Results 51 to 60 of about 254 (156)

Iron–Phosphorus–Carbon Coupled Cycling in Lacustrine System of Ordos Basin During the Middle Triassic

Geochemistry, Geophysics, Geosystems, Volume 27, Issue 2, February 2026.
Abstract Widespread organic‐rich shales are associated with perturbations in productivity or preservation conditions; however, the major controlling factors, especially the phosphorus (P) and iron (Fe) interactions and their impacts on organic carbon burial in the paleolake ecosystem remain poorly understood.
Bo Wang, Rukai Zhu, Pengcheng Ju, Quanyou Liu, Weiming Xu, Peng Li, Wang Zhang, Xinping Liang   +7 more
wiley   +1 more source

New Hirnantian orthide brachiopods from the type section of the Porkuni Stage (Porkuni quarry, northeastern Estonia) [PDF]

Estonian Journal of Earth Sciences, 2012
Four new Hirnantian species of orthide brachiopods, Sigmelasma peepi, Mendacella aerinensis, Drabovia? minuta and Tyronella siugensis are described from the type section of the Porkuni Regional Stage in the Porkuni quarry, northeastern Estonia.
Linda Hints
doaj   +1 more source

Mass concentration of Hirnantian cephalopods from the Siljan District, Sweden; taxonomy, palaeoecology and palaeobiogeographic relationships [PDF]

Fossil Record, 2011
The Hirnantian Glisstjärn Formation (Normalograptus persculptus graptolite Biozone) is a succession of limestones and shales onlapping the Katian Boda Limestone in the Siljan District, Sweden.
B. Kröger, J. O. R. Ebbestad, A. E. S. Högström, Å. M. Frisk   +3 more
doaj   +5 more sources

The regional stratotype section and point for the base of the Hirnantian Stage (the uppermost Ordovician) at Mirny Creek, Omulev Mountains, Northeast Russia [PDF]

Estonian Journal of Earth Sciences, 2008
A complete Hirnantian sequence comprising the Normalograptus extraordinarius and N. persculptus biozones is well developed at the Mirny Creek section in the Omulev Mountains.
Koren, Tatyana N., Sobolevskaya, Rimma F.   +1 more
doaj  

Mercury Deposition in South China Across the Ordovician‐Silurian Transition: Implications for Climate Change

Geochemistry, Geophysics, Geosystems, Volume 26, Issue 7, July 2025.
Abstract Most of the global climate changes are closely associated with volcanic activity. However, the link between global cooling during the Ordovician‐Silurian (O‐S) transition and volcanism remains unclear due to limited constraints on large volcanic events before, during, and after the peak of the Hirnantian glaciation (PHG). Here, we present high‐
Weiliang Kong, Zhen Qiu, Jiaqiang Zhang, Wen Liu, Qin Zhang   +4 more
wiley   +1 more source

New evidence for the Hirnantian (Upper Ordovician) in Belgium? An integrated isotopical, biostratigraphic and sedimentologic approach

Carnets de Géologie, 2005
The Hirnantian is an important time in Earth history as it includes one of the major episodes of continental glaciation and marine mass extinction (e.g. Brenchley et alii, 1994).
Grassineau Nathalie, Préat Alain, Yans Johan, Vanmeirhaeghe Jan, Verniers Jacques   +4 more
doaj  

A new euarthropod from the Soom Shale (Ordovician) Konservat‐Lagerstätte, South Africa, with exceptional preservation of the connective endoskeleton and myoanatomy

Papers in Palaeontology, Volume 11, Issue 2, March/April 2025.
Abstract A new exceptionally preserved euarthropod, Keurbos susanae gen. et sp. nov. from the Upper Ordovician Soom Shale Konservat‐Lagerstätte of South Africa, is described herein. Two specimens exhibit an unusual preservation style such that the cuticular exoskeleton is preserved in low relief but retains high‐fidelity details, whereas the internal ...
Sarah E. Gabbott, Gregory D. Edgecombe, Johannes N. Theron, Richard J. Aldridge   +3 more
wiley   +1 more source

δ13C chemostratigraphy of the Middle and Upper Ordovician succession in the Tartu-453 drillcore, southern Estonia, and the significance of the HICE [PDF]

Estonian Journal of Earth Sciences, 2014
The δ13C isotope data from the Tartu-453 core section in southern Estonia enabled creation of a continuous Ordovician carbon isotope record, ranging from the Floian to the end of the Hirnantian.
Heikki Bauert, Leho Ainsaar, Kairi Põldsaar, Siim Sepp   +3 more
doaj   +1 more source

Late Ordovician ironstone and its relation to ocean redox instability, climate and glaciation

Sedimentology, Volume 72, Issue 2, Page 631-665, February 2025.
Abstract The Upper Ordovician (Katian) Neda Formation, a phosphatic ironstone, records a widespread but short‐lived shift to ferruginous waters across a vast epicontinental area. Lithofacies and stratigraphic reappraisal indicate that Neda ironstone deposition occurred on a storm‐dominated ramp when coastal upwelling emplaced eutrophic ferruginous ...
Edward J. Matheson, Jackson D. Malone, Peir K. Pufahl, Eric E. Hiatt   +3 more
wiley   +1 more source

An Ordovician Assemblage of Cool Water‐Adapted Paleotropical Ostracods Suggests an Early Psychrosphere

Island Arc, Volume 34, Issue 1, January/December 2025.
ABSTRACT An ostracod assemblage from the Late Ordovician (Katian) Phu Ngu Formation of northern Vietnam, South China paleoplate, yields typical Baltic and Laurentian‐affinity genera together with some endemic forms. Detailed paleontological and sedimentary analysis of the Phu Ngu Formation suggests it was deposited in a deeper marine forearc setting ...
Anna McGairy, Phong Duc Nguyen, Mark Williams, Christopher P. Stocker, Thomas H. P. Harvey, Toshifumi Komatsu, Thomas W. Wong Hearing, C. Giles Miller, Chloé M. Marcilly, Alexandre Pohl   +9 more
wiley   +1 more source