DOI: 10.1002/2017GB005746
Scopus记录号: 2-s2.0-85032283791
论文题名: The Missing Silica Sink: Revisiting the Marine Sedimentary Si Cycle Using Cosmogenic 32Si
作者: Rahman S ; , Aller R ; C ; , Cochran J ; K
刊名: Global Biogeochemical Cycles
ISSN: 8866236
出版年: 2017
卷: 31, 期: 10 起始页码: 1559
结束页码: 1578
语种: 英语
英文关键词: authigenic clay formation
; biogenic silica cycle
; marine silica budget
; reverse weathering
; Si-32
Scopus关键词: authigenesis
; authigenic mineral
; burial (geology)
; clay
; coastal sediment
; coastal zone
; cosmogenic radionuclide
; marine sediment
; nearshore environment
; sedimentation rate
; silica
; Atlantic Ocean
; Coral Sea
; Gulf of Mexico
; Gulf of Papua
; Long Island Sound
; Pacific Ocean
; United States
英文摘要: Burial of biogenic silica (bSitotal) in high sedimentation rate continental margins remains highly uncertain. Cosmogenic 32Si (t1/2~140 years) can be used to trace the fates of bSitotal postdeposition, including as opal (bSiopal) and diagenetically altered opal (bSialtered), the latter dominantly authigenic clay (bSiclay). To determine the magnitude and form of bSitotal storage in coastal sediments, conventional operational leaches targeting bSiopal and bSialtered (including bSiclay) were modified for large-scale samples necessary for measurement of 32Si. The 32Si activity was used to estimate total biogenic silica burial (bSitotal = bSiopal + bSialtered) in several depositional settings: Gulf of Papua, Gulf of Mexico, Long Island Sound, and in the previously studied Amazon-Guianas deltaic system. In subtropical and temperate regions, 32Si was detected in both traditional biogenic silica leaches (bSiopal) and residual authigenic clays. Traditional bSiopal and modified operational leaches designed to target the most reactive authigenic silicates (~bSialtered) consistently underestimate authigenic clay formation (bSiclay) and thus the magnitude of bSitotal burial in temperate coastal zones and subtropical deltas by 2–4-fold. In tropical deltas, 32Si activities in the residual fraction after removal of bSiopal demonstrate rapid and almost complete alteration of initial bSiopal to new forms, most likely bSiclay. Globally, 4.5–4.9 Tmol/yr Si may be trapped in marine nearshore deposits as rapidly formed clay (bSiclay), 100% of the “missing silica sink” in the marine silica budget. ©2017. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/77694
Appears in Collections: 气候变化事实与影响
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作者单位: School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, United States; Now at Department of Geological Sciences, University of Florida, Gainesville, FL, United States
Recommended Citation:
Rahman S,, Aller R,C,et al. The Missing Silica Sink: Revisiting the Marine Sedimentary Si Cycle Using Cosmogenic 32Si[J]. Global Biogeochemical Cycles,2017-01-01,31(10)