Dynamics of marine inorganic carbon and silica: A field study of the mechanisms controlling seawater major element concentrations

Limnology and Oceanography, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 18, 2025

Abstract A highly resolved time series of dissolved major element (calcium, strontium, magnesium, and lithium) concentrations in the north Gulf Aqaba, Red Sea, reveals variability cation beyond analytic uncertainties. This is composed an interannual component that most important for calcium, a short‐term daily‐timescale lithium. As evident from covariation potential alkalinity, Sr/Ca, calcium carbonate cycle Aqaba dominated by coral calcification, there was increase calcification rates between 2017 2018. Variability lithium concentrations, larger changes magnesium than expected distribution coefficients minerals, suggest active aluminosilicate mineral dissolution, precipitation secondary silicate minerals.

Language: Английский

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Fossil eggshell diversity of the Mussentuchit Member, Cedar Mountain Formation, Utah

PLoS ONE, Journal Year: 2025, Volume and Issue: 20(2), P. e0314689 - e0314689

Published: Feb. 26, 2025

The first fossil eggshell from the Cenomanian-age Mussentuchit Member of Cedar Mountain Formation was described over fifty years ago. In half-century since, oodiversity this rock unit has been limited to a single, taxonomically unstable ootaxon, currently formulated as Macroelongatoolithus carlylei . Recently, there renewed effort recover and describe macrofauna Mussentuchit; however, these advances are body record. Here, we examine range eggshells present in assess preserved biodiversity they represent. Gross morphological microstructural inspection reveals greater diversity than previously described. We identify six ootaxa: three Elongatoolithidae oogenera ( , Undulatoolithus Continuoolithus ), eggs laid by oviraptorosaur dinosaurs; two oospecies Spheroolithus ornithopod Mycomorphoolithus kohringi crocodylomorph. requires co-occurrence at least putative oviraptorosaurs, oldest such phenomenon North America. occurrence crocodylomorph oogenus is recognized outside Europe, youngest yet documented. This new ooassemblage more representative known paleobiodiversity strata Western America complements record improving our understanding crucial—yet poorly documented—timeslice within broader evolution Cretaceous Interior Basin.

Language: Английский

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Extremely rapid, yet noncatastrophic, preservation of the flattened-feathered and 3D dinosaurs of the Early Cretaceous of China

Proceedings of the National Academy of Sciences, Journal Year: 2024, Volume and Issue: 121(47)

Published: Nov. 4, 2024

Northeast China's Early Cretaceous Yixian Formation preserves spectacular fossils that have proved extraordinarily important in testing evolutionary hypotheses involving the origin of birds and distribution feathers among nonavian dinosaurs. These occur either flattened with soft tissue preservation (including color) laminated lacustrine strata or as three-dimensional (3D) skeletons "life-like" postures more massive deposits. The relationships these deposits to each other, their absolute ages, extraordinary fossil been vigorously debated for nearly a half century, prevailing view being was linked violent volcanic eruptions lahars, similar processes preserved human remains at Pompeii. We present high-precision zircon U-Pb geochronology from cores outcrops, demonstrating accumulation rates are than an order magnitude higher usually estimated. Additionally, we provide provenance sedimentological data 3D dinosaur fossils, which imply death burial occurred collapsed burrows, rather via catastrophic volcanogenic mechanism. In studied area, three principal fossil-rich intervals cyclic sequence correspond periods high precipitation. Using Bayesian-Markov Chain Monte Carlo approaches, constrain total duration less ~93,000 y suggest climatic precession paced expression sediments. Rather representing multiple, Pompeii-like catastrophes, is instead brief snapshot normal life continental community.

Language: Английский

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A digging theropod? Enigmatic ankylosed phalanges from the Upper Cretaceous of Uzbekistan

PalZ, Journal Year: 2025, Volume and Issue: unknown

Published: April 16, 2025

Language: Английский

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J'ai planté le décor de l'endroit où les dinosaures ont marché

Nature Africa, Journal Year: 2024, Volume and Issue: unknown

Published: Sept. 13, 2024

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I set the scene for where dinosaurs walked

Nature Africa, Journal Year: 2024, Volume and Issue: unknown

Published: Sept. 13, 2024

Language: Английский

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