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DOI | 10.1002/joc.4700 |
Primordial helium entrained by the hottest mantle plumes | |
Jackson, M. G.1; Konter, J. G.2; Becker, T. W.3 | |
2017-02-16 | |
发表期刊 | NATURE |
ISSN | 0028-0836 |
EISSN | 1476-4687 |
出版年 | 2017 |
卷号 | 542期号:7641页码:340-+ |
文章类型 | Article |
语种 | 英语 |
国家 | USA |
英文摘要 | Helium isotopes provide an important tool for tracing early-Earth, primordial reservoirs that have survived in the planet's interior(1-3). Volcanic hotspot lavas, like those erupted at Hawaii and Iceland, can host rare, high He-3/He-4 isotopic ratios (up to 50 times(4) the present atmospheric ratio, Ra) compared to the lower He-3/He-4 ratios identified in mid-ocean-ridge basalts that form by melting the upper mantle (about 8Ra; ref. 5). A long-standing hypothesis maintains that the high-He-3/He-4 domain resides in the deep mantle(6-8), beneath the upper mantle sampled by mid-ocean-ridge basalts, and that buoyantly upwelling plumes from the deep mantle transport high-He-3/He-4 material to the shallow mantle beneath plume-fed hotspots. One problem with this hypothesis is that, while some hotspots have He-3/He-4 values ranging from low to high, other hotspots exhibit only low He-3/He-4 ratios. Here we show that, among hotspots suggested to overlie mantle plumes(9,10), those with the highest maximum He-3/He-4 ratios have high hotspot buoyancy fluxes and overlie regions with seismic low-velocity anomalies in the upper mantle(11), unlike plume-fed hotspots with only low maximum He-3/He-4 ratios. We interpret the relationships between He-3/He-4 values, hotspot buoyancy flux, and upper-mantle shear wave velocity to mean that hot plumes-which exhibit seismic low-velocity anomalies at depths of 200 kilometres-are more buoyant and entrain both high-He-3/He-4 and low-He-3/He-4 material. In contrast, cooler, less buoyant plumes do not entrain this high-He-3/He-4 material. This can be explained if the high-He-3/He-4 domain is denser than low-He-3/He-4 mantle components hosted in plumes, and if high-He-3/He-4 material is entrained from the deep mantle only by the hottest, most buoyant plumes(12). Such a dense, deep-mantle high-He-3/He-4 domain could remain isolated from the convecting mantle(13,14), which may help to explain the preservation of early Hadean (>4.5 billion years ago) geochemical anomalies in lavas sampling this reservoir(1-3). |
领域 | 地球科学 ; 气候变化 ; 资源环境 |
收录类别 | SCI-E |
WOS记录号 | WOS:000394451600035 |
WOS关键词 | HIGH HE-3/HE-4 RATIOS ; OCEAN ISLAND BASALTS ; RARE-GAS SYSTEMATICS ; MID-ATLANTIC RIDGE ; ISOTOPE GEOCHEMISTRY ; YELLOWSTONE PLUME ; HIMU RESERVOIR ; VOLCANIC-ROCKS ; LOIHI SEAMOUNT ; NOBLE-GASES |
WOS类目 | Multidisciplinary Sciences |
WOS研究方向 | Science & Technology - Other Topics |
引用统计 | |
文献类型 | 期刊论文 |
条目标识符 | http://119.78.100.173/C666/handle/2XK7JSWQ/36995 |
专题 | 气候变化 |
作者单位 | 1.Univ Calif Santa Barbara, Dept Earth Sci, Santa Barbara, CA 93106 USA; 2.Univ Hawaii Manoa, Sch Ocean & Earth Sci & Technol, Dept Geol & Geophys, 1680 East West Rd, Honolulu, HI 96822 USA; 3.Univ Texas Austin, Jackson Sch Geosci, 1 Univ Stn,C1160, Austin, TX 78712 USA |
推荐引用方式 GB/T 7714 | Jackson, M. G.,Konter, J. G.,Becker, T. W.. Primordial helium entrained by the hottest mantle plumes[J]. NATURE,2017,542(7641):340-+. |
APA | Jackson, M. G.,Konter, J. G.,&Becker, T. W..(2017).Primordial helium entrained by the hottest mantle plumes.NATURE,542(7641),340-+. |
MLA | Jackson, M. G.,et al."Primordial helium entrained by the hottest mantle plumes".NATURE 542.7641(2017):340-+. |
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