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Marco Balini - One of the best experts on this subject based on the ideXlab platform.
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the Carnian norian boundary succession at berlin ichthyosaur state park upper triassic central nevada usa
Palaeontologische Zeitschrift, 2015Co-Authors: Marco Balini, Michael J. Orchard, James F. Jenks, Riccardo Martin, Christopher A. Mcroberts, Norman J. SilberlingAbstract:The Upper Carnian-Lower Norian (Upper Triassic) Luning Formation at Berlin-Ichthyosaur State Park (BISP) in central NV (USA) has been sampled using for the first time the bed-by-bed approach for ammonoids, pelagic bivalves, and conodonts, more than 60 years after its first description by Silberling (U.S. Geological Survey Professional Paper 322: 1–63, 1959). BISP is historically important for the definition of the uppermost Carnian of the North American Triassic chronostratigraphic scale and is known worldwide as one of the most important ichthyosaur Fossil-Lagerstatte because of its extraordinary record of 37 articulated, large-sized specimens of Shonisaurus popularis. Nearly 190 ammonoids were collected from two stratigraphic sections, documenting all the latest Carnian to Early Norian ammonoid faunas previously described by Silberling. Halobiids were collected from five levels, and the first report of conodonts from BISP includes faunas from 13 levels. The ~340-m thick Brick Pile section, the most complete in the study area, includes the uppermost Carnian Macrolobatus Zone, which provides conodont faunas of the lower primitia zone and Halobia septentrionalis. The 200-m thick lowermost Norian Kerri Zone, which begins 52 m above the Macrolobatus Zone, yields conodonts of the upper primitia zone in its lower part, together with H. cf. beyrichi and H. cf. selwyni. The ichthyosaur-bearing interval, whose stratigraphic position has been interpreted quite differently by previous authors, is documented in the uppermost Carnian Macrolobatus Zone and is characterized by rich Tropites-dominated ammonoid faunas and by the onset of Halobia. All models proposed by various workers to explain the unusual ichthyosaur record are discussed and an additional explanation for the main ichthyosaur-bearing bed is proposed. The new hypothesis is that a harmful algal bloom (HAB) may have been the trigger for the mass mortality recorded in this level. Although the C/N boundary in the Brick Pile section lies within a 52 m interval that presently lacks paleontologic data, this succession is included in a small group of sections that are expected to contribute to the definition of the GSSP of the Norian stage. Correlation of the Brick Pile section with the best Carnian/Norian sections in northeastern British Columbia is discussed. Compared to the British Columbia Juvavites Cove and the GSSP candidate Black Bear Ridge sections, the Brick Pile section exhibits an ammonoid and Halobia record that is slightly more similar to that of the Tethyan sections. Correlation of the Brick Pile section with the second GSSP candidate Pizzo Mondello (Sicily, Italy) well demonstrates the significant problems encountered in calibration of the Tethyan and North American scales.
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The Carnian/Norian boundary succession at Berlin-Ichthyosaur State Park (Upper Triassic, central Nevada, USA)
Paläontologische Zeitschrift, 2014Co-Authors: Marco Balini, Michael J. Orchard, James F. Jenks, Riccardo Martin, Christopher A. Mcroberts, Norman J. SilberlingAbstract:The Upper Carnian-Lower Norian (Upper Triassic) Luning Formation at Berlin-Ichthyosaur State Park (BISP) in central NV (USA) has been sampled using for the first time the bed-by-bed approach for ammonoids, pelagic bivalves, and conodonts, more than 60 years after its first description by Silberling (U.S. Geological Survey Professional Paper 322: 1–63, 1959). BISP is historically important for the definition of the uppermost Carnian of the North American Triassic chronostratigraphic scale and is known worldwide as one of the most important ichthyosaur Fossil-Lagerstatte because of its extraordinary record of 37 articulated, large-sized specimens of Shonisaurus popularis. Nearly 190 ammonoids were collected from two stratigraphic sections, documenting all the latest Carnian to Early Norian ammonoid faunas previously described by Silberling. Halobiids were collected from five levels, and the first report of conodonts from BISP includes faunas from 13 levels. The ~340-m thick Brick Pile section, the most complete in the study area, includes the uppermost Carnian Macrolobatus Zone, which provides conodont faunas of the lower primitia zone and Halobia septentrionalis. The 200-m thick lowermost Norian Kerri Zone, which begins 52 m above the Macrolobatus Zone, yields conodonts of the upper primitia zone in its lower part, together with H. cf. beyrichi and H. cf. selwyni. The ichthyosaur-bearing interval, whose stratigraphic position has been interpreted quite differently by previous authors, is documented in the uppermost Carnian Macrolobatus Zone and is characterized by rich Tropites-dominated ammonoid faunas and by the onset of Halobia. All models proposed by various workers to explain the unusual ichthyosaur record are discussed and an additional explanation for the main ichthyosaur-bearing bed is proposed. The new hypothesis is that a harmful algal bloom (HAB) may have been the trigger for the mass mortality recorded in this level. Although the C/N boundary in the Brick Pile section lies within a 52 m interval that presently lacks paleontologic data, this succession is included in a small group of sections that are expected to contribute to the definition of the GSSP of the Norian stage. Correlation of the Brick Pile section with the best Carnian/Norian sections in northeastern British Columbia is discussed. Compared to the British Columbia Juvavites Cove and the GSSP candidate Black Bear Ridge sections, the Brick Pile section exhibits an ammonoid and Halobia record that is slightly more similar to that of the Tethyan sections. Correlation of the Brick Pile section with the second GSSP candidate Pizzo Mondello (Sicily, Italy) well demonstrates the significant problems encountered in calibration of the Tethyan and North American scales.
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a middle late triassic ladinian rhaetian carbon and oxygen isotope record from the tethyan ocean
Palaeogeography Palaeoclimatology Palaeoecology, 2014Co-Authors: Giovanni Muttoni, Dennis V. Kent, Michele Mazza, David Mosher, Miriam E. Katz, Marco BaliniAbstract:Abstract We obtained bulk-sediment δ18O and δ13C data from biostratigraphically-constrained Tethyan marine sections at Aghia Marina (Greece), Guri Zi (Albania), and Brumano and Italcementi Quarry (Italy), and revised the published chemostratigraphy of the Pizzo Mondello section (Italy). We migrated these records from the depth to the time domain using available chronostratigraphic tie points, generating Ladinian–Rhaetian δ13C and δ18O records spanning from ~ 242 to ~ 201 Ma. The δ18O record seems to be affected by diagenesis, whereas the δ13C record appears to preserve a primary signal and shows values increasing by ~ 1‰ in the Ladinian followed by an ~ 0.6‰ decrease across the Ladinian–Carnian boundary, followed by relatively constant (but oscillatory) Carnian values punctuated by a negative excursion at ~ 233 Ma in the early Carnian, a second negative excursion at ~ 229.5 Ma across the early–late Carnian boundary, and a positive excursion at ~ 227 Ma across the Carnian–Norian boundary. The Norian record is characterized by a long-term decreasing trend and a negative excursion at ~ 216 Ma. Rapid increases and decreases in δ13C have been observed in the Rhaetian, but these may be at least in part due to mixing of different sources of carbonate carbon with different δ13C values. Our Triassic δ13C record has been compared to data from the literature, and a composite δ13C record spanning the last ~ 242 Myr of Earth's history has been generated. This composite record shows a sequence of dated δ13C trends and events that can be used for stratigraphic correlation as well as for a better understanding of the global carbon cycle in the Mesozoic–Cenozoic.
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A Middle–Late Triassic (Ladinian–Rhaetian) carbon and oxygen isotope record from the Tethyan Ocean
Palaeogeography Palaeoclimatology Palaeoecology, 2014Co-Authors: Giovanni Muttoni, Dennis V. Kent, Michele Mazza, David Mosher, Miriam E. Katz, Marco BaliniAbstract:Abstract We obtained bulk-sediment δ18O and δ13C data from biostratigraphically-constrained Tethyan marine sections at Aghia Marina (Greece), Guri Zi (Albania), and Brumano and Italcementi Quarry (Italy), and revised the published chemostratigraphy of the Pizzo Mondello section (Italy). We migrated these records from the depth to the time domain using available chronostratigraphic tie points, generating Ladinian–Rhaetian δ13C and δ18O records spanning from ~ 242 to ~ 201 Ma. The δ18O record seems to be affected by diagenesis, whereas the δ13C record appears to preserve a primary signal and shows values increasing by ~ 1‰ in the Ladinian followed by an ~ 0.6‰ decrease across the Ladinian–Carnian boundary, followed by relatively constant (but oscillatory) Carnian values punctuated by a negative excursion at ~ 233 Ma in the early Carnian, a second negative excursion at ~ 229.5 Ma across the early–late Carnian boundary, and a positive excursion at ~ 227 Ma across the Carnian–Norian boundary. The Norian record is characterized by a long-term decreasing trend and a negative excursion at ~ 216 Ma. Rapid increases and decreases in δ13C have been observed in the Rhaetian, but these may be at least in part due to mixing of different sources of carbonate carbon with different δ13C values. Our Triassic δ13C record has been compared to data from the literature, and a composite δ13C record spanning the last ~ 242 Myr of Earth's history has been generated. This composite record shows a sequence of dated δ13C trends and events that can be used for stratigraphic correlation as well as for a better understanding of the global carbon cycle in the Mesozoic–Cenozoic.
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LADINIAN/Carnian AMMONOIDS AND CONODONTS FROM THE CLASSIC SCHILPARIO-PIZZO CAMINO AREA (LOMBARDY): REVALUATION OF THE BIOSTRATIGRAPHIC SUPPORT TO CHRONOSTRATIGRAPHY AND PALEOGEOGRAPHY
Rivista Italiana Di Paleontologia E Stratigrafia, 2000Co-Authors: Marco Balini, Daniela Germani, Alda Nicora, Eugenio RizziAbstract:This area played a key role in defining Middle Triassic stratigraphy. In the nineteenth century the study of several ammonoids collected in the Wengen Formation served as a basis for the definition of the Longobardian substage of the Ladinian. Moreover, during the 1960’s the modern Triassic Lithostratigraphy of Lombardy was founded on sections from this area. The present study represents the first bed-by-bed sampling of this area and is focused mainly on the Wengen Formation and Pratotondo Limestone. In particular, conodonts were found in both units for the first time. The age of some Middle Triassic formations is revised: the top of the Wengen Formation belongs definitively to the Lower Carnian in a sizeable portion of the study area. The overlying carbonate platform, previously attributed to the Upper Ladinian Esino Limestone, is instead Carnian and is coeval to the Breno Formation in the Southern Camonica Valley. the Pratotondo Limestone is dated Late Ladinian/Early Carnian, while the overlying Lozio shale is Carnian. These new data contradict the equivalence "Wengener Schichten" = Archelaus Zone = Longobardian so common in the literature. We demonstrate that the Regoledanus Zone represents a great part of the Wengen Formation. Moreover, at the top of the Wengen Formation the ammonoid and conodont fauna represents the early Carnian Daxatina or Aon Zone. The biochronostratigraphic revision of the basinal formations requires modification of both the chronostratigraphic schemes and the paleogeographic history of the lombardian Southern Alps during Ladinian-Carnian time.
Leopold Krystyn - One of the best experts on this subject based on the ideXlab platform.
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demise of late triassic sponge mounds along the northwestern margin of the yangtze block south china related to the Carnian pluvial phase
Palaeogeography Palaeoclimatology Palaeoecology, 2017Co-Authors: Zhiqiang Shi, Leopold Krystyn, Nereo Preto, Yang Zhang, James G. Ogg, Xin Jin, Haishui Jiang, Jinling YuanAbstract:Upper Triassic (Carnian) marine successions in the northwestern margin of Upper Yangtze Region (Sichuan Basin, China) show a lithological change from grey oolitic into a sponge-mound limestone (Units 1 and 2 of the lower member of the Ma'antang Formation), then overlain by greyish black to dark grey sandy shale and siltstone (Units 3 and 4 of the upper member of the Ma'antang Formation). Siliceous sponge mounds were built by Hexactinellida, and this succession was examined in three localities: Jushui section in Anxian (JS), and Guanyinya (HWG) and Qingyangou sections (HWQ) in Hanwang, Mianzhu. The conodont Quadralella polygnathiformis confirms a Carnian age for the biolithite and oolitic limestone of the lower Ma'antang Formation. Abundant ammonoids identified as belonging to the Discotropitid and Juvavitid families suggest a Tuvalian 1 (early Late Carnian) age for the lowermost part of the greyish black sandy shale that overlies the sponge mound at the Jushui Section. Field investigations and microfacies analysis suggest that sponge mounds had two stages of growth in relatively deeper water with low energy. The first sponge-growth mound stage ended in a regional karstified omission surface, and was followed by a sudden increase of siliciclastic input. Greyish black shales containing plant fossils cover a second Upper Carnian sponge mound stage, which is mainly recorded in HWG. The onset of these shales may be related to the Carnian Pluvial Phase (CPP) documented in the western Tethys region (e.g., in Italy, Austria and Hungary). The demise of the sponge mounds at all three sections may have been triggered by the joint effect of climatic changes associated with the fresh water input caused by CPP and with a relative sea-level change caused by local tectonic movements in the course of the Indosinian orogeny.
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a review of the evolution biostratigraphy provincialism and diversity of middle and early late triassic conodonts
Papers in Palaeontology, 2016Co-Authors: Yanlong Chen, Leopold Krystyn, Michael J. Orchard, Sylvain RichozAbstract:The taxonomy, diversity, evolutionary lineages, and stratigraphical distributions of Middle and early Late Triassic conodonts are reviewed and re-evaluated. Twenty-five genera are recognized in the Middle and early Late Triassic, including a new genus cited in open nomenclature. Of these, 24 genera are assigned to two families and seven subfamilies. The family Gondolellidae consists of the subfamilies Cornudininae, Epigondolellinae, Neogondolellinae, Novispathodinae, Paragondolellinae and Pseudofurnishiinae. The family Gladigondolellidae is monotypic, consisting of the subfamily Gladigondolellinae. The genus Neostrachanognathus is not assigned to any family or subfamily as its origin is unclear. Conodont provincialism was low in the early Anisian, but from the late Anisian faunistic differences started to increase and became stronger during the early Ladinian, reaching a peak around the mid-Ladinian. Provincialism remained strong until the earliest Carnian and changed to an all-Triassic low in the early Tuvalian. The provincialism between North America and Tethys rebounded on the specific level during the late Tuvalian. Diversities on generic and specific levels have been established, and two major conodont diversity cycles are recognized: the first ranges from the Bithynian (early Anisian) to the Julian (late early Carnian), and the second is restricted to the Tuvalian (late Carnian).
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Integrated Upper Carnian to Lower Norian biochronology and implications for the Upper Triassic magnetic polarity time scale
Earth and Planetary Science Letters, 2002Co-Authors: Leopold Krystyn, Yves Gallet, Jean Besse, Jean MarcouxAbstract:Abstract We summarize the ammonoid, conodont and halobiid biochronology of the Upper Carnian to Lower Norian, based on a discussion of data in the Alps, Sicily, Balkans, Turkey, Himalayas and Timor. With this integrated biostratigraphic scale, the Pizzo Mondello section (Sicily) can be recalibrated and the Carnian–Norian boundary more precisely located there. As a result, the magnetostratigraphy of this section is now in good agreement with previous results from Turkey, although the latter series are more condensed. Cross-correlation of available magnetostratigraphic data from marine Tethyan sections allow us to construct a composite Upper Carnian to Upper Norian geomagnetic polarity time scale (GPTS). This GPTS leads us to question previously proposed magnetobiostratigraphic and chronostratigraphic correlations within the Upper Triassic Newark non-marine sedimentary sequence.
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Carnian REEF BIOTA FROM A MEGABRECCIA OF THE HAWASINA COMPLEX (AL AQIL, OMAN)
Rivista Italiana Di Paleontologia E Stratigrafia, 1999Co-Authors: Senowbari-daryan, Leopold Krystyn, Michaela Bernecker, Miloš SiblíkAbstract:Carnian reef biota and brachiopods of the Misfah Formation (Hawasina complex) from a locality near the town of Al Aqil in Oman are described. A new brachiopod species, Oxycolpella arabica n. sp. is described. The composition of the Carnian reef biota in Oman is similar to those known from the Alpine-Mediterranean region. However, differences exist in the microfauna of reef dwellers, e.g. foraminifers. New stratigraphic data based on reef organisms and conodonts are presented.
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Magnetostratigraphy of the Mayerling section (Austria) and Erenkolu Mezarlik (Turkey) section: improvement of the Carnian (late Triassic) magnetic polarity time scale
Earth and Planetary Science Letters, 1994Co-Authors: Yves Gallet, Leopold Krystyn, Jean Besse, Hervé Théveniaut, Jean MarcouxAbstract:Abstract We present a magnetostratigraphic study of two Carnian (late Triassic) pelagic limestone sections from the Northern Calcareous Alps (Mayerling section) and southwestern Turkey (Erenkolu Mezarlik section). Biostratigraphic control is based on conodont zonation for the Mayerling section, and both on conodonts and ammonoids for the Erenkolu Mezarlik section. In both sections, the characteristic magnetization is essentially carried by a mineral of the magnetite family. Eight magnetic intervals are obtained from the Mayerling section and fourteen from Erenkolu Mezarlik. When these results are compared to the Carnian magnetostratigraphic sequence obtained from the Bolucektasi Tepe section, satisfactory correlations are observed and a composite Carnian magnetic polarity time scale containing 24 intervals can be proposed by combining all these results. The lower part of the upper Carnian is however missing (Tuvalian 1 zone and lower part of the Tuvalian 2 zone). No clear correlation is observed between our composite sequence and the other published magnetostratigraphic data of Carnian age. The satisfactory correlation observed between the Mayerling and the Bolucektasi Tepe sections indicates that both sections were deposited in the northern hemisphere, thus providing constraints on the origin of the Antalya nappes.
Spencer G. Lucas - One of the best experts on this subject based on the ideXlab platform.
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Record of the Carnian wet episode in strata of the Chinle Group, western USA
Journal of the Geological Society, 2018Co-Authors: Spencer G. Lucas, Lawrence H TannerAbstract:The Late Triassic Carnian wet episode was an interval of humid climate evident in the lowermost strata of the Upper Triassic Chinle Group in the western USA. Chinle deposition began with the development of major river systems of the Shinarump Formation and equivalents, laterally equivalent to and/or overlain by floodplain deposits containing kaolinitic gleyed to spodic palaeosols and local coal beds. The Chinle strata immediately above these wet episode strata are deposits of smaller rivers that lack coal or carbonaceous strata and contain non-kaolinitic palaeosols that are locally calcareous and vertic, indicative of drier but strongly seasonal climates. The lowermost Chinle strata contain fossil tetrapods, palynomorphs and conchostracans that are consistent with other data that indicate that the basal Chinle strata are of Julian age and immediately overlying lower Chinle strata are early Tuvalian, so these strata are the age of the Carnian wet episode. Identification of a ‘long Norian’ Stage places the Norian base in the Chinle Group near the top of the strata of the wet episode, which means that Norian strata sit directly on early Carnian strata, but there is no unconformity at this level to support recognition of such a long Norian in the Chinle section.
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the late triassic timescale age and correlation of the Carnian norian boundary
Earth-Science Reviews, 2012Co-Authors: Spencer G. Lucas, Lawrence H Tanner, Heinz W Kozur, Robert E Weems, Andrew B HeckertAbstract:The Late Triassic timescale is poorly constrained due largely to the dearth of reliable radio-isotopic ages that can be related precisely to biostratigraphy combined with evident contradictions between bio-stratigraphic and magnetostratigraphic correlations. These problems are most apparent with regard to the age and correlation of the Carnian–Norian boundary (base of the Norian Stage). We review the available age data pertaining to the Carnian–Norian boundary and conclude that the “long Norian” in current use by many workers, which places the Carnian–Norian boundary at ~228 Ma, is incorrect. The evidence supports a Norian stage that is much shorter than proposed by these workers, so the Carnian–Norian boundary is considerably younger than this, close to 220 Ma in age. Critical to this conclusion is the correlation of the Carnian–Norian boundary in nonmarine strata of Europe and North America, and its integration with existing radioisotopic ages and magnet-ostratigraphy. Three bio-stratigraphic datasets (palynomorphs, conchostracans and tetra-pods) reliably identify the same position for the Carnian–Norian boundary (within normal limits of bio-stratigraphic resolution) in nonmarine strata of the Chinle Group (American Southwest), Newark Supergroup (eastern USA–Canada) and the German Keuper. These biostratigraphic datasets place the Carnian–Norian boundary at the base of the Warford Member of the lower Passaic Formation in the Newark Basin, and, as was widely accepted prior to 2002, this correlates the base of the Norian to a horizon within Newark magnet-ozone E13n. In recent years a correlation based solely on magnetostratigraphy has been proposed between the Pizzo Mondello section in Sicily and the Newark section. This correlation, which ignores robust biostrati-graphic data, places the Norian base much too low in the Newark Basin section (~at the base of the Lockatong Formation), correlative to a horizon near the base of Newark magnet-ozone E8. Despite the fact that this correlation is falsifiable on the basis of the bio-stratigraphic data, it still became the primary justification for placing the Carnian–Norian boundary at ~228 Ma (based on Newark cyclo-stratigraphy). The “long Norian” created thereby is unsupported by either bio-stratigraphic or reliable radioisotopic data and therefore must be abandoned. While few data can be presented to support a Carnian–Norian boundary as old as 228 Ma, existing radio-isotopic age data are consistent with a Norian base at ~220 Ma. Although this date is approximately correct, more reliable and precise radio-isotopic ages still are needed to firmly assign a precise age to the Carnian–Norian boundary.
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South American occurrences of the Adamanian (Late Triassic: Latest Carnian) index taxon Stagonolepis (Archosauria: Aetosauria) and their biochronological significance
Journal of Paleontology, 2002Co-Authors: Andrew B Heckert, Spencer G. LucasAbstract:Aetosaur fossils from the Upper Triassic Ischigualasto Formation of Argentina formerly assigned to Aetosauroides scagliai Casamiquela and Argentinosuchus bonapartei Casamiquela are reassigned to Stagonolepis robertsoni Agassiz (small specimens) and S. wellesi (Long and Ballew) (larger specimens). Numerous features of the skull, vertebral column, appendicular skeleton, and particularly the armor, of these Argentinian aetosaurs are identical to those of Stagonolepis and differ from other aetosaurs. Identification of Stagonolepis in South America has important implications for the correlation of nonmarine strata across Late Triassic Pangea. Stagonolepis is an index taxon of the Adamanian land-vertebrate faunachron of latest Carnian age. Its occurrences in the Ischigualasto and Santa Maria formations, as well as at the type locality in the Lossiemouth Sandstone of Scotland and in the Blasensandstein of the German Keuper, cross-correlate with a well-established tetrapod biostratigraphy of the Chinle Group in western North America. Thus, all Stagonolepis records are of Adamanian (latest Carnian) age, not Otischalkian (early or “middle” Carnian) age, as proposed by some earlier workers. This correlation also demonstrates that the oldest known dinosaurs are not from the Ischigualasto and Santa Maria formations. Previous workers obtained radioisotopic dates of 227.8 Ma from the Ischigualasto Formation, providing a maximum numerical date for Stagonolepis-bearing units. This date must be late Carnian, not of Ladinian age, and thus supports the apparent age of the Ladinian-Carnian boundary (232 Ma) of time scales based on the Newark Supergroup in eastern North America.
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global triassic tetrapod biostratigraphy and biochronology
Palaeogeography Palaeoclimatology Palaeoecology, 1998Co-Authors: Spencer G. LucasAbstract:Abstract Eight, temporally successive assemblage zones of tetrapod fossils provide the basis for dividing Triassic time into eight land-vertebrate faunachrons. These land-vertebrate faunachrons, their type assemblage zones, and their approximate correlation to the standard global chronostratigraphic scale are (ascending order): (1) Lootsbergian (Lystrosaurus Assemblage Zone, Balfour, Katberg and Burgersdorp formations, Karoo basin, South Africa) = late Dorashamian–Induan; (2) Nonesian (Cynognathus Assemblage Zone, Burgersdorp Formation, Karoo basin, South Africa) = Olenikian; (3) Perovkan (Shansiodon Assemblage Zone, Donguz Formation, Russian Urals) = Anisian; (4) Berdyankian (Mastodonsaurus Assemblage Zone, Bukobay Formation, Russian Urals) = Ladinian–early Carnian; (5) Otischalkian (Paleorhinus Assemblage Zone, Chinle Group, Chinle basin, USA) = late-early to early-late Carnian; (6) Adamanian (Rutiodon Assemblage Zone, Chinle Group, Chinle basin, USA) = latest Carnian; (7) Revueltian (Pseudopalatus Assemblage Zone, Chinle Group, Chinle basin, USA) = Norian; (8) Apachean (Redondasaurus Assemblage Zone, Chinle Group, Chinle basin, USA), = Rhaetian. The Triassic land-vertebrate faunachrons provide a framework for the correlation of Triassic nonmarine deposits with a temporal resolution comparable to the seven Triassic Stage/Ages of the standard global chronostratigraphic scale.
Jean Marcoux - One of the best experts on this subject based on the ideXlab platform.
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Integrated Upper Carnian to Lower Norian biochronology and implications for the Upper Triassic magnetic polarity time scale
Earth and Planetary Science Letters, 2002Co-Authors: Leopold Krystyn, Yves Gallet, Jean Besse, Jean MarcouxAbstract:Abstract We summarize the ammonoid, conodont and halobiid biochronology of the Upper Carnian to Lower Norian, based on a discussion of data in the Alps, Sicily, Balkans, Turkey, Himalayas and Timor. With this integrated biostratigraphic scale, the Pizzo Mondello section (Sicily) can be recalibrated and the Carnian–Norian boundary more precisely located there. As a result, the magnetostratigraphy of this section is now in good agreement with previous results from Turkey, although the latter series are more condensed. Cross-correlation of available magnetostratigraphic data from marine Tethyan sections allow us to construct a composite Upper Carnian to Upper Norian geomagnetic polarity time scale (GPTS). This GPTS leads us to question previously proposed magnetobiostratigraphic and chronostratigraphic correlations within the Upper Triassic Newark non-marine sedimentary sequence.
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Magnetostratigraphy of the Mayerling section (Austria) and Erenkolu Mezarlik (Turkey) section: improvement of the Carnian (late Triassic) magnetic polarity time scale
Earth and Planetary Science Letters, 1994Co-Authors: Yves Gallet, Leopold Krystyn, Jean Besse, Hervé Théveniaut, Jean MarcouxAbstract:Abstract We present a magnetostratigraphic study of two Carnian (late Triassic) pelagic limestone sections from the Northern Calcareous Alps (Mayerling section) and southwestern Turkey (Erenkolu Mezarlik section). Biostratigraphic control is based on conodont zonation for the Mayerling section, and both on conodonts and ammonoids for the Erenkolu Mezarlik section. In both sections, the characteristic magnetization is essentially carried by a mineral of the magnetite family. Eight magnetic intervals are obtained from the Mayerling section and fourteen from Erenkolu Mezarlik. When these results are compared to the Carnian magnetostratigraphic sequence obtained from the Bolucektasi Tepe section, satisfactory correlations are observed and a composite Carnian magnetic polarity time scale containing 24 intervals can be proposed by combining all these results. The lower part of the upper Carnian is however missing (Tuvalian 1 zone and lower part of the Tuvalian 2 zone). No clear correlation is observed between our composite sequence and the other published magnetostratigraphic data of Carnian age. The satisfactory correlation observed between the Mayerling and the Bolucektasi Tepe sections indicates that both sections were deposited in the northern hemisphere, thus providing constraints on the origin of the Antalya nappes.
Michael J. Orchard - One of the best experts on this subject based on the ideXlab platform.
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a review of the evolution biostratigraphy provincialism and diversity of middle and early late triassic conodonts
Papers in Palaeontology, 2016Co-Authors: Yanlong Chen, Leopold Krystyn, Michael J. Orchard, Sylvain RichozAbstract:The taxonomy, diversity, evolutionary lineages, and stratigraphical distributions of Middle and early Late Triassic conodonts are reviewed and re-evaluated. Twenty-five genera are recognized in the Middle and early Late Triassic, including a new genus cited in open nomenclature. Of these, 24 genera are assigned to two families and seven subfamilies. The family Gondolellidae consists of the subfamilies Cornudininae, Epigondolellinae, Neogondolellinae, Novispathodinae, Paragondolellinae and Pseudofurnishiinae. The family Gladigondolellidae is monotypic, consisting of the subfamily Gladigondolellinae. The genus Neostrachanognathus is not assigned to any family or subfamily as its origin is unclear. Conodont provincialism was low in the early Anisian, but from the late Anisian faunistic differences started to increase and became stronger during the early Ladinian, reaching a peak around the mid-Ladinian. Provincialism remained strong until the earliest Carnian and changed to an all-Triassic low in the early Tuvalian. The provincialism between North America and Tethys rebounded on the specific level during the late Tuvalian. Diversities on generic and specific levels have been established, and two major conodont diversity cycles are recognized: the first ranges from the Bithynian (early Anisian) to the Julian (late early Carnian), and the second is restricted to the Tuvalian (late Carnian).
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the Carnian norian boundary succession at berlin ichthyosaur state park upper triassic central nevada usa
Palaeontologische Zeitschrift, 2015Co-Authors: Marco Balini, Michael J. Orchard, James F. Jenks, Riccardo Martin, Christopher A. Mcroberts, Norman J. SilberlingAbstract:The Upper Carnian-Lower Norian (Upper Triassic) Luning Formation at Berlin-Ichthyosaur State Park (BISP) in central NV (USA) has been sampled using for the first time the bed-by-bed approach for ammonoids, pelagic bivalves, and conodonts, more than 60 years after its first description by Silberling (U.S. Geological Survey Professional Paper 322: 1–63, 1959). BISP is historically important for the definition of the uppermost Carnian of the North American Triassic chronostratigraphic scale and is known worldwide as one of the most important ichthyosaur Fossil-Lagerstatte because of its extraordinary record of 37 articulated, large-sized specimens of Shonisaurus popularis. Nearly 190 ammonoids were collected from two stratigraphic sections, documenting all the latest Carnian to Early Norian ammonoid faunas previously described by Silberling. Halobiids were collected from five levels, and the first report of conodonts from BISP includes faunas from 13 levels. The ~340-m thick Brick Pile section, the most complete in the study area, includes the uppermost Carnian Macrolobatus Zone, which provides conodont faunas of the lower primitia zone and Halobia septentrionalis. The 200-m thick lowermost Norian Kerri Zone, which begins 52 m above the Macrolobatus Zone, yields conodonts of the upper primitia zone in its lower part, together with H. cf. beyrichi and H. cf. selwyni. The ichthyosaur-bearing interval, whose stratigraphic position has been interpreted quite differently by previous authors, is documented in the uppermost Carnian Macrolobatus Zone and is characterized by rich Tropites-dominated ammonoid faunas and by the onset of Halobia. All models proposed by various workers to explain the unusual ichthyosaur record are discussed and an additional explanation for the main ichthyosaur-bearing bed is proposed. The new hypothesis is that a harmful algal bloom (HAB) may have been the trigger for the mass mortality recorded in this level. Although the C/N boundary in the Brick Pile section lies within a 52 m interval that presently lacks paleontologic data, this succession is included in a small group of sections that are expected to contribute to the definition of the GSSP of the Norian stage. Correlation of the Brick Pile section with the best Carnian/Norian sections in northeastern British Columbia is discussed. Compared to the British Columbia Juvavites Cove and the GSSP candidate Black Bear Ridge sections, the Brick Pile section exhibits an ammonoid and Halobia record that is slightly more similar to that of the Tethyan sections. Correlation of the Brick Pile section with the second GSSP candidate Pizzo Mondello (Sicily, Italy) well demonstrates the significant problems encountered in calibration of the Tethyan and North American scales.
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The Carnian/Norian boundary succession at Berlin-Ichthyosaur State Park (Upper Triassic, central Nevada, USA)
Paläontologische Zeitschrift, 2014Co-Authors: Marco Balini, Michael J. Orchard, James F. Jenks, Riccardo Martin, Christopher A. Mcroberts, Norman J. SilberlingAbstract:The Upper Carnian-Lower Norian (Upper Triassic) Luning Formation at Berlin-Ichthyosaur State Park (BISP) in central NV (USA) has been sampled using for the first time the bed-by-bed approach for ammonoids, pelagic bivalves, and conodonts, more than 60 years after its first description by Silberling (U.S. Geological Survey Professional Paper 322: 1–63, 1959). BISP is historically important for the definition of the uppermost Carnian of the North American Triassic chronostratigraphic scale and is known worldwide as one of the most important ichthyosaur Fossil-Lagerstatte because of its extraordinary record of 37 articulated, large-sized specimens of Shonisaurus popularis. Nearly 190 ammonoids were collected from two stratigraphic sections, documenting all the latest Carnian to Early Norian ammonoid faunas previously described by Silberling. Halobiids were collected from five levels, and the first report of conodonts from BISP includes faunas from 13 levels. The ~340-m thick Brick Pile section, the most complete in the study area, includes the uppermost Carnian Macrolobatus Zone, which provides conodont faunas of the lower primitia zone and Halobia septentrionalis. The 200-m thick lowermost Norian Kerri Zone, which begins 52 m above the Macrolobatus Zone, yields conodonts of the upper primitia zone in its lower part, together with H. cf. beyrichi and H. cf. selwyni. The ichthyosaur-bearing interval, whose stratigraphic position has been interpreted quite differently by previous authors, is documented in the uppermost Carnian Macrolobatus Zone and is characterized by rich Tropites-dominated ammonoid faunas and by the onset of Halobia. All models proposed by various workers to explain the unusual ichthyosaur record are discussed and an additional explanation for the main ichthyosaur-bearing bed is proposed. The new hypothesis is that a harmful algal bloom (HAB) may have been the trigger for the mass mortality recorded in this level. Although the C/N boundary in the Brick Pile section lies within a 52 m interval that presently lacks paleontologic data, this succession is included in a small group of sections that are expected to contribute to the definition of the GSSP of the Norian stage. Correlation of the Brick Pile section with the best Carnian/Norian sections in northeastern British Columbia is discussed. Compared to the British Columbia Juvavites Cove and the GSSP candidate Black Bear Ridge sections, the Brick Pile section exhibits an ammonoid and Halobia record that is slightly more similar to that of the Tethyan sections. Correlation of the Brick Pile section with the second GSSP candidate Pizzo Mondello (Sicily, Italy) well demonstrates the significant problems encountered in calibration of the Tethyan and North American scales.
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triassic conodont biochronology its calibration with the ammonoid standard and a biostratigraphic summary for the western canada sedimentary basin
Bulletin of Canadian Petroleum Geology, 1997Co-Authors: Michael J. Orchard, E T TozerAbstract:ABSTRACT A refined conodont biochronology is presented for the Triassic of Western Canada Sedimentary Basin (WCSB). This is supplemented with additional conodont data from Arctic and western Canada and from the western U.S.A. The conodont scale is intercalibrated with ammonoid zones and standard Triassic stages to produce a continental conodont standard with good potential for global application. Griesbachian conodont faunas from the Canadian Arctic are regarded as wholly Triassic rather than as partly Permian. Above the base of the Triassic, a significant change in the conodont fauna is recognized within the upper Griesbachian Strigatus Zone. Neospathodus species and divergent lineages of 'Neogondolella' provide indices through Dienerian, Smithian and Spathian strata. Neogondolella regale characterizes strata of late Spathian through middle Anisian age and therefore did not develop from early Anisian Chiosella timorensis, which is reported for the first time from the WCSB. In the Late Anisian, the Neogondolella constricta group completely replaces the Neogondolella regale group. Ladinian conodont fauna changes significantly within the Meginae Zone, with Neogondolella ex. gr. constricta (N. aldae) characterizing the early part and Paragondolella ex gr. foliata dominating the later part. Budurovignathus spp. are important but occur sporadically through the Ladinian. The base of the Carnian is identified by the first appearance of Metapolygnathus. The Ladinian holdovers Paragondolella and Mosherella disappear within the Lower Carnian. In the Upper Carnian, rapid evolution of the Metapolygnathus nodosus group is represented by the M. samueli lineage and leads ultimately to M. primitius, the precursor of Norian Epigondolella. The latest Triassic conodont zonation is highly resolved on the basis of this genus, which ends with Rhaetian Epigondolella mosheri in WCSB. Biostratigraphic constraints are summarized for each of the formations for which conodont and molluscan data are available. Most of this data is from the outcrop belt of northeastern British Columbia where virtually all the present stratigraphic units have diachronous contacts. The Grayling Formation is Griesbachian-Smithian in age, the Toad Formation is Smithian-Ladinian, the Liard Formation is Ladinian, the Ludington Formation is late Ladinian-late Carnian, the Baldonnel Formation is Carnian, the Pardonet Formation is late Carnian-Rhaetian and the Bocock Limestone is Rhaetian. The Grayling-Toad formational boundary is younger in the south than in the north, the Toad-Liard formational boundary is younger in the west, and the base of the Pardonet Formation is younger in the east. On Williston Lake, a remarkable record of Smithian through Carnian conodonts occurs in the Toad and Ludington formations at Ursula Creek. The top of the Ludington at this locality is the same age as the base of the Pardonet Formation at Black Bear Ridge to the east, which itself is age-equivalent to the top of the Baldonnel Formation farther east at Carbon Creek. At the top of the Triassic succession, the Pardonet Formation is locally equivalent to the Rhaetian Bocock Limestone. RESUME Une biochronologie raffinee des Condontes est presentee pour le Triassique du Bassin sedimentaire de l'Ouest canadien (WCSB). Des donnees supplementaires sur les Conodontes de l'Arctique et de l'Ouest canadien ainsi que de l'Ouest des Etats-Unis ont ete rajoutees. L'echelle des Conodontes est intercalibree avec des zones d'Ammonidites et des etapes du Triassique de reference pour produire une reference pour les Conodontes continentaux avec bonne possibilite pour les applications globales. Les faunes de Condontes du Griesbachian de l'Arctique canadien sont vues comme etant entierement Triassique plutot que partiellement Permien. Au-dessus de la base du Triassique, un changement significatif de la faune de Conodontes est reconnu dans la Zone Strigatus du Griesbachian superieur. Les especes 1 Geological Survey Contribution No. 1996446 End_Page 675------------------------ Neospathodus et les lignees evolutives divergentes du "Neogondolella" fournissent des pistes dans les couches du Dienerien, Smithien et Spathien. Le Neogondolella regale caracterise les couches datant du Spathien tardif au Anisien moyen et ne s'est pas developpe du Chiosella timorensis de l'Anesien precoce, qui a ete rapporte pour la premiere fois en provenance du WCSB. Dans l'Anesien tardif, le groupe Neogondolella constricta remplace entierement le groupe Neogondolella regale. La faune de Conodontes Ladinien change significativement dans la Zone Meginae, avec le Neogondolella ex. gr. Constricta (N. aldae) caracterise dans la periode precoce et Paragondolella ex. gr. foliata dominant la periode plus tardive. Budurovignathus spp. sont importants mais se produisent sporadiquement pendant le Ladinien. La base du Carnien est identifiee par la premiere occurrence du Metapolygnathus. Les retenues du Ladinien Paragondolella et Mosherella disparaissent dans le Carnien inferieur. Dans le Carnien superieur, l'evolution rapide du groupe Metapolygnathus nodosus est represente par la lignee M. Samueli qui mene finalement au M. primitus, le precurseur du Epigondolella Norien. Le zonage des Conodontes du Triassique tardif est grandement resolu en se basant sur ces genres, qui se terminent par l'Epigondolella mosheri du Rhetien dans le WCSB. Les contraintes biostratigraphiques sont resumees pour chacune de ces formations pour lesquelles des donnees sur les Conodontes et les mollusques sont disponibles. La plupart de ces donnees proviennent de la zone d'affleurement du nordest de la Colombie-Britannique ou presque toutes les unites stratigraphiques possedent des contacts diachrones. La Formation Grayling est d'age du Griesbachien-Smithien, la Formation Toad est du Smithien-Ladinien, la Formation Liard est du Ladinien, la Formation Ludington est du Ladinien tardif-Carnien tardif, la Formation Baldonnel est du Carnien, la Formation Pardonet est du Carnien-Rhetien et le Bobock Limestone est du Rhetien. La limite de la Formation Grayling-Toad est plus precoce au sud qu'au nord; la limite de la Formation Toad - Liard est plus precoce a l'ouest et la base de la Formation Pardonet est plus precoce a l'est. Sur le Williston Lake, un rapport remarquable des Conodontes du Smithien au Carnien se produit dans les formations Toad et Ludington a Ursula Creek. La partie superieure du Ludington a cet emplacement est du meme que la base de la Formation Pardonet a Black Bear Ridge vers l'est, qui par elle-meme est du meme age que la partie superieure de la Formation Baldonnel plus a l'est a Carbon Creek. Sur la partie superieure de la succession Triassique, la Formation Pardonet est regionalement equivalente au Bobock Limestone Rhetien. Traduit par Marie-Louise Tomas