Tracking the redox history and nitrogen cycle in the pelagic Panthalassic deep ocean in the Middle Triassic to Early Jurassic: Insights from redox-sensitive elements and nitrogen isotopes

2016 ◽  
Vol 449 ◽  
pp. 397-420 ◽  
Author(s):  
Wataru Fujisaki ◽  
Yusuke Sawaki ◽  
Shinji Yamamoto ◽  
Tomohiko Sato ◽  
Manabu Nishizawa ◽  
...  
Keyword(s):  
Nitrogen Cycle ◽  
Middle Triassic ◽  
Nitrogen Isotopes ◽  
Deep Ocean ◽  
Early Jurassic ◽  
Redox History

Freboldia carinii sp. nov. from the Middle Triassic Brembana Valley (Esino Limestone, Southern Alps, Italy) – possibly the oldest known holoplanktonic gastropod

2020 ◽  
Vol 298 (1) ◽  
pp. 9-15
Author(s):  
Vittorio Pieroni ◽  
Alexander Nützel
Keyword(s):  
Life Style ◽  
Thin Shell ◽  
Type Species ◽  
Middle Triassic ◽  
Canadian Arctic ◽  
Southern Alps ◽  
Early Jurassic ◽  
Ellesmere Island ◽  
Gastropod Species ◽  
Mass Occurrence

A monospecific mass occurrence of the new gastropod species Freboldia carinii sp. nov. is described from the Middle Triassic Esino Limestone of the Brembana Valley, Southern Alps, Italy. It is the second species assigned to the genus Freboldia that was initially described from the Early Jurassic of Ellesmere Island, Canadian Arctic. This gastropod is unusual in being planispiral and inflated with a nearly bilateral symmetrical shape and in having a very thin shell. Like the Canadian type species of Freboldia, the new Triassic species is interpreted as a possibly holoplanktonic gastropod. If true, it would be the oldest known example of this life style in Gastropoda.

Chapter 18 Triassic history

1997 ◽  
Vol 17 (1) ◽  
pp. 340-362 ◽  
Author(s):  
W. Brian Harland ◽  
Isobel Geddes
Keyword(s):  
Middle Triassic ◽  
Early Jurassic ◽  
Late Triassic ◽  
Early Triassic ◽  
Marked Contrast ◽  
Angular Unconformity ◽  
Triassic Period ◽  
Age Determinations

The Triassic Period of about 40 million years dutation spanned about a third of that of the Carboniferous and Permian interval. The Triassic rocks of Svalbard are easily distinguished from the underlying Permian strata because of a distinct desconformity between them and a marked contrast in facies from the resistant. pale coloured, cherls and siliciclastics of the Kapp Starostin Formation to the softer, darker areno-argillaceous Vardebukta and equivalent formations. Figure 18.1 shows the distribution of Triassic strata in Svalbard.The minor angular unconformity represents a hiatus mainly in the Permian rather than the Triassic record. The dominantly argillaceous facies constitute the Early Triassic to Late Middle Triassic Sassendalen Group. The rocks can be well dated from ammonoids, typically within calcareous concretions in the shales.The succeding Kapp Toscana Group is distinguished by a dominatly sandy deltaic facies in which age determinations are difficult. It spans both Late Triassic and Early Jurassic spoehs (roughly mid-Ladinian to mid-Bathonian). The Triassic-Jurassic boundary is not easy to estimate. Nevertheless towards the end of Triassic time (e.g. Rhaetian) the overall scene changed. Thus of the three formations of the Kapp Toscana Group the lower two (Tschermakfjellet and De Geerdalen) belong to the Triassic story. The overlying Wilhelmøya Formation may possibly range from Latest Triassic through Liassic time, and due to its complexity it is also discussed in the Jurassic-Crataceous chapter (19).The facies of the two groups reflect two distinct environmental configurations. The Sassendalen Group was deposited on a distal marine muddy shelf with a

scholarly journals GEOLOGICAL CONTRIBUTION TO THE TECTONO- STRATIGRAPHY OF THE NAFPLION AREA (NW ARGOLIS, GREECE)

2017 ◽  
Vol 43 (3) ◽  
pp. 1495
Author(s):  
A. Photiades
Keyword(s):  
Deep Water ◽  
Late Jurassic ◽  
Middle Triassic ◽  
Carbonate Platform ◽  
Continental Collision ◽  
Late Eocene ◽  
Early Jurassic ◽  
Geological Mapping ◽  
Ophiolitic Mélange ◽  
Early Tertiary

The geological mapping in scale 1:5.000 in the greater Nafplion area indicated a Tertiary nappe stack of different Pelagonian-originated tectonic units structurally overlying the Subpelagonian series of Argolis Peninsula. The Subpelagonian series as lower unit is characterized by a shallow-water carbonate platform of Middle Triassic to Early Jurassic age, locally deep-water ammonitico-rosso facies and red cherts and is overlain by a tectono-sedimentary ophiolitic melange of Malm age. After the compressive tectonic phase of late Jurassic, the Nafplion area at that time records a severe extensional intra-Cretaceous syn-rift phase leading to the deposition of diachronous Meso-autochthonous Cretaceous limestone deposits rich in faulted-derived limestone breccias series, topped by deep-water limestone of Campanian-Maastrichtian and then from Lower Tertiary pelagic limestone facies passes upwards into post-Ypresian flysch. The different Pelagonian telescoped tectonic units were contemporaneously overthrusting northwestward, over the Subpelagonian post-Ypresian flysch sequence, during the Late Eocene compressive phase, are successively characterized by: (a) a middle tectonic unit of a flyschoidal melange of Late Cretaceous-Early Tertiary age, like the Adheres Melange surfaces in Southern Argolis, associated with various carbonate and ophiolite tectonosomes trapped and carried within this highly disrupted terrigenous flyschoidal melange and, (b) an upper unit consists of Cretaceous carbonate slivers bearing serpentinite sole (Palamidi, Akronafplia, Profitis Ilias, Aria) and/or of Middle Triassic-Early Jurassic carbonate platform slices. The above nappe stacking may be connected with the Eocene continental collision of the Hellenides.

scholarly journals Macroevolutionary patterns in the evolutionary radiation of archosaurs (Tetrapoda: Diapsida)

2010 ◽  
Vol 101 (3-4) ◽  
pp. 367-382 ◽  
Author(s):  
Stephen L. Brusatte ◽  
Michael J. Benton ◽  
Graeme T. Lloyd ◽  
Marcello Ruta ◽  
Steve C. Wang
Keyword(s):  
Strong Evidence ◽  
Fossil Record ◽  
Morphological Character ◽  
Middle Triassic ◽  
Early Jurassic ◽  
Late Triassic ◽  
Morphological Disparity ◽  
Faunal Abundance ◽  
Evolutionary Radiation ◽  
Early Middle Triassic

ABSTRACTThe rise of archosaurs during the Triassic and Early Jurassic has been treated as a classic example of an evolutionary radiation in the fossil record. This paper reviews published studies and provides new data on archosaur lineage origination, diversity and lineage evolution, morphological disparity, rates of morphological character change, and faunal abundance during the Triassic–Early Jurassic. The fundamental archosaur lineages originated early in the Triassic, in concert with the highest rates of character change. Disparity and diversity peaked later, during the Norian, but the most significant increase in disparity occurred before maximum diversity. Archosaurs were rare components of Early–Middle Triassic faunas, but were more abundant in the Late Triassic and pre-eminent globally by the Early Jurassic. The archosaur radiation was a drawn-out event and major components such as diversity and abundance were discordant from each other. Crurotarsans (crocodile-line archosaurs) were more disparate, diverse, and abundant than avemetatarsalians (bird-line archosaurs, including dinosaurs) during the Late Triassic, but these roles were reversed in the Early Jurassic. There is no strong evidence that dinosaurs outcompeted or gradually eclipsed crurotarsans during the Late Triassic. Instead, crurotarsan diversity decreased precipitously by the end-Triassic extinction, which helped usher in the age of dinosaurian dominance.

scholarly journals Impact of intensifying nitrogen limitation on ocean net primary production is fingerprinted by nitrogen isotopes

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Pearse J. Buchanan ◽  
Olivier Aumont ◽  
Laurent Bopp ◽  
Claire Mahaffey ◽  
Alessandro Tagliabue
Keyword(s):  
Climate Change ◽  
Primary Production ◽  
Ocean Circulation ◽  
Nitrogen Cycle ◽  
Nitrogen Limitation ◽  
Nitrogen Isotopes ◽  
Net Primary Production ◽  
Twilight Zone ◽  
Low Latitude ◽  
Source Sink

AbstractThe open ocean nitrogen cycle is being altered by increases in anthropogenic atmospheric nitrogen deposition and climate change. How the nitrogen cycle responds will determine long-term trends in net primary production (NPP) in the nitrogen-limited low latitude ocean, but is poorly constrained by uncertainty in how the source-sink balance will evolve. Here we show that intensifying nitrogen limitation of phytoplankton, associated with near-term reductions in NPP, causes detectable declines in nitrogen isotopes (δ15N) and constitutes the primary perturbation of the 21st century nitrogen cycle. Model experiments show that ~75% of the low latitude twilight zone develops anomalously low δ15N by 2060, predominantly due to the effects of climate change that alter ocean circulation, with implications for the nitrogen source-sink balance. Our results highlight that δ15N changes in the low latitude twilight zone may provide a useful constraint on emerging changes to nitrogen limitation and NPP over the 21st century.

scholarly journals Phanerozoic radiation of ammonia oxidizing bacteria

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
L. M. Ward ◽  
D. T. Johnston ◽  
P. M. Shih
Keyword(s):  
Nitrogen Cycle ◽  
Ammonia Oxidation ◽  
Deep Ocean ◽  
Nitrogen Isotope ◽  
Ammonia Oxidizing Bacteria ◽  
Crown Group ◽  
Geologic Time ◽  
Absolute Requirement ◽  
Isotope Record ◽  
Late Evolution

AbstractThe modern nitrogen cycle consists of a web of microbially mediated redox transformations. Among the most crucial reactions in this cycle is the oxidation of ammonia to nitrite, an obligately aerobic process performed by a limited number of lineages of bacteria (AOB) and archaea (AOA). As this process has an absolute requirement for O2, the timing of its evolution—especially as it relates to the Great Oxygenation Event ~ 2.3 billion years ago—remains contested and is pivotal to our understanding of nutrient cycles. To estimate the antiquity of bacterial ammonia oxidation, we performed phylogenetic and molecular clock analyses of AOB. Surprisingly, bacterial ammonia oxidation appears quite young, with crown group clades having originated during Neoproterozoic time (or later) with major radiations occurring during Paleozoic time. These results place the evolution of AOB broadly coincident with the pervasive oxygenation of the deep ocean. The late evolution AOB challenges earlier interpretations of the ancient nitrogen isotope record, predicts a more substantial role for AOA during Precambrian time, and may have implications for understanding of the size and structure of the biogeochemical nitrogen cycle through geologic time.

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