scholarly journals Dapedium sp. from the Toarcian (Lower Jurassic) Úrkút Manganese Ore Formation (Bakony Mts., Hungary) and an overview of diversity of dapediiform fishes

2019 ◽  
Vol 100 (1) ◽  
pp. 179-195
Author(s):  
Márton Szabó ◽  
József Pálfy
Keyword(s):  
Fossil Record ◽  
Temporal Distribution ◽  
Lower Jurassic ◽  
Late Triassic ◽  
Feeding Strategies ◽  
Manganese Ore ◽  
Body Parts ◽  
Ore Formation ◽  
Oceanic Anoxic Event ◽  
Actinopterygian Fishes

Abstract Dapediidae are a characteristic group of deep-bodied Mesozoic actinopterygian fishes with a moderate diversity at genus- and species-level. Here, we add a new occurrence to their patchy fossil record and describe in detail a nearly complete dapediid specimen from the pelagic deposit of the Toarcian Úrkút Manganese Ore Formation in the Transdanubian Range of Hungary. The preserved characters represent nearly all anatomically important body parts and allow assignment to Dapedium and comparison with other dapediid genera. This is the first reported occurrence of the order in Hungary and the Carpathian Basin that extends the known geographical range of the genus to the Mediterranean (western Tethyan) Jurassic. A review of the temporal distribution of published occurrences of dapediids permits speculation that the disappearance of exclusively Late Triassic genera, coincident with the end-Triassic extinction event, was likely related to their specialised feeding strategies and light or incomplete squamation. Multiple environmental crises (warming, acidification and anoxia) severely affected reefal habitats and favoured the survival of the generalist-durophagous Dapedium. The Úrkút specimen adds important data to the Early Jurassic, particularly Toarcian Lagerstätte-dominated fossil record of dapediids. In contrast to the end-Triassic, the Toarcian oceanic anoxic event did not lead to genus extinction among dapediids, possibly prevented by adaptations evolved during the preceding and similarly multi-stressor event. Continuing studies of Mesozoic fish specimens in Hungarian collections may provide new records and insights into other groups as well.

scholarly journals Smectite appearance in the footwall of the Úrkút manganese ore deposit, Bakony Mts., Hungary

2019 ◽  
Vol 62 (1) ◽  
pp. 100-118
Author(s):  
Máté Zsigmond Leskó ◽  
Richárd Zoltán Papp ◽  
Boglárka Anna Topa ◽  
Ferenc Kristály ◽  
Tamás Vigh ◽  
...  
Keyword(s):  
Flow System ◽  
Manganese Carbonate ◽  
Manganese Ore ◽  
Ore Formation ◽  
Ore Deposit ◽  
Oceanic Anoxic Event ◽  
The Past ◽  
Anoxic Event ◽  
Core Storage ◽  
The Relationship

The Úrkút manganese ore deposit (Transdanubian Range, Hungary) is one of the largest manganese accumulations to be formed during the Toarcian Oceanic Anoxic Event. In the past 60 years, the area was investigated intensively. The core storage facility of the manganese mine had more than 20,000 sample pieces. Most of these samples have never been investigated. During this study, which is the first widespread clay mineral study in the footwall of the Úrkút manganese ore deposit, we investigated 40 samples from seven boreholes (footwall rocks, black/gray shales below and above the first ore bed, and manganese carbonate ores). Although previous studies assumed that smectite is associated only with the ore beds, our research revealed its appearance in the footwall (Pliensbachian) as well. Simultaneously, tripoli (the local name of completely bleached chert) can also be found in the footwall. Based on the investigated samples, a sharp geochemical difference was detected between Pliensbachian and Toarcian sediments. In this paper, we try to trace the relationship between the smectite content of the footwall and the ore bed and compare these results with the observed geochemical changes. Based on the new data, we assume that the ore accumulation was caused by a flow system (upwelling-controlled ore formation).

scholarly journals The impact of the Toarcian Oceanic Anoxic Event (T-OAE) on the radiation of Early Jurassic dinoflagellate cysts in the Lusitanian Basin, Portugal

2019 ◽  
Author(s):  
Vânia Fraguito Correia ◽  
James B. Riding ◽  
Luís V. Duarte ◽  
Paulo Fernandes ◽  
Zélia Pereira
Keyword(s):  
Fossil Record ◽  
Lower Jurassic ◽  
Early Jurassic ◽  
Dinoflagellate Cysts ◽  
Dinoflagellate Cyst ◽  
Oceanic Anoxic Event ◽  
Eukaryotic Phytoplankton ◽  
The Family ◽  
The Impact ◽  
Lusitanian Basin

Dinoflagellates, together with diatoms and coccolithophores, form a major element of the marine eukaryotic phytoplankton, and are significant primary producers. Based on the fossil record, dinoflagellates appeared in Middle Triassic and during the Early Jurassic (late Pliensbachian) and underwent an important evolutionary radiation episode, with the occurrence of around 40 new species. The Lower Jurassic is particularly well-developed in the Lusitanian Basin of central western Portugal. This depocentre is filled mainly with marine Jurassic sediments, characterized by marl-limestone alternations. We analysed 214 samples from six Lower Jurassic sections in the Lusitanian Basin. The Pliensbachian–Toarcian succession in the Lusitanian Basin is characterised by relatively low dinoflagellate cyst diversity. Only fifteen taxa were recorded; these are assigned to seven genera. These are Luehndea, Mancodinium, Mendicodinium, Nannoceratopsis, Scriniocassis, Sentusidinium and Valvaeodinium. At the base of upper Pliensbachian (Amaltheus margaritatus ammonite biozone) the first dinoflagellate cyst appearances in the Lusitanian Basin are recorded, corresponding to the late Pliensbachian radiation event of this group. We identified the inceptions of Mancodinium semitabulatum, Luehndea spinosa, which belong to the family Mancodiniaceae, Nannoceratopsis gracilis and Nannoceratopsis senex, representing the family Nannoceratopsiaceae are also present. This family is confined to the Jurassic and the genus Nannoceratopsis is the only representative. These taxa became very common and abundant throughout the remaining late Pliensbachian and early Toarcian (Dactylioceras polymorphum ammonite biozone), before the T-OAE. The T-OAE in the Lusitanian Basin is expressed at the base of Hildaites levisoni ammonite biozone and is characterised by the apparent extinction of Luehndea spinosa and the disappearance of all dinoflagellate cyst taxa. During the remaining Toarcian only four new genera and families were identified and the abundance of this group is consistently very low. Apparently, the palaeoenvironmental changes associated with the T-OAE were more extensive in the Lusitanian Basin, compared with coeval basins in northern Europe. Hence, the T-OAE in this basin strongly affected the dinoflagellate cyst evolution patterns. Nevertheless, the late Toarcian of the Lusitanian Basin included an important evolutionary episode, namely the emergence of the first Gonyaulacaceae, due to the appearance of Sentusidinium. The family Gonyaulacaceae continued their diversification and became the most abundant family of cyst-forming dinoflagellates in the fossil record. In conclusion, the late Pliensbachian radiation of dinoflagellate cysts is well documented in the Lusitanian Basin and the T-OAE drastically affected the morphological experimentation period of this group during the remaining Early Jurassic.

scholarly journals The ‘Last Hurrah of the Reigning Darwinulocopines’? Ostracoda (Arthropoda, Crustacea) from the Lower Jurassic Moenave Formation, Arizona and Utah, USA

2018 ◽  
Vol 92 (4) ◽  
pp. 648-660 ◽  
Author(s):  
Lucas S. Antonietto ◽  
Lisa E. Park Boush ◽  
Celina A. Suarez ◽  
Andrew R.C. Milner ◽  
James I. Kirkland
Keyword(s):  
Asexual Reproduction ◽  
Fossil Record ◽  
Late Jurassic ◽  
Lacustrine Sediments ◽  
Lower Jurassic ◽  
Late Triassic ◽  
Geographical Isolation ◽  
Central Atlantic Magmatic Province ◽  
Central Atlantic ◽  
Moenave Formation

AbstractAn ostracode fauna is described from lacustrine sediments of the Hettangian, Lower Jurassic, Whitmore Point Member of the Moenave Formation. The Moenave is well known for its rich, Late Triassic?–Early Jurassic fossil record, which includes fossil fishes, stromatolites, ostracodes, spinicaudatans, and a diverse ichnofauna of invertebrates and vertebrates. Four ostracode species, all belonging to the suborder Darwinulocopina, were recovered from these sediments:Suchonellina globosa,S. stricta,Whipplella? sp. 1, andW.? sp. 2. The diversity and composition of the Whitmore Point Member ostracode fauna agree with previous interpretations about Lake Dixie and nearby paleoenvironments as shallow lakes inhabited by darwinulocopine species that survived the effects of the Central Atlantic Magmatic Province and the subsequent end-Triassic extinction and quickly recolonized these areas, thanks to asexual reproduction by parthenogenesis. The Lake Dixie region, in its geographical isolation, could represent the last episode of darwinulocopine dominance in nonmarine environments before the Late Jurassic diversification of the cypridocopine/cytherocopine modern ostracodes.

Protremaster, a new Lower Jurassic genus of asteroid from Antarctica

1985 ◽  
Vol 122 (4) ◽  
pp. 351-359 ◽  
Author(s):  
Andrew B. Smith ◽  
T. H. Tranter
Keyword(s):  
Fossil Record ◽  
Lower Jurassic ◽  
Early Jurassic ◽  
Late Triassic ◽  
Morphological Diversification ◽  
The Family

AbstractA new and well-preserved.asteroid, Protremaster uniserialis (gen. & sp.nov.) is described from the Lower Jurassic (Sinemurian) of Antarctica. This find extends the fossil record of the family Asterinidae and the subfamily Tremasterinae considerably and lends support to the idea that asteroids underwent an important morphological diversification in the late Triassic-early Jurassic.

scholarly journals The impact of the Toarcian Oceanic Anoxic Event (T-OAE) on the radiation of Early Jurassic dinoflagellate cysts in the Lusitanian Basin, Portugal

2019 ◽  
Author(s):  
Vânia Fraguito Correia ◽  
James B. Riding ◽  
Luís V. Duarte ◽  
Paulo Fernandes ◽  
Zélia Pereira
Keyword(s):  
Fossil Record ◽  
Lower Jurassic ◽  
Early Jurassic ◽  
Dinoflagellate Cysts ◽  
Dinoflagellate Cyst ◽  
Oceanic Anoxic Event ◽  
Eukaryotic Phytoplankton ◽  
The Family ◽  
The Impact ◽  
Lusitanian Basin

Dinoflagellates, together with diatoms and coccolithophores, form a major element of the marine eukaryotic phytoplankton, and are significant primary producers. Based on the fossil record, dinoflagellates appeared in Middle Triassic and during the Early Jurassic (late Pliensbachian) and underwent an important evolutionary radiation episode, with the occurrence of around 40 new species. The Lower Jurassic is particularly well-developed in the Lusitanian Basin of central western Portugal. This depocentre is filled mainly with marine Jurassic sediments, characterized by marl-limestone alternations. We analysed 214 samples from six Lower Jurassic sections in the Lusitanian Basin. The Pliensbachian–Toarcian succession in the Lusitanian Basin is characterised by relatively low dinoflagellate cyst diversity. Only fifteen taxa were recorded; these are assigned to seven genera. These are Luehndea, Mancodinium, Mendicodinium, Nannoceratopsis, Scriniocassis, Sentusidinium and Valvaeodinium. At the base of upper Pliensbachian (Amaltheus margaritatus ammonite biozone) the first dinoflagellate cyst appearances in the Lusitanian Basin are recorded, corresponding to the late Pliensbachian radiation event of this group. We identified the inceptions of Mancodinium semitabulatum, Luehndea spinosa, which belong to the family Mancodiniaceae, Nannoceratopsis gracilis and Nannoceratopsis senex, representing the family Nannoceratopsiaceae are also present. This family is confined to the Jurassic and the genus Nannoceratopsis is the only representative. These taxa became very common and abundant throughout the remaining late Pliensbachian and early Toarcian (Dactylioceras polymorphum ammonite biozone), before the T-OAE. The T-OAE in the Lusitanian Basin is expressed at the base of Hildaites levisoni ammonite biozone and is characterised by the apparent extinction of Luehndea spinosa and the disappearance of all dinoflagellate cyst taxa. During the remaining Toarcian only four new genera and families were identified and the abundance of this group is consistently very low. Apparently, the palaeoenvironmental changes associated with the T-OAE were more extensive in the Lusitanian Basin, compared with coeval basins in northern Europe. Hence, the T-OAE in this basin strongly affected the dinoflagellate cyst evolution patterns. Nevertheless, the late Toarcian of the Lusitanian Basin included an important evolutionary episode, namely the emergence of the first Gonyaulacaceae, due to the appearance of Sentusidinium. The family Gonyaulacaceae continued their diversification and became the most abundant family of cyst-forming dinoflagellates in the fossil record. In conclusion, the late Pliensbachian radiation of dinoflagellate cysts is well documented in the Lusitanian Basin and the T-OAE drastically affected the morphological experimentation period of this group during the remaining Early Jurassic.

The nasal cavity of two traversodontid cynodonts (Eucynodontia, Gomphodontia) from the Upper Triassic of Brazil

2021 ◽  
pp. 1-16
Author(s):  
Arymathéia Santos Franco ◽  
Rodrigo Temp Müller ◽  
Agustín G. Martinelli ◽  
Carolina A. Hoffmann ◽  
Leonardo Kerber
Keyword(s):  
Nasal Cavity ◽  
Fossil Record ◽  
Nasal Septum ◽  
Internal Surface ◽  
Nasolacrimal Duct ◽  
Upper Triassic ◽  
Late Triassic ◽  
Southern Brazil ◽  
Dorsal Region ◽  
Left And Right

Abstract Traversodontidae is a group of Triassic herbivorous/omnivorous cynodonts that represents the most diversified lineage within Cynognathia. In southern Brazil, a rich fossil record of late Middle/mid-Late Triassic cynodonts has been documented, with Exaeretodon riograndensis Abdala, Barberena, and Dornelles, 2002 and Siriusgnathus niemeyerorum Pavanatto et al., 2018 representing two abundant and well-documented traversodontids. The present study provides a comparative analysis of the morphology of the nasal cavity, nasal recesses, nasolacrimal duct, and maxillary canals of both species using computed tomography, highlighting the changes that occurred in parallel to the origin of mammaliaforms. Our results show that there were no ossified turbinals or a cribriform plate delimiting the posterior end of the nasal cavity, suggesting these structures were probably cartilaginous as in nonmammaliaform cynodonts. Both species show lateral ridges on the internal surface of the roof of the nasal cavity, but the median ridge for the attachment of a nasal septum is absent. Exaeretodon riograndensis and S. niemeyerorum show recesses on the dorsal region of the nasal cavity, which increase the volume of the nasal cavity, potentially enhancing the olfactory chamber and contributing to the sense of smell. On the lateral sides of the nasal cavity, the analyzed taxa show a well-developed maxillary recess. Although E. riograndensis and S. niemeyerorum have roughly similar nasal cavities, in the former taxon, the space between the left and right dorsal recesses of the nasal cavity is uniform along its entire extension, whereas this space narrows posteriorly in S. niemeyerorum. Finally, the nasolacrimal duct of S. niemeyerorum is more inclined anteroposteriorly than in E. riograndensis.

scholarly journals Multi-Proxy Provenance Analyses of the Kingriali and Datta Formations (Triassic—Jurassic Transition): Evidence for Westward Extension of the Neo-Tethys Passive Margin from the Salt Range (Pakistan)

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 573
Author(s):  
Shahid Iqbal ◽  
Michael Wagreich ◽  
Mehwish Bibi ◽  
Irfan U. Jan ◽  
Susanne Gier
Keyword(s):  
Lower Jurassic ◽  
Sediment Supply ◽  
Heavy Mineral ◽  
Passive Margin ◽  
Indian Plate ◽  
Late Triassic ◽  
Indian Shield ◽  
Margin Setting ◽  
Salt Range ◽  
Mineral Data

The Salt Range, in Pakistan, preserves an insightful sedimentary record of passive margin dynamics along the NW margin of the Indian Plate during the Mesozoic. This study develops provenance analyses of the Upper Triassic (Kingriali Formation) to Lower Jurassic (Datta Formation) siliciclastics from the Salt and Trans Indus ranges based on outcrop analysis, petrography, bulk sediment elemental geochemistry, and heavy-mineral data. The sandstones are texturally and compositionally mature quartz arenites and the conglomerates are quartz rich oligomictic conglomerates. Geochemical proxies support sediment derivation from acidic sources and deposition under a passive margin setting. The transparent heavy mineral suite consists of zircon, tourmaline, and rutile (ZTR) with minor staurolite in the Triassic strata that diminishes in the Jurassic strata. Together, these data indicate that the sediments were supplied by erosion of the older siliciclastics of the eastern Salt Range and adjoining areas of the Indian Plate. The proportion of recycled component exceeds the previous literature estimates for direct sediment derivation from the Indian Shield. A possible increase in detritus supply from the Salt Range itself indicates notably different conditions of sediment generation, during the Triassic–Jurassic transition. The present results suggest that, during the Triassic–Jurassic transition in the Salt Range, direct sediment supply from the Indian Shield was probably reduced and the Triassic and older siliciclastics were exhumed on an elevated passive margin and reworked by a locally established fluvio-deltaic system. The sediment transport had a north-northwestward trend parallel to the northwestern Tethyan margin of the Indian Plate and normal to its opening axis. During the Late Triassic, hot and arid hot-house palaeoclimate prevailed in the area that gave way to a hot and humid greenhouse palaeoclimate across the Triassic–Jurassic Boundary. Sedimentological similarity between the Salt Range succession and the Neo-Tethyan succession exposed to the east on the northern Indian passive Neo-Tethyan margin suggests a possible westward extension of this margin.

A Geographical Information System (GIS) study of Triassic vertebrate biochronology

2005 ◽  
Vol 142 (4) ◽  
pp. 327-354 ◽  
Author(s):  
E. J. RAYFIELD ◽  
P. M. BARRETT ◽  
R. A. McDONNELL ◽  
K. J. WILLIS
Keyword(s):  
Spatial Data ◽  
Geographical Information Systems ◽  
Western Europe ◽  
Temporal Distribution ◽  
Geographical Information ◽  
Late Triassic ◽  
Spatial And Temporal Scales ◽  
Potential Index ◽  
The Stability ◽  
Land Vertebrate

Geographical Information Systems (GIS) have been applied extensively to analyse spatial data relating to varied environmental issues, but have not so far been used to address biostratigraphical or macroevolutionary questions over extended spatial and temporal scales. Here, we use GIS techniques to test the stability, validity and utility of proposed Middle and Late Triassic ‘Land Vertebrate Faunachrons’ (LVFs), a global biostratigraphical framework based upon terrestrial/freshwater tetrapod occurrences. A database of tetrapod and megafloral localities was constructed for North America and Western Europe that also incorporated information on relevant palaeoenvironmental variables. This database was subjected to various spatial analysis techniques. Our GIS analysis found support at a global level for Eocyclotosaurus as an Anisian index taxon and probably Aetosaurus as a Norian indicator. Other tetrapod taxa are useful biostratigraphical/biochronological markers on a regional basis, such as Longosuchus and Doswellia for Late Carnian time. Other potential index fossils are hampered, however, by taxonomic instability (Mastodonsaurus, Metoposaurus, Typothorax, Paleorhinus, Pseudopalatus, Redondasaurus, Redondasuchus) and/or are not clearly restricted in temporal distribution (Paleorhinus, Angistorhinus, Stagonolepis, Metoposaurus and Rutiodon). This leads to instability in LVF diagnosis. We found only in the western Northern Hemisphere is there some evidence for an Anisian–Ladinian biochronological unit amalgamating the Perovkan and Berdyankian LVFs, and a possible late Carnian unit integrating the Otischalkian and Adamanian.Megaplants are generally not useful for biostratigraphical correlation in the Middle and Upper Triassic of the study area, but there is some evidence for a Carnian-age floral assemblage that corresponds to the combined Otischalkian and Adamanian LVFs. Environmental biases do not appear to strongly affect the spatial distribution of either the tetrapods or megaplants that have been proposed as index taxa in biostratigraphical schemes, though several examples of apparent environmental bias were detected by the analysis. Consequently, we argue that further revision and refinement of Middle and Late Triassic LVFs is needed before they can be used to support global or multi-regional biostratigraphical correlations. Caution should therefore be exercised when using the current scheme as a platform for macroevolutionary or palaeoecological hypotheses. Finally, this study demonstrates the potential of GIS as a powerful tool for tackling palaeontological questions over extended timescales.

Provenance of Jurassic sedimentary rocks of south-central Quesnellia, British Columbia: implications for paleogeography

2004 ◽  
Vol 41 (1) ◽  
pp. 103-125 ◽  
Author(s):  
Nathan T Petersen ◽  
Paul L Smith ◽  
James K Mortensen ◽  
Robert A Creaser ◽  
Howard W Tipper
Keyword(s):  
Detrital Zircon ◽  
Middle Jurassic ◽  
Sedimentary Rocks ◽  
Source Area ◽  
Lower Jurassic ◽  
Early Jurassic ◽  
Late Triassic ◽  
Nd Isotopes ◽  
South Central ◽  
History Of

Jurassic sedimentary rocks of southern to central Quesnellia record the history of the Quesnellian magmatic arc and reflect increasing continental influence throughout the Jurassic history of the terrane. Standard petrographic point counts, geochemistry, Sm–Nd isotopes and detrital zircon geochronology, were employed to study provenance of rocks obtained from three areas of the terrane. Lower Jurassic sedimentary rocks, classified by inferred proximity to their source areas as proximal or proximal basin are derived from an arc source area. Sandstones of this age are immature. The rocks are geochemically and isotopically primitive. Detrital zircon populations, based on a limited number of analyses, have homogeneous Late Triassic or Early Jurassic ages, reflecting local derivation from Quesnellian arc sources. Middle Jurassic proximal and proximal basin sedimentary rocks show a trend toward more evolved mature sediments and evolved geochemical characteristics. The sandstones show a change to more mature grain components when compared with Lower Jurassic sedimentary rocks. There is a decrease in εNdT values of the sedimentary rocks and Proterozoic detrital zircon grains are present. This change is probably due to a combination of two factors: (1) pre-Middle Jurassic erosion of the Late Triassic – Early Jurassic arc of Quesnellia, making it a less dominant source, and (2) the increase in importance of the eastern parts of Quesnellia and the pericratonic terranes, such as Kootenay Terrane, both with characteristically more evolved isotopic values. Basin shale environments throughout the Jurassic show continental influence that is reflected in the evolved geochemistry and Sm–Nd isotopes of the sedimentary rocks. The data suggest southern Quesnellia received material from the North American continent throughout the Jurassic but that this continental influence was diluted by proximal arc sources in the rocks of proximal derivation. The presence of continent-derived material in the distal sedimentary rocks of this study suggests that southern Quesnellia is comparable to known pericratonic terranes.

scholarly journals Mesozoic micropalaeontology of exploration well Elf 55/30–1 from the Fasnet Basin, offshore southwest Ireland

1986 ◽  
Vol 5 (1) ◽  
pp. 19-29 ◽  
Author(s):  
Nigel R. Ainsworth ◽  
Nicola F. Horton
Keyword(s):  
Lower Cretaceous ◽  
Lower Jurassic ◽  
Late Triassic ◽  
Ecological Distribution ◽  
Exploration Well

Abstract. The geology, biostratigraphy and palaeoecology of exploration well Elf 55/30–1 in the Fastnet Basin are summarised. The biostratigraphical and ecological distribution of the foraminifera and Ostracoda from the late Triassic, the Lower Jurassic and the Lower Cretaceous are reviewed with reference to microfaunas elsewhere in Europe. Selected microfossil taxa are illustrated.

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