The Experts below are selected from a list of 258 Experts worldwide ranked by ideXlab platform
Pei Ni - One of the best experts on this subject based on the ideXlab platform.
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stromatolites in Middle Ordovician carbonate evaporite sequences and their carbon and sulfur isotopes stratigraphy ordos basin northwestern china
Carbonates and Evaporites, 2019Co-Authors: Fanwei Meng, Zhi-li Zhang, Pei NiAbstract:At the present day, stromatolites are very rare and limited to high-salinity settings. However, abundant and variable stromatolite fossils occur in thick evaporite sequences, the Middle Ordovician Majiagou Formation of the Ordos Basin, northwestern China. The setting and fossil assemblage imply that the high salinity prevented metazoan grazing and allowed stromatolites to flourish. The carbon isotope curve based on new data (average data range from −4.52 to +0.56‰) from drilling cores in Majiagou Formation is in good agreement with Middle Ordovician (Darriwilian), and supports the Middle Ordovician age inferred from biostratigraphy. Sulfur isotopes values (range from +27.1 to +28.0‰) are higher than those of the Upper Ordovician but much lower than those of the Lower Middle Cambrian; thus, the sulfur values imply that the Majiagou Formation is of Middle Ordovician age. New carbon and sulfur isotope data imply that these strata are of Middle Ordovician age, in good agreement with previous paleontological dating.
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Stromatolites in Middle Ordovician carbonate–evaporite sequences and their carbon and sulfur isotopes stratigraphy, Ordos Basin, northwestern China
Carbonates and Evaporites, 2017Co-Authors: Fanwei Meng, Zhi-li Zhang, Pei NiAbstract:At the present day, stromatolites are very rare and limited to high-salinity settings. However, abundant and variable stromatolite fossils occur in thick evaporite sequences, the Middle Ordovician Majiagou Formation of the Ordos Basin, northwestern China. The setting and fossil assemblage imply that the high salinity prevented metazoan grazing and allowed stromatolites to flourish. The carbon isotope curve based on new data (average data range from −4.52 to +0.56‰) from drilling cores in Majiagou Formation is in good agreement with Middle Ordovician (Darriwilian), and supports the Middle Ordovician age inferred from biostratigraphy. Sulfur isotopes values (range from +27.1 to +28.0‰) are higher than those of the Upper Ordovician but much lower than those of the Lower Middle Cambrian; thus, the sulfur values imply that the Majiagou Formation is of Middle Ordovician age. New carbon and sulfur isotope data imply that these strata are of Middle Ordovician age, in good agreement with previous paleontological dating.
Thomas W Hearing - One of the best experts on this subject based on the ideXlab platform.
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survival of burgess shale type animals in a Middle Ordovician deep water setting
Journal of the Geological Society, 2016Co-Authors: Joseph P Botting, Lucy A Muir, Thomas W Hearing, David A Legg, Patrick D Mcdermott, Stephanie Faulkner, Adam C Taylor, Martin D BrasierAbstract:Exceptional preservation of non-biomineralized arthropods, sponges and vermiform taxa occurs in the Darriwilian (Middle Ordovician) Llanfallteg Formation of South Wales, UK. The assemblage contains elements typical of Ordovician communities juxtaposed with those more commonly associated with Cambrian Konservat-Lagerstatten. This assemblage is preserved in rocks of a deep-marine succession dominated by fine-grained siliciclastic and volcaniclastic density-current deposits. Non-biomineralized taxa of Cambrian aspect are preserved as pyritized carbonaceous compressions on the spectrum of Burgess Shale-type preservation. Trilobites with phosphatized digestive structures have also been recovered. The assemblage of the Llanfallteg Formation Konservat-Lagerstatte demonstrates that some Burgess Shale-type faunal elements survived into the Middle Ordovician within cool, deep-water refugia in the Welsh Basin, offshore from communities dominated by typical Ordovician taxa. Supplementary material: Assemblage composition data and sedimentological images can be found at https://doi.org/10.6084/m9.figshare.c.2182218.
Svend Stouge - One of the best experts on this subject based on the ideXlab platform.
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Middle Ordovician aporthophyla brachiopod fauna from the roof of the world southern tibet
Palaeontology, 2014Co-Authors: Renbin Zhan, David A T Harper, Yan Liang, Lars Stemmerik, Svend StougeAbstract:A Darriwilian (late Middle Ordovician) brachiopod fauna from the Lower Formation of the Chiatsun Group at Jiacun, northern Nyalam, southern Tibet, consists of ten brachiopod species, forming a distinct Aporthophyla–Paralenorthis Association. Its taxonomic composition is typical of the Aporthophyla Fauna that occupied lower BA2 to upper BA3 benthic environments on sandy lime mud substrates. The occurrence of Paralenorthis in southern Tibet is confirmed for the first time, represented by P. costata sp. nov. Numerical analyses (PCA and CA) of 18 Darriwilian brachiopod faunas from ten palaeoplates or terranes indicate that: (1) the Aporthophyla Fauna was confined to a specific latitudinal belt although it had a wide lateral distribution from the large palaeocontinents of Gondwana to Laurentia; (2) the Saucrorthis Fauna, a typical late Middle Ordovician regional fauna, is limited to a much smaller area, marginal to the Gondwana supercontinent; (3) the strong provincialism persistent in the late Middle Ordovician contributed to increased gamma biodiversity during the Great Ordovician Biodiversification Event.
Fanwei Meng - One of the best experts on this subject based on the ideXlab platform.
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stromatolites in Middle Ordovician carbonate evaporite sequences and their carbon and sulfur isotopes stratigraphy ordos basin northwestern china
Carbonates and Evaporites, 2019Co-Authors: Fanwei Meng, Zhi-li Zhang, Pei NiAbstract:At the present day, stromatolites are very rare and limited to high-salinity settings. However, abundant and variable stromatolite fossils occur in thick evaporite sequences, the Middle Ordovician Majiagou Formation of the Ordos Basin, northwestern China. The setting and fossil assemblage imply that the high salinity prevented metazoan grazing and allowed stromatolites to flourish. The carbon isotope curve based on new data (average data range from −4.52 to +0.56‰) from drilling cores in Majiagou Formation is in good agreement with Middle Ordovician (Darriwilian), and supports the Middle Ordovician age inferred from biostratigraphy. Sulfur isotopes values (range from +27.1 to +28.0‰) are higher than those of the Upper Ordovician but much lower than those of the Lower Middle Cambrian; thus, the sulfur values imply that the Majiagou Formation is of Middle Ordovician age. New carbon and sulfur isotope data imply that these strata are of Middle Ordovician age, in good agreement with previous paleontological dating.
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Stromatolites in Middle Ordovician carbonate–evaporite sequences and their carbon and sulfur isotopes stratigraphy, Ordos Basin, northwestern China
Carbonates and Evaporites, 2017Co-Authors: Fanwei Meng, Zhi-li Zhang, Pei NiAbstract:At the present day, stromatolites are very rare and limited to high-salinity settings. However, abundant and variable stromatolite fossils occur in thick evaporite sequences, the Middle Ordovician Majiagou Formation of the Ordos Basin, northwestern China. The setting and fossil assemblage imply that the high salinity prevented metazoan grazing and allowed stromatolites to flourish. The carbon isotope curve based on new data (average data range from −4.52 to +0.56‰) from drilling cores in Majiagou Formation is in good agreement with Middle Ordovician (Darriwilian), and supports the Middle Ordovician age inferred from biostratigraphy. Sulfur isotopes values (range from +27.1 to +28.0‰) are higher than those of the Upper Ordovician but much lower than those of the Lower Middle Cambrian; thus, the sulfur values imply that the Majiagou Formation is of Middle Ordovician age. New carbon and sulfur isotope data imply that these strata are of Middle Ordovician age, in good agreement with previous paleontological dating.
Kathlyn J Mcvey - One of the best experts on this subject based on the ideXlab platform.
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a new lagerstatte from the Middle Ordovician st peter formation in northeast iowa usa
Geology, 2006Co-Authors: Robert Mckay, Jean N Young, Brian J Witzke, Kathlyn J McveyAbstract:A new fossil fauna has been discovered from a recently recognized shale unit within the Middle Ordovician St. Peter Formation in northeast Iowa. It contains a variety of invertebrates and vertebrates, including soft body tissues, impressions, and 3-dimensionalpreservations. The exceptional preservation reveals a new Konservat-Lagerstatte, the Winneshiek Lagerstatte, and opens a unique window into the community that inhabited the margins of the Laurentian cratonic seaway during Middle Ordovician transgression. Among the fossils, several conodont assemblages, including the apparatus of enigmatic coleodontids, are preserved. Some conodont assemblages associated with soft body tissues are particularly noteworthy.