BazTech - Yadda

1

New dimorphic species of the genus Rollierites Jeannet from southern Poland

Jain Sreepat, Mazur Marek

Annales Societatis Geologorum Poloniae

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2021

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Vol. 91, No. 4

405--418

EN

A new ammonite assemblage from the lower beds of the Ogrodzieniec Quarry (southern Poland), the only Callovian section in the middle part of the Polish Jura Chain, is described. It includes the presence of Kosmoceras rotundum (Quenstedt), followed by the first example of co-occurring micro- and macroconchs in the genus Rollierites (R. biplicatum sp. n.) and above it, the association of Euaspidoceras sp. and Peltoceratoides (Parawedekindia) gerberi Prieser. Both R. biplicatum sp. n. (m and M; microconch and macroconch) and K. rotundum are assigned to the late Callovian Lamberti Zone. P. (P.) gerberi characterizes the early Oxfordian Cordatum Zone. This is the first record of the genus Rollierites from Poland. This study extends the upper age limit of the middle Callovian Rollierites up to the late Callovian Lamberti Zone. On the basis of morphological and stratigraphical data, it is tentatively proposed that the origin of the early–middle Oxfordian Tornquistes may be in the middle–late Callovian Rollierites, rather than the previously proposed late Callovian Pachyceras. However, this is speculation, as the present data set is insufficient.

2

Pseudosonninia, a new genus of oppeliid ammonite (Haploceratoidea) from the Callovian (Middle Jurassic) of the Neuquén Basin, Argentina

Parent Horacio, Garrido Alberto C., Schweigert Günter, Brambilla Luciano

Volumina Jurassica

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2019

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Vol. 17, no. 1

39--48

EN

From the uppermost part of the Los Molles Formation (upper Lower and lower Middle Callovian) in Chacay Melehué (Neuquén Province, Argentina), a group of hecticoceratine ammonites with a conspicuous morphology not assimilable to any known genus of this subfamily has been recently discovered. These forms are inflated oxycones with a prominent, sharp keel developed from the juvenile phragmocone up to the adult peristome. The new genus Pseudosonninia is established on the basis of these ammonites, with Pseudosonninia chacaymelehuensis n. gen. n. sp. as its type species. The new genus seems to be endemic to the Neuquén Basin and is recorded here from the upper Lower and lower Middle Callovian of Chacay Melehué and Río de Los Patos.

3

Detailed biostratigraphy of the Middle Callovian – lowest Oxfordian in the Mikhaylov reference section (Ryazan region, European part of Russia) by ammonites

Kiselev D. N., Rogov M. A.

Volumina Jurassica

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2018

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Vol. 16, no 1

73--186

EN

Study of the sections near the Mikhaylov (Ryazan region) has made it possible to improve the infrazonal subdivision of the Middle Callovian – Lower Oxfordian of the European Russia by ammonites. The Athleta Zone is the most complete in the studied sections. A sequence of kosmoceratid biohorizons (phaeinum, proniae, rowlstonense and kuklikum) is established here, as well as infrazonal units based on a phylogenetic sequence of species of the genus Funiferites. A study of the paleobiodiversity and frequency of occurrence of ammonites at different intervals of the section showed that the ammonite assemblages of the Athleta Zone are Sub-Boreal or Sub-Tethyan, while in the Lamberti Zone they are Boreal, and in the Lower Oxfordian they are Arctic. It is also shown that the change in ammonite composition in the sections coincides with the cycles of transgressions and regressions of Boreal basins. New species and subspecies of the ammonites Funiferites allae compressum, Cadoceras (Eichwaldiceras) intermedium, Brightia (B.) lominadzei, B. (B.) progzhellensis, B. (B.) eccentrtica, B. (Glyptia) canaliculata stankevitchae, Zieteniceras rarecostatum are described.

4

Crinoids (Crinoidea, Echinodermata) from the Middle Jurassic (Callovian) of eastern Poland : a case study from the Żebrak IG 1 borehole

Salamon M. A., Feldman-Olszewska A.

Annales Societatis Geologorum Poloniae

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2018

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Vol. 88, No. 3

273--283

EN

A taxonomic account of the Callovian crinoid fauna from the Żebrak IG 1 borehole (eastern Poland) is presented. The assemblage contains numerous isocrinid ossicles (Isocrinidae) assigned to the following taxa: Isocrinus cf. nicoleti (Desor), Isocrinus sp., Chariocrinus andreae (Desor), Balanocrinus cf. subteres (Münster in Goldfuss) and Pentacrinites sp. These isocrinids are associated with a few ossicles of cyrtocrinids (Cyrtocrinida; Cyrtocrinida indet.). The crinoid remains are poorly preserved; they all are isolated ossicles, showing broken margins and/or abraded surfaces. Such a state of preservation documents a long distance of transportation and/or re-deposition in a high-energy, shallow-water setting. The crinoid assemblage differs significantly from those of southern Poland (the Polish Jura Chain and the Mesozoic margin of the Holy Cross Mountains), in which sessile crinoids, such as cyrtocrinids (Cyrtocrinida), inhabiting mostly deeper-water carbonate facies, are predominant.

5

The ammonite faunas of the Callovian-Oxfordian boundary interval in Europe and their relevance to the establishment of an Oxfordian GSSP

Page K., Melendez G., Wright J.

Volumina Jurassica

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2009

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Vol. 7, no. 1

89-99

EN

At Moenkopi Wash along the Ward Terrace escarpment of northern Arizona strata of the upper Dinosaur Canyon Member of the Moenave Formation contain sedimentary structures we interpret as casts of tetrapod burrows. Sandstone casts and in situ burrows occur concentrated in two horizons that extend several hundred meters along the Ward Terrace escarpment. The structures, hosted in beds of eolian sandstone, form interconnecting networks of burrows that branch at right angles. Individual burrow casts have sub-circular cross sections and consist of nearvertical tunnels and horizontal to low-angle galleries that connect to larger chambers. Most burrow casts measure 5 to 15 cm in diameter, are filled by sandstone of similar grain size as the host rock, and have walls that are unlined and lack external ornamentation. Bedding plane exposure of the lower horizon reveals that the density of burrows exceeds 30 vertical tunnels per square meter. One exposure in the upper horizon reveals burrows concentrated in a mound-like structure with 1 m of relief. Rhizoliths, distinguished from burrows by their typical smaller diameters, calcareous infilling, and downward branching, co-occur with these burrows in the upper horizon. The fossil burrows in the Moenave Formation appear to have been constructed by a fossorial tetrapod with social behavior similar to the modern Mediterranean blind mole-rat. Although no skeletal remains are associated with the burrows, the fossil record suggests that the most likely producers of the Moenave burrows were tritylodontid cynodonts.

6

The ammonite faunas of the Callovian/Oxfordian boundary interval in Europe and their relevance to the establishment of an Oxfordian GSSP

Melendez G., Page K., Wright J., Atrops F.

Volumina Jurassica

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2006

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Vol. 4, no. 1

185-185

EN

The latest Callovian and Early Oxfordian represent one of the most dynamic intervals in the history of Jurassic Ammonoidea and is characterized by one of the highest levels of mixing of Boreal, Submediterranean and even Mediterranean faunas. In particular the massive expansion of Boreal Cardioceratidae from their original “home” in Arctic areas as far south as South East France, brings them into contact with Mediterranean-style faunas rich in Phylloceratidae. This so-called “Boreal Spread” (after J. H. Callomon) provides the framework within which high-resolution inter-bioprovincial correlations are possible and hence the context for a sucessful GSSP designation for the base of the Oxfordian Stage within Europe (and hence the beginning of the Upper Jurassic). Associated with the Cardioceratidae, however, is a great variety of Perisphinctina, including Aspidoceratidae, Periphinctidae, Grossouvridae and rarer Pachyceratidae as well as frequent Hecticoceratidae and rarer Phylloceratidae. The latter groups are much more abundant in southern areas (Tethyan Realm), but the Aspidoceratidae do persist well into the Boreal Realm. Crucially, several groups of the Perisphinctina persist beyond Europe and therefore provide tantalising indications that a truly global correlation of any GSSP established in Europe will ultimately be possible. The current paper will review the stratigraphical, taxonomic and palaeobiogeographical context and significance of the trans Callovian/Oxfordian boundary faunas within Europe, building on recent results from the UK and France. Conclusions will be drawn concerning the appropriate – or convenient – level at which the place the Callovian-Oxfordian in Europe and its potential interpretation elsewhere. Such conclusions are highly relevant to the eventual establishment of an Oxfordian GSSP.

7

Integrated stratigraphical study of the candidate Oxfordian Global Stratotype Section and Point (GSSP) at Redcliff Point, Weymouth, Dorset, UK

Page K., Melendez G., Hart M., Price G., Wright J., Bown P., Bello J.

Volumina Jurassica

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2006

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Vol. 4, no. 1

200-201

EN

Redcliff Point near Weymouth, Dorset (SW England) exposes one of Europe’s most complete Callovian-Oxfordian boundary sequences and has been the subject of a rigorous multidisciplinary assessment. The boundary sequence lies entirely within the clay facies of the Oxford Clay Formation, the relatively high carbonate content of which facilitates the excellent preservation of both macro- and microfaunas (and floras) as well as geochemical information. Ammonites, in particular, are conspicuous, and partly retain an aragonitic shell. By convention, the stage boundary is drawn at the first occurrence of the genus Cardioceras, which has been interpreted as corresponding to the transition between “Quenstedtoceras” paucicostatum (Lang) and Cardioceras ex gr. scarburgense (Young and Bird), specifically at the first occurrence of C. woodhamense Arkell sensu Callomon (non Marchand). This transition is well seen at Redcliff and provides the primary means through which the boundary can be correlated. Associated Perisphinctina (including Peltoceras, Alligaticeras, Properisphinctes and Euaspidoceras) provide additional biostratigraphical information. Other macrofossil groups show less discernible changes, although the end of the Callovian in England marks the local, virtual disappearance of Boreal cylindroteuthid belemnites with the persistence of Tethyan hibolithids into the Early Oxfordian. Isotopic studies of recovered belemnites record important information on carbon and strontium isotopes and provide new, high resolution data for the refinement of the global curves. The isotope data are also consistent with continuous sedimentation across the boundary. Foraminiferal assemblages are dominated by poorly preserved epistominids. Planktonic Foraminifera are recorded, mainly as pyrite steinkerns. This makes identification difficult although a flood close to the boundary appears to be Globuligerina oxfordiana. Other planktonic taxa are present, including one species that may be new. Nannofloras are well preserved, common to abundant and dominated by Watznaueria britannica with conspicuous Zeugrhabdotus erectus, podorhabdids and Stephanolithion bigotii. The presence of Stephanolithion bigotii maximum throughout, places the samples within the NJ14 biozone. Ostrocoda and holothurian spicules are also recorded. These results are synthesised to provide a multidisciplinary, integrated review of the suitability of Redcliff Point for the definition of an Oxfordian GSSP. Correlations with the French candidate site in Savournon, Haute-Provence are discussed and proposals made for formally establishing a GSSP for the base of the Oxfordian Stage in Europe.

8

Callovian to Berriasian pelagic carbonates in the Western Fore-Balkan, Bulgaria: microfacies, ammonite and microfossil zonations

Ivanova D., Koleva-Rekalova E., Lakova I., Metodiev L.

Volumina Jurassica

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2006

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Vol. 4, no. 1

175-177

EN

The Callovian to Berriasian pelagic carbonates in the Western Fore-Balkan crop out as a part of the Middle Jurassic – Lower Cretaceous peri-platform marine sediments deposited on the northern Tethyan continental margin. This pelagic record consists of marl-limestone alternation (Bov Formation), grey micritic limestones with reddish nodular limestones (Javorets Formation), Ammonitico Rosso type red nodular limestones (Gintsi Formation) and Biancone-type grey micritic regularly bedded limestones (Glozhene Formation) (Sapunov 1976). The total thickness of this succession exceeds 400 m. Rich ammonite faunas recorded from the Bov, Javorets and Gintsi Formations enabled ammonite zonation and age assignment: Macrocephalites spp., Hecticoceras spp. and Kosmoceras spp. zones (Callovian), P. athletoides, C. renggeri, P. (D.) episcopallis, P. (D.) antecedens and G. riazi zones (Oxfordian), H. beckeri zone (Upper Kimmeridgian) and H. hybonotum, S. schwertschlageri and V. rothpletzi zones (Tithonian). The stratigraphic distribution and relative abundance of pelagic microplankton organisms (thin-shelled bivalves, planktonic foraminifers, radiolarians, calcareous dinocysts, pelagic echinoderms and calpionellids) have been used for biostratigraphy and/or recognition of microbiofacies. Within the Oxfordian- Berriasian interval the calcareous dinocyst zones: C. fibrata, C. borzai, C. tithonica, P. malmica, C. tenuis, C. fortis, St. proxima and St. wanneri are recorded. The Middle Tithonian to Berriasian interval is characterized by the successive calpionellid zones: Chitinoidella, Praetintinnopsella, Crassicollaria, Calpionella and Calpionellopsis (Lakova et al. 1999). Five microbiofacies within the pelagic carbonates are superposed: mudstone and wackestone with filaments of pelagic bivalves (Callovian), Globuligerina wackestone and radiolarian wackestone [Oxfordian-Kimmeridgian(?)], Saccocoma wackestones (Kimmeridgian – Lower Tithonian) Globochaete mudstone (Middle Tithonian) and calpionellid mudstone (Upper Tithonian and Berriasian) (Fig. 1). The estimated average rate of sedimentation within the Callovian-Berriasian pelagic succession in the Western Fore-Balkan varying from 9 to 26 mm/10 3 years is characteristic for the transition from relatively condensed to stratigraphically expanded sections in the Upper Jurassic of the Tethyan region. This rate is lower during the Callovian to Kimmeridgian and increased significantly in the Tithonian and Berriasian. Probable explanations are partial carbonate dissolution of the red nodular limestones in the Late Jurassic and the increased bioproductivity of nannoplankton in the Berriasian.

9

Callovian crinoidal sandstone from North East Świętokrzyskie Mts. (Central Poland)

Ostrowski S.

Volumina Jurassica

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2006

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Vol. 4, no. 1

101-102

EN

Monotonous calcareous sandstones outcropping on the northern slopes of Kamienna River North East Świętokrzyskie Mts. (Holy Cross Mts.) are recognized as Callovian mostly on the basis of superposition (Samsonowicz 1932) and scarce occurrence of ammonites Macrocephalites and belemnites. Although the rocks are exploited for over 200 years, there is no complete sedimentological study available. Outcropping rocks are yellow and brown, quartz-calcareous sandstones, poorly horizontally bedded. Cross-bedding, horizontal laminations and ripplemark laminations are scarce in the sequence. Grains are well sorted, bigger fragments can be found only in lower parts of some beds. Bigger grains are exclusively fragments of crinoids. Typically rocks are composed of quartz grains and crinoid ossicles of 0.1-0.2 mm in diameter. The proportion of these components is close to equal. Quartz grains are well rounded, mostly monnocrystalline. Fragments of crinoids are broken, but marks of noticeable corrosion are lacking. Grains are cemented by blocky calcite, forming syntaxial overgrowth (sensu Bathurst 1975) on crinoids. Statistic comparison of diameter of quartz grains and fragments of crinoids revealed that crinoids are about 10% bigger in diameter. However statistic parameters of grain diameters calculated separately for quartz and crinoids are similar in individual samples, and fractionation of diameter for both grain types are close to normal. Differences of mean diameter of both grain types can be attributed to crinoid porosity (resultant lower density). Quartz grains and fragments of crinoids were brought together to sedimentation area by currents. The second ones did not experience long transport - porous fragments of crinoids are prone to destruction (abrasion). The large quantity of crinoids suggests that the area where they flourished was placed nearby.Areas of intensive crinoid growth can be often found on distinctive submarine slopes (Maliszewska 1998; Ostrowski 2003). Tectonically active Radom-Kraśnik Fault zone (Gutowski et al. 2003) could represent the area of development of crinoids in question.

10

Biostratigraphy and palaeoenvironmental development of the Callovian-Valanginian carbonate platform from the Lyubash unit (SW Bulgaria)

Ivanova D., Koleva-Rekalova El, Kołodziej B., Metodiev L., Roniewicz E.

Volumina Jurassica

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2006

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Vol. 4, no. 1

174-175

EN

This study deals with the successions located in the Lyubash unit (SW Bulgaria), which represents a part of the Moesian Carbonate Platform in Middle Jurassic – Early Cretaceous time interval. According to the recent tectonic scheme of Bulgaria (Dabovski et al. 2002) the Lyubash unit belongs to Srednogorie tectonic zone of the Balkan orogenic system. Three sections have been sampled and studied – Rebro, Lyalintsi and Velinovo, which are built up by thick-bedded to massive light grey to whitish organogenic and micritic limestones of the Javorets, Gintsi and Slivnitsa formations. Detailed studies on foraminifera and calcareous dinocyst, provided new biostratigraphic data, and confirmed the Middle Callovian-Valanginian age of the examined sediments as assumed previously by Sapunov et al. (1985). Foraminifera are particularly abundant in the lagoon facies, and represented by genera: Globuligerina, Ophthalmidium, Cornuspira, Ammobaculites, Mesoendothyra, Labyrinthina, Kurnubia, Pseudocyclammina, Dobrogelina, Rumanoloculina, Hechtina, Meandrospira, Valvulina, Trocholina, and Neotrocholina. The sedimentological analysis allowed recognizing microfacies groups assigned to three facies zones: platform slope facies, reef and peri-reef facies and lagoon-tidal flat facies. The development of the platform is characterized by complex vertical and lateral alternation of the studied microfacies. Platform slope facies are prevalent at the section Rebro; the Lyalintsi section is dominated by reef and peri-reef facies, and the section Velinovo is mainly dominated by lagoon facies. Sea-level fluctuations are observed, however generally, a shallowing-upward trend in the platform evolution is observed in all three sections. Coral-microbial reefs are developed as biostromes, and contain numerous and highly differentiated scleractinian corals: 70 species (6 new) from 50 genera (4 new). Among them following corals are the most common: phacelloid Latomeandra, Stylosmilia, Thecosmilia, Cladophyllia, ramose Solenocoenia, Meandrophyllia, lameller Synastraea and Microsolena. Reef development has been disturbed by sea level rise, evidenced by limestones with Saccocoma, intercalated with coral biostromes.

11

Rediscovery of the classic locality of Callovian in Babiarzowa

Wierzbowski A., Schlögl J., Aubrecht R., Krobicki M.

Volumina Jurassica

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2005

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Vol. 3, no. 1

11-14

EN

Red-coloured laminated wackestones to packstones of the filament (Bositra-like) microfacies occurring within crinoidal limestones of the Smolegowa Limestone Formation in the Babiarzowa Klippe (Pieniny Klippen Belt, Carpathians) represent infilling of subhorizontal neptunian dyke of Callovian age. The locality is well-known in geological literature as it yielded the rich fossil assemblage of Callovian age (ammonites, gastropods, pelecypods, brachiopods and others) described by Uhlig (1878, 1881).

PL

Skałka Babiarzowa koło Nowego Targu w zachodniej części pienińskiego pasa skałkowego Polski jest stanowiskiem szeroko znanym w literaturze geologicznej (fig. 1), które dostarczyło bogatego zespołu skamieniałości, w tym zwłaszcza amonitów, ślimaków, małży i ramienionogów wieku kelowejskiego (Uhlig 1878, 1881, 1890). Znaczenie tego stanowiska wiąże się przede wszystkim z faktem, że skamieniałości wieku kelowejskiego są w pienińskim pasie skałkowym słabo poznane, i tym samym, że stanowiło ono główny punkt odniesienia dla znajomości fauny tego wieku w omawianym rejonie (Birkenmajer 1963). Niestety zarówno dokładna lokalizacja wspomnianego stanowiska, jak i sytuacja geologiczna występujących tu utworów pozostawały nieznane. Dlatego też obecne odkrycie wspomnianego stanowiska na Babiarzowej Skałce posiada doniosłe znaczenie zarówno dla poznania zespołów faunistycznych jak i zawierających je utworów. Utwory keloweju są tu wykształcone jako drobnolaminowane czerwone wapienie typu wackestone i packstone o mikrofacji filamentowej, lecz wzbogacone w warstewki materiału krynoidowego (fig. 2, 3). Utwory te stanowią wypełnienie poziomej żyły neptunicznej rozwiniętej w obrębie wapieni krynoidowych bajosu należących do formacji wapienia ze Smolegowej. Szczegółowe studia paleontologiczne zebranych skamieniałości są w toku.

12

Callovian and Oxfordian echinoids of Zalas

Radwańska U.

Volumina Jurassica

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2005

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Vol. 3, no. 1

63--74

EN

Within the Callovian-to-Oxfordian sequence, transgressive upon the Variscan rhyodacite laccolith exposed at Zalas in the Cracow Upland, southern Poland, and far-known due to its ubiquitous fossils of various kinds, to this study subjected are the echinoids. The Callovian assemblage from the variably-sized clastics is low-diversified, to contain 4 taxa of a wider regional occurrence. The Lower (up to the base of Middle) Oxfordian assemblage appears the richest in the Oxfordian of Poland. Its content is typified by the representatives of the orders Cidaroida Claus, 1880, and Phymosomatoida Mortensen, 1904. Amongst the recognised 12 species, of special attention are those first reported from the Jurassic sequences of Poland, viz. Eosalenia miranda Lambert, 1905, and Heterocidaris dumortieri Cotteau, 1871, the latter of which is still a great rarity to the science. Discussed are the life requirements of some of the recognised taxa, as apparent from the functional analysis of their tests. banalnych form nieregularnych pojawia się tutaj (patrz pl. 1: 3a-3b) duży osobnik regularny, Stomechinus heberti Cotteau, 1884, nieznany dotąd w środkowej jurze Polski. Zespół jeżowców z osadów oksfordu (patrz pl. 2- 3) składa się z 12 taksonów (patrz fig. 2), spośród których sześć z podgromady Cidaroidea Claus, 1880, zostało omówionych wcześniej (Radwańska 2003). Zespół ten obejmuje wyłącznie jeżowce regularne o zbliżonych wymaganiach życiowych wskazujące na ujednolicenie warunków środowiskowych w czasie rozszerzającej się transgresji. Uwagę zwraca w nim gatunek Heterocidaris dumortieri Cotteau, 1871, o wprawdzie niejasnej pozycji systematycznej (patrz Fell 1966), a reprezentowany niestety tylko w postaci ułamków pancerzy (pl. 2: 5) znacznych rozmiarów (średnicy ponad 10 cm), ale będący niezmierną rzadkością w jurze europejskiej (patrz Cotteau 1860, 1871; Fell 1966) i nieznany dotychczas z obszaru Polski.

PL

Profil osadów jurajskich odsłaniający się w stropie wielkiego kamieniołomu waryscyjskich riodacytów Zalasu (patrz fig. 1) okazuje się znaczącym ze względu na bogactwo szczątków różnorodnych szkarłupni (liliowców, rozgwiazd, wężowideł), spośród których na szczególną uwagę zasługują jeżowce . W dotychczasowych opracowaniach profilu Zalasu, dostępnego dawniej w niewielkich odsłonięciach naturalnych lub lokalnych łomikach, jeżowce były notowane sporadycznie, jako towarzyszące obfitej faunie gąbek, amonitów i innych mięczaków, oraz ramienionogów (patrz Siemieradzki 1893; Wójcik 1910). Rozlegle odsłonięcie w kamieniołomie riodacytów, rozbudowywanym od lat 1970-tych, umożliwiło szczegółowe rozpoznanie wykształcenia facjalnego osadów jurajskich, ich inwentarza faunistycznego i przede wszystkim ich biostratygrafii wyznaczającej pozycję stratygraficzną profilu w przedziale dolny kelowej - niższa część oksfordu środkowego (patrz Giżejewska i Wieczorek 1977; Matyja i Tarkowski 1991; Tarkowski 1989). Badane przez autorkę jeżowce, pochodzące częściowo z rozmaitych kolekcji (publicznych i prywatnych), a w większości zebrane osobiście, stanowią w sumie dosyć istotny element w rozpoznaniu faun jurajskich Polski. Zespół jeżowców z osadów keloweju (patrz pl. 1) obejmuje tylko 4 gatunki (patrz fig. 2) o różnych wymaganiach życiowych wskazujących na nieustabilizowane warunki środowiskowe w czasie postępującej transgresji morskiej. Oprócz dość Analiza funkcjonalna pancerzy (patrz Smith 1978, 1984; Radwańska 1999) pozwoliła na bardziej szczegółowe rozpatrzenie sposobu życia i wymogów środowiskowych badanych gatunków jeżowców z keloweju i oksfordu Zalasu, zaś analiza taksonomiczna na unacześnienie rozpoznań autorów wcześniejszych (Siemiradzki 1893; Wójcik 1910; patrz fig, 3). Zespół jeżowców oksfordzkich Zalasu okazuje się najbogatszym spośród wszystkich dotychczas badanych stanowisk oksfordu w Polsce (por. Radwańska 2000,2003, 2004b), zaś jego środowiskowe siedlisko - wśród obfitych gąbek, ich mumii i budowli (por. Matyja i Tarkowski 1981, fig. 2B-3) - nadzwyczaj podobne do przedstawionego dla środkowego oksfordu Szwajcarii (patrz Hess 1975, fig. 27).

13

Biostratygrafia i paleośrodowisko środkowej jury z kamieniołomu Ogrodzieniec

Barski M., Dembicz K., Praszkier T.

Volumina Jurassica

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2004

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Vol. 2, no. 1

61-68

EN

The uppermost Bathonian and Callovian deposits from the newly exposed section of Ogrodzieniec were studied. The biostratigraphical analysis was based on both ammonite and dinocyst zonations. The uppermost Bathonian Orbis and Discus and the Callovian Herveyi, Jason, Coronatum, Athleta, Lamberti zones were distinguished. State of preservation of ammonites and lack of dinocysts made it impossible to distinguish Koenigi and Calloviense zones of the lowest Callovian. The position of the Bathonian/Callovian boundary was found in the clayey part of the section. Earlier the boundary was thought to be erosional. The new data indicate, however, the presence of continuous sedimentation, with low sedimentation rate, during Discus and Herveyi chrons. The presence of Gtenidodinium combazii in Orbis, Discus and Herveyi zones shows normal sea conditions in this time. The change of the dinocyst assemblage the Bathonian/Callovian boundary indicates the sea water cooling.