DOI: 10.1016/j.palaeo.2013.05.001
论文题名: New records of Oligocene diffuse hydrocarbon seeps, northern Cascadia margin
作者: Nesbitt E.A. ; Martin R.A. ; Campbell K.A.
刊名: Palaeogeography, Palaeoclimatology, Palaeoecology
ISSN: 0031-0182
出版年: 2013
卷: 390 起始页码: 116
结束页码: 129
语种: 英语
英文关键词: Benthic foraminifera
; Carbon and oxygen isotopes
; Cascadia margin
; Hydrocarbon seep
; Methane
; Siletzia
英文摘要: Fossil methane seeps are preserved in late Eocene through Pliocene marine sedimentary units of the Cascadia margin of the northeastern Pacific. All Cascadia fossil seeps are situated in the uplifted accretionary wedge that overlies extensive Middle Eocene coal-bearing units and the Paleocene-Early Eocene Siletzia large igneous province. This study describes eight previously unrecorded Oligocene seeps, all of which are identified by small, scattered carbonates with or without accompanying characteristic seep macrofauna, from both inner and outer shelf depths. We interpret these deposits as reflecting spatially and temporally diffuse seepage of hydrocarbon-enriched fluids, sourced from various carbon sources within the actively deforming accretionary prism, and term them diffuse seeps. δ13C and δ18O values from foraminiferal carbonate from the studied stratigraphic units have broad variability. Authigenic carbonates occurring as nodules, blebs, burrow fill and fracture fill indicated microbial and thermogenic methane, and multiple fluid flow pathways from within the actively deforming accretionary wedge. It is apparent that the complex fluid-flow regime observed in modern seeps of the Cascadia margin is a continuation of one established in the late Eocene. © 2013. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/69594
Appears in Collections: 过去全球变化的重建
There are no files associated with this item.
作者单位: Burke Museum of Natural History and Culture, University of Washington, Box 353010, Seattle, WA 98195-3010, United States; School of Environment, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
Recommended Citation:
Nesbitt E.A.,Martin R.A.,Campbell K.A.. New records of Oligocene diffuse hydrocarbon seeps, northern Cascadia margin[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2013-01-01,390