,Mauritsch andFrisch, 1978; Channell et al., 1990, 1992; Gallet et al.,1993]. Some paleomagnetic sites were also studied[Mauritsch and Becke, 1987] in the Gosau Group (UpperCretaceous–Eocene) because of the tectonic importance ofthis time lapse. The Adnet Formation was reported to have astable and primary magnetization (two polarities) carried byhematite and partially magnetite. On the other hand, theGosau sediments display a wide spectrum of magneticbehavior due to the variety of lithofacies. Because of theobjectives of this study, a much wider variety of rock typeshas been studied to serve as a database for future studies(Figure A1). The Gutenstein Formation (early MiddleTriassic; Anisian) outcrops mostly in the Lammer unit(Hallstatt Melange) and at the southern border of theStauffen-Hollengebirge nappe (near the contact with thebasement) and presents a very stable magnetic behavior.Low-coercivity carriers are dominant, more than 80% of thesaturation of the isothermal remanent magnetization (IRM)was acquired below 0.3 Tesla. Unblocking temperaturesdeduced from thermal demagnetization of IRM analysesrange between 400 and 500�C (mostly carried by the low-coercivity components; Hc < 0.1 T). Natural remanentmagnetization (NRM) displays a moderate-high intensity,around 10�3 A/m. This rock type has provided veryrepeatable results and very regular demagnetization dia-grams. The ubiquitous Dachstein Limestone (Upper Trias-sic) was rejected in previous studies because of its weakNRM (normally below 5 � 10�4 A/m), the same reason canbe applied to the Hauptdolomite Formation (same age) andto the Kossen Formation (upper Norian-Rhaetian). Howev-er, the three formations have given, in most cases, reason-ably good results (Table 2). Like the Gutenstein Formation,the magnetization is dominantly carried by low-coercivityphases with maximum unblocking temperatures below theCurie point of magnetite. In a few samples of the DachsteinFormation a moderate contributions of very high coercivity

minerals, unblocking close to the Curie temperature ofhematite, are also present.[53] In Jurassic rocks, the Klaus Formation (Dogger)

represents a condensed sequence that shows similar behav-ior to the Adnet Formation (Lias): high NRM intensitycarried by magnetite and hematite. Notably the StrubbergFormation (upper Dogger–lower Malmian) sequence ofbreccias and deep basinal deposits (radiolarites and siliceousrocks) gave excellent results (specially the radiolarite rocks) dueto their high natural magnetic intensity (more than 10�3 A/m).Low-coercivity and intermediate unblocking temperatures,as deduced from IRM curves and the thermal demagneti-zation of the three components IRM, characterize themagnetic carriers of these rocks. Demagnetization diagramsare mutually consistent. An entirely different response isshown by the Upper Jurassic limestones (Oberalm Forma-tion; upper Malmian) that have a very weak initial magne-tization (often below 10�4 A/m) carried by low-coercivity(and sometimes intermediate) unblocking temperature min-erals is associated with this sequence of relatively highsedimentation rate. Regardless of this problem, relativelygood results were obtained for some of the sites. TheTauglboden Formation (lower-middle Malmian) has, in con-trast, relatively high initial magnetization (5 � 10�4 A/m).Together with Klaus and Adnet formations, the TauglbodenFormation has shown a few reverse polarities.[54] Cretaceous rocks are characterized by a high diver-

sity of rock types including detritic facies represented in theSchrambach and Rossfeld Formations (Lower Cretaceous)and Gosau Group (Upper Cretaceous-Eocene). A generalpattern is of moderate to low magnetization, normally below3 � 10�4 A/m, and an unstable variability of directionalbehavior. Maximum unblocking temperatures may varyconsiderably (from 400�C to 680�C) but most are carriedby low-coercivity (>0.1 T) minerals, except for a few GosauGroup samples were hard carriers can be found. In contrastwith other types the Cretaceous (Tertiary) rocks were lesssuccessful and almost 40% of the studied rocks wererejected because of their poor consistency.

[55] Acknowledgments. This paper has been fully financed by theAustrian Science Foundation (FWF) project: P13688-GEO Additional fi-nancial support at the end of the development of the paper came from theproject CGL-2006-2289-BTE (MEC). Gabriela, Martin, Michael, and Sigridhelp us in the field during the sampling campaigns, Hermine and Hans SillerandAli helped us to fill like-at-home in the Lammertal (Oberschefau). Sigrid,Gernot, Lissi, Sandra, Markus, and Hanna did most part of the extensivelaboratory work. Paleomagnetic data processing has been made using the‘‘Paldir’’ program by Utrecht Paleomagnetic Laboratory. Stereographicprojections were made using ‘‘Stereonet’’ program (4.5.9) by RichardAllmendinger. Fold tests were carried out with the help of SuperIAPD byT. H. Torsvik, J. C. Briden, and M. A. Smethurst to whom we are indebted.Demagnetization file’s conversion between Gillette and Paldir formats waspossible with the program ‘‘Makeutrecht’’ by Roberto Molina-Garza. Wegratefully acknowledge positive reviews from Don Tarling, Franz Neubauer,and three anonymous reviewers to earlier versions of the manuscript.


23 of 25

TC5011

ReferencesAllerton, S. (1998), Geometry and kinematics of verti-

cal-axis rotations in fold and thrust belts, Tectono-physics, 299, 15 –30.

Auer, M., and G. H. Eisbacher (2003), Deep structureand kinematics of the northern Calcareous Alps(TRANSALPProfile), Int. J. Earth Sci., 92, 210–227.

Banerjee, S., and R. D. Elmore (1997), Chemicalremagnetization related to maturation of organicmatter, in Second International Conference on


24 of 25

TC5011

Fluid Evolution, Migration and Interaction inSedimentary Basins and Orogenic Belts, editedby J. P. Hendry et al., pp. 2 –5, Antony Rowe,Belfast.

Becke, M., and H. J. Mauritsch (1985), Die Entwick-lung der Nordlichen Kalkalpen aus palaomagne-tischer Sicht, Arch. Lagerstaettenforsch. Geol.

Bundesanst., 6, 113–116.Behrmann, J. H., and D. C. Tanner (2006), Structural

synthesis of the northern Calcareous Alps, TRANS-ALP segment, Tectonophysics, 414, 225 –240.

Besse, J., and V. Courtillot (2002), Apparent and truepolar wander and the geometry of the geomagneticfield over the last 200 Myr, J. Geophys. Res.,107(B11), 2300, doi:10.1029/2000JB000050.

Bigi, G., D. Cosentino, M. Parotto, R. Sartori, andP. Scandone (1983), Structural model of Italy, scale1:500,000, Cons. Naz. delle Rech., Rome.

Bohm, F., J. L. Dommergues, and C. Meister (1995),Breccias of the Adnet Formation: Indicators of aMid-Liassic tectonic event in the northern Calcar-eous Alps (Salzburg, Austria), Geol. Rundsch., 84,272–286.

Cairanne, G., C. Aubourg, and J. P. Pozzi (2002), Syn-folding remagnetization and the significance of thesmall circle test: Examples from the Vocontiantrough (SE France), Phys. Chem. Earth, 27,1151–1159.

Channell, J. E. T., and J. S. Stoner (1994), Comment on‘‘Magnetostratigraphy of the Hettangian Langmoossection (Adnet, Austria): Evidence for time-delayedphases of magnetization’’, Geophys. J. Int., 119(3),1005–1006.

Channell, J. E. T., R. Brandner, A. Spieler, and N. P.Smathers (1990), Mesozoic paleogeography of theNorthern Calcareous Alps: Evidence from paleo-magnetism and facies analysis, Geology, 18, 828–831.

Channell, J. E. T., R. Brandner, A. Spieler, and J. S.Stoner (1992), Paleomagnetism and paleogeogra-phy of the northern Calcareous Alps (Austria), Tec-tonics, 11, 792–810.

Cisowski, S. M. (1984), Evidence for early Tertiaryremagnetization of Devonian rocks from the Or-cadian Basin, northern Scotland, and associatedtranscurrent fault motion, Geology, 12, 369 –372.

Collombet, M., J. C. Thomas, A. Chauvin, P. Tricart,J. P. Bouillin, and J. P. Gratier (2002), Counter-clockwise rotation of the western Alps since theOligocene: New insights from paleomagneticdata, Tectonics, 21(4), 1032, doi:10.1029/2001TC901016.

Egger, H. G., H. G. Krenmayr, W. Mandl, A. Matura,A. Nowotny, G. Pascher, G. Pescal, J. Pistonik,M. Rockenschaub, and W. Schanabel (1999), Geo-logical map of Austria, Geol. Surv. of Austria,Vienna.

Eldredge, S., V. Bachtadse, and R. Van der Voo (1985),Paleomagnetism and the orocline hypothesis,Tectonophysics, 119, 153–179.

Elmore, R. D., J. Kelley, M. Evans, and M. T. Lewchuk(2001), Remagnetization and orogenic fluids; test-ing the hypothesis in the Central Appalachians,Geophysical J. International, 144(3), 568–576.

Elmore, R. D., J. L.-E. Foucher, M. Evans, M. Lewchuk,and E. Cox (2006), Remagnetization of the Tono-loway Formation and the Helderberg Group in theCentral Appalachians: Testing the originof syntilting magnetizations, Geophys. J. Int.,166, 1062 – 1076, doi:10.1111/j.1365-246X.2006.02875.x.

Faupl, P., and M. Wagreich (2000), Late Jurassic toEocene palaeogeography and geodynamic evolu-tion of the Eastern Alps, Mitt. Oesterr. Geol. Ges.,92(1999), 79–94.

Fisher, R. A. (1953), Dispersion on a sphere, Proc. R.Soc. London, Ser. A, 217, 295–305.

Frank, W., and W. Schlager (2006), Jurassic strikeslip versus subduction in the Eastern Alps, Int.J. Earth Sci., 95, 431–450, doi:10.1007/s00531-005-0045-7.

Frisch, W. (1979), Tectonic progradation on plate tec-tonic evolution of the Alps, Tectonophysics, 60,121–139.

Frisch, W., and H.-J. Gawlick (2003), The nappe struc-ture of the central northern Calcareous Alps and itsdisintegration during Miocene tectonic extrusion: Acontribution to understand the orogenic evolution ofthe Eastern Alps, Int. J. Earth Sci., 92, 712–727.

Frisch, W., J. Kuhlemann, I. Dunkl, and A. Brugel(1998), Palinspastic reconstruction and topographicevolution of the Eastern Alps during late Tertiarytectonic extrusion, Tectonophysics, 297, 1 – 15.

Frisch, W., I. Dunkl, and J. Kuhlemann (2000), Postcollisional orogen-parallel large-scale extension inthe Eastern Alps, Tectonophysics, 327, 239–265.

Gallet, Y., D. Vandamme, and L. Krystyn (1993), Mag-netostratigraphy of the Hettangian Langmoos sec-tion (Adnet, Austria): Evidence for time-delayedphases of magnetization, Geophys. J. Int., 115,575–585.

Gallet, Y., J. Besse, L. Krystyn, H. Theveniaut, andJ. Marcoux (1994), Magnetostratigraphy of theMayerling sections (Austria) and Erenkolu Mezar-lik (Turkey) section: Improvement of the Carnian(late Triassic) magnetic polarity time scale, EarthPlanet. Sci. Lett., 125, 173–191.

Gallet, Y., J. Besse, L. Krystyn, and J. Marcoux (1996),Norian magnetostratigraphy from the Scheiblkogelsection, Austria: Constraint on the origin of theAntalya Nappes, Turkey, Earth Planet. Sci. Lett.,140, 113–122.

Gallet, Y., L. Krystyn, and J. Besse (1998), Upper An-isian to Lower Carnian magnetostratigraphy fromthe northern Calcareous Alps, J. Geophys. Res.,103, 605–621.

Gawlick, H.-J., and F. Bohm (2000), Sequence andisotope stratigraphy of Late Triassic distal peri-platform limestones—An example from the north-ern Calcareous Alps (Kalberstein Quarry,Berchtesgaden Hallstatt Zone), Int. J. Earth Sci.,89, 108 –129.

Gawlick, H.-J., and W. Frisch (2003), The Middle toLate Jurassic carbonate clastic radiolaritic flyschsediments in the northern Calcareous Alps: Sedi-mentology, basin evolution and tectonics—Anoverview, Neues Jahrb. Geol. Paleontol. Abh.,230, 163–213.

Gawlick, H.-J., L. Krystyn, and R. Lein (1994), Cono-dont colour alteration indices: Paleotemperatures andmetamorphism in the northern Calcareous Alps—A general view, Geol. Rundsch., 83, 660–664.

Gawlick, H.-J., W. Frisch, A. Vecsei, T. Steiger, andF. Bohm (1999), The change from rifting tothrusting in the northern Calcareous Alps as re-corded in Jurassic sediments, Geol. Rundsch., 87,644–657.

Hannah, J. L., and K. L. Verosub (1980), Tectonic im-plications of remagnetized upper Paleozoic strata ofthe northern Sierra Nevada, Geology, 8, 520–524.

Hargraves, R. B., and A. G. Fischer (1959), Remanentmagnetism in Jurassic Red Limestones and Radiolaritesfrom the Alps, Geophys. J. R. Astron. Soc., 2, 34–41.

Haubold, H., R. Scholger, W. Frisch, H. Summesberger,and H. J. Mauritsch (1999), Reconstruction of thegeodynamic evolution of the Northern CalcareousAlps by means of paleomagnetism, Phys. Chem.Earth, Part A, 24, 697–703.

Heer, W. (1982), Palamagnetische Testuntersuchungenin den Nordlichen Kalkalpen im Gebiet zwischenGolling und Kossen, Master thesis, Tec. Univ.Munchen, Munich, Germany.

Heller, F., W. Lowrie, and A. M. Hirt (1989), A reviewof palaeomagnetic and magnetic anisotropy resultsfrom the Alps, in Conference on Alpine Tectonics,edited by M. P. Coward, D. Dietrich, and R. G.Park, Geol. Soc. Spec. Publ., 45, 399–420.

Hoinkes, G., F. Koller, G. Rantitisch, E. Dachs,V. Hock, F. Neubauer, and R. Schuster (1999), Al-pine metamorphism in the Eastern Alps, Schweiz.Mineral. Petrogr. Mitt., 79(1), 155–181.

Katz, B., R. D. Elmore, M. Cogoini, and S. Ferry(1998), Widespread chemical remagnetization: Oro-

genic fluid or burial diagenesis of clays?, Geology,26, 603–606.

Kechra, F., D. Banadme, and P. Rochette (2003),Tertiary remagnetization of normal polarity inMesozoic marly limestones from SE France, Tecto-nophysics, 362, 219–238.

Kirschvink, J. L. (1980), The least-squares line andplane and the analysis of the paleomagnetic data,Geophys. J. R. Astron. Soc., 62, 699–718.

Kligfield, R., and J. E. T. Channell (1981), Widespreadremagnetization of Helvetic limestones, J. Geophys.Res., 86, 1888–1900.

Lammerer, B., and M. Weger (1998), Footwall uplift inan orogenic wedge: The Tauern Window in theEastern Alps of Europe, Tectonophysics, 285,213 –230.

Lein, R. (1987), Evolution of the northern CalcareousAlps during Triassic times, in Geodynamics of the

Eastern Alps, edited by H. W. Flugel and P. Faupl,pp. 85 –102, F. Deuticke, Vienna, Austria.

Linzer, H. G., L. Ratschbacher, and W. Frisch (1995),Transpressional collision structures in the uppercrust: The fold thrust belt of the northern Calcar-eous Alps, Tectonophysics, 242, 41– 61.

Linzer, H. G., F. Moser, F. Nemes, L. Ratschbacher, andN. Sperner (1997), Build-up and dismembering ofthe eastern northern Calcareous Alps, Tectonophy-sics, 272, 97– 124.

Linzer, H. G., K. Decker, H. Peresson, R. Dell’Mour,and W. Frisch (2002), Balancing lateral orogenicfloat of the Eastern Alps, Tectonophysics, 354,211 –237.

Liu, Y., J. Genser, R. Handler, G. Friedl, andF. Neubauer (2001), 40Ar/39Ar muscovite ages fromthe Penninic-Austroalpine plate boundary, EasternAlps, Tectonics, 20, 526–547.

Lowrie,W. (1990), Identification of ferromagnetic miner-als in a rock by coercivity and unblocking tempera-ture properties, Geophys. Res. Lett., 17, 159–162.

Luschen, E., B. Lammerer, H. Gebrande, K. Millan,R. Nicolich, and TRANSALP Working Group(2004), Orogenic structure of the Eastern Alps,Europe, from TRANSALP deep seismic reflec-tion profiling, Tectonophysics, 388, 85–102.

Mandl, G. W. (2000), The Alpine sector of the tethyanshelf. Examples of Triassic to Jurassic sedimenta-tion and deformation from the northern CalcareousAlps, Mitt. Oesterr. Geol. Ges., 92(1999), 6 –77.

Marton, E., J. Kuhlemann, W. Frisch, and I. Dunkl(2000), Miocene rotations in the Eastern Alps-Pa-leomagnetic results from intramontane basin sedi-ments, Tectonophysics, 323, 163–182.

Mauritsch, H. J., and M. Becke (1987), Paleomagneticinvestigations in the Eastern Alps and the southernborder zone, in edited by H. W. Flugel and P. Faupl,pp. 282–308, F. Deuticke, Vienna, Austria.

Mauritsch, H. J., and W. Frisch (1978), Palaeomagneticdata from the central part of the northern Calcar-eous Alps, Austria, J. Geophys., 44, 623–637.

Mauritsch, H. J., and W. Frisch (1980), Palaeomagneticresults from the Eastern Alps and their comparisonwith data from the southern Alps and the Car-pathians, Mitt. Oesterr. Geol. Ges., 73, 5 –13.

Mauritsch, H. J., and E. Marton (1995), Escape modelsof the Alpine-Carpathian-Pannonian region in thelight of palaeomagnetic observations, Terra Nova,7, 44 –50.

McCabe, C., and R. D. Elmore (1989), The occurrenceand origin of late Paleozoic remagnetization in thesedimentary rocks of North America, Rev. Geo-phys., 27, 471–494.

McCaig, A. M., and E. McClelland (1992), Palaeomag-netic techniques applied to thrust belts, in ThrustTectonics, edited by K. R. McClay, pp. 209–216,Chapman and Hall, London.

McElhinny, M. W. (1964), Statistical significance of thefold test in paleomagnetism, Geophys. J. R. Astron.Soc., 8, 338–340.

Muttoni, G. D., and V. Kent (1994), Paleomagnetism oflatest Anisian (middle Triassic) sections of PrezzoLimestone and Buchenstein formation, southernAlps, Italy, Earth Planet. Sci. Lett., 122, 1 – 18.


25 of 25

TC5011

Neubauer, F., J. Genser, and R. Handler (2000), TheEastern Alps: Result of a two-stage collision pro-cess, Mitt. Oesterr. Geol. Ges., 92(1999), 117–134.

Oliva, B., E. L. Pueyo, and J. C. Larrasoana (2007),Magnetic reorientation induced by pressuresolution: A potential mechanism for orogenic-scale remagnetizations, Earth Planet. Sci. Lett,in press.

Plochinger, B. (1995), Tectonics of the northern Calcar-eous Alps: A review, Mem. Sci. Geol., 47, 73 –86.

Pober, E., and P. Faupl (1988), The chemistry of detri-tical chromian spinels and its implications for thegeodynamic evolution of the Eastern Alps, Geol.Rundsch., 77, 641–670.

Pueyo, E. L., H. Mauritsch, and R. Scholger (2001),Pervasive remagnetizations in the Northern Calcar-eous Alps: Preliminary evidences and implicationsin the Salzach region, Geol. Palaentol. Mitt. In-

nsbruck, 25, 163–165.Pueyo, E. L., M. Schneider, H. J. Mauritsch, R. Scholger,

and R. Lein (2002), A paleomagnetic cross sectionthrough the eastern northern Calcareous Alps: Pre-liminary data in the Mariazell meridian, paper pre-sented at PANGEO I Austria. Earth Sciences inAustria, Inst. fur Geol. und Palaontol., Univ. Salz-burg, Salzburg, Austria.

Pueyo, E. L., A. Pocovı, H. Millan, and A. Sussman(2004), Map-view models for correcting and calcu-lating shortening estimates in rotated thrust frontsusing paleomagnetic data, in Orogenic Curvature;Integrating Paleomagnetic and Structural Ana-lyses, edited by A. J. Sussman, and A. B. Weil,Spec. Pap. Geol. Soc. Am., 383, 57 –71.

Pueyo, E. L., T. Feischl, R. Scholger, and H. J. Mauritsch(2007), ‘‘Gamsstack’’: A program for stacking paleo-magnetic data, Comput. Geosci, in press.

Ratschbacher, L., W. Frisch, G. Linzer, and O. Merle(1991), Lateral extrusion in the Eastern Alps: 2.Structural analysis, Tectonics, 10, 257–271.

Rochette, P., and G. Lamarche (1986), Evolution desproprietes magnetiques lors des transformationsminerales dans les roches: Exemple du JurassiqueDauphinois (Alpes francaises), Bull. Mineral.,109(6), 687–696.

Schatz, M., J. Tait, V. Bachtadse, H. Heinisch, andH. Soffel (2002), Palaeozoic geography of theAlpine realm, new palaeomagnetic data fromthe northern greywacke zone, Eastern Alps, Int.J. Earth. Sci., 91, 979 –992, doi:10.1007/s00531-002-0289-4.

Scheepers, P. J. J., and J. D. A. Zijderveld (1992),Stacking in paleomagnetism: Application to marine

sediments with weak NRM, Geophys. Res. Lett.,19, 1519–1522.

Schneider, M. (2002), Palaomagnetische Untersuchun-gen in den Niederosterreichisch-Steirischen Kalkal-pen, MSc. thesis, 100 pp., Univ. Wien, Vienna,Austria.

Scholger, R., and K. Stingl (2004), New paleomagneticresults from the middle Miocene (Karpatian andBadenian) in northern Austria, Geol. Carpathica,55(2), 199–206.

Scholger, R., K. Stingl, and H. J. Mauritsch (2003),New palaeomagnetic results from the EasternAlpine Neogene basins indicate rotations of mi-cro-plates during the Miocene: VI ALPSHOPWorkshop, Sopron (abstract), Ann. Univ. Sci. Buda-pestinensis, Sect. Geol., 35, 89–90.

Schweigl, J., and F. Neubauer (1997), Structural evolu-tion of the northern Calcareous Alps: Significancefor the Jurassic to Tertiary geodynamic in the Alps,Eclogae Geol. Helv., 90, 303–323.

Smathers, N. P. (1987), The paleomagnetism of Jurassicand Triassic limestones in the upper Austroalpineunit and the tectonic implications, Master thesis,189 pp., Univ. of Fla., Gainesville.

Soffel, H. (1975), The paleomagnetism of the Permianeffusives near St. Anton, Vorarlberg (Austria) andthe anticlockwise rotation of the northern Calcar-eous Alps through 60 degrees, Neues Jahrb. Geol.Palaeontol. Monat., 6, 375–384.

Soffel, H., and D. Wohl (1986), Paleomagnetism oflower Triassic red sandstones in the southern Kai-sergebirge (Austria), Mitt. Oesterr. Geol. Ges., 80,173–183.

Soto, R., A. M. Casas-Sainz, and E. L. Pueyo (2006),Along-strike variation of orogenic wedges asso-ciated with vertical axis rotations, J. Geophys.Res., 111, B10402, doi:10.1029/2005JB004201.

Spotl, C., F. J. Longstaffe, K. Ramseyer, M. J. Kunk,and R. Wiesheu (1998), Fluid-rock reactions in anevaporitic melange, Permian Haselgebirge, Aus-trian Alps, Sedimentology, 45, 1019–1044.

Thomas, J. C., M. E. Claudel, M. Collombet, P. Tricart,A. Chauvin, and T. Dumont (1999), First paleomag-netic data from the sedimentary cover of the FrenchPenninic Alps; evidence for Tertiary counterclock-wise rotations in the Western Alps, Earth Planet.

Sci. Lett., 171, 561–574.Thoni, M., and C. Miller (1996), Garnet Sm-Nd data

from the Saualpe and the Koralpe (Eastern Alps,Austria): Chronological and PT constraints on thethermal and tectonic history, J. Metamorph. Geol.,14, 453–466.

Thony, W., H. Ortner, and R. Scholger (2006), Paleo-magnetic evidence for large en-bloc rotations in theEastern Alps during Neogene orogeny, Tectonophy-sics, 414, 169–189.

Tollmann, A. (1973), Geologie Von Osterreich, vol. 1,766 pp., Deuticke, Vienna, Austria.

Tollmann, A. (1985), Geologie Von Osterreich, vol. 2,710 pp., Deuticke, Vienna, Austria.

Tollmann, A. (1987), Late Jurassic/Neocomian gravita-tional tectonics in the northern Calcareous Alps inAustria, in Geodynamics of the Eastern Alps, editedby H. W. Flugel and P. Faupl, pp. 112–125,F. Deuticke, Vienna, Austria.

TRANSALP Working Group (2002), First deep seismicreflection images of the Eastern Alps revealgiant crustal wedges and transcrustal ramps,Geophys. Res. Lett., 29(10), 1452, doi:10.1029/2002GL014911.

Van der Voo, R. (1990), The reliability of paleomag-netic data, Tectonophysics, 184, 1 –9.

Wagreich, M. (1993), Subcrustal tectonic erosion inorogenic belts: A model for the Late Cretaceoussubsidence of the northern Calcareous Alps (Aus-tria), Geology, 21, 941–944.

Wagreich, M. (1995), Subduction tectonic erosion andLate Cretaceous subsidence along the northern Aus-troalpine margin (Eastern Alps, Austria), Tectono-physics, 242, 63– 78.

Wagreich, M., and K. Decker (2001), Sedimentary tec-tonics and subsidence modelling of the Upper Cre-taceous Gosau basin (northern Calcareous Alps),Int. J. Geol. Sci., 90, 714–726.

Zankl, H. (1971), Upper Triassic carbonate facies in thenorthern Limestone Alps, in Sedimentology of Partsof Central Europe, edited by G. Muller and G. Fried-man, pp. 145–185, Kramer, Frankfurt, Germany.

��W. Frisch, Institut fur Geologie und Palaontologie,

Universitat Tubingen, Sigwartstrasse 10, D-72076Tubingen, Germany.

H.-J. Gawlick, Institute of Geosciences, Universityof Leoben, Peter-Tunner Strasse 5, A-700 Leoben,Austria.

H. J. Mauritsch and R. Scholger, PaleomagneticLaboratory, University of Leoben, Gams 45, A-8130Frohnleiten, Austria.

E. L. Pueyo, Instituto Geologico y Minero deEspana, Unidad de Geologıa y Geofısica, ManuelLasala 44, 9C., E-50009 Zaragoza, Spain. ([email protected])

New evidence for block and thrust sheet rotations in the central …gilder/Re... · 2016-03-08 · New evidence for block and thrust sheet rotations in the central northern Calcareous

Documents