DOI: 10.1016/j.palaeo.2012.11.018
论文题名: Radiogenic isotope composition of Carboniferous seawater from North American epicontinental seas
作者: Woodard S.C. ; Thomas D.J. ; Grossman E.L. ; Olszewski T.D. ; Yancey T.E. ; Miller B.V. ; Raymond A.
刊名: Palaeogeography, Palaeoclimatology, Palaeoecology
ISSN: 0031-0182
出版年: 2013
卷: 370 起始页码: 51
结束页码: 63
语种: 英语
英文关键词: Carboniferous
; Conodonts
; Epicontinental seas
; Nd isotopes
; North America
; Rheic Ocean
英文摘要: Abundant marine sedimentary deposits accumulated in the epeiric seas of North America during the Carboniferous Period (359-299Ma) when the Earth's climate shifted from a global "greenhouse" to "icehouse". Geochemical records extracted from these deposits are often assumed to reflect global ocean processes and are increasingly being used to infer relationships between tectonism, carbon cycling and climate change. We analyzed radiogenic isotopes (Sr, Nd) in biogenic apatite along a North American transect to constrain the degree of coupling between the epicontinental seas and the open ocean. In many samples the primary Sr signal is altered, however the original Nd isotopic composition of the biogenic apatite seems to be preserved. The εNd(t) values range from -8.6 to -4.5 in the US midcontinent basins and from -11.4 to -5.7 at Arrow Canyon (Nevada, USA), indicating the development of an east-west geochemical gradient throughout the Pennsylvanian. This apparent decoupling of the epicontinental seas from the open ocean was established by the latest Mississippian. Thus, circulation of waters between epicontinental seaways of western US and the basins to the east and south was periodically restricted. Shifts toward unradiogenic Nd at Arrow Canyon seem to correspond with glacio-eustatic changes across the mid-Carboniferous boundary. These εNd(t) variations may have been caused by changes in weathering rates/sources, marine circulation or a combination of both. © 2012 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/69854
Appears in Collections: 过去全球变化的重建
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作者单位: Department of Oceanography, Texas A and M University, College Station, TX 77843-3146, United States; Department of Geology and Geophysics, Texas A and M University, College Station, TX 77843-3115, United States
Recommended Citation:
Woodard S.C.,Thomas D.J.,Grossman E.L.,et al. Radiogenic isotope composition of Carboniferous seawater from North American epicontinental seas[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2013-01-01,370