DOI: 10.1002/2014GL059424
论文题名: A common mantle plume source beneath the entire East African Rift System revealed by coupled helium-neon systematics
作者: Halldõrsson S.A. ; Hilton D.R. ; Scarsi P. ; Abebe T. ; Hopp J.
刊名: Geophysical Research Letters
ISSN: 0094-10171
EISSN: 1944-9902
出版年: 2014
卷: 41, 期: 7 起始页码: 2304
结束页码: 2311
语种: 英语
英文关键词: Composition of the mantle
; Geochemistry
; Hotspots
; Intra-plate processes
; Mantle processes
Scopus关键词: Geochemistry
; Helium
; Isotopes
; Composition of the mantles
; Depleted MORB mantles
; East African Rift
; Hotspots
; Intra-plate process
; Mantle plume sources
; Mantle process
; Sub-continental lithospheric mantles
; Thermal plumes
; helium
; hot spot
; intraplate process
; lava
; magmatism
; mantle chemistry
; mantle plume
; neon
; xenolith
; East African Rift
; Mbeya [Tanzania]
; Mount Rungwe
; Tanzania
英文摘要: We report combined He-Ne-Ar isotope data of mantle-derived xenoliths and/or lavas from all segments of the East Africa Rift System (EARS). Plume-like helium isotope (3He/4He) ratios (i.e., greater than the depleted MORB mantle (DMM) range of 8-±-1RA) are restricted to the Ethiopia Rift and Rungwe, the southernmost volcanic province of the Western Rift. In contrast, neon isotope trends reveal the presence of an ubiquitous solar (plume-like) Ne component throughout the EARS, with (21Ne/ 22Ne)EX values (where (21Ne/ 22Ne)EX is the air-corrected 21Ne/ 22Ne ratio extrapolated to Ne-B) as low as 0.034, close to that of solar Ne-B (0.031). Coupling (21Ne/22Ne)EX with 4He/3He ratios indicates that all samples can be explained by admixture between a single mantle plume source, common to the entire rift, and either a DMM or subcontinental lithospheric mantle source. Additionally, we show that the entire sample suite is characterized by low 3He/22NeS ratios (mostly-<-0.2) - a feature characteristic of oceanic hot spots such as Iceland. We propose that the origin of these unique noble gas signatures is the deeply rooted African Superplume which influences magmatism throughout eastern Africa. We argue that the Ethiopia and Kenya domes represent two different heads of this common mantle plume source. Key Points He-Ne-Ar isotope data of xenoliths and lavas from the East Africa Rift System He-Ne systematics suggest a single mantle plume source The African Superplume influences magmatism throughout eastern Africa © 2014. American Geophysical Union. All Rights Reserved. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84897304528&doi=10.1002%2f2014GL059424&partnerID=40&md5=ca21709b0ffb2c3c9f4dd12fe9313cdd
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/7435
Appears in Collections: 气候减缓与适应
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作者单位: Fluids and Volatiles Laboratory, Scripps Institution of Oceanography, University of California, San Diego, CA, United States
Recommended Citation:
Halldõrsson S.A.,Hilton D.R.,Scarsi P.,et al. A common mantle plume source beneath the entire East African Rift System revealed by coupled helium-neon systematics[J]. Geophysical Research Letters,2014-01-01,41(7).