Results 71 to 80 of about 3,916,400 (215)

Nacre in Molluscs from the Ordovician of the Midwestern United States

open access: yesGeosciences, 2013
Nacre was previously thought to be primitive in the Mollusca, but no convincing Cambrian examples are known. This aragonitic microstructure with crystal tablets that grow within an organic framework is thought to be the strongest, most fracture-resistant
Steven D.J. Baumann   +3 more
doaj   +1 more source

FAULT SYSTEMS IN THE UPPER CRUST OF THE CENTRAL ASIAN FOLDING BELT

open access: yesИзвестия высших учебных заведений: Геология и разведка, 2020
This article considers the disjunctive deformation of the upper crust in the Tien Shan and Altai-Sayan regions of the Central Asian folding belt. An analysis of the diagrams of fault directions constructed on the basis of information on more than 3000 ...
V. S. Burtman
doaj   +1 more source

Depositional and stratigraphic evolution of a Permian megalake system: Implications for seiche‐influenced models

open access: yesThe Depositional Record, Volume 12, Issue 2, April 2026.
During the Late Permian, the rise of the Gondwanides Belt trapped marine waters, giving birth to a vast megalake. This lake shifted between overfilled, balanced‐fill and underfilled stages that are recorded by high‐frequency accommodation changes, while meteorological seiches shaped the sedimentary dynamic and produced heterolithic beds.
B. Christofoletti   +6 more
wiley   +1 more source

Revealing patterns of endemism in the transatlantic family Chelodesmidae (Polydesmida: Diplopoda)

open access: yesCladistics, Volume 42, Issue 2, Page 159-171, April 2026.
Abstract With fossil records dating back to the Silurian/Late Ordovician, millipedes stand out as one of the earliest terrestrial animal groups. Their limited vagility and high endemism make them valuable tools for formulating and testing biogeographic hypotheses, including those related to macro‐vicariance events.
Rodrigo Salvador Bouzan   +4 more
wiley   +1 more source

Evolution of the Ordovician top boundary and its relationship to reservoirs' development, Ordos Basin

open access: yesPetroleum Exploration and Development, 2012
The control of structural evolution on the development of different types of Ordovician reservoirs in the Ordos Basin is discussed by studying the evolution of the Ordovician top boundary in geological times, and the mechanisms of formation and evolution
Xinquan RAN   +5 more
doaj   +1 more source

Coesite Discovery in Eclogites Confirms UHP Metamorphism in the Orlica‐Śnieżnik Dome (SW Poland)

open access: yesJournal of Metamorphic Geology, Volume 44, Issue 3, Page 200-225, April 2026.
ABSTRACT Eclogite lenses are exposed within the orthogneiss‐dominated core of the Orlica‐Śnieżnik Dome in the Sudetes, which forms the northeastern margin of the Bohemian Massif (Variscan Belt of Central Europe). The presence of coesite inclusions in garnet and omphacite confirms that these eclogites underwent ultrahigh‐pressure metamorphism.
Małgorzata Nowak   +4 more
wiley   +1 more source

Vertical decoupling in Late Ordovician anoxia due to reorganization of ocean circulation

open access: yesNature Geoscience, 2021
A. Pohl   +10 more
semanticscholar   +1 more source

The late Ordovician Soom Shale Lagerstätte: an extraordinary post-glacial fossil and sedimentary record

open access: yesJournal of the Geological Society, 2016
Fossils of the Late Ordovician Soom Shale Lagerstätte are characterized by exceptional preservation of their soft tissues in clay minerals. The low-diversity community lived in an unusual cold-water setting, dominated by anoxic bottom waters, in the ...
S. Gabbott   +3 more
semanticscholar   +1 more source

Global Comparison of Aqueous Geochemistry and Dissolved H2/CH4 in Continental Low Temperature Serpentinization–Influenced Environments

open access: yesHydrological Processes, Volume 40, Issue 3, March 2026.
Conceptual diagram of hydrological and geochemical processes within the Santa Elena Ophiolite, Costa Rica. It highlights watershed cross‐sections, soil genesis, hyperalkaline Type II waters (pH > 11.6) with calcite crust and trapped H2/CH4 gases, seepage into surface waters, storm‐impacted stream profiles, weathered vs.
Alexandra May   +8 more
wiley   +1 more source

New Zealand Geological Timescale 2025

open access: yesNew Zealand Journal of Geology and Geophysics, Volume 69, Issue 1, March 2026.
New Zealand Geological Timescale 2025 (NZGT 2025) is the first comprehensive update and revision of the New Zealand Geological Timescale in a decade. The criteria used to establish age ranges of New Zealand Stages within the NZGT have been reviewed, calibrated, and revised where required against the 2023/04 International Chronostratigraphic Chart and ...
Christopher D. Clowes   +13 more
wiley   +1 more source

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