Lithofacies and stratigraphy of the Ordovician Guniutan Formation in its type area, China

Stable ocean redox during the main phase of the Great Ordovician Biodiversification Event

“…2 ), which suggest reducing conditions in the local depositional environment 59 . In addition, a similar lithological change is also observed in coeval limestones in South China 58 , 60 . Therefore, the abrupt lithological shift in the rather uniform carbonate succession in two distinct and widely separated paleocontinents suggests the transition from stable to unstable conditions was initiated by a global event that disrupted sedimentary cycles and the marine redox landscape.…”

“…Thus, relative diversification slows down when the redox landscape becomes unstable, and the carbon cycle is globally disturbed. Further, extinction rates increase, and brachiopod richness 57 , 58 reaches a low when the δ 238 U curve suggests a shift towards more euxinic water masses in the oceans, around the unconformity of the section (Dw2–Dw3 boundary) (Fig. 3 ).…”

Lower and Middle Ordovician conodont diversity of the Yichang Region, Hubei Province, Central China

“…Several conodont studies were published (e.g. An 1981An et al 1981An et al , 1985Ni 1981;Zeng et al 1987;Wang & Bergström 1995, 1999Wang et al 1996;Zhang 1996Zhang , 1997Wang et al 1993Zhang 1998;Li et al 2004b).…”

Aserian and Lasnamägian (Middle Ordovician) conodont biostratigraphy and lithology at Kullstaberg and Lunne in Jämtland, central Sweden

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