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1

Detailed biostratigraphic scales as based on the palaeobiogenetical approach (an example of the Upper Bajocian – Lower Bathonian ostracod scale of the Russian Platform)

Shurupova Y. A., Tesakova E. M.

Volumina Jurassica

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2017

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Vol. 15, no 1

121--138

EN

Two new species of ostracods of the family Progonocytheridae Sylvester-Bradley Camptocythere (C.) lateres Tesakova et Shurupova, sp. nov. and C. (C.) angustius Tesakova et Shurupova, sp. nov. from the Michalskii and Besnosovi ammonite zones (Upper Bajocian – Lower Bathonian, Middle Jurassic) of the Sokur section (Saratov) are described. The changes in ontogenesis in the phylogeny of Camptocythere (C.) lateres Tesakova et Shurupova in the stratigraphical interval corresponding to the Palaeocytheridea kalandadzei ostracod Zone, and especially to the beds with C. (C.) lateres, have been studied. The levels of the change in the predominant type of sculpture (corresponding to evolutionary boundaries) are recognized in the sculpture development among the adult representatives of the species in its phylogeny. This palaeobiogenetic (heterochrony) approach allows subdivision of the beds with C. (C.) lateres into three stratigrapical intervals characterized by changes in the type of sculpture.

2

Middle Jurassic-Early Cretaceous foraminiferal biozonation of the Amran Group, eastern Sana’a Basin, Yemen

Al-Wosabi M., El-Anbaawy M., Al-Thour K.

Geologos

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2017

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Vol. 23, No. 2

75--87

EN

Two sections of strata assigned to the Amran Group at Jabal Salab and Jabal Yam in the eastern Sana’a governorate were sampled and correlated. These sections are part of a carbonate platform that extends from the city of Marib in the east to Naqil Ibn Ghailan, 20 km east of the city of Sana’a to the west. Palaeontological analysis of samples recovered has resulted in identification of 123 foraminiferal species, which are used to subdivide the sequence of the Amran Group into five biostratigraphic zones, aged between Bathonian (Middle Jurassic) and Berriasian (Early Cretaceous). The proposed biozones are those of Riyadhella rotundata, Kurnubia jurassica, Ammomarginulina sinaica, Alveosepta jaccardiand Pseudocyclammina sulaiyana/Furitilla caspianseis. These biozones were constructed and correlated with the equivalent zones reported from several localities.

3

Palaeoenvironmental implications of Middle Jurassic trace fossils from the Jaisalmer Formation, India, with emphasis on the ichnogenus Asteriacites Lumbricalis von Schlotheim

Gurav S.S., Kulkarni K. G., Paranjape A. R., Borkar V. D.

Annales Societatis Geologorum Poloniae

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2014

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Vol. 84, No. 3

249–-257

EN

The Hamira Member (Bathonian) of the Jaisalmer Formation records the first marine transgression within the Jaisalmer Basin. It also contains the ichnogenus Asteriacites von Schlotheim, 1820, as documented here for the first time. This was used to refine interpretations of the palaeoenvironment. Crowded ophiuroid resting traces, Asteriacites lumbricalis, occur in a silty limestone unit 1 m thick. This is preceded by a monospecific assemblage of Diplocraterion parallelum towards the base of this unit, while towards the top there is an assemblage, comprising Gyrochorte comosa, Protovirgularia rugosa, Rhizocorallium commune and Rosselia socialis. Colonisation by the Asteriacites trace makers occurred in a shallow-water, marginal-marine, normal-salinity, fully oxygenated, high-energy setting with steady rates of sedimentation. From an ichnological perspective, the sequence investigated shows a shift in environmental conditions from the middle shoreface to the off shore transition zone. Addressing the Asteriacites/Heliophycus nomenclatorial dilemma, Knaust (2012) suggested that the generic designation Asteriacites should be retained. His view was found to be appropriate and supported to avoid further confusion.

4

Life span and growth rate of Middle Jurassic mesohibolitid belemnites deduced from rostrum microincrements

Wierzbowski H.

Volumina Jurassica

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2013

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Vol. 11, no. 1

1--18

EN

The microincrements of nine Middle Jurassic mesohibolitid belemnite rostra (Hibolithes jurensis, Pachybelemnopsis fusiformis and Pachybelemnopsis “subhastatus”) were analysed to measure the ontogenic age and growth rate of the belemnites. The microincrements are interpreted to have been formed daily based on analogy with extant coleoid cephalopods and the frequency of circadian rhythms in animal activity. The mesohibolitid belemnites are found to have had a short life span of ca. 1 year. The short life span of the belemnites studied is similar to the life span of modern coleoids (squids, cuttlefishes and common octopuses). It restricts the utility of belemnite rostra as a proxy for average secular seawater temperatures and chemistry. Short-lived cycles (2–8 days) in the belemnite growth rate are linked to variations in the metabolic activity of these animals. Minor diagenetic alteration revealed by the dull cathodoluminescence of some rostra is found to have no effect on the preservation of the growth rings.

5

Palynofacies from Bathonian (Middle Jurassic) ore-bearing clays at Gnaszyn, Kraków-Silesia Homocline, Poland, with special emphasis on sporomorph eco-groups

Gedl P., Ziaja J.

Acta Geologica Polonica

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2012

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Vol. 62, no. 3

325-349

EN

The palynological organic matter of dark clays from Bathonian ore-bearing clays exposed at Gnaszyn (Częstochowa, Kraków-Silesia Homocline, Poland) consists of high proportions of land-derived particles; aquatic elements (mainly dinoflagellate cysts) are comparatively rare. Terrestrial particles include black opaque phytoclasts, dark brown phytoclasts, cuticle remains and subordinate sporomorphs. The latter are represented by eighty-four taxa of spores and pollen grains. They represent various groups of plants, including Bryophyta, Sphenophyta, Lycophyta, Pteridophyta, Pteridospermophyta, Cycadophyta or Ginkgophyta and Coniferophyta. The most frequent sporomorphs in almost all samples from Gnaszyn are Callialasporites (Araucariaceae), Cerebropollenites and Perinopollenites elatoides (Taxodiaceae) pollen grains, fern spores with triradiate tetrad mark, bisaccate pollen grains belonging to conifers (Pinaceae or Podocarpaceae) and also to Pteridospermophyta. Quantitative analysis of the palynofacies shows fluctuations of particular element ratios, which correlate with lithology. Clay intervals that contain siderite concretion levels yielded lower amounts of cuticles in relation to sporomorphs (mainly pollen grains) and dinoflagellate cysts. Intervals of monotonous clays and silts are characterized by a higher ratio of cuticles in relation to other elements, especially dinoflagellate cysts. Also, quantitative analysis of the sporomorphs shows changes in frequency of the representatives of various plant communities, which coexisted during the Jurassic: Upland, Lowland, River, Pioneer, Coastal and Tidally-influenced. These changes might have reflected sealevel fluctuations, which affected vegetation growing on adjacent land. However, the dominance of Callialasporites pollen grains, which belong to the Coastal community, indicates that the Gnaszyn assemblage was mainly influenced by the seashore vegetation. The high frequency of Araucariaceae pollen grains and the presence of ferns representing the Osmundaceae, Cyatheaceae, Dicksoniaceae, Schizeaceae, Gleicheniaceae and Matoniaceae indicate a warm climate without large seasonal amplitudes during the deposition of the Gnaszyn succession.

6

Palaeoenvironmental significance of iron carbonate concretions from the Bathonian (Middle Jurassic) ore-bearing clays at Gnaszyn, Kraków-Silesia Homocline, Poland

Witkowska M.

Acta Geologica Polonica

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2012

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Vol. 62, no. 3

307-324

EN

Iron carbonate concretion horizons are characteristic features of the Bathonian (Middle Jurassic) claystone-mudstone succession at Gnaszyn. They occur in single horizons, which generally represent the same genetic type. The siderite concretions are the main type of iron carbonate concretions at Gnaszyn; a second type is represented by phosphate-siderite concretions. On the basis of the fieldwork, and their petrographical and mineralogical characteristics, the genesis of the concretions and their palaeoenvironmental significance is discussed. The results of this study (based on the localization, mode of occurrence, mineralogy of iron carbonate concretions and also the textural relationship between the concretions and host sediment layers) suggest an early diagenetic origin of the concretions. The preferential occurrence of the concretion horizons in single layers in the ambient sediments was associated with particular conditions of their deposition and early diagenesis, favored by a slower sedimentation rate and more intense bioturbation, and related primarily to the greater availability of reactive iron ions. From the viewpoint of physicochemical conditions the horizons with iron carbonate concretions in the study area reflect the redox boundary between oxic/bioturbated and anoxic/non-bioturbated zones. The conditions favoring the formation of such horizons was possibly due to longer periods of diminished sedimentation rate when the redox boundary remained in the same position within the sediment.

7

Palaeoenvironmental reconstruction of Bathonian (Middle Jurassic) ore-bearing clays at Gnaszyn, Kraków-Silesia Homocline, Poland

Gedl P., Kaim A., Leonowicz P., Boczarowski A., Dudek T., Kędzierski M., Rees J., Smoleń J., Szczepanik P., Sztajner P., Witkowska M., Ziaja J.

Acta Geologica Polonica

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2012

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Vol. 62, no. 3

463-484

EN

Multidisciplinary studies of the Middle-Upper Bathonian ore-bearing clays at Gnaszyn revealed variable palaeoenvironmental conditions during the deposition of this seemingly monotonous sequence. We interpret the conditions in the bottom environment and the photic zone, and also evaluate the influence of the adjacent land areas, based on sedimentology, geochemistry, sporomorphs and palynofacies composition, benthic (foraminifera, gastropods, bivalves, scaphopods, echinoderms), planktonic (calcareous nannoplankton, dinoflagellate cysts), and nektonic (sharks) fossils. The Gnaszyn succession originated relatively close to the shore, within reach of an intense supply of terrestrial fine clastic and organic particles. The latter are mainly of terrestrial origin and range from 1.5 to 2.5 wt.%. The precise water depth is difficult to estimate but most likely ranges from several tens of metres to a few hundred metres. All fossil groups show minor changes throughout the succession. As the climate seems to have been quite stable during this period we consider sea-level fluctuations to have been the main factor responsible for the changes. The terrestrial input, including freshwater and land-derived clastic and organic particles (sporomorphs and cuticles), increased during periods of sea-level lowstand. As a consequence, stress conditions (lower salinity, higher nutrient availability, lower water transparency) in the photic zone caused blooms of opportunistic planktonic taxa. Furthermore, a faster sedimentation rate led to oxygen depletion and deterioration of the living conditions in the bottom environment due to an increased accumulation of organic matter. As a result, the benthic biota became taxonomically impoverished and commonly dominated by juvenile forms. During periods of high sea level, the source areas were shifted away from the basin, resulting in a decrease in the terrestrial influx, increase in the salinity of surface waters, the appearance of more diverse phytoplankton assemblages, a lower sedimentation rate, and an improvement of living conditions at the bottom.

8

Palaeoenvironmental interpretation of echinoderm assemblages from Bathonian ore-bearing clays at Gnaszyn (Kraków-Silesia Homocline, Poland)

Boczarowski A.

Acta Geologica Polonica

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2012

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Vol. 62, no. 3

351-366

EN

This paper presents the results of an investigation into the variability of echinoderm assemblages from Bathonian ore-bearing clays from Gnaszyn. Remains of Crinoidea, Asteroidea, Ophiuroidea, Echinoidea, and Holothuroidea have been studied from 38 rock samples. The most common echinoderms represented are the crinoids Balanocrinus berchteni and Chariocrinus andreae and a few species of the holothurian genera Priscopedatus, Calclamna, Staurocaudina, Eocaudina, Achistrum, Theelia and Hemisphaeranthos. The echinoderms from Gnaszyn show various life strategies: benthic or epibenthic forms, sessile sestonophages (Crinoidea), motile macrophages (Asteroidea) and detritivores (Asteroidea, Ophiuroidea, Echinoidea), infaunal and epifaunal detritus feeders, sediment feeders or rake-feeders (Holothuroidea). Their presence suggests well oxygenated and presumably relatively cold bottom marine waters. The parts of the Gnaszyn section around concretion horizons and characterized by the ubiquitous occurrence of the holothurian Theelia and echinoids were deposited during phases of optimal living conditions with sufficient influx of plant detritus and good oxygenation of the sea bottom. These parts commonly host echinoderm associations dominated by crinoid remains, which occasionally are still articulated (or disarticulated but remaining intact) - this points to a quiet environment with normal oxygenation of the bottom waters but anaerobic/dysaerobic conditions in the sediment.

9

Palaeoecological implications of neoselachian shark teeth from the Bathonian (Middle Jurassic) ore-bearing clays at Gnaszyn, Kraków-Silesia Homocline, Poland

Rees J.

Acta Geologica Polonica

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2012

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Vol. 62, no. 3

397-402

EN

Systematic sampling through the Middle and Upper Bathonian strata at Gnaszyn has resulted in the discovery of 13 neoselachian teeth. Systematically, the teeth represent five taxa including Sphenodus sp., Protospinax sp. 1, Protospinax sp. 2, Palaeobrachaelurus sp. and another, indeterminate orectolobiform. The presence of two species of the flattened and bottom-dwelling Protospinax and two different orectolobiforms that are likely to have lived near the bottom, is a strong indication of oxygenated bottom conditions at the time of deposition. The dietary preferences of these taxa included a wide variety of benthic invertebrates. The synechodontiform Sphenodus may have been the first pelagic predatory neoselachian in the Jurassic, equipped with high and slender piercing teeth that formed a tearing-type dentition. The diet of Sphenodus probably included bony fish, smaller sharks and cephalopods.

10

Organic-walled dinoflagellate cysts from the Bathonian ore-bearing clays at Gnaszyn, Kraków-Silesia Homocline, Poland - a palaeoenvironmental approach

Gedl P.

Acta Geologica Polonica

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2012

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Vol. 62, no. 3

439-461

EN

A succession of Middle-Upper Bathonian (Subcontractus.Retrocostatum zones) ore-bearing clays exposed at Gnaszyn has been investigated for the presence of dinoflagellate cysts. The assemblages are dominated by Ctenidodinium. However, analysis of diversity shows some subtle differences throughout the succession, possibly related to the palaeoenvironmental conditions in the photic zone. Impoverished assemblages, dominated by Ctenidodinium, occur mainly in monotonous muddy intervals. More diverse assemblages, albeit also dominated by Ctenidodinium, occur in intervals which contain siderite concretion levels. The taxonomic composition of the former assemblage seems to reflect slightly restricted conditions in the photic zone, possibly related to a minor reduction in salinity and/or increase in nutrient availability. More diverse dinoflagellate cyst assemblages reflect periods of less intense terrigenous influx and relatively higher, possibly normal, salinity. These changes were possibly caused by variable intensity of freshwater influx into the basin, controlled by sea-level fluctuations. Sea-level changes may be related to migrations of Tethyan water masses, which were probably partly responsible for the composition of the dinoflagellate cyst assemblages.

11

Faunal dynamics of gastropods in the Bathonian (Middle Jurassic) ore-bearing clays at Gnaszyn, Kraków-Silesia Homocline, Poland

Kaim A.

Acta Geologica Polonica

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2012

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Vol. 62, no. 3

367-380

EN

The succession of gastropods in the Gnaszyn section is quite monotonous and shows significant changes only in the proximity of concretion layers, at least partially because of diagenetic reasons. Otherwise, the section is dominated by gastropods (cylidrobullinids, bullinids, and mathildids) most of which preyed probably on sedentary organisms (polychaetes and/or coelenterates) that possibly flourished on the sea bottom at that time. The other groups of gastropods are represented by larval or juvenile shells. Their presence shows that the environmental conditions that were probably unfavourable for gastropods living directly on the sea bottom most likely because of a soupy substrate consistency, possible oxygen deficiency near the sediment-water interface and/or oxygen content fluctuations. Adult and/or subadult individuals of these gastropods occur only in the higher part of the section, reflecting a time when these conditions improved. A new heterostrophic gastropod species, Promathildia gedli, is described.

12

Faunal dynamics of bivalves and scaphopods in the Bathonian (Middle Jurassic) ore-bearing clays at Gnaszyn, Kraków-Silesia Homocline, Poland

Kaim A., Sztajner P.

Acta Geologica Polonica

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2012

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Vol. 62, no. 3

381-395

EN

The environment at the Gnaszyn section - as deduced from bivalve and scaphopod dynamics - was controlled by the substrate consistency and possibly oxygen deficiency near the sediment-water interface and/or oxygen content fluctuations. The middle part of the section dominated by nuculoid and corbulid bivalves and Laevidentalium-type scaphopods probably reflects a soupy substrate and possibly oxygen deficiency in the sediment. Slightly coarser and better-oxygenated silts in the upper and lower parts of the section offered a less soupy substrate consistency, allowing the development of communities dominated by astartids, byssate bivalves, and Dentalium- and Plagioglypta-type scaphopods.

13

Calcareous nannofossils from the Bathonian (Middle Jurassic) ore-bearing clays at Gnaszyn as palaeoenvironmental indicator, Kraków-Silesia Homocline, Poland

Kędzierski M.

Acta Geologica Polonica

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2012

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Vol. 62, no. 3

421-437

EN

Qualitative and quantitative studies on calcareous nannofossils have been carried out on the Middle-Upper Bathonian succession of Gnaszyn (Kraków-Silesia Homocline, Częstochowa region). The nannofossil assemblages are moderately or well-preserved and are dominated by Watznaueria britannica; also common are Staurolithites lumina and Zeugrhabdotus erectus. The presence of delicate nannofossil forms together with dissolution-resistant taxa shows that the changes in composition of some of the nannoplankton assemblages reflect original variations. The frequency and diversity changes of the calcareous nannofossil assemblages have been interpreted in relation to fluctuations of sedimentation rate versus changes in trophic conditions within the photic zone. The highest diversity assemblages contain a high percentage of palaeofertility indicators, and are impoverished in the genus Watznaueria. This is interpreted as a reflection of a lower sedimentation rate and more stable, possibly mesotrophic conditions within the photic zone. On the other hand, W. britannica-dominated assemblages with low species diversity may represent more unstable environments with a high influx of terrestrial material related to a high sedimentation rate and a high nutrient influx, i.e. eutrophic conditions in the photic zone.

14

Copepod-infested Bathonian (Middle Jurassic) echinoids from northern France

Radwańska U., Poirot E.

Acta Geologica Polonica

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2010

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Vol. 60, no. 4

549-555

EN

New examples of Bathonian (Middle Jurassic) parasitic exocysts on acrosaleniid echinoid tests are recorded from northern France. These exocysts can be attributed to the life activity of copepod crustaceans and are considered to have been formed as a result of copepod larval settlement in these echinoids by way of the gonopores. Sexual dimorphism is recognised in copepod-infested Acrosalenia spinosa L. Agassiz, 1840, on the basis of size and position of gonopores, those in females being larger and wider apart, those in males smaller and situated subcentrally. The previous stratigraphic range of copepod cysts of this type (i.e., Middle Oxfordian to Middle Kimmeridgian) can now be extended down to the base of the Bathonian (convergens Subzone).

15

A preliminary report on dinosaur track assemblages from the Middle Jurassic of the Imilchil area, Morocco

Gierliński G. D., Menducki P., Janiszewska K., Wicik I., Boczarowski A.

Geological Quarterly

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2009

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Vol. 53, No 4

477-482

EN

Dinosaur tracks are reported from three new localities near Imilchil, in the Central High Atlas of Morocco. New dinosaur track assemblages are recognized in Bathonian and Bajocian beds. The Bathonian track assemblage comprises theropod, sauropod and ornithopod footprints. The Bajocian deposits contain a sauropod-thyreophoran track assemblage.

16

The carbon and oxygen isotope records of Upper Bajocian-Bathonian calcareous fossils from the Polish Jura Chain

Wierzbowski H., Joachimski M.

Volumina Jurassica

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2006

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Vol. 4, no. 1

220-222

EN

A collection of stratigraphically well-dated calcitic and aragonitic fossils (belemnites, ammonites, nautiloids and oysters), derived from Upper Bajocian - Upper Bathonian clays from the Polish Jura Chain (central Poland), were studied for oxygen and carbon isotopes. The preservation state of the shell material was investigated by means of cathodoluminescence microscopy, trace element geochemistry and X-ray diffraction. Palaeotemperatures calculated from the oxygen isotope composition of calcitic shells (belemnites and oysters) are similar to each other despite the significant spread in 18O values (Fig. 1). The 18O values of calcitic fossils generally vary from -0.1 to +1.1‰ VPDB for the studied interval, which corresponds to palaeotemperatures between +7.9 and +12.4°C (calculated with the equation of Anderson & Arthur 1983). The palaeotemperatures derived from the oxygen isotope composition of aragonitic ammonoid and nautiloid shells are distinctly higher (Fig. 1) with most of the estimates ranging from 15 to 23°C (calculated with the equation of Grossman & Ku 1986). The observed temperature difference may have resulted from different depth habitats of the organisms. The ammonites and nautiloids might have lived in surface waters and the temperature contrast might represent a palaeotemperature gradient between thermally stratified surface and deep waters of the Late Bajocian - Late Bathonian sea in the Polish Jura Chain. The ?13C values for the Upper Bajocian - Upper Bathonian belemnite rostra do not indicate major secular variations (Fig. 1). However, the data show a significant scatter of about 1.5‰. Several oyster shells show considerable higher 13C values (around +3‰ VPDB) compared to coeval belemnite rostra (between 0 and +1.5‰ VPDB). This may point to a metabolic fractionation effect that resulted in disequilibrium fractionation of carbon isotopes within belemnite skeletons (cf. Wierzbowski 2002). The aragonitic ammonite and nautiloid shells show a significant variation in 13C with values ranging from -3.7 to +2.2‰ VPDB. The carbon isotope composition of the oysters and the belemnites may suggest that the ?13C value of ancient seawater bicarbonate (HCO3-) averaged +3‰ VPDB.

17

Protoglobigerinids and Oberhauserellidae (Foraminifera) of the Bajocian-Bathonian from the Southern Jura Mts., France

Gorog A., Wernli R.

Volumina Jurassica

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2006

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Vol. 4, no. 1

233-233

EN

The Jurassic protoglobigerinids and other Globigerina-like foraminifera with aragonitic wall are generally considered as the ancestors of the Cretaceous planktonic foraminifera. They have been known for a long time as isolated specimens or in rock thin-sections, but they still raise several morphological and taxonomic problems. A detailed inventory of the Bajocian-Bathonian protoglobigerinids and other globigerina-like Foraminifera from the several localities of Southern Jura Mountains reveals a moderate abundance (>20%) of the Foraminifera fauna - and an unsuspected diversity, with 7 species of Conoglobigerinidae and 2 species of Oberhauserellidae. The discovery of two umbilical apertures in Oberhauserella as well as in some Conoglobigerina questions the generic taxonomy and makes the comparison with literature difficult. For these reasons, five new species have been proposed: Oberhauserella parocula and O.(?) aff. parocula (with 2 apertures), "Conoglobigerina" trilocula and "C". biapertura (with 2 apertures), C. solaperta and C. pupa. We demonstrate that Globuligerina balakhmatovae (Morozova 1961) (here emended) has a small globuligerine aperture as well as G. aff. dagestanica (Morozova 1961). Despite the different taxonomic concepts the Southern Jura Mountains associations, that are typical of the epicontinental platform, resemble the best those of the Dagestan and of the NW Caucasus (Morozova & Moskalenko 1961; Gorbachik 1986). They strongly differ from those of the oceanic Tethys, which are also very diverse (Gorog & Wernli 2002, 2003; Wernli & Gorog 1999, 2000).

18

Bathonian ammonites from the Polish Tatras

Galacz A., Matyja B.

Volumina Jurassica

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2006

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Vol. 4, no. 1

162-162

EN

In the sedimentary sequence of the Polish High Tatras, thin limestone beds with Middle Jurassic, mainly Bathonian fossils have been reported. The best known of these occurrences is that of Wielka Âwistówka Cirques in the Mi´tusia Valley with extremely rich ammonite fauna which became famous for the classic monographs of Passendorfer in 1935 and 1938. The fauna occurs in a condensed bed overlying with considerable hiatus the Middle Triassic shallow-water carbonates, and is covered by Upper Jurassic pelagic limestone. The 8-12 cm thick bed yielded nautiloids, belemnites, ammonites and brachiopods in great profusion, and less commonly other molluscs (bivalves and gastropods). The revision of the ammonite fauna in the collections of Passendorfer indicated that most of the forms is typical of the higher Middle Bathonian Bremeri Zone, with the rich representation of the zonal index and other diagnostic forms, e.g. Prohecticoceras ochraceum, Bullatimorphites eszterensis. Within the perisphinctids, Procerites is dominant and Wagnericeras is rarer which could indicate the lower part of the Bremeri Zone. As interesting rarities, Phlycticeras, Oecoptychius, Thraxites, etc. also appear. However, the collections contain some macrocephalitids and rare Hecticoceras suggesting the presence of the Lower Callovian. While preservational differences cannot be seen between the Bathonian and Callovian fossils, and the recent state of the Wielka Âwistówka exposure did not show this, the best explanation is to suppose an occurrence of a thin, intermittent Callovian layer in between the Bathonian and Upper Jurassic beds as the source of these stratigraphically younger ammonites in the collections. The ammonite fauna is dominated by suborder Ammonitina (66.6%) of which nearly half belongs to the Perisphinctidae, and phylloceratids are represented 32%. This is a faunal composition very close to those from other Bathonian condensed ammonite beds occurring in the Carpathian-Pannon region (e.g. Swinitza in the Southern Carpathians, Villány in South Hungary).

19

Bathonian ammonites of the families Sphaeroceratidae Buckman and Tulitidae Buckman from the Polish Jura Chain (Southern Poland)

Kopik J.

Polish Geological Institute Special Papers

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2006

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Vol. 21

1-68

EN

Early to Middle Bathonian ammonites of the families Sphaeroceratidae Buckman and Tulitidae Buckman have been carefully examined. Specimens were collected from fine grained sediments, which belong to Middle Jurassic "Częstochowa Ore-bearing Clay Formation" of the Polish Jura Chain. Usually ammonites were found within sphaerosiderite nodules. Nodules were collected from numerous clay-pits of Częstochowa suburbs, and from underground mines of Włodowice and Zawiercie regions. Single, well preserved specimen of the rare, Early Bathonian genus Praetulites Westermann (P. rugosus sp. nov.) is the only representative of the family Sphaeroceratidae Buckman. It was discovered in iron-ore mine, in Włodowice, and it represents the youngest known evolutionary member of the genus Praetulites. Family Tulitidae Buckman is widely represented among examined ammonites. It consists of representatives of two subfamilies: Tulitinae Callomon, Dietl, Niederhöfer (genera and subgenera: Tulites Buckman, Rugiferites Buckman, Morrisiceras Buckman and Holzbergia Torrens), and Bullatimorphitinae Callomon, Dietl, Niederhöfer (genera: Sphaeroptychius Lissajous and Bullatimorphites Buckman). New evaluation of the age of subgenera Tulites and Rugiferites is of special interest. Despite previous opinions about their occurrence only within Tulites subcontractus Zone (Middle Bathonian), they have been found within Lower Bathonian of Włodowice, Rudniki, and vicinity of Częstochowa regions. These subgenera were represented by both: new species, and widely known taxa, characteristic for Middle Bathonian of Western Europe. Other representatives of the subfamilies Tulitinae (Morrisiceras, Holzbergia), and Bullatimorphitinae (Sphaeroptychius, Bullatimorphites) were present mostly within upper parts of Middle Bathonian, which confirms previous observations. State of preservation (as sideritic internal moulds with final growth stages of conchs preserved) allowed in many cases to make existing species’ diagnosis more complete.

PL

Szczegółowym badaniom poddano znaleziska dolno- i środkowobatońskich amonitów, należących do rodzin Sphaeroceratidae Buckman i Tulitidae Buckman, pochodzące z serii osadów mułowcowo-ilastych, wchodzących w skład środkowojurajskiej formacji osadowej Jury Polskiej (Polish Jura Chain) częstochowskich iłów rudonośnych. Amonity występowały najczęściej w sferosyderytach, odsłaniających się w licznych gliniankach na obrzeżach Częstochowy oraz w podziemnych wyrobiskach kopalnianych w rejonie Włodowic i Zawiercia. Rodzinę Sphaeroceratidae Buckman, w tym zespole fauny, charakteryzował jeden, dobrze zachowany, pochodzący z dolnego batonu okaz. Należy on do bardzo rzadko stwierdzanego rodzaju Praetulites Westermann (P. rugosus sp. nov.). Znaleziony w kopalni rud żelaza we Włodowicach reprezentuje najmłodsze, z dotychczas poznanych, ogniwo ewolucyjne rodzaju Praetulites. Rodzina Tulitidae była w badanym zespole amonitów znacznie liczniej reprezentowana. Tworzy ją szereg gatunków, często nowych, należących do rodzajów i podrodzajów: Tulites Buckman, Rugiferites Buckman, Morrisiceras Buckman i Holzbergia Torrens (podrodzina Tulitinae Callomon, Dietl, Niederhöfer) oraz taksony podrodziny Bullatimorphitinae Callomon, Dietl, Niederhöfer, na którą składają się gatunki rodzajów Sphaeroptychius Lissajous i Bullatimorphites Buckman. Szczególnie interesująca okazała się ocena wieku znalezionego we Włodowicach i Rudnikach, oraz w bliżej nieokreślonym stanowisku w okolicach Częstochowy, zespołu gatunków z podrodzajów Tulites i Rugiferites. Wbrew dotychczasowym poglądom o ich wyłącznym występowaniu w europejskim środkowym batonie (poziom Tulites subcontractus), znaleziska te odkryte zostały w dolnym batonie. Reprezentowane były zarówno przez nowe gatunki, jak i przez taksony dotychczas uznawane za typowe dla zachodnioeuropejskiego batonu środkowego. Kolejni reprezentanci podrodziny Tulitinae (Morrisiceras, Holzbergia) i Bullatimorphitinae (Sphaeroptychius, Bullatimorphites) zgodnie z dotychczasowymi obserwacjami grupowały się w wyższych odcinkach środkowego batonu. Bardzo dobry na ogół stan ich zachowania (zsyderytyzowane ośródki z końcowymi stadiami wzrostowymi muszli) pozwalał częstokroć uzupełniać dotychczasowe diagnozy gatunkowe.

20

Pyritization of microfossils: crinoid remains from the Middle Jurassic of Ogrodzieniec (Kraków-Częstochowa Upland, Poland)

Szczepanik P., Sawłowicz Z.

Studia Geologica Polonica

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2005

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Vol. 124

37-52

EN

Pyritized crinoid skeletal elements have been found in the so-called "ore-bearing clays" of the Middle Jurassic exposed in Ogrodzieniec (Kraków-Częstochowa Upland, Poland). Their assem- blage consists of columnals, cirrals and brachials; calyx plates have not been found. Ossicles occur both as unpyritized and pyritized. Three main types of pyritization have been distinguished in investigated material: (a) original calcitic skeleton is not replaced by pyrite but its void spaces are infilled with pyrite; (b) calcitic skeleton is replaced by pyrite, with or without void infilling; (c) pyritization overwhelms the primary morphology of the ossicle. The first two types predominate in the studied material. The types of pyritization have been explained by several subsequent stages of this process. The main stage of crinoid pyritization happened probably in the sediment during early diagenesis and was limited to microenvironments of fossils. Different morphological forms of pyrite registered in the same ossicles (euhedra, framboids and massive pyrite, can be explained by different position and time of the fossil pyritization, the type and location of organic matter, porosity, several stages of pyritization, "openness" of skeleton, different assemblages of bacteria, and probably many other factors.