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Matoniaceous ferns preserved in growth position in Lower Jurassic dune sandstones of the Holy Cross Mountains (Poland)

Pacyna Grzegorz

Annales Societatis Geologorum Poloniae

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2021

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Vol. 91, No. 2

137--148

EN

The occurrence of the fern Matonia braunii (Goeppert) Harris, preserved in the growth position in sandstones of dune origin, is documented from the late Pliensbachian Szydłowiec Sandstone of the Drzewica Formation in the Holy Cross Mountains. This plant formed monotypic stands on coastal dunes during a marine highstand. The presence of this common Early Jurassic fern in such an unfavourable environment attests to the huge ecological plasticity of this species.

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High resolution ammonite stratigraphy of the Charmouth Mudstone Formation (Lower Jurassic: Sinemurian-Lower Pliensbachian) in south-west England, UK

Page K.

Volumina Jurassica

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2009

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Vol. 7, no. 1

19-29

EN

The "Lower Lias" mudrocks of the Charmouth Mudstone Formation inWest Dorset coast are world famous for their ammonite faunas, which range from mid Lower Sinemurian (Semicostatum Chronozone) to Lower Pliensbachian (topmost Davoei Chronozone) in age. The succession includes significant non-sequences, however, and as certain other intervals yield only crushed and relatively poorly preserved material, much of the sequence of ammonite faunas of this interval in south-west England has remained poorly understood. Inland, however, although it has been realised for many years that some of the missing horizons reappear, the Formation is very poorly exposed and as a consequence little has been known about its detailed stratigraphy and palaeontology. The systematic recording over 40 years by Mr H.C. Prudden (Montacute) of temporary excavations in East Somerset (around 20 km north of the Dorset coast), combined with material collected by others from similar exposures has now, however, revealed a virtually complete sequence of ammonite faunas through the interval represented by the Formation including from many of the which are missing on the Dorset coast. In particular, only one subchronozone remains to be conclusively proven in the region, the terminal Sinemurian, Aplanatum Subchronozone (Raricostatum Chronozone). This faunal succession is correlated with that on the coast to provide a detailed synthesis of the sequence of ammonite biohorizons in the region, which is correlated with a contemporary Standard Zonation and high-resolution biohorizonal/ zonule scheme for interval in North-West Europe. The significance for regional and international correlations of the Lower Lias is also discussed.

3

Tropy wielkich teropodów z osadów górnego pliensbachu Gór Świętokrzyskich

Niedźwiedzki G., Remin Z.

Przegląd Geologiczny

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2008

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Vol. 56, nr 9

823-823

EN

New gigantic theropod dinosaur footprints were discovered in the upper Pliensbachian deposits of the Holy Cross Mountains (Poland). This discovery provides new ichnological evidence for the global occurrence of gigantic predatory dinosaurs in the earliest Jurassic time. Interestingly, this is the third find of gigantic theropod ichnites in the Lower Jurassic of Poland. The first record of gigantic tracks from this area came from the well-known lower Hettangian tracksite in Sołtyków. New finds from the Szydłówek quarry were discovered in siliciclastic strata, which are interpreted as nearshore, shoreface and marginal marine. Hitherto, five isolated specimens of gigantic theropod footprints (40–60 cm long) were found in this tracksite. Another large theropod footprints (30–40 cm) identified at Szydłówek, resemble classic theropod ichnotaxa of the Newark Supergroup (i.e., Eubrontes). Intriguing gigantic theropod ichnites from the Holy Cross Mountains are more similar to large prints left byMiddle and Late Jurassic theropods than to those from the Early Jurassic. These footprints seem even larger because of their large metatarsophalangeal area. Relatively large metatarsophalangeal area is often observed in the large theropod footprints from the post-Liassic strata. New paleoichnological finds from Poland suggest rapid increase of predatory dinosaur body size in Early Jurassic time.

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The Pliensbachian/Toarcian boundary in Canada: ammonite succession and correlations

Macchioni F., Palfy J., Smith P.

Volumina Jurassica

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2006

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Vol. 4, no. 1

182-182

EN

The Pliensbachian-Toarcian transition in North America is best typified by the Queen Charlotte Island ammonite succession where 3 assemblages are recognized, all of which include representatives of Lioceratoides, Protogrammoceras and Tiltoniceras. The lower assemblage also includes Fanninoceras, Amaltheus and Arieticeras, and is placed in the Pliensbachian (Carlottense Zone). The upper assemblage also includes the first occurrences of Dactylioceras and is placed in the Toarcian (Kanense Zone). The correlation of the intermediate assemblage is uncertain and it was initially placed in the Pliensbachian because it occurred beneath Dactylioceras and above Amaltheus. However, Pleuroceras that characterizes the northwest European uppermost Pliensbachian does not occur in British Columbia and it is also questionable whether the incoming of the genus Dactylioceras can be used as a means of correlation with the basal Toarcian (Tenuicostatum Zone) of northwest Europe. Consequently, it has been difficult to confidently correlate the Pliensbachian-Toarcian transition as defined in North America with the boundary as defined in northwest Europe. Light is being shed on this problem by recent work on faunas from the Laberge Group in the Yukon Territory and the Spatsizi Formation (Hazelton Group) in northcentral British Columbia. As has often been noted, Canadian sequences show stronger affinities with Mediterranean successions rather than the Boreal successions of northwest Europe. In addition to representatives of Fontanelliceras, Neolioceratoides, Canavaria, Bouleiceras and Tauromeniceras, there are several new occurrences of Dactylioceras. The Tethyan Dactylioceras cf. simplex occurs low in the Kanense Zone and suggests a correlation with the D. simplex horizon of the basal Polymorphum Zone in the Mediterranean area, which predates the basal Tenuicostatum Zone of NW Europe.

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Sinemurian to lowermost Toarcian ammonites of the Brescian Alps (Southern Alps, Italy): biostratigraphical framework and correlations

Meister Ch., Schirolli P., Dommergues J-L.

Volumina Jurassica

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2006

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Vol. 4, no. 1

184-185

EN

A set of 28 ammonite biohorizons or faunal assemblages can be proposed for the Sinemurian, the Pliensbachian and the lowermost Toarcian in the Brescian Alps, in part based on the data from Dommergues et al. (1997) and partly on new results, deriving both from recent field investigations and from the study of the historical collection of the Lower Jurassic ammonites preserved in the Museum of Natural Sciences of Brescia (Northern Italy), placed into their stratigraphical framework (Fig. 1). The biohorizons are referred to the Liassic carbonate succession of the Brescian Alps, outcropping between the eastern surroundings of Brescia (Botticino), to the East, and the Lake Iseo, to the West. Since the Hettangian the region was subjected to the paroxismal phase of the Jurassic rifting and the area of study was located in the eastern border of the wide Lombardian Basin, a part of the southern continental passive margin of the Tethys. At the beginning of Jurassic, an articulated fault-system, composed of N-S master faults (W-dipping) and W-E transfer faults, located from Brescia to the North, separated a western growing basinal area from the eastern Botticino structural high. Since Hettangian to the onset of Toarcian, almost 1000 m of well-stratified cherty marly limestones of the Medolo Group (Gardone Val Trompia Limestone and Domaro Limestone formations) represent the synrift deposition of the Sebino Basin, following the drowning of the Raethian-Hettangian Corna Platform. In contrast, after the Early Sinemurian a coeval reduced sequence (50 m thick), composed by the Rezzato Encrinite (Lower Sinemurian to Upper Carixian) and the overlying thinly-bedded and nodular ammonitic marly limestones of the Botticino Corso Rosso (Upper Carixian and Domerian), covered the Corna Platform in the Botticino High. The recognized ammonite biohorizons and assemblages are quite well integrated and correlable with either the NW European standard zonation or the different zonations given for the Tethyan realm (Appennines, Subbeticas and Austrian and Hungarian Upper Austroalpine). Most of these stratigraphical units are based on Tethyan taxa. Only two horizons (U. cf. jamesoni horizon and P. solare horizon) show NW European affinites. Moreover the E. quenstedti horizon is only known from the northern margin of the Tethys, mainly from the Upper Austroalpine units.

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Sequence stratigraphy and depositional setting of the Pliensbachian and Toarcian marly limestones in the Lusitanian Basin, Portugal

Duarte L.

Volumina Jurassica

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2006

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Vol. 4, no. 1

157-158

EN

The Pliensbachian and Toarcian series in the Lusitanian Basin (Portugal) are generally dominated by hemipelagic deposits, represented by marl/limestone alternations that are very rich in nektonic and benthic fauna. These sediments are included in the following four formations: Vale das Fontes, Lemede, S. Giăo and, partially, Póvoa da Lomba. The weak lateral facies variation, generally observed at the basin scale, suggests that these sediments were deposited in an epicontinental extensional basin on a homoclinal carbonate ramp controlled by eustatic fluctuations and regional tectonics. Considering the Late Triassic – Late Callovian large cycle, the sediments correspond to the maximum transgressive facies which can be widely observed throughout the succession. A detailed studied of several stratigraphic sections in terms of sedimentological, geochemical and paleontological analysis shows that the Pliensbachian-Toarcian series is subdivided into two second-order sequences (SP and ST). The Pliensbachian succession shows a typical second-order transgressive/regressive sequence, with a dominant marly deposition at the base and a calcareous dominant facies at the top. The basal discontinuity of the SP is particularly well observed in the western part of the basin, dating roughly from the Sinemurian/Pliensbachian boundary. The series shows a large transgressive phase, ending in the middle-upper part of the Margaritatus Zone (around Subnodosus/Gibbosus subzones boundary) associated with an organic-rich deposition verified at the basin scale. During the Spinatum Zone the sedimentation returned to a calcareous regime very rich in benthic macrofauna. The upper discontinuity of the SP observed in the whole basin dates from the lowermost Polymorphum Zone (intra-Mirable Subzone). The base of ST (Polymorphum Zone) corresponds to an abrupt flooding event, through a generalised marly accumulation in the whole basin. However, around the Polymorphum-Levisoni interval, an important tectonic activity occurred, responsible for a great sedimentary change with special facies features in some positions of the basin. The dominance of marl observed at the top of the Levisoni Zone marks the maximum peak transgression of the Toarcian second-order sequence, showing some evidence of pelagic deposition, with thin-shelled bivalve-rich (Bositra sp.) horizons. The Upper Toarcian – Lower Aalenian succession shows a regressive trend, ending ST with an upward increase of calcareous and bioclastic content, including ahermatipic corals in the eastern sectors. The upper discontinuity dates from the Opalinum Zone and shows different sedimentary records across the basin. ST it is subdivided into four third-order depositional sequences (St1 to St4), each bounded by regional discontinuities, recognized over most parts of the Lusitanian Basin.

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Pliensbachian – lowermost Toarcian chemostratigraphy (elemental and TOC) of the Peniche section (Lusitanian Basin, Portugal)

Veiga de Oliveira L., Duarte L., Rodrigues R.

Volumina Jurassica

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2006

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Vol. 4, no. 1

217-218

EN

In Portugal, the Peniche section constitutes one of the most continuous series of Lower Jurassic. This study is based on a detailed chemostratigraphic analysis of the Pliensbachian - lowermost Toarcian marly limestones, belonging to the Vale das Fontes, Lemede and Cabo Carvoeiro formations. 196 samples of limestones and marls were analyzed in terms of minor and major elements (Fig. 1). Total organic carbon (TOC) was determined in 233 samples. Besides the stratigraphic distribution of these geochemical parameters, the aim of this work is to perform a discussion about biogenic influx and aluminosilicate phasefluxes. The Al concentrations are a good indicator of detrital flux and good correlations between them signify aluminosilicate affiliation. In Peniche, K (0.98), Si (0.96) and Ti (0.98) show, in all section, excellent correlation with Al2O3. Mg (0.82), Ba (0.80), Cr (0.78), Li (0.80), Na (0.74), Sc (0.80), V (0.81) and Zr (0.86) correlate well with Al2O3 but other secondary factors, beyond the detrital flux, affect the resultant concentrations. The Pearson's coefficients between Al2O3 and CaO is strongly negative (-0.98), suggesting divergent behaviours for this elements. Al2O3 and Fe2O3 correlate moderately (0.61). However, the correlation coefficients calculated for each stratigraphic unit show variable values. Lemede Formation and the Members Marls and Limestones with Uptonia and Pentacrinus (MLUP), Lumpy Marls and Limestones (LML), to the Vale das Fontes Formation, and CC1, to the Cabo Carvoeiro Formation, show high correlation coefficients between Al2O3 and Fe2O3 (0.87, 0.91, 0.88 and 0.97, respectively). On the other hand, the Member CC2 has moderate correlation (0.67) and the Member Marls and Limestones with Bituminous Shales (MLBF) has weak correlation (0.20). These variations suggest that the elemental inputs change during the Pliensbachian - lowermost Toarcian, in the Peniche area. Ba enrichment is considered an indicator of high flux of biogenic material and high surface-water productivity. But, in the studied section, correlation between Al2O3 and Ba is high (0.80) and Ba lacks any correlation with TOC (0.17). Thus, in the Peniche region, the distribution of Ba is dominated by the original detrital flux and transported to the basin, mainly, as a constituent of clays. The mainly TOC values in the Pliensbachian - lowermost Toarcian of the Peniche section are below 2. But the MLBF (Ibex to Margaritatus zones) represents a high TOC interval with concentrations up to 15%, correlated with the 2nd order flooding interval, well know in the Lusitanian Basin.

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Pliensbachian calcareous nannofossil zones vs ammonite zones along the western and northern margins of the Iberian Massif and biostratigraphical potential of nannobiohorizons

Perilli N., Veiga de Oliveira L., Comas-Rengifo M., Duarte L.

Volumina Jurassica

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2006

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Vol. 4, no. 1

202-203

EN

Calcareous nannofossils, one of the main components of Lower Jurassic marly/limestone alternations, were studied along the western and northern margins of the Iberian Massif. Consequently, they were used to date the lithological successions as well abiotic signals (e.g. isotope or TOC profiles). Our work focuses on the main changes of calcareous nannofossil record and the biohorizons recognized in some reference Pliensbachian sections from Basque-Cantabrian area (Spain) and Lusitanian Basin (Portugal). The remarkable changes in composition are the appearances and abundance increases of the Biscutaceae (Similiscutum) and of Watznaueriaceae (Lotharingius). The appearances of large Biscutum (B. grande and B. finchii) and of medium-sized Lotharingius species (L. sigillatus) are also clearly detectable though their occurrence is discontinuous. The other events include the appearances of Biscutum dubium, Bussonius prinsii, Biscutum novum and Crepidolithus impontus and the disappearance of Parhabdolithus robustus. The reconstructed distribution pattern of the age-significant species supports the identification and description of the nannofossil zones and subzones proposed for NW Europe. The NJ3/NJ4, NJ4/NJ5 zone boundaries are easily identified by the FO of Similiscutum cruciulus (Lower Pliensbachian) and the FO of Lotharingius hauffii (Upper Pliensbachian), respectively. The subzone boundaries should be carefully checked because the zonal markers are rare and occur discontinuously. However, the other events are helpful to correlate the biostratigraphic frames outlined for the investigated areas and to calibrate the NJ4a/NJ4b, NJ5a/NJ5b zone boundaries with respect to the ammonite zones. Based on the achieved data, the main differences between the two schemes are related to the very low abundance and discontinuous occurrence of the some species in their initial (e.g., B. grande, B. finchii) or final (e.g., P. robustus) ranges. Since for the Basque-Cantabrian area ammonite zone and subzones are well constrained, some discrepancies should be related with a discontinuous or incomplete ammonite record from the Lusitanian Basin. Nevertheless, the biostratigraphic frames proposed for both areas could improve biochronocorrelation between the Pliensbachian successions cropping out along the western and northern margin of the Iberian Massif.

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High resolution ammonite stratigraphy of the Charmouth Mudstone Formation (Lower Jurassic: Sinemurian – Lower Pliensbachian) in South West England (UK)

Page K.

Volumina Jurassica

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2006

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Vol. 4, no. 1

200-200

EN

The “Lower Lias” mudrocks of the Charmouth Mudstone Formation in West Dorset coast are world famous for their ammonite faunas, which range from mid Early Sinemurian (Semicostatum Chronozone) to Early Pliensbachian (topmost Davoei Chronozone) in age. The succession includes significant non-sequences, however, and as certain other intervals yield only crushed and relatively poorly preserved material, much of the sequence of ammonite faunas of this interval in South West England has remained poorly understood. Inland, however, although it has been realized for many years that some of the missing horizons reappear, the Formation is very poorly exposed and as a consequence little has been known about its detailed stratigraphy and palaeontology. The systematic recording over 40 years by Mr H. C. Prudden (Somerset Geology Group) of temporary excavations in East Somerset (around 20 km north of the Dorset coast) has now, however, revealed a virtually complete sequence of ammonite faunas through the interval represented by the Formation. In particular, many levels have now been identified which are missing in the major non-sequences on the Dorset coast, thereby revealing a much more complete stratigraphical sequence in the region than previously realized. In particular, only one subchronozone remains to be conclusively proven – the Aplanatum Subchronozone of the Raricostatum Chronozone – although this could still be due to collection failure as nodular facies do not appear to be present at this level and near-surface clay exposures are often too degraded to yield determinable specimens. This faunal succession is correlated with that on the coast to provide a detailed synthesis of the sequence of ammonite biohorizons in the region, which is correlated with a contemporary Standard Zonation and high-resolution biohorizonal/zonule scheme for interval in North West Europe. The significance for regional and international correlations of the Lower Lias is also discussed.

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Calcareous nannofossils biostratigraphy and oxygen isotope composition of belemnites: Pliensbachian – lowermost Toarcian of Peniche (Lusitanian Basin, Portugal)

Veiga de Oliveira L., Duarte L., Rodrigues R., Perilli N.

Volumina Jurassica

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2006

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Vol. 4, no. 1

219-219

EN

The Lusitanian Basin is located in the western Iberian margin, opened during the Triassic.The Lower Jurassic is particularly well represented at Peniche, which exhibits a continuous seriesof carbonate sediments, more than 450 m thick and aged between Sinemurian and Toarcian.In lithostratigraphic terms it corresponds to the Agua de Madeiros, Vale das Fontes, Lemede and CaboCarvoeiro formations. In this study, 145 m thick section (from the Jamesoni to the Levisoni ammonite zones),was analyzed in terms of calcareous nannofossils biostratigraphy and oxygen isotopes of belemnite rostra.The nannofossil biozones NJ4a, NJ4b, NJ5a (Pliensbachian; upper part of Jamesoni to Spinatumammonite zones), NJ5b (uppermost Pliensbachian - lowermost Toarcian; upper part of Spinatumto Levisoni ammonite zones) and NJ6 (lowermost Toarcian; upper part of Levisoni ammonite Zone) wereidentified based on proposed NW European schema and correlated with ammonite zones. Additionally,the secondary biostratigraphic events were registered which will be useful to refine the nannofossilsbiozonation: the first occurrences (FO) of Biscutum grande and B. finchii were found in the upper part ofthe NJ4a biozone (lower part of Margaritatus ammonite Zone); the FO of Lotharingius frodoi wasidentified at the same stratigraphical level as L. hauffii; the FO of L. sigillatus was found in the upper partof the NJ5a biozone (Spinatum Zone); the first common occurrence (FCO) of Calyculus spp. was recognizedin the NJ5b base, near the Pliensbachian/Toarcian boundary; the FO of Carinolithus spp. was identifiedwithin NJ5b biozone, correlated with the lower part of the Levisoni ammonite Zone and below the extinctionlevels of Calcivascularis jansae and B. grande which are other nannofossil secondary events.The oxygen-isotope profile of the Peniche section seems to reflect primary signals and can be usedto interpret the sea water paleotemperatures variations. In the Early Pliensbachian the temperature showsa gradual cooling trend (NJ3 and the lower part of the NJ4a; Jamesoni ammonite Zone). Afterward,there is a warm period (NJ4a and NJ4b; Jamesoni to lower part of Spinatum ammonite Zone) correlatedwith high TOC values interval (up to 15%), suggesting a relative sea level rise and concomitant high surfacewaterproductivity. In fact, the Margaritatus ammonite Zone corresponds, in the Lusitanian Basin,to 2nd-order flooding interval. In the Late Pliensbachian and Early Toarcian (NJ5a and lowermost partof NJ5b; Spinatum to Polymorphum ammonite zones), the isotopic values show slight variations.However, they suggest a small cooling trend in the upper part of Spinatum ammonite Zone and a warmtendency in the lower part of Polymorphum ammonite Zone.