Carboniferous Fauna of the Krkono‰e Piedmont Basin Karbonská fauna podkrkono‰ské pánve Jaroslav Zajíc Institute of Geology, Academy of Sciences of the Czech Republic, v.v.i., Rozvojová 269, 165 00 Praha 6 - Lysolaje, Czech Republic. [email protected]Abstract:The complete faunal list has been completed for the Upper Carboniferous lake deposits of the Krkono‰e Piedmont Basin. Fauna-bearing sites and boreholes of the PlouÏnice lake are divided into two main areas and two subareas on the basis of their sedimentary facies and faunal content. Stratigraphy and inter-basin correlations are discussed. Key words: faunal list, palaeogeography, palaeoenvironment, stratigraphy, Upper Carboniferous, Bohemian Massif. ACTA MUSEI REGINAEHRADECENSIS S. A., 32 (2007): 11-16 ISBN: 978-80-85031-73-7 11 INTRODUCTION The Krkono‰e Piedmont Basin (Fig. 2) belongs to a system of post-orogenic extensional/transitional basins which formed in the Bohemian Massif (Fig. 1) in the early post-orogenic phase (Martínek et al. 2006). Northern and southern regions of the basin often differ in their litholo- gical development. The main Permo-Carboniferous fossil- bearing strata of the Krkono‰e Piedmont Basin were tra- ditionally called horizons until recently. The nature of the main ones (such as the PlouÏnice, Rudník, and Kalná Horizons) is, however, totally different. Their usual thick- ness of several tens of meters suggests that they represent members, not horizons. Recent papers concerning the Per- mian sediments referred to “horizons”, such as the Kalná Lake deposits (Blecha, Martínek & Mihaljeviã 1999) or the Rudník Member (Martínek et al. 2006). This paper uses the term “lake deposits” because no exact definitions of members have been provided yet for the Carboniferous “horizons” of the Krkono‰e Piedmont Basin. For a sim- plified geological map of the basin, see Fig. 2. Carbonife- rous sediments of the basin are divided into three sections – the Kumburk, Syfienov, and Semily Formations (see Fig. 3). No fauna has been reported from the Kumburk For- mation. The generally known fauna of the Syfienov For- mation still comes from the Lt-1 Lib‰tát borehole but its significance for stratigraphic correlation with other basins of the Czech Republic is substantial. The richest fauna (in both specimens and taxa) is known from the youngest Carboniferous. This paper was prepared within the IGCP project 491 - Middle Palaeozoic Vertebrate Biogeography, Palaeoge- ography, and Climate. Herein presented data concerning the Gzhelian age are mostly based on the unpublished final report (Blecha et al. 1997) of the grant project No. 205/94/0692 (Environmental changes on the Carbonife- rous/Permian boundary and their impact on the assem- blages of organisms in fossiliferous horizons in the Krkono‰e Piedmont Basin ) of the Czech Science Foun- dation. Other data were summarized and shortly publis- hed by Zajíc in Pe‰ek et al. (2001) as a result of the grant project No. 205/96/1231 (Origin and sedimentary filling of the limnic Permo-Carboniferous basins in the Bohe- mian Massif) supported by the same grant agency. Recent investigations (e. g. ·tamberg 2001) yielded additional or corrected data. The fauna-bearing localities and boreholes are supple- mented with sheets of maps 1: 25,000 in parentheses. No faunal remains come from the Kumburk Formation yet. The Syfienov Formation The Lower Syfienov Formation, Kasimovian (Stepha- nian B) The only known fauna of this section comes from the lowermost part of the formation. The lacustrine origin of these sediments is assumed. No fauna is known from the overlying Syfienov Coal Seams. Fig. 1. Location of the Krkono‰e Piedmont Basin (black, simplified) in the Czech Republic (dash-and-dot line) and in the Bohemian Massif (continuous line).
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Carboniferous Fauna of the Krkonoše Piedmont Basin
The complete faunal list has been completed for the Upper Carboniferous lake deposits of the Krkonoše Piedmont Basin. Fauna-bearing sites and boreholes of the PlouÏnice lake are divided into two main areas and two subareas on the basis of their sedimentary facies and faunal content. Stratigraphy and inter-basin correlations are discussed.
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Carboniferous Fauna of the Krkono‰e Piedmont Basin
Karbonská fauna podkrkono‰ské pánve
Jaroslav Zajíc
Institute of Geology, Academy of Sciences of the Czech Republic, v.v.i., Rozvojová 269, 165 00 Praha 6 - Lysolaje, Czech Republic. [email protected]
Abstract:The complete faunal list has been completed for the Upper Carboniferous lake deposits of the Krkono‰e Piedmont Basin. Fauna-bearingsites and boreholes of the PlouÏnice lake are divided into two main areas and two subareas on the basis of their sedimentary facies and faunal content.Stratigraphy and inter-basin correlations are discussed.
K e y w o r d s : faunal list, palaeogeography, palaeoenvironment, stratigraphy, Upper Carboniferous, Bohemian Massif.
ACTA MUSEI REGINAEHRADECENSIS S. A., 32 (2007): 11-16 ISBN: 978-80-85031-73-7
11
INTRODUCTION
The Krkono‰e Piedmont Basin (Fig. 2) belongs to asystem of post-orogenic extensional/transitional basinswhich formed in the Bohemian Massif (Fig. 1) in the earlypost-orogenic phase (Martínek et al. 2006). Northern andsouthern regions of the basin often differ in their litholo-gical development. The main Permo-Carboniferous fossil-bearing strata of the Krkono‰e Piedmont Basin were tra-ditionally called horizons until recently. The nature of themain ones (such as the PlouÏnice, Rudník, and KalnáHorizons) is, however, totally different. Their usual thick-ness of several tens of meters suggests that they representmembers, not horizons. Recent papers concerning the Per-mian sediments referred to “horizons”, such as the KalnáLake deposits (Blecha, Martínek & Mihaljeviã 1999) orthe Rudník Member (Martínek et al. 2006). This paperuses the term “lake deposits” because no exact definitionsof members have been provided yet for the Carboniferous“horizons” of the Krkono‰e Piedmont Basin. For a sim-plified geological map of the basin, see Fig. 2. Carbonife-rous sediments of the basin are divided into three sections– the Kumburk, Syfienov, and Semily Formations (see Fig.3). No fauna has been reported from the Kumburk For-mation. The generally known fauna of the Syfienov For-mation still comes from the Lt-1 Lib‰tát borehole but itssignificance for stratigraphic correlation with other basinsof the Czech Republic is substantial. The richest fauna (inboth specimens and taxa) is known from the youngestCarboniferous.
This paper was prepared within the IGCP project 491- Middle Palaeozoic Vertebrate Biogeography, Palaeoge-ography, and Climate. Herein presented data concerningthe Gzhelian age are mostly based on the unpublishedfinal report (Blecha et al. 1997) of the grant project No.205/94/0692 (Environmental changes on the Carbonife-rous/Permian boundary and their impact on the assem-
blages of organisms in fossiliferous horizons in theKrkono‰e Piedmont Basin ) of the Czech Science Foun-dation. Other data were summarized and shortly publis-hed by Zajíc in Pe‰ek et al. (2001) as a result of the grantproject No. 205/96/1231 (Origin and sedimentary fillingof the limnic Permo-Carboniferous basins in the Bohe-mian Massif) supported by the same grant agency.Recent investigations (e. g. ·tamberg 2001) yieldedadditional or corrected data.
The fauna-bearing localities and boreholes are supple-mented with sheets of maps 1: 25,000 in parentheses. Nofaunal remains come from the Kumburk Formation yet.
The Syfienov Formation
The Lower Syfienov Formation, Kasimovian (Stepha-nian B)
The only known fauna of this section comes from thelowermost part of the formation. The lacustrine origin ofthese sediments is assumed. No fauna is known from theoverlying Syfienov Coal Seams.
Fig. 1. Location of the Krkono‰e Piedmont Basin (black, simplified) inthe Czech Republic (dash-and-dot line) and in the Bohemian Massif(continuous line).
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Fig
. 2.A
sim
plifi
ed g
eolo
gica
l map
of t
he K
rkon
o‰e
Pie
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t Bas
in (
base
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Ble
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97;
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f the
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Num
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.
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Locality:* Lt-1 Lib‰tát borehole (03-413 Semily); depth 860.60 m;
(Zajíc 1986, Zajíc in Blecha et al. 1997) Elonichthys sp.(scales)
The Black Shales Lake Deposits of the Upper Forma-tion, Gzhelian (Stephanian B)
The thickness of the deposits is 13–23 m (Prouza &Tásler in Pe‰ek et al. 2001). The finely laminated deep-water claystones were sedimentologically paralleled withthe M‰ec Member (Central and Western BohemianBasins) and the Jívka Member (Intra-Sudetic Basin) bySkoãek (1990). The correlation with the large and deepM‰ec Lake is in accordance with the faunal content. Areinterpretation of the determinable actinopterygian scalesfrom the Lt-1 Lib‰tát borehole was made by Zajíc inPe‰ek et al. (2001)
795.10–807.25 m; (Zajíc 1986; Zajíc in Blecha et al.1997, Zajíc in Pe‰ek et al. 2001) Spinarichthys dispersus(scales); Zaborichthys fragmentalis (scales); Elonichthyssp. (scales); Actinopterygii indet. (scales, teeth)
The Semily Formation
Lacustrine deposits of the Middle Semily Formationare represented by two different facies (see chapter Palae-ogeography of the PlouÏnice Lake).
·tûpanice-âikvásky Lake Deposits (northern area ofthe basin), Gzhelian (Stephanian C)
Member is formed by two or three intervals of a com-plete thickness of 95–130 m including intercalated strata(Prouza & Tásler in Pe‰ek et al. 2001). Coal seams are
locally present. For the location of the adits see Havlena(1957, Fig. 2).
Localities:* HK-1 Horní Kalná borehole (03-413 Semily); depth
899.15 m; (Zajíc 1984; Zajíc 1989; Zajíc in Blecha et al.1997)
The PlouÏnice Lake extended over almost the wholearea of the Krkono‰e Piedmont Basin (about 150 km2) andprobably reached to the Mnichovo Hradi‰tû Basin (Tásler& Prouza 1985). The known fauna-bearing sites are divi-ded into two main areas (see Fig. 2) each with one loca-lity with somewhat different development. The sedimen-tary facies were established by Blecha & Martínek in Ble-cha et al. (1997).
·tûpanice-âikvásky area (northern part of thebasin)
The presence of suboxic and anoxic offshore facies (greyand blackish grey finely laminated mudstones and organic-rich carbonates), conglomerates, and sandstones are charac-teristic for the northern part of the basin. A relatively deeplake and a steeper gradient of the bottom are assumed here.The paludal nearshore conditions (swamps) and the waterlevel oscillation induced the origin of thin coal seams.
Fauna of this area comes from dark grey siltstones,dark grey laminated mudstones and blackish grey finelylaminated mudstones with coal laminae. Disarticulation ofthe fish remains together with the type of sedimentationcorrespond to the hypolimnion of a shallower stratifiedlake. The insect remains found at some sites possibly indi-cate a relative proximity of the lake shore.
The HK-1 Horní Kalná borehole lies at a considerablydistance from other sites of the northern area. Disarticulated
15
fish remains from the blackish grey laminated claystoneevidence poorly aerated water conditions near the bottom.
PlouÏnice area (southern part of the basin)The southern part of the basin has a platform-like cha-
racter with a low gradient. The plain relief induced consi-derable lateral variations of sedimentary conditions.
The facies of the brown mudstone with traces of lami-nation (typically in section PlouÏnice A) indicates condi-tions of a shallow lake with relatively well aerated waternear the bottom (an epilimnion of a stratified lake).
The facies of the purplish brown or grey finely lamina-ted mudstone (typically in section PlouÏnice C) indicateslacustrine environment with well aerated water near thebottom.
Tetrapod footprints from the facies of the grey lamina-ted siltstone (Kyje) indicate temporary terrestrial conditi-ons.
The site of Nová Paka – aerodrome yielded commonconchostracans together with insect wing remains. Thisassociation suggests a shallower epilimnion of a stratifiedlake close to the shoreline. Abundant conchostracans pos-sibly imply repeated episodes of eutrophication. Theseconditions indicate a shallow embayment.
STRATIGRAPHIC NOTES
The fish local biozonation (Zajíc 2000, 2004) waslabelled by Lucas, Schneider & Cassinis (2006) as alocal ecostratigraphy of some Bohemian basins. Somefeatures of ecostratigraphy are unquestionable, and thelocal character of the biozonation was always pointedout. Some significant taxa (notably Elonichthys andSphaerolepis) are, however, found in various lake faciesof the Stephanian basins of the Bohemian Massif. Com-mon remains of these taxa are known from the depositsof the deep, shallow or paludal lakes. The occurrences ofthese taxa did not depend on the predominant oxygena-tion of the water near the lake bottom either. Both oxicand anoxic conditions show similar actinopterygianassociations.
The correlation between the Central and WesternBohemian Basins and the Krkono‰e Piedmont Basinshows differences from the conception of Roscher &Schneider (2005; Fig. 2) in my opinion. The MiddleSemily Formation (the PlouÏnice Lake) is well corre-lable with the lower part of the Línû Formation (Klobukyand Zdûtín Lakes) on the basis of both sedimentologyand bio/eco zonation.
SOUHRN
Je podán kompletní seznam fauny svrchnokarbonsk˘chjezerních uloÏenin podkrkono‰ské pánve. Lokality a vrtys faunou jsou na základû sedimentárních facií a fauny roz-dûleny do dvou hlavních oblastí a dvou podoblastí. Je dis-kutována stratigrafie a mezipánevní korelace.
REFERENCES
BLECHA M. et al. (1997): Zmûny prostfiedí na rozhraní karbonu a
permu a jejich dopad na spoleãenstva organismÛ ve fosiliferních
obzorech podkrkono‰ské pánve. - Závûreãná zpráva za grant GA âR,
âesk˘ geologick˘ ústav, MS, 1-177. Praha.
BLECHA M., MARTÍNEK K. & MIHALJEVIâ M. (1999): Paleoenvi-
ronmental changes of the semipermanent Kalná Lake (Lower Per-
mian), Krkono‰e Piedmont Basin, Czech Republic: sedimentary and
geochemical record. – Acta Universitatis Carolinae, Geologica, 43, 4,
657-665. Praha.
FRIâ A. (1912): Studien im Gebiete der Permformation Böhmens. –
Archiv für die naturwissenschaftliche Landesdurchforschung Böh-
mens, 15, 2, 1-52. Prag.
FRITSCH A. (1901): Fauna der Gaskohle und der Kalksteine der Perm-
formation Böhmens. IV/3. - F. ¤ivnáã, 63-101. Prag.
HAVLENA V. (1957): Petrografie uhlí podkrkono‰ského permokarbonu
a poznámky k jeho geologii. – Sborník Ústfiedního ústavu geologic-
kého, Oddíl geologick˘, 24, 157-188.
LUCAS S. G., SCHNEIDER J. W. & CASSINIS G. (2006): Non-marine
Permian biostratigraphy and biochronology: an introduction. - In S.
G. Lucas, G. Gassinis & J. W. Schneider (eds): Non-Marine Permian
Biostratigraphy and Biochronology. – Geological Society, London,
Special Publications, 265, 1-14. London.
KAMARÁD L. (1951): Revise ãesk˘ch permokarbonsk˘ch Pseudesthe-