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Development and chronology of the Late Jurassic shallow-water carbonate deposits of the Holy Cross Mountains area, central Poland

Wierzbowski Andrzej

Volumina Jurassica

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2023

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Vol. 21

39--82

EN

The Late Jurassic shallow-water carbonates with intervening clayey-marly deeper-water deposits in the Holy Cross Mts. area formed over large bank of the elevated part of the Northern Tethyan Shelf during about 12 myr. They comprise three main successions (I, II and III) deposited partly in different environmental conditions, controlled by tectonic and climatic factors, and still preserved in the north-eastern margin, the north-western margin and the south-western margin of the Holy Cross Mountains. The history of sedimentation is presented according to the concept of the large tectono-stratigraphic units COK, LUK and KVB, which owe their origin to variable rates of tectonic subsidence, as introduced by Kutek (1994) for the area of central Poland. The studied deposits of the COK megasequence cor- responding to the Upper Oxfordian and the Lower Kimmeridgian up to the Hypselocyclum Zone consist of coral limestones, various grained (including oolitic) limestones, and micritic limestones formed over the gradually enlarging shallow-water carbonate platform of the Holy Cross Mts. This platform was subsequently subdivided into two elevated areas, separated by a depressed zone in the middle, bounded by the Nowe Miasto–Iłża–Bałtów Fault Zone in the north-east and the Holy Cross Fault System in the south. The younger mega- sequence LUK with it strongly transgressive character marks the successive stages of the marine transgression which entered the central, lowered part of the area of the Holy Cross Mts. from the west, where it appeared already in the early Hypselocyclum Chron. It succes- sively spread across the Holy Cross Mts. area towards the north-east and south bringing everywhere the deposition of various oyster lu- machelles and marls with ammonites at the end of the Hypselocyclum Chron and during the Divisum Chron of the Early Kimmeridgian to the Acanthicum/Mutabilis Chron of the earliest Late Kimmeridgian. The following megasequence KVB is represented by the detrital lu- machelles and chalky limestones with nereineids of the Eudoxus Chron of the Late Kimmeridgian marking the development of still younger shallow-water carbonate platform in the uplifted areas in the north-eastern and possibly the south-western margins of the moun- tains, allegedly subdivided by a deeper area of sedimentation of marly deposits. The youngest Late Jurassic deposits of the Holy Cross Mts., are very fragmentarily preserved, mostly because of Early Cretaceous uplift and erosion. They suggest an initial episode of complete drowning of the carbonate platform which became covered by marly deposits during the Early Tithonian, and the subsequent restoration of shallow-water carbonate sedimentation at the end of the Early Tithonian.

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Lower Kimmeridgian facies and sedimentary succession of a shallow-water coated-grain-dominated carbonate ramp of the northern peri-Tethyan shelf : an example from the Radomsko Folds (central Poland)

Olchowy Piotr, Krajewski Marcin

Geological Quarterly

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2020

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Vol. 64, No. 4

969--987

EN

An Upper Jurassic succession is exposed in the active Rogaszyn Quarry (Kodrąb area) located in the Radomsko Folds structure (central Poland). Six facies types were distinguished, comprising oolitic, oncolitic, biodetrital and pelitic limestones as well as marls and marly clays. Typical lithologies are limestones with coated grains deposited in shallow-water, fore-shoal, shoal and lagoonal parts of a carbonate ramp. Three types of ooid and three types of oncoid were identified, which display several shapes and sizes, and a complex structure of cortices. The ooid types show micritic, radial-fibrous and mixed, micritic/radial-fibrous cortices. Type 1 oncoids comprise micritic or bioclastic nuclei enveloped by non-laminated or laminated micritic cortices. Type 2 oncoids are composed of micritic or bioclastic nuclei and laminated, fossil-bearing cortices covered by microbial envelopes. Type 3 oncoids are the largest of the oncoids observed, attaining cm-scale dimensions. These oncoids are formed of a Bacinella-dominated meshwork incorporating smaller ooids and oncoids, or they have bioclastic or micritic nuclei covered by complex cortices with micritic, laminated, fossil-bearing, Bacinella-dominated fabric and microbial envelopes. Boundaries between the specific types of cortical envelopes are usually sharp and accentuated by organic encrustations, elongated bioclasts or borings. Commonly found are chambers of the ichnogenus Entobia representing the boring traces of carbonate-excavating sponges and the cryptoendolithic foraminifer Troglotella incrustants. The complex cortices indicate different growth stages of oncoids at different conditions of currents and microbial activity. Carbonate deposition was accompanied by mixed siliciclastic-carbonate sedimentation resulting in multiple intercalated layers of marls and pelitic limestones as well as marly clays. The deposits exposed in the Rogaszyn Quarry as well as in the Kodrąb area are compared with the neighbouring Upper Jurassic deposits of the Szczerców area and the Sw margin of the Holy Cross Mts. (both central Poland). The successions from the Kodrąb area are generally similar to the Lower Kimmeridgian sequences known from adjacent areas, but with locally observed facies variability.

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Late Jurassic facies succession of the Kleszczów Graben area (southern border of the Łódź Depression, peri-Tethyan shelf, central Poland)

Olchowy Piotr, Krajewski Marcin, Felisiak Ireneusz

Geological Quarterly

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2019

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Vol. 63, No. 4

657--682

EN

Numerous fully cored boreholes completed in the last years in central Poland (Kleszczów Graben area, southern border of the Łódź Depression) enabled the researchers to obtain new sedimentological data on the Oxfordian-Tithonian continuous sedimentary record in the Polish part of the northern Tethys shelf. Twenty-two facies were distinguished in the sedimentological succession. The facies represent the outer-, mid- and inner-ramp environments, including evaporitic episodes and palaeosols. The facies document that the Oxfordian-Lower Kimmeridgian (up to Hypselocyclum) carbonate ramp has evolved to the Upper Kimmeridgian-Tithonian carbonate-siliciclastic ramp. Among the Kimmeridgian deposits, numerous hardgrounds, tidal channel deposits and gravity flow sediments were identified. The Kleszczów Graben sedimentary succession is discussed along with the lithostratigraphical units known from the adjacent regions of southern and central Poland.

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Pinnidae (Bivalvia) from the Reuchenette Formation (Kimmeridgian, Upper Jurassic) of northwestern Switzerland

Koppka J.

Acta Geologica Polonica

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2018

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Vol. 68, no. 1

21--51

EN

The shallow-marine carbonate deposits of the Reuchenette Formation (Kimmeridgian, Upper Jurassic) in northwestern Switzerland and adjacent France yield highly diverse bivalve associations, but only rarely contain remains of pinnid bivalves. The three occurring taxa Pinna (Cyrtopinna) socialis d’Orbigny, 1850, Stegoconcha granulata (J. Sowerby, 1822) and Stegoconcha obliquata (Deshayes, 1839) have been revised. A lectotype for Pinna (C.) socialis was designated and the taxon is assigned herein to P. (Cyrtopinna) Mörch, 1853, the first record of the subgenus from the Jurassic. A brief review of Stegoconcha Böhm, 1907 revealed two species groups within the genus. Species close to the type species S. granulata are characterized by a nearly smooth anterior shell, followed posteriorly by deep radial furrows and rows of pustules covering the dorsal flank. Another group comprises radially ribbed species related to S. neptuni (Goldfuss, 1837). It includes among others the Paleogene species S. faxensis (Ravn, 1902), extending the known range of Stegoconcha from the Middle Jurassic into the Paleogene. The paper suggests a relationship between Stegoconcha and the Cretaceous Plesiopinna Amano, 1956, with S. obliquata as a possible intermediate species leading to Plesiopinna during the Early Cretaceous. Furthermore, a possible relationship between Stegoconcha and Atrina Gray, 1842 is discussed.

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Comments on the identification of Ammonites planula Hehl in Zieten, 1830 (Upper Jurassic, SW Germany)

Schweigert G., Kuschel H.

Volumina Jurassica

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2017

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Vol. 15, no 1

1--16

EN

Ammonites planula Hehl in Zieten, 1830 is the type species of the Late Jurassic ammonite genus Subnebrodites Spath, 1925 and the index species of the well-established Planula Zone of the Submediterranean Province. Recently, Enay and Howarth (2017) classified this stratigraphically important ammonite species as a ʻnomen dubiumʼ and considered it to be the possible macroconch counterpart of Idoceras balderum (Oppel, 1863). These authors claimed “Subnebrodites planula Spath, 1925” instead of Ammonites planula (Hehl in Zieten, 1830) to be the type species of Subnebrodites. However, their nomenclatorial acts are based on erroneous assumptions. For future taxonomic stability we here propose a neotype for Ammonites planula (Hehl in Zieten, 1830) and a lectotype for Ammonites planula gigas Quenstedt, 1888. In addition, dimorphism within the stratigraphically much younger Idoceras balderum (Oppel) is demonstrated showing that there is no morphological resemblance and no closer relationship with Ammonites planula (Hehl in Zieten, 1830).

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Biostratigraphy, geochemistry and sedimentology of Middle to Late Jurassic strata in the Strážovce section (Strážovské vrchy Mts), Krížna Nappe of the Central Carpathians, Slovakia

Michalík J., Bąk M., Lintnerová O., Méres Š

Volumina Jurassica

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2017

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Vol. 15, no 1

161--178

EN

The Jurassic / Lower Cretaceous sequence of the Strážovce section has been deposited in the central, axial part of the Zliechov Basin. Its most characteristic part – the Ždiar Formation consists of bedded siliceous radiolarian limestones and radiolarites. The radiolar¬ian assemblage typical of the North Tethyan Bioprovince lived during mid Oxfordian – Early Kimmeridgian in a warm upper part of the well stratified water column, partially near to the thermocline. Radiolarian abundance decreases upwards. Productivity decrease is quanti¬fied by the share of biogenic SiO2 as well as by high EFSi values during sedimentation of both the Ždiar and Jasenina formations. The geochemical data indicate relatively stable volume of the siliciclastic component of the rocks and a felsic character comparable to the Average Shale. The chemically homogeneous sedimentary signal indicates values of both CPA and EF ≤ 1 of Ti, Zr, Fe, Na, K, Rb, V and U. The values of EF > 1 signal enrichment of elements with affinity to carbonate minerals (Sr, Mn, P, Y, and Mg). Metal enrichment (Cu, Zn and Ni) indicates metal mobilization from other sources or due to carbonate diagenesis. In comparison to the Average Shale, decreased ΣREE´s and negative Cech and Euch anomalies could be regarded as a typical deep sea water signal. The differentiated REE record of higher calcareous beds of the Jasenina Fm. suggests basinal dysoxic conditions. The “bell-shape” of curves (normalized to shale) indicate that REEs were slightly affected by carbonate diagenesis. The Oxfordian / Kimmeridgian siliceous sedimentation in the Zliechov Basin was influenced probably more by monsoon-controlled input of land derived weathered material than by hydrothermal fluids from the bottom rifts.

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First record of the Mediterranean zonal index Mesosimoceras cavouri (Gemmellaro, 1872) in the Upper Jurassic (Pseudomutabilis Zone, semicostatum γ horizon) of SW Germany and its stratigraphical significance

Scherzinger A., Schweigert G., Főzy I.

Volumina Jurassica

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2016

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Vol. 14, no. 1

145--154

EN

The ammonite species Mesosimoceras cavouri (Gemmellaro), the index of the Mediterranean Cavouri Zone, is recorded for the first time from the Submediterranean Upper Jurassic of SW Germany. It occurs in the Untere-Felsenkalke Formation, within a rich ammonite association of the late Pseudomutabilis Zone characterized by fine-ribbed variants of Aulacostephanus pseudomutabilis (de Loriol) and a still undescribed flexuous-ribbed variant of Aulacostephanus eudoxus (d’Orbigny). This ammonite association represents the here newly introduced Lingulaticeras semicostatum γ horizon. The record of Mesosimoceras cavouri (Gemmellaro) confirms at least a partial correlation of the Mediterranean Cavouri Zone with the Submediterranen Pseudomutabilis Zone and the Subboreal Eudoxus Zone.

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Habitat and hydrocarbon potential of the Kimmeridgian strata in the central part of the Polish Lowlands

Więcław D.

Geological Quarterly

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2016

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Vol. 60, No. 1

192--210

EN

The quantity, genetic type and maturity of organic matter dispersed in the Kimmeridgian strata of the central part of the Polish Lowlands were determined on the basis of results of Rock-Eval, stable carbon isotope composition of bitumen, their fractions and kerogen, biomarker distribution in saturate and aromatic hydrocarbon fraction, elemental composition of kerogen, vitrinite reflectance and maceral composition analyses of 225 rock samples collected from 32 boreholes. The study was conducted separately for Lower and Upper Kimmeridgian rocks in the Szczecin-Miechów and Kościerzyna-Puławy synclinoriums and Mid-Polish Anticlinorium. The best source rocks with TOC up to 6.8 wt.%, were found in the vicinity of Gostynin in the Mid-Polish Anticlinorium. Generally, the Upper Kimmeridgian strata are fair and good potential source-rocks whereas the Lower Kimmeridgian strata have much lower hydrocarbon potential. Gas-prone, terrigenous Type-III kerogen predominates in the Lower Kimmeridgian strata. The contribution of oil-prone, marine Type-II kerogen increases in the Upper Kimmeridgian rocks. In the whole profile, only low-sulphur kerogen was recorded, although the situation, when high-sulphur Type-IIS kerogen was mixed with re-worked, non-generative Type-IV kerogen supplied to the sedimentary basin with rocks from eroded land, cannot be excluded. Sedimentary conditions of organic material were variable, usually anoxic and suboxic with domination of siliclastic material in mineral matrix. The maturity of the dispersed organic matter refers mostly to the final phase of the microbial process, or to the initial phase of the low-temperature thermogenic process (oil window). The most mature rocks, corresponding up to 0.75% in the vitrinite reflectance scale, were recognised in the deepest buried parts of the basin (axial part of the Mogilno-Łódź Segment of the Szczecin-Miechów Synclinorium). The most prospecting source rocks were recognised in this area.

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Integrated biostratigraphy of the Jurassic strata of the Wagad Uplift, Kachchh, western India

Rai J., Garg S., Gupta M., Singh A., Pandey D. K., Fürsich F. T., Alberti M., Garg R.

Volumina Jurassica

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2015

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Vol. 13, no. 2

55--80

EN

An integrated study based on calcareous nannofossils, organic-walled dinoflagellate cysts, and ammonites from the Washtawa and Kanthkot formations of the Wagad Uplift have allowed a detailed documentation of the stratigraphic position of these formations within the Oxfordian and Kimmeridgian sediments of the Kachchh Basin, western India. The nannofossil assemblages from the lower part of the Nara Shale Member exposed in the Nara and Washtawa domes, the Kanthkot Ammonite Beds along the Trambau River section, and the Patasar Shale Member exposed along the Trambau River section and the Patasar Tank section in the eastern part of the Wagad Uplift belong to the NJ 14 Cyclagelosphaera margerelli Zone of the Early Oxfordian, the NJ 15a Lotharingius sigillatus Zone of the Middle Oxfordian, and the NJ 15b Cretarhabdus conicus of Early Kimmeridgian age, respectively. Zonation schemes, based on calcareous nannofossils, dinoflagellate cysts, and ammonites were calibrated highlighting their biostratigraphic potential. These studies may represent a reference biochronology for Oxfordian–Kimmeridgian age strata applicable to the Tethyan realm of which India was a part during Late Jurassic times.

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Fluvial architecture element analysis of the Brushy Basin Member, Morrison Formation, western Colorado, USA

Galli K.

Volumina Jurassica

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2014

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Vol. 12, no. 2

69--106

EN

The 85-m Brushy Basin Member of the Morrison Formation in western Colorado, USA, comprises dinosaur-bearing sandstones (architectural element CHR and CH), crevasse-splay deposits and minor levee deposits (architectural element CS), mudstones, marlstones, altered ash beds and minor limestones as well as caliche paleosols and noncalcareous paleosols (architectural element FF). Channel sandstones occur at five stratigraphic levels at Trail Through Time (TT), eleven levels at Fruita Paleontological Research Area (FP), and at five levels at Echo Canyon (EC). River-channel sandstones hosted by floodplain mudstones tend to have cut down to resistant caliche paleosols. Depositional facies and architectural element analysis show that the rivers were low gradient, mainly anastomosing, with perennial flow, but seasonal with “flashy” peaks in discharge. Dinosaur bone accumulations are found in some floodplain ponds. Isolated bones are present in anastomosing channel sandstones at TT and in channel sandstone 2 at EC. At FP, major accumulations of bones were rapidly buried in the deep pools at three bends in the meandering river resulting in the formation of channel sandstone 2. There is no evidence for a large lacustrine or playa system at the three localities.

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New stratigraphic and isotope data on the Kimmeridgian-Volgian boundarybeds of the Subpolar Urals, Western Siberia

Rogov M. A., Price G. D.

Geological Quarterly

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2010

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Vol. 54, No 1

33-40

EN

A review and new data regarding the ammonite faunas and biostratigraphy of the uppermost Kimmeridgian-lowermost Volgian of theSubpolar Urals are presented. The combined ranges of almost all ammonite genera in the lowermost Volgian of the Subpolar Urals supports the traditional point of view regarding the equivalence of the Magnum Zone with the two lowermost Bolonian Zones and with thebulk of the Klimovi Zone. This stratigraphic interpretation permits the stable isotope data (carbon and oxygen) derived from associatedbelemnites to be presented in context. The isotopic records from the belemnites suggest that the lower Volgian sediments of the YatriaRiver, Subpolar Ural Mountains were deposited in a warm marine environment consistent with a warm high latitude scenario. If reducedsalinites are invoked apparent temperatures are lowered by ~5°C, but still remain well above freezing and are relatively warm comparedto some recent modelled estimates of Late Jurassic ocean temperatures.

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The succession of ammonites of the genus Amoeboceras in the Upper Oxfordian – Kimmeridgian of the Nordvik section in northern Siberia

Rogov M., Wierzbowski A.

Volumina Jurassica

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2009

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Vol. 7, no. 1

147-156

EN

A collection of ammonites of the genus Amoeboceras located carefully in the section of Nordvik Peninsula in northern Siberia has enabled recognition of the standard Boreal ammonite zones of the Upper Oxfordian and Kimmeridgian. The recognition of the standard Amoeboceras zones, well known in NW Europe and the Barents Sea area, in northern Siberia indicates the uniform character of the Late Oxfordian and Kimmeridgian ammonite faunas across the whole Boreal Province. Some comments on the occurrence of Boreal oppeliids of the genus Suboxydiscites in the studied section are also given.

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Upper Oxfordian – Lower Kimmeridgian ammonite succession (Amoeboceras, Suboxydiscites) in the Nordvik section (northern Siberia)

Rogov M., Wierzbowski A.

Volumina Jurassica

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2006

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Vol. 4, no. 1

211-212

EN

Nordvik Peninsula situated at the Laptiev Sea, east of Taimyr Peninsula provides one of the most fossiliferous Jurassic - Lower Cretaceous successions of northern Siberia. The succession consists of clays and mudstones with numerous levels of phosphatic and calcareous concretions. The Mesozoic deposits of the area were discovered at the beginning of XX century, but more detailed studies were undertaken by Russian geologists from sixties to eighties of the century: see Zakharov et al. (1983) and earlier papers cited therein. The present study is based on the collection of ammonites gathered during joint field-trip of the Russian (Zakharov V., Rogov M.) and Czech geologists (Kostak M., Chadima M., Slechta S., Mazuch M.) in August 2003. The collection of Upper Oxfordian - Kimmeridgian ammonites consists of about 60 specimens carefully located in the 20 meters thick section. The most abundantly represented and zonally diagnostic are representatives of the genus Amoeboceras, whereas rarely encountered but palaeogeographically important are representatives of the genus Suboxydiscites. The Amoeboceras ammonites enable recognition of the standard Boreal ammonite zones of the Upper Oxfordian and Kimmeridgian. These of the Upper Oxfordian (cf. Sykes & Callomon 1979) include: the Glosense Zone with ammonites Amoeboceras transitorium Spath, A. glosense (Bigot et Brasil); the Serratum Zone with A. serratum (Sowerby), A. koldeweyense Sykes et Callomon, A. nunningtonense Wright; the Regulare Zone with A. freboldi Spath, A. regulare Spath; the Rosenkrantzi Zone with A. rosenkrantzi Spath. The Kimmeridgian ammonite zones (cf. Wierzbowski & Smelror 1993) include: the Bauhini Zone with A. lineatum (Quenstedt); the Kitchini Zone with A. subkitchini Spath below (Subkitchini Subzone), and A. kitchini Salfeld and A. modestum Mesezhnikov et Romm above (Modestum Subzone); the Elegans Zone with A. elegans Spath and A. decipiens Spath. The Kochi Zone is the only standard zone not recognized in the succession, but the interval possibly corresponding to this zone in the Kimmeridgian unfortunately has not yielded recognizable ammonites. The recognition of the standard Amoeboceras zones in the northern Siberia well known in NW Europe and the Barents Sea area indicates the uniform character of the Late Oxfordian to Kimmeridgian ammonite faunas in the Boreal Province. The ammonites of the genus Suboxydiscites appear for the first time in the studied succession in the upper part of the Kitchini Zone of the Kimmeridgian, and do occur in the younger interval of the Kimmeridgian. The ammonites represent the group of oppeliids of the Submediterranean roots (Ochetoceras(?), see Rogov 2001) that colonized the Boreal Province during Late Kimmeridgian. In the studied section Suboxydiscites are represented by both microconchs and macroconchs, belonging to the new species.

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Upper Jurassic dinoflagellate cyst biostratigraphy of the Shaim petroleum-bearing region (Western Siberia)

Trubicyna A., Ilyina V.

Volumina Jurassica

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2006

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Vol. 4, no. 1

216-217

EN

The results of palynological analysis of the sediments of the Abalak Formation from five boreholes in the Shaim petroleum-bearing region (northwestern part of Western Siberia) allow determining the Late Jurassic (Oxfordian to Volgian) age of the deposites in question. The study of taxonomic composition and stratigraphic distribution of dinoflagellate cyst as well as spores and pollen grains, acritarchs and prasinophyts have provided the basis for a local biostratigraphic subdivision of these deposits. The geosequence of five dinozones has been defined.

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The base of the Tithonian Stage – historical review and state of the art

Schweigert G., Atropos F.

Volumina Jurassica

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2006

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Vol. 4, no. 1

213-214

EN

When introducing the Tithonian Stage in a preliminary way, Oppel in 1865 listed several localities, which, according to him, yielded typical faunas of this age. The original list of Oppel comprises 117 taxa, mostly ammonites. The main localities which proliferated these taxa are: Rogoenik, Radzichov (Polish Carpathians), Ignaziberg, Koniakow, Willamowice, TeĘin (Silesia), Stramberk (Moravia), Trento, Rovereto (Southern Alps), Ruhpolding (Eastern Alps), Solnhofen, Eichstatt, Neuburg a. d. Donau (Bavaria), Nusplingen (Swabia), Grenoble, Val d'Ormonds (Switzerland), Chambery (Savoie), Boulogne-sur-Mer (Normandy), and Portland (Dorset). However, no type locality was ever selected. One of the localities in Oppel's list, Nusplingen, is not a time equivalent of the Solnhofen Limestones in Franconia, as suggested by Oppel in disregard of the completely different ammonite faunas. In the original definition of the Tithonian no zonal subdivision was presented. The first ammonite zone of the Tithonian, the Hybonotum Zone, was informally proposed by Benecke (1866, "Schichten des Ammonites hybonotus and lithographicus"), who focussed on the correlation between the Tithonian in the Tethyan Late Jurassic - mainly the Ammonitico Rosso Superiore of the Southern Alps - and its supposed coeval deposits in SW Germany. This Hybonotum Zone was an assemblage range zone, which included the taxa from the Diphyakalk of the Southern Alps, intercalated between the beds containing Aspidoceras acanthicum and the Early Cretaceaous Biancone, thus being approximately synonymous with the Tithonian Stage of Oppel. Neumayr introduced the Beckeri Zone in 1873 by subdividing the Acanthicum Zone. An increase of provincialism in the Late Jurassic forced the establishment of several independent zonal schemes and stages. Today, the Tithonian Stage starting with the Hybonotum Zone is regarded as standard for chronostratigraphy in the Jurassic. More recently several attempts for a definition of the Kimmeridgian/Tithonian boundary, the base of the Hybonotum Zone, were made. Sections in SW Germany were studied in detail but it was not possible to find suitable sites for the proposal of a GSSP. The only published suggestion is from Contrada Fornazzo near Castellammare in W Sicily, but the flatter section is rather poor in respect of its ammonite faunas and hence of little correlation value, especially in contrast to sections in SE France (Canjuers, Mt. Crussol). The latter provide rich, well-preserved faunas with a succession of chronospecies of Hybonoticeras (in ascending order): Hybonoticeras kamicense (Schopen) - H. n. sp. - H. pseudohybonotum Vigh - H. n. sp. (=autharis sensu Berckhemer & Holder) - H. hybonotum (Oppel) - H. n. sp. They are accompanied by numerous perisphinctids, oppeliids and aspidoceratids. The final decision of a GSSP for the base of the Tithonian Stage is a formal convention, in which these valuable data should be taken into account, and we warn of a premature decision

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Ontogeny in a macroconchiate Idoceras from Mexico: a key for interpreting suprageneric classification of genus Idoceras based on phenotype expression

Villasenor A., Oloriz F.

Volumina Jurassica

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2006

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Vol. 4, no. 1

245-247

EN

Genus Idoceras was created one hundred years ago by C. Burckhardt (1906). Mainly focused on "un grand nombre d'especes appartenant aux groupes de l'Ammonites planula Hehl, et de l’Ammonites balderus Oppel" collected from Kimmeridgian beds at Sierra de Mazapil (Zacatecas), Burckhardt did not give precise hypotheses about relationships with morphologically related taxa. Aside from comparisons with Middle Jurassic taxa (e.g., Parkinsonia) made by pioneer European ammonitologists, Burckhardt recognized that the European ammonites planula, balderus and related ones had been interpreted as related to Perisphinctes or Simoceras. In addition, he stated that both ventral sculpture and sutural pattern serve for separation from typical Perisphinctes. On the assumption that ventral sculpture is of subordinate value in the case-study, the following quotations taken from Burckhardt's definition of genus Idoceras are both of relevance and introductory for its updated interpretation at the suprageneric level: Coquille discoidale, generalement aplatie, peu renflee… La plupart des cotes se subdivide en deux branches secondaires souvent mal reliees…, quelques-unes resten simples; quelquefois aussi il y a des cotes tripartites, bidichotomes ou intercalees… avec l'age… les cotes ont la tendance a de se renfler faiblement pourtour de l'ombilic et sourtout au bord externe des tours, tandis qu'elles s'affaiblissent sur les flancs jusqu'a s'effacer. According to Burckhardt, Idoceras" identification involves: occurrence of loose coiling, common simple ribs, and the sutural pattern, all these being of use for easy distinction from typical simoceratids; difficulty for separation from some, unnamed groups of both perisphinctids and "simoceratids"; and the foreseeable inclusion of mainly Tethyan "simoceratids" in his new genus Idoceras. Together with inconclusive knowledge about the origin and phylogenetical relationships of Idoceras in the original description, its suprageneric interpretation has been controversial during the past century. Idoceras has been included in the subfamilies Idoceratinae and Ataxioceratinae, mainly included within the family Perisphinctidae. The inclusion of genus Idoceras in the polyphyletic Ataxioceratinae has been made taking Subnebrodites as synonym and, therefore, embracing Late Oxfordian ammonites of the planula group and related species. Restriction of Ataxioceratinae to embrace mainly the Kimmeridgian perisphinctids is widely accepted, and the appearance of its "key-innovation" (i.e., virgatotome ribbing, and related ones such as polygyrate, fascipartite) has been proposed to identify ataxioceratids from the Upper Oxfordian onward in the Upper Jurassic. Disassembling of a well-preserved, macroconchiate Idoceras showing the greatest size known, collected ex-situ from "Idoceras beds" in Sierra de Mazapil (Fig. 1), allows the precise description of the ontogenetical course in terms of sculpture and shell-type: from quasi-platycone to discocone shell; increasing relative compression and, therefore, from suboval to high-oval whorl-section; from moderately involute to involute shell; decreasing expression of narrow, shallow, oblique constrictions; from bifurcated, isocostate ribbing to increasing more or less complete ataxioceratoid and periumbilically reinforced ribs; and increasing shell smoothing from the end of the phragmocone. Thus, the combination of shell-type and ataxioceratoid ribbing, as well as stratigraphy (upper Lower Kimmeridgian), support the interpretation of genus Idoceras as belonging to Ataxioceratinae. The use of subfamily Idoceratinae is disfavored.

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High-resolution cyclostratigraphic analysis of magnetic susceptibility record from a Kimmeridgian alternating marl-limestone succession (La Méouge, Vocontian Basin, France)

Boulila S., Galbrun B., Collin P-Y., Collin P-Y., Schnyder J.

Volumina Jurassica

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2006

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Vol. 4, no. 1

149-150

EN

The Kimmeridgian deep-water sediments of La Méouge section (South East Basin of France) show alternating marl-limestone successions. The limestone beds are mudstones or wackstones with benthic foraminifera, radiolarians and filaments which are characteristic of the pelagic realm (Colombié & Strasser 2003). We studied a 43 m thick well exposed interval of mainly Early Kimmeridgian (De Rafélis 2000). Cyclostratigraphic studies of marl-limestone alternations are commonly based on measuring the thickness of beds and bundles and counting their number to extract sedimentary cyclicities. By using high resolutions magnetic susceptibility (MS) measurements, we developed a methodology for detecting and quantifing sedimentary cyclicities recorded in this kind of facies. To perform high-resolution MS measurements, the sampling interval was fixed at nearly 7 cm. All the samples were measured with a Kappabridge KLY-2 susceptometer. The MS variations follow a net cyclic pattern (high and low frequencies). Spectral analysis of MS data show evidence of about all range of Milankovitch cyclicities (precession, obliquity, 100 ky and 400 ky-eccentricity) as demonstrated by the frequencies” ratios methodology and tuning technique. For this latter, we tuned MS data to 405 ky-eccentricity of astronomical solutions (Laskar et al. 2004). Moreover, we found highly significant periods of climatic precession not only in the original MS record but also in the tuned MS. Evolutive harmonic analysis (Maurer et al. 2004) was performed to examine the persistence of the Milankovitch properties throughout the whole section and the possible variations of sedimentation rate. Specifically, the two high peaks, seen in power spectra domain representing the short and the long precession, are characterized in amplitude spectrogram domain by obvious continuous lines, particularly the latter. This means that the precession cycles have much larger amplitudes than the other recognized cycles and are persistent too throughout the entire section. Furthermore, we noted that the long precession cycles show a sudden change in sedimentation rate occurring in the lower part of Lothari ammonite Subzone where the sedimentation rate shifted roughly from 2 to 3 cm/ky. This study proved that MS is a very useful tool for cyclostratigraphic analysis of Mesozoic sections, particularly in alternating marl-limestone successions, and it is also a powerful proxy to detect and estimate possible variations in sedimentation rate.

18

First complete holothurian skeletons from Poland (Early Kimmeridgian, Bełchatów, Central Poland)

Boczarski A.

Volumina Jurassica

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2006

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Vol. 4, no. 1

231-232

EN

First complete holothurian skeletons (scleritome) and sclerite aggregates from the Early Kimmeridgian of Poland (Bełchatów, Central Poland) were described in this paper. The sclerites (hard parts) of the living holothurians are connect only by soft tissues. These tissues decompose after death of the animals very quickly, and the skeletons undergo quick dispersion in the sediment. Complete specimens of Holothurioidea are extremely rare finds (Boczarowski 2001). The scleritome is an association of all types of skeletal elements of single species (Bengtson 1985). Well-preserved holothurian remains were found in two marly limestone samples coming from boreholes Bełchatów 126 GP (depth 135.2 m) and Szczerców PS 68 (depth 219.8 m). Six complete or almost complete holothurian skeletons (Achistrum sp.), 35 skeletal aggregates (Achistrum sp., Hemisphaeranthos sp., Priscularites sp.) and thousands of isolated sclerites were found (Figs 1-2). Many recent species belonging to order Apodida Brandt, 1835 live buried in muddy or sandy sediments (Boczarowski 2001). These holothurians are able to very quickly dig itself in sediment through co-ordinating the action of tentacles and the cramps of the body. Achistrum Etheridge, 1881 emend. Frizzel & Exline 1955 and Hemisphaeranthos Terquem & Berthelin, 1875 emend. Frizzel & Exline 1955 probably lived as funnel-feeders (digging the tentacles into the sediment and making funnel shaped depression). Sclerite assemblages of Priscularites Deflandre-Rigaud, 1962 are very similar to scleritome of molpadid holothurians (order Molpadida Haeckel, 1896), especially to representatives of family Eupyrgidae Semper, 1868 and mostly to genus Eupyrgus Lutken, 1857. The representatives of this genus occur in most of seas of the northern hemisphere at present time. Thousands of them buried in the soft sediment. They are conveyor belt-feeders (digging the tentacles into the sediment and transferring them to the mouth permanently). Specimens found in marly limestones of Be.chatów probably lived on soft bottom, in the sediment as infaunal or semiinfaunal animals (Achistrum sp., Hemisphaeranthos sp. and Priscularites sp.). After the death their body quickly decayed, however the remains did not undergo the dispersion in sediments.

19

Microfacies and stratigraphic position of the Upper Jurassic Rogoża coquinas at Rogoźnik, Pieniny Klippen Belt, Carpathians

Reháková D., Wierzbowski A.

Volumina Jurassica

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2005

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Vol. 3, no. 1

15-27

EN

The Rogoża Coquina Member (Pieniny Klippen Belt, Carpathians, Poland) develped as red micritic ammonite coquinas covers the stratigraphical interval from Kimmeridgian to Upper Tithonian as indicated by microfossils study (calcareous dinocysts and calpionellids) in the type-section of the unit, in the Rogoźnik Quarry. These deposits are overlain by white micritic limestones attributed to the Sobótka Limestone Member of Lower to Middle Berriasian.

PL

Czerwone muszlowce amonitowe odsłonięte w nieczynnym kamieniołomie w Rogoźniku stanowią wzorzec litostratygraficzny dla ogniwa muszlowców z Rogoży (dawniejsza nazwa "czerwone muszlowce rogoźnickie" - Birkenmajer 1962, 1963, 1977). Pozycja chronostratygraficzna tych utworów i ich związek ze słynnymi muszlowcami ogniwa muszlowców z Rogoźnika (dawna nazwa "białe muszlowce rogoźnickie" - Birkenmajer 1962, 1963, 1977) pozostawały przez dłuższy czas nie w pełni wyjaśnione. Pierwotnie (Birkenmajer 1977), sądzono, że ogniwo muszlowców z Rogoży jest starsze od ogniwa muszlowców z Rogoźnika; później (Kutek & Wierzbowski 1986), wyrażono opinię, że ogniwa te są równowiekowe - czerwone mikrytowe muszlowce z Rogoży zastąpione są obocznie przez muszlowce z Rogoźnika o silnie zrekrystalizowanym matryksie przekształconym w dużym stopniu w grubokrystaliczny kalcyt. Przeprowadzone obecnie szczegółowe badania płytek cienkich z prób zebranych w profilu muszlowców z Rogoży w kamieniołomie w Rogoźniku (fig. 1 i 2, pl. 1-3) pozwoliły na pełne przedstawienie charakterystyki mikrofacjalnej i określenie pozycji chronostratygraficznej tych utworów w oparciu o cysty wapiennych Dinoflagellata oraz kalpionelle. Widoczne w profilu muszlowce mają miąższość około 11 metrów (spąg ogniwa muszlowców z Rogoży jest tu nieodsłonięty) i wykształcone są w niższej części jako czerwone wapienie typu wackestone i packstone o mikrofacji sakkokomowo-globochetowej, a w części wyższej - jako czerwonawe i różowe wapienie typu wackestone o mikrofacji kalpionellowo-radiolariowej. Pozycja chronostratygraficzna niższej części muszlowców zawiera się w przedziale od kimerydu i dolnego tytonu (poziomy dinoflagellatowe: Parvula, Moluccana, Borzai oraz Pulla-Tithonica w klasyfikacji Rehakowej 2000) do środkowego tytonu/najniższego górnego tytonu (poziomy kalpionellowe: Chitinoidella oraz Praetintinnopsella w klasyfikacji Rehakowej i Michalika 1997). Datowania te pokazują, że omawiane utwory obejmują przedział stratygraficzny, odpowiadajacy rozwiniętym w klasycznej postaci muszlowcom z Rogoźnika w profilu skałek Rogoży (por. Kutek i Wierzbowski 1986). Wyższa część ogniwa muszlowców z Rogoży w badanym profilu zawiera liczne kalpionelle wskazujące na górnotytoński poziom Crassicolaria i jego wszystkie trzy podpoziomy: Remanei, Brevis i Colomi (por. Reháková i Michalik 1997). Utwory bezpośrednio nadścielające muszlowce z Rogoży w profilu kamieniołomu w Rogoźniku reprezentowane są przez białe i biało-szare wapienie typu wackestone, a lokalnie też mudstone, wykształcone w mikrofacji radiolariowo-kalpionellowej lub kalpionellowej. Obecne tu zespoły kalpionelli wskazują na dolny i środkowy berias (poziom Calpionella), przy czym jak wydaje się, najniższa część tego poziomu, odpowiadająca podpoziomowi Alpina, jest tu nieobecna lub silnie zredukowana miąższościowo. Może to wskazywać na istnienie luki stratygraficznej pomiędzy ogniwem muszlowców z Rogoży, a omawianymi nadległymi wapieniami, które swoim charakterem litologicznym, a także swoją pozycją stratygraficzną, wyraźnie nawiązują do ogniwa wapienia z Sobótki w schemacie litostratygraficznym Birkenmajera (1977).

20

Kolonie korali z muszlowców ostrygowych i oolitów dolnego kimerydu Małogoszcza

Radwański A., Roniewicz E.

Volumina Jurassica

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2005

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Vol. 3, no. 1

97--107

EN

Scleractinian corals occurring scarcely in the Lower Kimmeridgian Actinostl'eon (=Lopha, =Alectryonia) shellbeds at Malogoszcz in the Holy Cross Mountains, Central Poland, are represented by abraded colonies densely riddled by rock-boring bivalves (Lithophaga inclusa Phillips, GastTOchaena sp.) and polychaetes (potamilla sp.). The taxonomically recognised specimens include C01nplexastrea bUJ'gundiae (de Blainville, 1830), D 'imorphocoenia sp., Ovalastrea caryophylloides (Goldfuss, 1826), and Thamnasteria graeilis (Miinster, 1826). AlI colonies are preserved in the form of hollows, the wall s of which bear moulds of coral calyces, and of bivalve and polychaete borings. Taking into account the structural features of shellbeds and their faunistic content (uprooted crinoids Apioerinites, dug-out deeply-infaunal bivalves), stormy agitation is postulated as a basic agent responsible for damaging AeUnostreon communities, and their associates. The studied corals are thought to have lived aside the Aetinostreon gardens, up on a muddy bottom, from where they have been stirred-up during the storm cataclysm, having been then abraded and riddled by rock-borers repeatedly until laid down in a shellbed and transferred in to the fossil record. The extremely shallow-water conditions, under which the ostreid Actinostreon has lived, suggest the typically opportunistic nature or the associated corals, the same as of Ovalastrea caryophylloides (Goldfuss, 1826) from oolitic shoals, and the only colony of which completes the coral assemblage of Malogoszcz. The opportunism or ali these corals differs them from the habit of hermatypie forms from coeval and Oxfordian patch-reef communities of the Holy Cross Mountains (ef. Roniewicz & Roniewicz 1968, 1971).