DOI: 10.1016/j.palaeo.2016.12.043
论文题名: Permian endemic bivalves of the “Irati anoxic event”, Paraná Basin, Brazil: Taphonomical, paleogeographical and evolutionary implications
作者: Matos S.A. ; Warren L.V. ; Varejão F.G. ; Assine M.L. ; Simões M.G.
刊名: Palaeogeography, Palaeoclimatology, Palaeoecology
ISSN: 0031-0182
出版年: 2017
卷: 469 起始页码: 18
结束页码: 33
语种: 英语
英文关键词: Allochthonous shells
; Anoxic crisis
; Black shales
; Endemic bivalves
; Permian
; Southern Gondwana
英文摘要: Anoxic to dysoxic conditions must have existed in the Paraná Basin during the deposition of the Permian oil-bearing shales of the Irati Formation, reflecting the marine isolation of the basin from the Panthalassic Ocean. In this environment, benthic invertebrates are extremely rare, in contrast to the overlying Serra Alta and Teresina formations, which were deposited in dysoxic/oxic waters, respectively. Hence, the abundant shallow-burrowing, endemic bivalves recorded in the shales of the basal portion of the Irati Formation are one of the most distinctive features of this stratigraphic interval. Their preservation in offshore deposits is, however, a product of storm flows in shallow waters that swept the shells to distal settings. Subsequently, these were sorted by long-lasting shelf currents that produced dense (2–5 shells/20 cm2) pavements in which shells in a hydrodynamically stable posture (convex-up) predominate, forming thin, complex shell concentrations despite their simple internal stratigraphy. The new data presented here have important paleoecologic, paleogeographic and evolutionary implications and indicate that (a) during the deposition of the oil-rich shales of the Irati Formation, numerous benthic bivalves thrived in the contemporary shallow-water bottoms of the Paraná Basin; (b) the mono- to paucispecific nature of the studied shell-rich pavements is, in part, due to hydrologic shell transport; and (c) restricted connections to open ocean waters (Panthalassa) existed during Irati times. Therefore, the origin of the endemic Passa Dois molluscan fauna occurred somewhere between the interval represented by the underlying Palermo Formation and the basal portion of the Irati Formation. Finally, these endemic bivalves appeared at least ~ 10 million years earlier than previously thought. © 2016 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/67943
Appears in Collections: 过去全球变化的重建
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作者单位: Instituto de Geociências, Programa de Pós-graduação em Geoquímica e Geotectônica, Universidade de São Paulo, Rua do Lago 562, São Paulo, SP, Brazil; Instituto de Geociências e Ciências Exatas, Departamento de Geologia Aplicada, Universidade Estadual Paulista, Avenida 24-A, Bela Vista, 178, Rio Claro, SP, Brazil; Instituto de Biociências, Departamento de Zoologia, Universidade Estadual Paulista, Distrito de Rubião Junior s/n, 510, Botucatu, SP, Brazil
Recommended Citation:
Matos S.A.,Warren L.V.,Varejão F.G.,et al. Permian endemic bivalves of the “Irati anoxic event”, Paraná Basin, Brazil: Taphonomical, paleogeographical and evolutionary implications[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2017-01-01,469