The Maastrichtian – Danian at General Roca (Patagonia, Argentina): a reappraisal of the chronostratigraphy and biostratigraphy of a type locality

The Maastrichtian ndash Danian at General Roca (Patagonia Argentina)a reappraisal of the chronostratigraphy and biostratigraphy of a type locality

Claudia J del Riacuteo Andrea Concheyro Buenos Aires and Sergio A Martiacutenez Montevideo

With 12 figures and 6 tables

DEL RIacuteO C J CONCHEYRO A amp MARTIacuteNEZ S A (2011) The Maastrichtian ndash Danian at GeneralRoca (Patagonia Argentina) a reappraisal of the chronostratigraphy and biostratigraphy of a typelocality ndash N Jb Geol Palaumlont Abh 259 129ndash156 Stuttgart

Abstract The Late Cretaceous ndash Early Paleogene succession exposed in the type area of theRoca Formation (General Roca Riacuteo Negro Province) has been sampled in detail Analyses of thecalcareous nannofossil assemblages indicate the Late Maastrichtian ndash Early Danian interval(CC26-NP4 zones MARTINI 1971) which is the first proved evidence of the Late Maastrichtian inthe mentioned type area Moreover the ldquoRocanenserdquo invertebrate fauna has been placed in a highresolution biostratigraphic scheme based on the nannofossil zones and three assemblages havebeen recognized

Key words Biostratigraphy Roca Formation Jaguumlel Formation Late Maastrichtian Daniannannofossils mollusks echinoderms

1 Introduction

The marine sediments of the Maastrichtian ndash Danianinterval cover a wide area of Patagonia and yieldwell documented assemblages of planktic andbenthic foraminifera ostracods palynomorphs andcalcareous nannofossils which are useful tools indating these marine sedimentary horizons providinginformation of the faunal transition and recoveryafter the terminal Cretaceous mass extinction eventAfter decades of being almost ignored and becauseof the world aroused interest in the CretaceousPaleogene (KPg) boundary the attention of manypaleontologists was directed towards the Patagonianbiota of this interval (BERTELS 1980 and biblio -graphy therein CONCHEYRO 1995 NANtildeEZ ampCONCHEYRO 1997 among others) However thedifferent criteria in defining units (bio-chrono -stratigraphic vs lithostratigraphic criteria) the stillincomplete chronostratigraphic data and the fact that

many studies focused on partial sections dated with-out detailed sampling resulted in different viewsabout age and units identity These factors alongwith the partial knowledge of accurate stratigraphiclocation of some invertebrate groups have led toconfuse the biochron of some species as it happenedin the type area of the Roca Formation where somebiostratigraphic conclusions dealing with decapodsoysters echinoderms were built upon on partial data(FELDMANN et al 1995 FELDMANN amp SCHWEITZER

2006 and bibliography therein CASADIacuteO 1998PARMA amp CASADIacuteO 2005)

The aim of this paper is to re-evaluate the age ofthe Jaguumlel and Roca formations in the type area ofthe latter unit considering the calcareous nannofossilcontent for the first time The biostratigraphic andchronostratigraphic results will be compared withthose obtained by BERTELS (1970a 1973) whocarried out the pioneer studies in this area based onforaminifera and ostracods It will also be attempted

copy 2011 E Schweizerbartʼsche Verlagsbuchhandlung Stuttgart Germany wwwschweizerbartde

DOI 1011270077-774920110103 0077-774920110103 $ 700

N Jb Geol Palaumlont Abh 2592 129ndash156 ArticleStuttgart February 2011

to provide the detailed geographic location andchronostratigraphic placement of the ldquoRocanenserdquofaunas recently collected as well as that of thematerial recovered previously by S ROTH WSCHILLER and A ROMERO This contribution seeksto improve the knowledge on the age of the Maas-trichtian ndash Danian rocks in the study area providingnew information which could be helpful in futurebiostratigraphic and biotic interpretations

2 The Maastrichtian ndash Danian sedimen-tites in the Neuqueacuten EmbaymentA summary

G e o g r a p h i c d i s t r i b u t i o n ndash Marine sedi-mentary rocks deposited during Maastrichtian ndashDanian times are extensively distributed in Pata -

gonia varying lithostratigrahic nomenclature in thedifferent basins Arroyo Barbudo and Pedro Luroformations (Colorado Basin) Lefipaacuten and Sala -manca formations (San Jorge Basin) and CerroCazador Cerro Dorotea Policarpo and Riacuteo Claroformations (Austral Basin) In the Neuqueacuten Embay-ment of the Neuqueacuten Basin sediments from thisinterval are known as Jaguumlel Huantraicoacute Roca andSaldentildeo formations and the uppermost part of theLoncoche Formation After being discovered in thesurroundings of the city of General Roca (Riacuteo NegroProvince) by RHODE (in DOumlRING 1882) subsequentauthors such as BODENBENDER (1892) GERTH (19131925) WINDHAUSEN (1914) WICHMANN (1924) andWEAVER (1927 1931) among others expanded thearea where Maastrichtian and Danian sedimentswere found to the western and northern sectors ofthe Neuqueacuten Embayment Outcrops are recognized

130 CJ del Riacuteo et al

Fig 1 Geographic location of main regionswith exposures of the Maastrichtian ndashDanian marine sediments in the NeuqueacutenEmbayment (gray area modified fromScasso et al 2005) as explained in the text1 ndash Matuasto section 2 ndash Lago Pellegrini -General Roca (enlargement in Figure 3)3 ndash SW La Pampa Province 4 ndash SierraHuantraicoacute - Sierra Auca Mahuida5 ndash Lui Malal section 6 ndash Malarguumle-BardasBlancas 7 ndash Western Cordillera

in at least seven regions 1 - Matuasto section 2 -Lago Pellegrini ndash General Roca (Northern Riacuteo NegroProvince) 3 - Southwestern La Pampa Province4 - Sierras de Auca Mahuida and Huantraicoacute (North-eastern Neuqueacuten Province) 5 - Lui Malal section6 - Malarguumle-Bardas Blancas and 7 - Western Cor-dillera (Mendoza Province) (Fig 1)

Sequence stratigraphy analyses involving thesesediments were carried out by ULIANA (1975)ULIANA amp DELLAPEacute (1981) LEGARRETA ampGULISANO (1989) LEGARRETA et al (1989) andBARRIO (1990) who included them in the upper partof the Malarguumle Group stating that these depositswould represent the final Atlantic transgressive-regressive phase of the sea that flooded the Easternsector of the Neuqueacuten Basin during Late Cretaceousndash Paleogene times The regressive phase is repre -sented by the Roca Formation WEAVER 1927 whichcomprises marls and bioclastic limestones withabundant skeletal fragments and by the JaguumlelFormation (BERTELS 1969a) Huantraicoacute Formation(BERTELS 1969a) and the uppermost part of theLoncoche Formation (GROEBER 1946) which con-sists of marls mudstones claystones and siltstonesThe Roca Formation is recognized in all of thementioned regions whereas the Jaguumlel Formation isknown in the Riacuteo Negro and La Pampa Provincesand in the Auca Mahuida area The HuantraicoacuteFormation and the marine section of the LonconcheFormation are restricted to the south of Malarguumle(BERTELS 1969 a BARRIO 1990 PARRAS et al 1998)

L i t h o l o g y ndash The Roca and Jaguumlel formationsshow lithological variations depending on theirpalaeogeographic locations in the basin during theMaastrichtian ndash Danian interval In the case of theJaguumlel Formation variations are mostly restricted tocharacteristics of the carbonate deposition whichchanges from mudstones and bioclastic limestonebeds in the Auca Mahuiacuteda and Huantraicoacute areas toan intercalation of marls and coquinas towards theEastern sector of the embayment In turn variationsin the Roca Formation are stronger than thoserecorded in the Jaguumlel Formation and are relatedto thickness and facies changes The thickness ofcarbonate deposits varies from 25 m in the eastern-most sections to 150 m in the Huantraicoacute area In thesurroundings of General Roca- Lago Pellegrini theoutcrops are dominated by intercalations of cal -careous sandstones mudstones and limestonesyielding abundant skeletal fragments with scarcematrix Westwards in the Huantraicoacute and Auca

Mahuiacuteda regions bioclastic sedimentation is repre-sented by bioruditic limestones packstones andgrainstones interbedded with sandy calcarenites andcalcareous mudstones (BARRIO 1990) Calcareousmudstones have lenticular geometry and representtidal channels (LANES pers comm) or biohermbodies (LEANZA et al 1985)

A g e ndash BERTELS (1964 1968a b 1969a b 1970ab 1972 1973 1974 1975a b 1980) provided thefirst detailed descriptions of numerous sectionswidespread in the Neuqueacuten Embayment Based ontheir microfaunal assemblages (foraminifera andostracods) the Jaguel and the Huantraicoacute formationswere distinguished from the Roca Formation Whilethis latter unit was placed in the Danian the Jaguumleland the Huantraicoacute formations were considered to beof Early ndash Middle Maastrichtian age

During the last decades the knowledge on thesesedimentary deposits has been enhanced (seeCAMACHO 1992 for a synthesis) many other sectionswere studied in the Neuqueacuten Embayment and newchronostratigraphic information has been providedby calcareous nannofossils The pioneer analysesbased on this group were carried out by MALUMIAacuteN

(1969) and MALUMIAacuteN et al (1984) who placed theJaguumlel Formation from General Roca and Allenrsquoswell in the Middle Maastrichtian ANGELOZZI (1987)gave a Danian age to the Jaguumlel and Roca formationsexposed in Lomas Blancas (Auca Mahuida region)A Late Maastrichtian age was first proposed byA CONCHEYRO for the Cretaceous marine depositsin Bajada del Jaguumlel and Opaso sections (AucaMahuida region) and Cerros Bayos (CASADIacuteO ampCONCHEYRO 1992 CONCHEYRO 1995 DEL RIacuteO etal 2004 2007) CONCHEYRO amp VILLA (1996) de -monstrated that the Jaguumlel Formation exposed in theLui Malal section is part of the Late Maastrichtian ndashDanian interval Integrated studies based on fora -minifera calcareous nannofossils and palynomorphscorroborated a Late Maastrichtian - Danian age forall the sections mentioned above (CONCHEYRO ampNANtildeEZ 1994 NANtildeEZ amp CONCHEYRO 1997 PAPU etal 1999)

More recently the accuracy obtained near theKPg in the Neuqueacuten Basin has been improvedvarying the precision of sampling intervals betweenone meter to two centimetres depending on rockfeatures and location of sections in the basin Ex -amples of this are the Matuasto and Bajada delJaguumlel sections where the KPg interval has beenaccurately identified on the base of foraminifera and

The Maastrichtian ndash Danian at General Roca (Patagonia Argentina) 131

calcareous nannofossils (CONCHEYRO et al 2002SCASSO et al 2005 KELLER et al 2007)

In reference to the age of the Roca FormationBERTELS (1969) CONCHEYRO amp VILLA (1996)NANtildeEZ amp CONCHEYRO (1997) and KELLER et al(2007) gave a Danian age to exposures of this unit inthe Bajada del Jaguumlel Huantraicoacute and Lui Malallocalities CASADIacuteO amp CONCHEYRO (1992) and DEL

RIacuteO et al (2004 2007) placed the Roca Formation ofCerros Bayos (Southwestern La Pampa Province) inthe Danian The Saldentildeo Formation correlated withthe Roca and Pircala formations was placed in theLate Maastrichtian by TUNIK et al (2004) andKIESSLING et al (2006) assigned this unit exposed inHuantraicoacute to the Early ndash Late Maastrichtian

3 The Jaguumlel and Roca formationsin the study area General Roca(Riacuteo Negro Province)

P r e v i o u s w o r k s ndash The sedimentary sequenceexposed in the yellow cliffs that run in west-eastdirection and to the north of General Roca (region 2in Fig 1) consists of the lacustrine Allen Formationat the bottom the marine Jaguumlel and Roca for -mations in the middle and the lacustrine CarrizoFormation at the top (Fig 2)

The first recognition of the fossiliferous beds ofthe Roca Formation was made by G ROHDE (men-tioned in DOumlRING 1882) but it was ROTH (1899) whopublished preliminary data providing a very simple

stratigraphic regional scheme for this sequenceWINDHAUSEN (1914) was the pioneer author indescribing these sediments and SCHILLER (1922)sampled a section along the Zanjoacuten Roca from thecity of General Roca northwards to the ldquoHorno deCal continuordquo (Permanent lime kiln) He proposedthe lime kiln as the ldquoclassic areardquo and considered thecliffs westwards from the lime kiln as the ldquomodelareardquo of these beds (Fig 3)

WEBER (1964) described two sections close to theldquoclassic areardquo of SCHILLER (1922) naming them asNCW (Cuchillas Noroeste de Roca) and NR (RocaNorte) and BERTELS (1964 1970) included materialfrom a third locality (RS = Riacuteo Seco) Probably inaccordance with the region proposed by SCHILLER

(1922) as the ldquoclassicrdquo area BERTELS (1969a1970a) chose the NR section as the type locality ofthe Roca Formation (HC in Fig 3)

According to BERTELS (1970a) the NR type sec-tion consists of 14 m of basal marls that are overlainby 22 m of intercalated marls and fossiliferous lime-stones that show a gradual upward increase in thick-ness and culminate in a hard massive limestonedevoid of fossils In the RS and NWC sections sherecognized the Roca and Jaguumlel formations and dis-tinguished them under biostratigraphic criteria onlyBased on the foraminifera and ostracod content thecomplete type section of the Roca Formation wasplaced in the Danian and the Jaguumlel Formation in theMiddle Maastrichtian or in the Lower ndash MiddleMaastrichtian (BERTELS 1964 1970a 1972 19731975a) BERTELS (1970a) argued that the absence

132 CJ del Riacuteo et al

Fig 2 Panoramic view of exposures of the Jaguumlel and Roca formations to the north of General Roca

of Late Maastrichtian rocks in the area and inthe whole of the Neuquen Basin was due to a bio -stratigraphic hiatus

Later ULIANA amp DELLAPEacute (1981) proposed alithostratigraphic criterion to separate the Jaguumlel andRoca formations In this way they included the basalgreenish calcareous muddy strata of the type sectionof the Roca Formation (as defined by BERTELS

1969a 1970a) in the upper part of the Jaguumlel For -mation and used the first occurrence of a fossili -ferous limestone to delimit the base of the RocaFormation

The Roca Formation contains a diverse andabundant fauna of invertebrates mainly dominatedby mollusks followed by decapods echinodermsbryozoans and corals Fossils were first studied by

BURCKHARDT (1901) and OPPENHEIM (in BOumlHM

1903) who described and illustrated 11 species ofmollusks and two species of echinoderms Know -ledge of this fauna was substantially increased byIHERING (1902 1903 1904 1907) with the de -scription of other 28 taxa 24 of which were newspecies IHERING (1907) differentiated it from theyoungest Tertiary Patagonian assemblages includingit in the ldquoRocanense Stagerdquo Since then this assem-blage has been always referred to as ldquoRocanensefaunardquo in geological literature With the exceptionof the description of a reduced number of speciesfrom the type area that involve to carditids (FOSSA-MANCINI 1938) oysters (CASADIacuteO 1998) nautiloids(CASADIacuteO et al 1999) mytilids (GRIFFIN et al 2008)and pectinoideans (DEL RIacuteO et al 2008) the ldquoRoca-

The Maastrichtian ndash Danian at General Roca (Patagonia Argentina) 133

Fig 3 Topographic map showing measured sections placed to the north of the city of General Roca (region 2 in Fig 1)ZR = Zanjoacuten Roca PS = Picada Siacutesmica HC = Horno de Cal (Type section of the Roca Formation = NR section ofBERTELS 1969a) CH = Cantera Cholino TP = Cerro Tres Picos (NCW and RS correspond to localities describedby WEBER (1964) and BERTELS (1970a)

134 CJ del Riacuteo et al

Fig 4 Lithology and correlation of the studied sections (NR = Roca Norte section of BERTELS (1970a) masl = metersabove sea level)

The Maastrichtian ndash Danian at General Roca (Patagonia Argentina) 135

nenserdquo fauna has remained almost unknown sinceIHERINGrsquos times

Minor groups such as decapods and echinoidsalso received little attention After first mentioned byBOumlHM (1901) decapods were studied by FELDMANN

et al (1995) and later revised by SCHWEITZER (2005)SCHWEITZER et al (2000 2004) and KARASAWA ampSCHWEITZER (2004) (see FELDMANN amp SCHWEITZER

2006 for the listed bibliography) Echinoids wererevised by PARMA amp CASADIacuteO (2005) who includedthe description of two species recorded in the typearea

4 Material and methods

Most of the exposures in the area have been highlyeroded or partially destroyed by mining activitywhich resulted in the mixing of fossils from differentstratigraphic horizons However some very goodexposures are located along gullies such as theZanjoacuten Roca or along the creek that runs from theCantera Cholino (Cholinorsquos Quarry) down to thebase of the Cerro Tres Picos The type section of theRoca Formation as defined by BERTELS (1969a1970a) was recognized sampled and named HC

(Horno de Cal 38deg 56rsquoS ndash 67deg 35rsquoW) Moreover fournew complementary sections named Cantera Cholino(38deg 53rsquoS ndash 67deg 40rsquoW) Cerro Tres Picos (38deg 54rsquoS ndash67deg 40rsquoW) Picada Siacutesmica and Zanjoacuten Roca (38deg55rsquoS ndash 67deg 32rsquoW) (CH TP PS and ZR acronymsrespectively in Fig 3) were measured at 1100 scalewhere samples for microfossil studies were collectedin some cases every 10 cm interval (Fig 4)

Calcareous nannofossils were analyzed throughsimple smear-slides (EDWARDS 1963 BOWN ampYOUNG

1998) and standard light-microscope techniques usinga Leica DMLP at 1000 X magnification Sampleswere semi-quantitatively logged and slides wereobserved for at least 30 min in most cases muchlonger covering at least two transverse transectsalong the major axis of the slide Abundance and pre-servation categories are given in the range charts(Tables 1-5) where species presence is in dicated withan ldquoXrdquo Samples for SEM observations were pre -pared using ultrasonic and successive decantationmethods centrifugation and concentration in acellulose nitrate filter Estimation of preservation isbased on the scheme of ROTH amp THIERSTEIN (1972)as follows P = poor severe dissolution fragmen -tation andor overgrowth have occurred most pri-mary features have been destroyed and many speci-

Fig 5 Maastrichtian beds of the Jaguumlel Formation exposed at the base of Cerro Tres Picos

136 CJ del Riacuteo et al

mens cannot be identified at the specific level M =moderate dissolution andor overgrowth are evidenta significant proportion (up to 25 ) of the speci-mens cannot be identified to species level with ab -solute certainty G = good little dissolution andorovergrowth is seen diagnostic characteristics are pre -served and all specimens can be identified E = ex -cellent no dissolution andor overgrowth is observedall specimens can be identified Taxa consideredherein are listed in Appendix where they are arrangedalphabetically by generic epithets

The mollusk fauna considered in this study in -cludes the earliest collections made in the area by SROTH between 1895 and 1896 and A ROMERO whosent his collection to the Museo Argentino deCiencias Naturales B RIVADAVIA (MACN) in 1903Only a small number of specimens (mainly holo -types) described by H V IHERING between 1902 and1907 were incorporated into the col lections of theMACN while the rest of the material was lost untilrecently identified by the curators of the Paleo -invertebrate Division Moreover it is considered the

Fig 6 ndash Intercalation of marlstones and shell-beds with Thalassinoides horizons in the uppermost section of the RocaFormation at Cantera Cholino

Fig 7 1 ndash Panoramic view of the Maastrichtian nannoflora 2-4 ndash Eiffellithus turriseiffelii (DEFLANDRE) REINHARDTBAFC-NP 3047 2 distal view partially overgrowth 3 lateral view 5-6 ndash Eiffellithus gorkae VEKSHINA BAFC-NP 30475 distal view 6 proximal view 7 ndash Eiffellithus parallelus PERCH-NIELSEN BAFC-NP 3047 distal view 8 ndash Predis-cosphaera stoveri (PERCH-NIELSEN) SHAFIK amp STRADNER BAFC-NP 3047 proximal views 9 ndash Manivitella pemmatoidea(DEFLANDRE) THIERSTEIN BAFC-NP 3047 distal view 10 ndash Prediscosphaera spinosa (BRAMLETTE amp MARTINI)GARTNER BAFC-NP 3047 distal view 11 ndash Ahmuellerella octoradiata (GARTNER) REINHARDT BAFC-NP 3047 distalview 12 ndash Watznaueria barnesiae (BLACK) PERCH-NIELSEN BAFC-NP 3047 distal view 13-15 ndash Arkhangelskiellacymbiformis VEKSHINA BAFC-NP 3047 13 distal view 14 proximal view 15 distal view The white bar indicates2 μm

The Maastrichtian ndash Danian at General Roca (Patagonia Argentina) 137

Fig 7 (Legend see p 136)

138 CJ del Riacuteo et al

Fig 8 (Legend see p 139)

material recently collected by the authors whichincludes the already known taxas and new species ofechinoids (holasteroids and spatangoids) bivalves(malletids nuculanids and pterioids) and gastropodsof the Families Epitoniidae Trochidae TudiclidaePseudolividae Fasciolaridae Ficidae and Tudiclidae

5 Stratigraphic sections

In the present analyses the lithostratigraphic schemeproposed by ULIANA amp DELLAPEacute (1981) whendescribing the lithology of sections is followed(Fig 4) Both the Jaguumlel and the Roca formationswere recognized comprising a sedimentary se -quence that dips less than 1ordm to the east The J a g uuml e lF o r m a t i o n is composed of a 25 m thick homo -genous succession of laminated greenish to yel -lowish marls interbedded with numerous thingypsum layers and crossed by veins of secondarygypsum (Fig 5) Fossils are restricted to scarcelyspread minute and unidentified molds of micro -mollusks and contain an abundant rich and ex -ceptionally well preserved nannofossil assemblageThe contact with the underlying Allen Formation isdifficult to distinguish in the field because of thestrong lithological similarity between both units Thebase of the Jaguumlel Formation can only be recognizedby the occurrence of the first marine microfossilassemblage The R o c a F o r m a t i o n consists ofa basal carbonate section and of an upper sectioncharacterized by deposition of thick gypsum bedsThe carbonate sector is 25-28 m thick and is com-posed of intercalated greenish marls fossiliferouslimestones and abundant thin gypsum layers Marlsare almost indistinguishable from those of the under-lying Jaguumlel Formation and usually yield rareminute molds of unidentified mollusks The fre -quency of limestones intercalations shows a gradualupward increase The lowermost coquinas are verythin (not more than 10 cm thick) massive lenticularbodies with planar or erosive lower contacts thatusually cannot be traced laterally for more than a few

meters In many cases these basal coquinas cannotbe recognized because they have been eroded andfossils from different stratigraphic intervals are inter-mixed Nonetheless they are very well exposed inour studied sections An exceptional thick basallimestone is that exposed in Zanjoacuten Roca section(sample 28 in Fig 4) where a hard 25 m thickamalgamated lenticular and highly fossiliferous bedconstitutes the base of the Roca Formation Theuppermost limestone of this carbonate section cor -responds to 2 m thick amalgamated tabular co -quinas Together with the overlying dolomite bedthis limestone constitutes a pronounced topographicstep placed around 400 m above sea level which canbe observed in the area for over 50 km This lastcoquina exhibits highly erosive internal surfaces andbeds with Thalassinoides that in some cases stretchlaterally for up 5 km (Fig 6)

The described carbonate deposits are super -imposed by up to 25 m thick whitish and grayishgypsum beds that constitute the top of the RocaFormation and cause the second and the uppermosttopographic step of the cliffs

6 Analysis of the calcareous nannofossils

The recovered nannoflora is one of the best pre-served in Argentina and comprises two differentassociations of Maastrichtian and Danian ages aswill be described below with special focus on somerelevant taxa (Figs 7-9 Tables 1-5)

M a a s t r i c h t i a n a s s o c i a t i o n ndash The mainrepresentative species of the Maastrichtian asso -ciation are Cribrosphaerella daniae PERCH-NIELSENCribrosphaerella ehrenbergii (ARKHANGELSKY) DE -FLANDRE in PIVETEAU Micula decussata VEKSHINAMicula concava (STRADNER in MARTINI amp STRADNER)VERBEEK Lithraphidites quadratus BRAMLETTE ampMARTINI Nephrolithus frequens GOacuteRKA Kampt -nerius magnificus DEFLANDRE Arkhangelskiella

The Maastrichtian ndash Danian at General Roca (Patagonia Argentina) 139

Fig 8 1 ndash Kamptnerius magnificus DEFLANDRE BAFC-NP 3047 proximal view 2 ndash Rhagodiscus angustus (STRADNER)REINHARDT BAFC-NP 30474 distal view 3 ndash Acuturris scotus (RISATTI) WIND amp WISE in WISE amp WIND AFC-NP3047 lateral view 4 ndash Panoramic view of the Danian nannoflora 5 ndash Braarudosphaera bigelowi (GRAN amp BRAARUD)DEFLANDRE BAFC-NP 3075 distal view 6 ndash Markalius inversus (DEFLANDRE) BRAMLETTE amp MARTINI BAFC-NP3075 proximal view 7 ndash Hornibrookina edwardsii PERCH-NIELSEN BAFC-NP 3075 proximal view 8-11 ndash Cruci -placolithus primus PERCH-NIELSEN BAFC-NP 3075 12 ndash Lanthernithus duocavus LOCKER BAFC-NP 3075 distalview 13-15 ndash Toweius africanus (PERCH-NIELSEN) PERCH-NIELSEN BAFC-NP 3003 13 coccosphaere 14 distal view15 proximal view The white bar indicates 2 μm

140 CJ del Riacuteo et al

cymbiformis VEKSHINA Ahmuellerella octoradiata(GOacuteRKA) REINHARDT Gartnerago segmentatum(STOVER) THIERSTEIN Prediscosphaera stoveri(PERCH-NIELSEN) SHAFIK amp STRADNER Eiffellithusturriseiffelii (DEFLANDRE in DEFLANDRE amp FERT)REINHARDT and Eiffelithus gorkae REINHARDTThese taxa constitute part of a well diversifiedfrequent to abundant nannoflora with a moderate togood species preservation without major over-growth effects

Micula decussata Arkhangelskiella cymbiformisand Eiffellithus turriseiffelii predominate as the mostfrequent species in every Maastrichtian samplesprobably due to their high resistance to dissolution(THIERSTEIN 1980) or to palaeoecological require-ments (LADNER amp WISE 1999 THIBAULT amp GARDIN

2006)

The presence of Nephrolithus frequens andCribrosphaerella daniae confirms a Late Maas -trichtian age for the interval particularly CC26 Zone(PERCH-NIELSEN 1985a) in agreement with theage established for the Jaguumlel Formation in otherlocalities of the Neuqueacuten Embayment (CONCHEYRO

19952001 CONCHEYRO amp NAacuteNtildeEZ 1994 CONCHEYRO

amp VILLA 1996 NAacuteNtildeEZ amp CONCHEYRO 1997 PAPU

et al 1999)Neprolithus frequens is a taxon from cool waters

with a geographic distribution that ranges from highto medium latitudes being considered an importantmarker for high latitudes (WIND amp WISE 1976 WIND

1979) It displays a diachronous biochron in theMaastrichtian and along with Cribrosphaerelladaniae has been used to indicate the Late Maas-trichtian in absence of other Maastrichtian markers

Fig 9 1-3 ndash Placozygus sigmoides BRAMLETTE amp SULLIVAN BAFC-NP 3003 1 distal view 2 proximal view 3 lateralview 4-5 ndash Neochiastozygus primitivus PERCH-NIELSEN BAFC-NP 3003 distal views 6 ndash Neochiastozygus modestusPERCH-NIELSEN BAFC-NP 3003 proximal view 7 ndash Hornibrookina teurensis EDWARDS BAFC-NP 3003 distal view8-9 ndash Neochiastozygus modestus PERCH-NIELSEN BAFC-NP 3003 distal views The white bar indicates 2 μm

The Maastrichtian ndash Danian at General Roca (Patagonia Argentina) 141

With the exception of M decussata the remain-ing Maastrichtian species are also known as coolwater taxa (THIBAULT amp GARDIN 2006) and theirpersistence through all Maastrichtian samples reflectcool conditions or a considerable input of australspecies to the Neuqueacuten Basin as was pointed out byCONCHEYRO amp VILLA (1996) and later mentioned byCASADIacuteO et al (2004)

The cosmopolitan taxon Micula decussata isdominant in all Maastrichtian samples and many dis-cussions have been built upon its high abundancewhich could be due to differential preservation or toany particular paleoecological requirement (LADNER

amp WISE 1999 OVECHKINA amp ALEKSSEV 2005) as itwas also suggested by KELLER et al (2007) in Bar-ranca del Jaguumlel Its high abundance could suggestlow productivity and high-stress conditions closeto the KPg boundary (THIBAULT amp GARDIN 2006)This situation has been clearly observed throughoutthe Neuqueacuten Basin and has also been detected inthe type area of the Roca Formation where it is com-monly recorded in all samples placed immediatelybelow the KPg boundary

D a n i a n a s s o c i a t i o n ndash Its richness andabundance are low the preservation varies frompoor with commonly fragmented specimens near theKPg boundary to moderate and good upwards inthe section Among the most abundant and commonfossils are Biantholithus sparsus BRAMLETTE ampMARTINI Thoracosphaera operculata BRAMLETTE

amp MARTINI Thoracosphaera saxea STRADNERMicrantholithus pinguis BRAMLETTE amp SULLIVANMicrantholithus vesper DEFLANDRE in DEFLANDRE

amp FERT Braarudosphaera bigelowi (GRAN ampBRAARUD) DEFLANDRE Markalius inversus(DEFLANDRE in DEFLANDRE amp FERT) BRAMLETTE ampMARTINI Markalius apertus PERCH-NIELSENCyclagelosphaera reinhardtii (PERCH-NIELSEN)ROMEIN Chiastozygus ultimus PERCH-NIELSEN andNeochiastozygus primitivus PERCH-NIELSEN Fol-lowing PERCH-NIELSEN et al (1982) and BURNETT

(1998) among others the Danian association is con-stituted by four different categories of nannofossilswhich are identified as ldquoCretaceous speciesrdquo ldquoCreta-ceous survivor speciesrdquo ldquoincoming Paleogenespeciesrdquo and ldquoreworked speciesrdquo

Among the ldquoCretaceous speciesrdquo there must bementioned Nephrolithus frequens Micula decus -sata Arkhangelskiella cymbiformis Cribrosphaerel-la daniae Eiffellithus turriseiffelii Watznaueriabarnesiae (BLACK) PERCH-NIELSEN Watznaueria

ovata BUKRY and Cyclagelosphaera margereliiNOumlEL which remain as rare taxa in almost all Daniansamples and show a general trend of decreasingabundance

The ldquoCretaceous survivor speciesrdquo such asPlacozygus sigmoides (BRAMLETTE amp SULLIVAN)ROMEIN Micrantholithus pinguis BRAMLETTE ampSULLIVAN Micrantholithus vesper Braarudosphaerabigelowi Thoracosphaera operculata and Thora-cosphaera saxea have a bloom at the base of theDanian allowing them to be considered in theliterature as one of the earliest Danian associations(BURNETT 1998 MAI et al 1994 KELLER et al2007) Braarudosphaera bigelowi has been con -sidered as an opportunistic species (KONNO et al2007) and its presence in the study area constitutingreal chalks confirms that hypothesis Moreover itsphysical association in the chalks with M pinguisand M vesper led us to the conclusion that thesepentalithids should have had the same behaviourThoracosphaerids and pentalithids blooms are men-tioned in the literature for the Early Danian and thespecies Thoracosphaera saxea T operculata (bothconsistently present in the complete Daniansequence in the studied area) along with Micranto -lithus pinguis Micrantholithus vesper and Braaru-dosphaera bigelowi confirm the KPg transition inmany regions (JIANG amp GARTNER 1986 PERCH-NIELSEN 1985b POSPICHAL amp WISE 1990 ROMEIN

et al 1996 GARDIN 2002) being all of them charac-teristic inhabitants of shallow waters

The ldquoIncoming Paleogene speciesrdquo are charac -terized by the common presence of Biantholithussparsus BRAMLETTE amp MARTINI Hornibrookinaedwardsii PERCH-NIELSEN Hornibrookina teuriensisEDWARDS Cruciplacolithus primus PERCH-NIELSENCruciplacolithus tenuis (STRADNER) HAY ampMOHLER and Chiasmolithus danicus (BROTZEN)HAY amp MOHLER a clear Danian marker (PERCH-NIELSEN 1985b VAROL 1998) Hornibrookinaedwardsii is common to abundant in many samplesand it has been mentioned as a basal Danian speciesand Hornibrookina teuriensis a taxon larger than Hedwardsii is usually well preserved being a frequentto abundant species in the uppermost part of themeasured sections Small specimens of Crucipla -colithus primus have been identified in most Daniansamples throughout the studied area and its firstcommon occurrence confirms the base of the DanianHowever MAI et al (2003) mentioned its first occur-rence just in the Late Maastrichtian where it is

142 CJ del Riacuteo et al

Fig 10 1-2 ndash Pycnodonte burckhardti IHERING MACN -Pi 5219 3-4 ndash Gryphaostrea callophylla (IHERING) holotypeMACN-Pi 138 5-6 ndash ldquoVenericardiardquo iheringii var burckhardtii IHERING holotype MACN-Pi 356 I 7-8 ndash Pseudo -tylostoma romeroi IHERING holotype MACN-Pi 693a 9-10 ndash ldquoRostellariardquo rothi IHERING holotype MACN-Pi 75911-12 ndash Arca ameghinorum (IHERING) holotype MACN-Pi 340 All specimens in natural size

The Maastrichtian ndash Danian at General Roca (Patagonia Argentina) 143

Fig 11 1-2 ndash Strutiochenopus patagonensis (IHERING) holotype MACN-Pi 759 (x15) 3 ndash Turritella burckhardtiIHERING holotype MACN-Pi 5218 (x1) 4 ndash Neilo sp MACN-Pi 5223 (x2) (= Malletia ornata SOWERBY in IHERING

1907) 5-6 ndash ldquoLedardquo cf ldquoLedardquo perdita FERUGLIO MACN-Pi 5220 (x2) 7-8 ndash ldquoPhacoidesrdquo rocana IHERING holotypeMACN-Pi 5217 (x1) 9 ndash ldquoDosiniardquo burckhardti IHERING holotype MACN-Pi 415 (x1) 10-11 13 ndash ldquoTellinardquo bur -meisteri IHERING 10-11 holotype MACN-Pi 5216 (x1) 13 MLP 5527 (x1) 12 ndash Plicatula sp MACN-Pi 5222 (x2)14-15 ndash Cubistostrea ameghinoi (IHERING) holotype MACN-Pi 167 (x1) 16 19 ndash ldquoChlamysrdquo salamanca (IHERING)MACN-Pi 5212 (x2) 17 ndash Leionucula dynastes (IHERING) holotype MACN-Pi 5215 (x1) 18 ndash Gregariella amaraGRIFFIN et al MACN-Pi 5221 (x2) 20 ndash Arca ameghinorum (IHERING) MACN ndash Pi 5213 (x1)

144 CJ del Riacuteo et al

normally overlooked due to its small size In thebasal Danian where its first common occurrence isrecorded the taxa show an increment in size and canbe easily recognized

Biantholithus sparsus is another interestingnannofossil with 7-9 simple calcitic triangular torounded elements (MAI et al 1994) Although some-times considered as a ldquoCretaceous survivor speciesrdquooccurring in Maastrichtian assemblages (VAN HECK

amp PRINS 1987 MAI et al 2003) it has extensivelybeen used to indicate the base of the Danian (BRAM-LETTE amp MARTINI 1964 PERCH-NIELSEN 1979PERCH-NIELSEN 1985b VAN HECK amp PRINS 1987POSPICHAL amp WISE 1990 VAROL 1998) The ac -ceptance in the present study of the first occurrence(FO) of B sparsus as ldquoincoming Paleogene speciesrdquoand as Early Danian marker is in accordance withobservations carried out in the Austral Ocean by

Fig 12 Biostratigraphic distributionof the Danian ldquoRocanenserdquo inverte-brates in the type area of the RocaFormation related to calcareousnannofossil zones

POSPICHAL amp WISE (1990) as well as with thosestudies made by A CONCHEYRO in other regions ofthe Neuqueacuten Embayment (CONCHEYRO 1995 CON -CHEYRO et al 2002)

ldquoReworked speciesrdquo such as Micrantholithushoschulzii (REINHARDT) THIERSTEIN Micrantho -lithus obtusus STRADNER Nannoconus circularisDERES amp ACHERITEacuteGUY Nannoconus steinmanniKAMPTNER and Zeugrhabdotus embergerii (NOumlEL)PERCH-NIELSEN have also been observed in thetypical assemblages that characterize the VacaMuerta and Agrio formations (Tithonian to Valan -ginian-Upper Hauterivian in age) (BOWN amp CON -CHEYRO 2004) Their presence in the studied sectionsindicates important reworking This situation hadbeen previously recognized in the southern area ofMendoza Province (CONCHEYRO amp VILLA 1996) andit could be explained either by variations in theregional subsidence or eustatic oscillations whichwould have favoured the erosion of older sedimentsfrom the western flank as the result of the latestMaastrichtian-earliest Danian Laramide tectonicphase (onset of the Andean Orogeny) or as thecombination of both factors

7 Biostratigraphy

The Maastrichtian association is assigned to theCC26 Zone due to the presence of Nephrolithusfrequens and Cribrosphaerella daniae (PERCH-NIELSEN 1985a BURNETT 1998 POSPICHAL amp WISE

1990 CONCHEYRO 1995) being the first confirmedrecord of the Late Maastrichtian in the type area andtype section of the Roca Formation The blooms ofPlacozygus sigmoides Thoracosphera operculataT saxea Biantholithus sparsus and pentalithids sug-gest the presence of the Early Danian NP1 Zone(MARTINI 1971) (OKADA amp BUKRY 1980 GARDIN

2002) The permanent presence of some ldquoCretaceoussurvivor speciesrdquo indicates a most refined biostrati-graphic event According to VAROL (1998) the NP1in the North Sea can be subdivided into two zonesand three subzones (NNTp1a - NNTp1b - NNTp2)using the successive FO of Biantholithus sparsusCyclagelosphaera alta Placozygus sigmoides andCruciplacolithus primus respectively The recogni-tion of these bioevents in the study area led us toallocate the nannoflora in the lowest Danian

Although an association assigned to the NP2Zone is recognized in the sequence no markers suchas the FO of Cruciplacolithus intermedius VAN HECK

amp PRINS and of Coccolithus pelagicus (WALLICH)SCHILLER have been detected For this reason theboundary between NP1 and NP2 cannot be accur -ately defined by their lithological continuity

The NP3 Zone is determined by the FO of Chias-molithus danicus and Neochiastozygus modestusthe presences of Hornibrookina edwardsii andHornibrookina teuriensis and the bloom of Toweiusafricanus (PERCH-NIELSEN) PERCH-NIELSEN whichdisplays excellent preserved coccospheres

The NP4 Zone is recognized by the FO ofNeochiastozygus perfectus PERCH-NIELSEN onlyfound in the Cantera Cholino section This specieshas been used as a zonal marker by VAN HECK ampPRINS (1987)

8 The Danian ldquoRocanenserdquo invertebrateassemblages

With the exception of the oysters Gryphaostreacallophylla (IHERING) Cubistostrea ameghinoi(IHERING) and Pycnodonte (Phygraea) burckhardti(IHERING) that have been mentioned in other sectorsof the basin (CASADIacuteO 1998 DEL RIacuteO et al 2007)references to the ldquoRocanenserdquo assemblage are usual-ly restricted to the type area of the Roca FormationThis fauna is mainly represented by oysters cardi-tids veneroids and the gastropods ldquoRostellariardquo rothi(IHERING) and ldquoTurritellardquo burckhardti (IHERING)(Table 6 Figs 10-11) Because most of the speciesnamed by IHERING (1903 1907) were defined oninternal or composite molds of articulated speci-mens it is not possible to make any revision at thegeneric level but the material is easily re cognized atthe species level Just in a few cases minor modi -fications to IHERINGrsquos generic assignments must beintroduced IHERING (1907) placed molds of mal-letids into Malletia ornata SOWERBY an Oligocene-Miocene species of Patagonia actually belonging tothe genus Neilo New findings of material that haveparts of the shell preserved have allowed to distin-guish it from N ornata since the ldquoRocanenserdquo shellshave a much thinner and densely spaced commargin-al ridges than N ornata which probably places it ina different species (Fig 114) Also preserved inter-nal characters such as adductor and pallial bloodvessel scars of specimens of Tellina burmeisteriIHERING indicate that this species cor responds tosome lucinoidean genus (Figs 1110-11 1113) Thehinge of a poorly preserved mold of a right valve ofVenericardia ameghinorum IHERING from Cantera

The Maastrichtian ndash Danian at General Roca (Patagonia Argentina) 145

146 CJ del Riacuteo et al

Cholino confirms that this taxa belongs to Arca(Fig 1120)

The only biostratigraphic study dealing with thisfauna corresponds to that provided by ROSSI DE

GARGIacuteA amp LEVY (1984) who based on a compiledsection probably from the type area proposed fourroughly defined ldquozonesrdquo From base to top theseldquozonesrdquo are Gryphaostrea callophylla Zone Cubis-tostrea ameghinoi Zone Venericardia sp Zone andOdontogryphaea Zone

In this study three Danian assemblages asso -ciated with the nannofossil zones are locally distin-guished (Fig 12) The oldest assemblage is asso -ciated with the NP1-NP2 zones recorded at the baseof Cerro Tres Picos and Zanjoacuten Roca sections AtCerro Tres Picos (samples 10rsquo and 11rsquo) the assem-blage is yielded in the extremely thin lenticular basalcalcareous bodies and is represented by a poorlydiversified fauna constituted by Gryphaostrea callo-phylla Pycnodonte burckhardti ldquoChlamysrdquo sala-manca (IHERING) and ldquoVenericardia iheringi varburckhardtirdquo IHERING associated to bryozoans andscarse corals At Zanjoacuten Roca this assemblage iscontained in the thick multi-event shell bed (sample28) present at the base of the Roca Formation whereapart from the mentioned taxa Delectopectenneuquensis DEL RIacuteO et al new pectinids trochidsand Calyptraea cf pileolus have been recorded

The second association is contained in the NP3Zone and is represented in the Cerro Tres Picos(sample 23) Picada Siacutesmica (samples 7 and 10)Horno de Cal (samples 7 10 and 13) and ZanjoacutenRoca (sample 29) sections It is recognized by the firstoccurrences of Cubitostrea ameghinoi (IHERING)Turritella burckhardti (IHERING) numerous gastro -pods of the Families Fasciolariidae Ficiidae Tudi-clidae and Pseudolividae and soft-bottom dwellerssuch as Leionucula dynastes (IHERING) Neilo spldquoPhacoidesrdquo rocana (IHERING) ldquoDosiniardquo burck-hardti (IHERING) ldquoTellinardquo burmeisteri (IHERING)Holasteroidea indet Linthia sp Hemiaster spPlesiaster sp and Linthia joannisboehmi (OPPEN-HEIM in BOumlHM 1903 MARTINEZ et al 2011) amongthe most abundant taxa In strata belonging to sample7 in the Picada Siacutesmica section this assemblage iscontained in uni-event shell-beds that laterally varyfrom a concentration of Leionucula dynastes andldquoPhacoidesrdquo rocana to accumulations of ldquoDosiniardquoburckhardti and ldquoTellinardquo burmeisteri In Cerro TresPicos (sample 23) this assemblage is replaced by awell diversified soft-bottom dweller assemblage re -presented by abundant still undetermined nuculanids

The third and youngest association is contained inthe uppermost shell-beds of the Roca Formation thatunderlies the dolomite bed It is much more diversethan the others and is well recorded in Cantera Cho -lino (samples 5-17) where it is associated with theNP4 Zone in Horno de Cal (samples 15 and 17)Picada Siacutesmica (sample 12) and Zanjoacuten Roca (sam-ples 36-37) The taxa restricted to this assemblageare Pseudotylostoma romeroi (IHERING) ldquoStruthio-chenopusrdquo patagonensis (IHERING) ldquoRostellariardquorothi (IHERING) Parvamussium bayoense DEL RIacuteO etal Plicatula sp Hercoglossa romeroi (IHERING)and still undetermined species of the Limidae Nucu-lanidae and Scaphandridae This assemblage isusually contained in shell-supported multi-eventbeds with horizons almost exclusively representedby Cubistostrea ameghinoi Pycnodonte burckhardtildquoRostellariardquo rothi and ldquoTurritellardquo burckhardtiThese beds frequently vary laterally to monospecificuni ndash event concentrations of Cubistostrea ameghi-noi to accumulations of Pycnodonte burckhardti andldquoRostellariardquo rothi

With the exception of the abundance of Gry -phaostrea callophylla at the base of the sections andof Pyconodonte burckhardti at the top (which issame that Odontogryphaea burckhardti) no agree-ment has been found with the ldquozonesrdquo proposed byROSSI DE GARGIacuteA amp LEVY (1984)

9 Discussion and conclusions

The Jaguumlel Formation (BERTELS 1969a) and the RocaFormation (WEAVER 1927) were studied in the typearea of the Roca Formation in the surroundings ofGeneral Roca BERTELS (1970 a) stated the absenceof Late Maastrichtian sediments in the type area ofthe Roca Formation and did not recognize depositsolder than the Danian at the base of the type sectionof this unit However Nephrolithus frequensCribrosphaerealla daniae Arkhangelskiella cymbi-formis and Predicosphaera stover were recoveredfrom the 20 m thick marls (Jaguumlel Formation) thatseparate the base of the Roca Formation (as definedby BERTELS 1969a) from the Allen Formation Thisfinding documents the presence of Late Maas -trichtian sediments (CC26 Zone) for the first time inthis area proving that the biostratigraphic hiatusproposed by BERTELS (1970a) which would haveextended from the Middle Maastrichtian to theDanian does not exist

The sampling and dating of the studied sectionsallowed the correlation proposed in Fig 4 which has

been based on the calcareous nannofossil zonesyielded in the marlstones the uppermost bioclasticaccumulations and the overlying dolomite bed TheJaguumlel Formation contains two calcareous nanno -fossil assemblages one of Late Maastrichtian age(CC26 Zone) and another one of Danian age (NP1-NP2 Zone) The sampling interval does not allow todistinguish the KPg transition but the presence ofboth assemblages are clearly identified in ZanjoacutenRoca and Cerro Tres Picos consequently allowingthe correlation of the basal sedimentites of thesection The transition between the NP1 and NP2zones is not recognized because of the absence ofCruciplacolithus intermedius due to the poor diversi-ty of the assemblage In the Roca Formation threeDanian calcareous nannofossil assemblages aredistinguished The oldest one belongs to the NP1-NP2 zones and is contained in the 20-30 cm thickmarlstones that overlay the first coquinas of the unitUpwards the NP3 Zone is identified and its transi-tion with the NP1-NP2 Zone has been recognized inCerro Tres Picos and Zanjoacuten Roca which led to thecorrelation of the middle part of the study sectionsFinally an assemblage assigned to the NP4 Zone hasbeen only identified in Cantera Cholino with the firstoccurrence of Neochiastozygus perfectus Bioclasticbeds contained in the NP4 Zone in Cantera Cholinoconsist of accumulations of Cubistostrea ameghinoiPycnodonte burckhardti ldquoRostellariardquo rothi andHercoglossa sp associated with Thalassinoideshorizons These fossiliferous concentrations arerecognized in the Horno de Cal Picada Siacutesimica andZanjoacuten Roca where the interbedded marlstones aredevoid of calcareous nannofossils Along with theoverlying dolomite bed these fossiliferous stratamake possible the correlation of the uppermost strataof the fossiliferous sector of the Roca Formation allthese horizons being probably correlated with theNP4 Zone

As a result of the correlation that was carried outamong sections a detailed stratigraphic location ofthe ldquoRocanenserdquo fauna was obtained placing it inthe NP1-NP4 zones and allowing the recognition ofthree associations related to the nannofossils zonesAccording to this biostratigraphic distribution andsimilar to what happen with other Danian sections(ie Cerros Bayos DEL RIacuteO et al 2007) in the typearea of the Roca Formation an upwards increase inthe number of recorded species is also observedgoing from 10 species in the NP1-NP2 zones to 29species in the NP4 Zone showing a gradual recoveryduring the Danian

Acknowledgements

The authors acknowledge with thanks to A MACKERN

who improved the language M TUNIK T MUSSO andR ORTIZ helped during the field work A MARCHISIO gaveus his hospitality in the city of General Roca and FTRICAacuteRICO took the SEM photographs S WEIDEMEYER SCASADIacuteO and an anonymous reviewer provided usefulcomments The present paper has been supported by theResearch Project PIP2144

References

ANGELOZZI G N (1987) Nanofoacutesiles paleocenos delNoreste de la Cuenca Neuquina Repuacuteblica Argentinandash Ameghiniana 24 (3-4) 299-307

BARRIO C A (1990) Late Cretaceous ndash Early Tertiarysedimentation in a semi-arid foreland basin (NeuqueacutenBasin western Argentina) ndash Sedimentary Geology66 255-275

BERTELS A (1964) Micropaleontologiacutea del Paleoceno deGeneral Roca ndash Revista del Museo de La Plata (nuevaserie) 4 Paleontologiacutea 23 125-184

ndash (1968a) Huantraiconella ngen (Ostracoda Buntoni-inae) del Terciario Inferior (Daniano) de Argentina ndashAmeghiniana 5 (7) 252 -256

ndash (1968b) Micropaleontologiacutea y estratigrafiacutea del liacutemiteCretaacutecico-Terciario en Huantrai-co (provincia deNeuqueacuten) Ostracoda Parte 1 ndash Ameghiniana 5 (8)279-278

ndash (1969a) Estratigrafiacutea del Liacutemite Cretaacutecico-Terciarioen Patagonia Septentrional ndash Revista de la AsociacioacutenGeoloacutegica Argentina 24 (1) 41-54

ndash (1969b) Micropaleontologiacutea y estratigrafiacutea del liacutemiteCretaacutecico-Terciario en Huantrai-co (provincia deNeuqueacuten) Ostracoda Parte 2 ndash Ameghiniana 6 (4)253-290

ndash (1970a) Los foraminiacuteferos planctoacutenicos de la CuencaCretaacutecico-Terciaria en Patagonia septentrional (Ar -gentina) con consideraciones sobre la estratigrafiacutea deFortiacuten General Roca (Provincia de Riacuteo Negro) ndashAmeghiniana 7 (1) 1-56

ndash (1970b) Hiltermannia n gen (Foraminiferiida) delCretaacutecico Superior (Maastrichtiano) de Argentina ndashAmeghiniana 7 (12) 167-172

ndash (1972) Buliminacea y Cassidulinacea (Foramini -ferida) guiacuteas del Cretaacutecico superior (Maastrichtianomedio) y Terciario inferior (Daniano inferior) de laRepuacuteblica Argentina ndash Revista Espantildeola de Micro -paleontologiacutea 4 (3) 327-353

ndash (1973) Ostracodes of the type locality of LowerTertiary (lower Danian) Rocanian Stage and RocaFormation of Argentina ndash Micropaleontology 19 (3)308-340

ndash (1974) Upper Cretaceous (lower Maastrichtian)ostracods from Argentina ndash Micropaleontology 20(4) 385-397

ndash (1975a) Harringtonia gen nov (Ostracoda Crustacea)y nuevas especies del Terciario de la RepuacuteblicaArgentina ndash Ameghiniana 12 (3) 259-279

The Maastrichtian ndash Danian at General Roca (Patagonia Argentina) 147

148 CJ del Riacuteo et al

ndash (1975b) Upper Cretaceous (middle Maastrichtian)ostracods from Argentina ndash Micropaleontology 21(1) 97-130

ndash (1980) Estratigrafiacutea y Foraminiacuteferos (Protozoa) bentoacute -nicos del liacutemite Cretaacutecico-Terciario en el aacuterea tipo dela Formacioacuten Jaguumlel Provincia de Neuqueacuten RepuacuteblicaArgentina ndash Actas 2ordm Congreso Argentino de Pale -ontologiacutea y Bioestratigrafiacutea y 1ordm Congreso Latino -americano de Paleontologiacutea (Buenos Aires 1978) 247-91

BODENBENDER G (1892) Sobre el terreno Juraacutesico yCretaacuteceo en los Andes argentinos entre el riacuteo Dia-mante y el riacuteo Limay Boletiacuten de la Academia Nacionalde Ciencias de Coacuterdoba 13 1-44

BOumlHM J (1903) Uumlber Ostreen von General Roca am RiacuteoNegro ndash Zeitschrift der Deutschen GeologischenGesellschaft 63 37-41

BOWN P (1998) Calcareous Nannofossil Biostratigraphyndash British Micropalaeontological Society PublicationSeries 314 pp London (Chapman amp Hall)

BOWN P R amp YOUNG J R (1998) Techniques ndash InBown P R (Ed) Calcareous Nannofossil Biostra -tigraphy 16-28 Dordrecht (Kluwer Academic Press)

BOWN P R amp CONCHEYRO A (2004) Lower CretaceousCalcareous Nannoplankton from the Neuquen BasinArgentina ndash Marine Micropaleontology 52 51-84

BRAMLETTE M N amp MARTINI E (1964) The greatchange in calcareous nannoplankton fossils betweenthe Maastrichtian and Danian ndash Micropaleontology10 (3) 291-322

BURCKHARDT C (1901) Le gisement supracreacutetacique deRoca (Riacuteo Negro) ndash Revista del Museo de La Plata10 207-223

BURNETT J A (1998) Upper Cretaceous ndash In BOWN P(Ed) Calcareous Nannofossil Biostratigraphy ndashBritish Micropalaeontological Society PublicationsSeries 132-199 London (Chapman amp Hall)

CAMACHO H H (1992) Algunas consideraciones acercade la transgresioacuten marina paleocena en la Argentina ndashMiscelanea de la Academia Nacional de Ciencias 851-41

CASADIacuteO S (1998) Las ostras del liacutemite Cretaacutecico-Paleoacutegeno de la Cuenca Neuquina (Argentina) Suimportancia bioestratigraacutefica y paleobiogeograacutefica ndashAmeghiniana 35 449-471

CASADIacuteO S amp CONCHEYRO A (1992) Facies y ambi-entes de sedimentacioacuten en el liacutemite Cretaacutecico ndashTerciario de La Pampa Argentina ndash Actas 3ordm Con gresoGeoloacutegico de Espantildea y 8ordm Congreso Latinoamericanode Geologiacutea 4 30-34

CASADIacuteO S GRIFFIN M PARRAS A CONCHEYRO AFELDMANN R GASPARINI Z amp PARMA G (2004)Biotic and Environmental changes across the KPboundary in Patagonia 10ordm Reunioacuten de Sedimento -logiacutea Simposio liacutemite KT de Argentina San LuiacutesActa de Resuacutemenes 187-188

CASADIacuteO S RODRIGUEZ M F REICHLER V A ampCAMACHO H H (1999) Tertiary Nautiloids fromPatagonia Southern Argentina ndash Ameghiniana 36189-202

CONCHEYRO A (1995) Nanofoacutesiles calcaacutereos del Cretaacute -cico Superior y Paleoacutegeno de Patagonia Argentina ndashTesis de Doctorado Universidad de Buenos Aires(unpublished)

ndash (2001) Nanofoacutesiles calcaacutereos del liacutemite Cretaacutecico-Paleoacutegeno de la Cuenca Neuquina Occidente deArgentina ndash 4ordm Congreso de Geologiacutea y Mineriacutea de laSociedad Cubana de Geologiacutea (digital version)

CONCHEYRO G A amp NANtildeEZ C (1994) Microfossils andbiostratigraphy of the Jaguumlel and Roca formations(Maestrichtian-Danian) Province of Nuequeacuten ndashAmeghiniana 31 (4) 397-398

CONCHEYRO G A NANtildeEZ C amp CASADIacuteO S (2002) Elliacutemite Cretaacutecico-Paleoacutegeno en Trapalco Provincia deRiacuteo Negro Argentina Una localidad clave en Ameacutericadel Sur ndash Actas 15ordm Congreso Geoloacutegico Argentino(El Calafate) 1 590-595

CONCHEYRO G A amp VILLA G (1996) Calcareous Nan-nofossils across the Maestrichtian ndash Danian of LiuMalal Section Northern Patagonia Argentina ndashPaleopelagos 6 281-297

DEL RIacuteO C J BEU A amp MARTIacuteNEZ S A (2008) ThePectinoidean genera Delectopecten STEWART 1930and Parvamussium SACCO 1897 in the Danian ofPatagonia (Argentina) ndash Neues Jahrbuch fuumlr Geologieund Palaumlontologie Abhandlungen 249 281-295

DEL RIacuteO C J CONCHEYRO A MARTIacuteNEZ S amp STIL-WELL J (2004) Macro y nanofoacutesiles de Cerros Bayos(Daniano) Cuenca Neuquina Provincia de La PampaArgentina 10ordm Reunioacuten de Sedimentologiacutea Simposioliacutemite KT de Argentina San Luiacutes Acta deResuacutemenes 190

DEL RIacuteO C J STILWELL J D CONCHEYRO A ampMARTIacuteNEZ S A (2007) Paleontology of the DanianCerros Bayos section (La Pampa Province Argentina)ndash Alcheringa 31 (3) 241-269

DOumlRING A (1882) Geologiacutea Informe oficial de laComisioacuten cientiacutefica agregada al Estado Mayor Generalde la expedicioacuten al Riacuteo Negro (Patagonia) realizada enlos meses de abril mayo y junio de 1879 bajo lasoacuterdenes del General Julio A Roca Buenos Aires1881 Entrega 3 parte 3 Buenos Aires 295-530

EDWARDS A (1963) A preparation technique for calca -reous nannoplankton ndash Micropaleontology 9 103-104

FELDMANN R M CASADIacuteO S CHIRINO-GALVEZ L ampAGUIRRE URRETA M B (1995) Fossil Decapod crus-taceans from the Jaguumlel and Roca formations (Maas-trichtian-Danian) of the Neuqueacuten Basin Argentina ndashThe Paleontological Society Memoirs 43 22 pp

FELDMANN R M amp SCHWEITZER C R (2006) Paleobio-geography of Southern Hemisphere decapod Crus-tacea ndash Journal of Paleontology 80 83-103

FOSSA-MANCINI E (1938) La ldquoCardita beaumontirdquo y laldquoCardita morganianardquo en la literatura geoloacutegicaargentina ndash Notas del Museo de La Plata 3 Paleon-tologiacutea 14 205-230

GARDIN S (2002) Late Maastrichtian to Early Daniancalcareous nannofossils at Elles (Northwest Tunisia)A tale of one million years across the K-T boundary ndashPalaeogeography Palaeoclimatology Palaeoecology178 211-231

GERTH E (1913) Stratigraphie und Bau der argentini -schen Kordillere zwischen dem Riacuteo Grande und RiacuteoDiamante ndash Zeitschrift der Deutschen GeologischenGessellschaft 65 568-575

ndash (1925) Estratigrafiacutea y distribucioacuten de los sedimentosmesozoicos en los Andes argentinos ndash Actas de laAcademia Nacional de Ciencias 9 (1) 11-55

GRIFFIN M PARRAS A amp CASADIacuteO S (2008) Maas-trichtian ndash Danian Mytilids and Pinnids (MolluskaBivalvia) from Northern Patagonia Argentina ndashAmeghiniana 45 (1) 139-152

GROEBER P (1946) Observaciones geoloacutegicas a lo largodel meridiano 70ordm I-Hoja de Chos Malal ndash Revista dela Sociedad Geoloacutegica Argentina 177-208

IHERING H V (1902) Historia de las ostras argentinas ndashAnales del Museo Nacional de Buenos Aires 7 109-123

ndash (1903) Les Mollusques des Terrains CreacutetaciquesSupeacuterieurs de lrsquoArgentine Orientale ndash Anales delMuseo Nacional de Buenos Aires 9 (serie 3) 2 193-229

ndash (1904) Nuevas observaciones sobre moluscos cretaacute -cicos y terciarios de Patagonia ndash Revista del Museo deLa Plata 11 229-243

ndash (1907) Les Mollusques fossiles du Tertiaire et duCretaceacute Supeacuterieur de lrsquoArgentine ndash Anales del MuseoNacional de Buenos Aires serie 3 14 (7) 1-611

JIANG M amp GARTNER S (1986) Calcareous nannofossilsuccession across the Cretaceous-Tertiary boundary ineast-central Texas ndash Micropaleontology 32 232-255

KELLER G ADATTE T TANTAWY A A BERNER Z ampSTUEBEN D (2007) High stress Late Cretaceous toEarly Danian paleoenvironment in the Neuquen BasinArgentina ndash Cretaceous Research 28 939-960

KIESSLING W SCASSO R ABERHAN M RUIZ L ampWEIDEMEYER S (2006) A Maastrichtian microbialreef and associated limestones in the Roca Formationof Patagonia (Neuqueacuten Province Argentina) ndash FossilRecord 9 (2) 183-197

KONNO S HARADA N NARITA H amp JORDAN R(2007) Living Braarudosphaera bigelowii (GRAN ampBRAARUD) DEFLANDRE in the Bering Sea ndash Journal ofNannoplankton Research 29 (2) 78-87

LADNER B amp WISE S (1989) Calcareous nannofossilbiostratigraphy of Upper Cretaceous to Paleocenesediments from Leg 173 Iberia Abyssal plain Sites1067-1069 ndash Proceedings of the Ocean DrillingProgram Scientific Results 173 1-50

LEANZA H A amp HUGO C A (1985) Los biohermasostreros de la Formacioacuten Roca (Paleoceno) en el sud-este de la provincia de La Pampa Argentina ndash Ame -ghiniana 2 143-149

LEGARRETA L amp GULISANO C A (1989) Analisis estrati-graacutefico secuencial de la Cuenca Neuquina (Triaacutesicosuperior ndash Terciario inferior) ndash In CHEBLI G ampSPALLETTI A (Eds) Cuencas Sedimentarias Argen -tinas 221-243

LEGARRETA L KOKOGIAN D A amp BOGGETTI D A(1989) Depositional sequences of the Malarguumle Group(Upper CretaceousndashLower Tertiary) Neuqueacuten BasinArgentina ndash Cretaceous Research 10 337-356

MAI H ROMEIN A J T amp WILLEMS H (1994) Coccos-pheres of a rare nannofossil species Biantholithus

sparsus BRAMLETTE amp MARTINI 1964 ndash MarineMicropaleontology 24 1-2

MAI H SPEIJER R amp SCHULTE P (2003) Calcareousindex nannofossils (coccoliths) of the lowermostPaleocene originated in the Late Maastrichtian ndashMicropaleontology 49 (2) 189-195

MALUMIAacuteN N (1969) First report on fossil nannoplank-ton from Neuqueacuten Argentina ndash Verhandlungen derGeologischen Bundesanstalt Sonderband 3 93

MALUMIAacuteN N ECHEVARRIacuteA A MARTIacuteNEZ MACCHIA -VELLO J amp NAacuteNtildeEZ C (1984) Los microfoacutesiles ndashActas 9ordm Congreso Geoloacutegico Argentino (SC deBariloche) Relatorio 2 485-526

MARTIacuteNEZ S DEL RIacuteO CJ amp CONCHEYRO A (2011)Danian (Early Paleocene) echinoids from the RocaFormation northern Patagonia Argentina ndash NeuesJahrbuch fuumlr Geologie und Palaumlontologie (in press)

MARTINI E (1971) Standard Tertiary and Quaternarycalcareous nannoplankton zonation ndash In FARINACCIA (Ed) Proceedings of the 2nd Planktonic Con -ference 739-785 Rome (Tecnoscienza)

NANtildeEZ C amp CONCHEYRO A (1997) El liacutemite Cretaacutecico-Paleoacutegeno ndash In Geologiacutea y Recursos Minerales delDepartamento de Antildeelo Provincia de NeuqueacutenRepuacuteblica Argentina Escala 1200000 ProyectoNacional de Cartas Geoloacutegicas de la RepublicaArgentina Anales 25 129-150

OKADA H amp BUKRY D (1980) Supplementary modi -fication and introduction of code numbers to the low-latitude coccolith biostratigraphic zonation ndash MarineMicropaleontology 5 321-325

OVECHKINA M amp ALEKSSEV A (2005) Quantitativechanges of calcareous nannoflora in the Saratov region(Russian Platform) during the late Maastrichtianwarming event ndash Journal of the Iberian Geology 31(1) 149-165

PAPU O H PRAacuteMPARO M B NANtildeEZ C amp CONCHEYROA (1999) Palinologiacutea y micropaleontologiacutea de laFormacioacuten Jaguumlel (Maastrichtiano-Daniano) perfilOpaso Cuenca Neuquina Argentina ndash Actas del Sim-posio Paleoacutegeno de Ameacuterica del Sur (Buenos Aires1996) ndash Anales del Servicio Geoloacutegico y Minero 3317-31

PARMA S G amp CASADIacuteO S (2005) Upper Cretaceous-Paleocene echinoids from Northern PatagoniaArgentina ndash Journal of Paleontology 79 1072-1087

PARRAS A M CASADIacuteO S amp PIRES M (1998) Secuen-cias depositacionales del Grupo Malarguumle y el liacutemiteCretaacutecico-Paleoacutegeno en el sur de la provincia deMendoza Argentina Simposio del Paleoacutegeno deAmeacuterica del Sur y de la peniacutensula Antaacutertica ndashAsociacioacuten Paleontoloacutegica Argentina PublicacioacutenEspecial 5 61-69

PERCH-NIELSEN K (1979) Calcareous nannofossils zona-tion at the Cretaceous-Tertiary boundary in Denmarkndash In CHRISTENSEN W K amp BIRKELUND T (Eds)Cretaceous Tertiary Boundary Events 1 115-135Copenhagen (University of Copenhagen)

ndash (1985a) Mesozoic calcareous nannofossils ndash InBOLLI H H SAUNDERS J B amp PERCH-NIELSEN K(Eds) Plankton Stratigraphy 329-426 Cambridge(Cambridge University Press)

The Maastrichtian ndash Danian at General Roca (Patagonia Argentina) 149

150 CJ del Riacuteo et al

ndash (1985b) Cenozoic Calcareous nannofossils ndash InBOLLI H H SAUNDERS J B ampPERCH-NIELSEN K(Eds) Plankton Stratigraphy 427-554 Cambridge(Cambridge University Press)

PERCH-NIELSEN K MCKENZIE J A amp HE Q (1982)Biostratigraphy and isotope stratigraphy and the ldquocata-strophicrdquoextinction of calcareous nannoplankton at theCretaceous Tertiary boundary ndash Geological Society ofAmerica Special Paper 190 353-371

POSPICHAL J amp WISE S (1990) Maestrichtian calcareousnannofossils biostratigraphy of Mand Rise ODP Leg113 Sits 689 and 690 Weddell Sea ndash Proceeding of theOcean Drilling Program Scientific Results 113 465-487

ROMEIN A J T WILLEMS H amp MAI H (1996) Calca -reous nannoplankton of the Geulhemmerberg KTboundary section Maastrichtian type area the Nether-lands ndash Geologie en Mijnbouw 75 231-238

ROSSI DE GARCIA E amp LEVY R (1984) Megafaunas deinvertebrados terciarios 9ordm Congreso Geoloacutegico Ar -gentino Relatorio 2 (6) 467-484

ROTH S (1899) Apuntes sobre la geologiacutea y la paleon-tologiacutea de los territorios del Riacuteo Negro y NeuqueacutenReconocimiento de la regioacuten andina de la RepuacuteblicaArgentina ndash Revista del Museo de La Plata 9 141-197

ROTH P H amp THIERSTEIN H (1972) Calcareous nanno-plankton Leg 14 of the Deep Sea Drilling Project 14421-485

SCHILLER W (1922) Los sedimentos marinos del liacutemiteentre el Cretaacuteceo y Terciario de Roca en la Patagoniaseptentrional ndash Revista del Museo de La Plata 26(serie 3) 2 256-280

SCASSO R CONCHEYRO A KIESSLING W ABERHAMM HECHT L MEDINA F amp TAGLE R (2005) Atsunami deposit at the Cretaceous-Tertiary boundaryin the Neuqueacuten Basin of Argentina ndash CretaceousResearch 26 283-297

THIBAULT N amp GARDIN S (2006) Maastrichtian calca -reous nannofossil biostratigraphy and paleoecology inthe Equatorial Atlantic (Demerara Rise ODP Leg 207Hole 1258A) ndash Revue de Micropaleacuteontologie 49199-214

THIERSTEIN H (1980) Selective dissolution of LateCretaceous and Earliest Tertiary nannofossils Ex -perimental evidence ndash Cretaceous Research 2 165-179

TUNIK M A CONCHEYRO A OTTONE EG amp AGUIRRE

URRETA B (2004) Paleontologiacutea de la FormacioacutenSaldentildeo (Maastrichtiano) Alta Cordillera de MendozaArgentina ndash Ameghiniana 41 (2) 143-160

ULIANA M (1975) Geologiacutea de la regioacuten comprendidaentre los riacuteos Colorado y Negro Provincias deNeuqueacuten y Riacuteo Negro ndash Tesis Doctoral UniversidadNacional de La Plata (unpublished)

ULIANA M amp DELLAPEacute D (1981) Estratigrafiacutea y Evo -lucioacuten paleoambiental de la sucesioacuten Maestrichtiano-Eoterciaria del Engolfamiento Neuquino (PatagoniaSeptentrional) ndash Actas 8ordm Congreso Geoloacutegico Argen -tino 3 673-711

VAN HECK S E amp PRINS B (1987) A refined nanno-plankton zonation for the Danian of the Central NorthSea ndash Abhandlungen der Geologischen Bundesanstalt39 285-303

VAROL O (1998) Paleogene ndash In BOWN P R (Ed)Calcareous Nannofossil Biostratigraphy 200-224Dordrecht (Kluwer Academic Press)

WEAVER C E (1927) The Roca Formation in Argentinandash American Journal of Science series 5 12 417-434

ndash (1931) Paleontology of the Jurassic and Cretaceous ofWest Central Argentine ndash University of WashingtonMemoirs 1 82-89

WEBER E I (1964) Estudio geoloacutegico de General RocaTesis de Doctorado en Ciencias Naturales Universidadde Buenos Aires ndash 149 pp (unpublished)

WICHMANN R (1924) Nuevas observaciones geoloacutegicasen la parte oriental del Neuqueacuten y en el territorio delRiacuteo Negro ndash Publicacioacuten de la Direccioacuten General deMinas Geologiacutea e Hidrologiacutea 2 (Geologiacutea) 3-22

WIND F H (1979) Maastrichtian-Campanian nannofloralprovinces of the southern Atlantic and Indian Oceansndash In TALWANI M HAY W W amp RYAN W B F(Eds) Results of Deep Drilling in the Atlantic OceansContinental margins and paleoenvironments ndash Ameri-can Geophysic Union Maurice Ewing series 3 123-137

WIND F H amp WISE S (1976) Jurassic to Holocenecalcareous nannofossils from the Falkland (Malvinas)Plateau ndash Antarctic Journal of United States 11 (3)169-171

WINDHAUSSEN A (1914) Contribucioacuten al conocimientogeoloacutegico de los territorios del Riacuteo Negro y Neuqueacutenndash Anales del Ministerio de Agricultura SeccioacutenGeologiacutea Mineralogiacutea y Mineriacutea 10 (1) 9-60

Manuscript received July 3rd 2009Revised version accepted by the Stuttgart editor Novem-ber 26th 2009

Addresses of the authors

CLAUDIA J DEL RIacuteO Museo Argentino de CienciasNaturales B Rivadavia A Gallardo 470 C1405DJRBuenos Aires Argentinae-mail cdelriomacngovar

ANDREA CONCHEYRO Facultad de Ciencias Exactas yNaturalese-mail andreafcenubaar

SERGIO A MARTIacuteNEZ Instituto de Geologiacutea y Paleon-tologiacutea Facultad de Ciencias - Iguaacute 4225 11400 Monte -video Uruguaye-mail smartfcieneduuy

The Maastrichtian ndash Danian at General Roca (Patagonia Argentina) 151

Table 1 Cantera Cholino ndash Calcareous nannofossil range chart

Table 2 Picada Siacutesmica ndash Calcareous nannofossil range chart

152 CJ del Riacuteo et al

Table 3 Cerro Tres Picos ndash Calcareous nannofossil range chart

Table 4 Horno de Cal (Type section of the Roca Formation) ndash Calcareous nannofossil range chart

The Maastrichtian ndash Danian at General Roca (Patagonia Argentina) 153

Table 3 Cerro Tres Picos ndash Calcareous nannofossil range chart Cont

Table 4 Horno de Cal (Type section of the Roca Formation) ndash Calcareous nannofossil range chart Cont

Appendix

Taxonomic list A full list of all taxa cited in the rangecharts Most bibliographic references can be found inPERCH-NIELSEN (1985a b) and BOWN (1998)

Ahmuellerella octoradiata (GOacuteRKA 1957) REINHARDT

1966Acuturris scotus (RISATTI 1973) WIND amp WISE in WISE ampWIND (1977)Ahmuellerella regularis (GOacuteRKA 1957) REINHARDT ampGOacuteRKA 1967Arkhangelskiella cymbiformis VEKSHINA 1959Arkhangelskiella maastrichtiana BURNETT 1997aBiantholithus sparsus BRAMLETTE amp MARTINI 1964Biscutum constans (GORKA 1957) BLACK in BLACK ampBARNES (1959)Biscutum melaniae (GOacuteRKA 1957) BURNETT 1997Biscutum notaculum WIND amp WISE in WISE amp WIND 1977Braarudosphaera bigelowii (GRAN amp BRAARUD 1935)DEFLANDRE 1947

Chiasmolithus danicus (BROTZEN 1959) HAY amp MOHLER

1967Chiastozygus garissoinii BUKRY 1969Chiastozygus ultimus PERCH-NIELSEN 1981Coccolithus pelagicus (WALLICH 1871) SCHILLER 1930 Cretarhabdus conicus BRAMLETTE amp MARTINI (1964)Cribrosphaerella daniae PERCH-NIELSEN (1973)Cribrosphaerella ehrenbergii (ARKHANGELSKY 1912)DEFLANDRE in PIVETEAU (1952)Cruciplacolithus primus PERCH-NIELSEN 1977Cruciplacolithus tenuis STRADNER 1961) HAY amp MOHLER

in HAY et al 1967Cyclagelosphaera margerelii NOEumlL (1965)Cyclagelosphaera reinhardtii (PERCH-NIELSEN 1968)ROMEIN 1977Eiffellithus gorkae REINHARDT 1965Eiffellithus parallelus PERCH-NIELSEN 1973Eiffellithus turriseiffelii (DEFLANDRE in DEFLANDRE ampFERT 1954) REINHARDT (1965)Gartnerago segmentatum (STOVER 1966) THIERSTEIN

1974

Table 5 Zanjoacuten Roca ndash Calcareous nannofossil range chart

154 CJ del Riacuteo et al

Appendix Cont

Hornibrookina edwardsii PERCH-NIELSEN 1977Hornibrookina teuriensis EDWARDS 1973Kamptnerius magnificus DEFLANDRE 1959Lanthernithus duocavus LOCKER 1967Lithraphidites carniolensis DEFLANDRE 1963Lithraphidites quadratus BRAMLETTE amp MARTINI 1964Lucianorhabdus cayeuxii DEFLANDRE (1959)Manivitella pemmatoidea (DEFLANDRE in MANIVIT 1965)THIERSTEIN 1971Markalius apertus PERCH-NIELSEN (1979b)Markalius inversus (DEFLANDRE in DEFLANDRE amp FERT

1954) BRAMLETTE amp MARTINI 1964Micrantholithus pinguis BRAMLETTE amp SULLIVAN 1961Micrantholithus vesper DEFLANDRE in DEFLANDRE ampFERT 1954Microrhabdulus decoratus DEFLANDRE 1959Micula concava (STRADNER in MARTINI amp STRADNER

1960) VERBEEK 1976Micula decussata VEKSINA (1959)

Micula murus (MARTINI 1961) BUKRY 1973Micula swastica STRADNER amp STEINMETZ 1984Nannoconus circularis DEacuteRES amp ACHERITEacuteGUY 1980Neochiastozygus modestus PERCH-NIELSEN 1971Neochiastozygus perfectus PERCH-NIELSEN 1971Neochiastozygus primitivus PERCH-NIELSEN 1981Neocrepidolithus cruciatus ( PERCH-NIELSEN 1979)PERCH-NIELSEN 1981Neocrepidolithus dirimosus ( PERCH-NIELSEN 1979)PERCH-NIELSEN 1981Nephrolithus frequens GOacuteRKA 1957Nodosella elegans PERCH-NIELSEN 1981Octolithus multiplus (PERCH-NIELSEN 1973) ROMEIN 1979Placozygus sigmoides (BRAMLETTE amp SULLIVAN 1961)ROMEIN 1979Prediscosphaera cretacea (ARKHANGELSKY 1912) GART-NER 1968Prediscosphaera spinosa (BRAMLETTE amp MARTINI 1964)GARTNER 1968Prediscosphaera stoveri (PERCH-NIELSEN 1968) SHAFIK ampSTRADNER 1971

The Maastrichtian ndash Danian at General Roca (Patagonia Argentina) 155

Table 5 Zanjoacuten Roca ndash Calcareous nannofossil range chart Cont

156 CJ del Riacuteo et al

Table 6 Stratigraphic distribution of recorded ldquoRocanenserdquo fauna in the studied sections of the Roca Formation in thetype area ( taxa described by IHERING (1902 1903 1907) and recognized in the present analysis)

Appendix Cont

Retecapsa crenulata (BRAMLETTE amp MARTINI 1964) GRUumlN

in GRUumlN amp ALLEMANN 1975Retecapsa surirella (DEFLANDRE amp FERT 1954) GRUumlN inGRUumlN amp ALLEMANN 1975Rhagodiscus angustus (STRADNER 1963) REINHARDT 1971Rhagodiscus reniformis PERCH-NIELSEN 1973Rhagodiscus splendens (DEFLANDRE 1953) VERBEEK 1977Staurolithites mielnicensis (GORKA 1957) PERCH-NIELSEN

(1968) sensu CRUX in LORD (1982)Thoracosphaera operculata BRAMLETTE amp MARTINI 1964Thoracosphaera saxea STRADNER 1961Toweius africanus (PERCH-NIELSEN 1981) PERCH-NIELSEN

1984

Watznaueria barnesiae (BLACK 1959) PERCH-NIELSEN

1968Watznaueria biporta BUKRY 1969Watznaueria britannica (STRADNER 1963) REINHARDT

1964Watznaueria fossacincta (BLACK 1971) BOWN in BOWN ampCOOPER 1989Watznaueria ovata BUKRY 1969Zeugrhabdotus diplogrammus (DEFLANDRE in DEFLANDRE

amp FERT 1954) BURNETT in GALE et al 1996Zeugrhabdotus embergeri (NOEumlL 1958) PERCH-NIELSEN

1984Zygodiscus spiralis BRAMLETTE amp MARTINI 1964