Oceanic Island Basalts and Mantle Plumes: The Geochemical Perspective
Oceanic Island Basalts and Mantle Plumes: The Geochemical Perspective
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DOI：
10.1146/annurev-earth-040809-152450
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发表时间：
2010-04
影响因子：
14.9
通讯作者：
W. White
中科院分区：
文献类型：
--
作者：
W. White
地幔岩柱--通常，但并非总是，在化学上与大洋中脊玄武岩(MORB)不同--可能植根于核-地幔边界，开始于引发大规模喷发的巨大头部，或者是无头的，出现在地幔中段。地球化学提供了令人信服的证据，表明地幔热柱比正常上地幔高100-300℃，熔融区内的上升流速度快于大洋中脊下。186Os/188Os暗示夏威夷羽流中可能有来自地核的物质，但这在其他大洋岛玄武岩(OIB)中看不到，也没有得到182W/184W测量的证实。热柱中高的3He/4He不需要原始的深地幔储集层。地幔热柱的地球化学特征主要来自上地幔的熔融，可能是大洋岩石圈的形成和俯冲，但细节仍不清楚。羽流在岩性上是不同的，由镁铁质材料的弦线组成。
Mantle plumes—which are usually, but not always, chemically distinct from the mid-ocean ridge basalt (MORB)—may be rooted in the core-mantle boundary and begin with large voluminous heads triggering massive eruptions or be headless and arise in the mid-mantle. Geochemistry provides convincing evidence that mantle plumes are 100–300°C hotter than normal upper mantle and that upwelling rates within the melting region are faster than beneath mid-ocean ridges. 186Os/188Os hints at the possibility of material from Earth's core in the Hawaiian plume, but this is not seen in other oceanic island basalt (OIB) and has not been confirmed by 182W/184W measurements. High 3He/4He in plumes does not require a primordial deep-mantle reservoir. The geochemical signature of mantle plumes originates primarily through melting in the upper mantle, probably through creation and subduction of oceanic lithosphere, but the details remain obscure. Plumes are lithologically heterogeneous, consisting of stringers of mafic material ...