70 m.y. history (139-69 Ma) for the Caribbean large igneous province
70 m.y. history (139-69 Ma) for the Caribbean large igneous province
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DOI：
10.1130/g20574.1
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发表时间：
2004-08-01
期刊：
影响因子：
5.8
通讯作者：
van den Bogaard, P
中科院分区：
文献类型：
--
作者：
Hoernle, K;Hauff, F;van den Bogaard, P
人们普遍认为，大型火成岩省是在热点(地幔热柱)形成时，在几百万年内发生在大片地区的灾难性火山事件而形成的。来自哥斯达黎加尼科亚半岛的新的40Ar/39Ar年龄(111-139 Ma)和地球化学结果，将加勒比海大火成岩省的火山活动年龄范围扩大到70英里。(69-139 Ma)。我们的结果与这个巨大的火成岩省是在地幔热柱(如加拉帕戈斯)的初始阶段通过单一的热柱头部形成的并不一致。相反，我们认为在俯冲过程中积累了多个大洋板内火成岩结构，如高原和热点轨迹。这些火成岩结构可能是加拉帕戈斯热点早期历史的遗迹，使其成为地球上最古老的活动热点之一。或者，它们可能来自于几个空间上不同的地幔熔融事件，这些事件采样了类似的来源物质，例如类似年龄的大洋岩石圈。
It is commonly accepted that large igneous provinces are formed through catastrophic volcanic events occurring over vast areas within a few million years at the initiation of hotspots (mantle plumes). New 40Ar/39Ar ages (111-139 Ma) and geochemical results from the Nicoya Peninsula, Costa Rica, extend the age range of volcanism in the Caribbean large igneous province to 70 m.y. (69-139 Ma). Our results are not consistent with the formation of this vast igneous province through a single plume head at the initiation of a mantle plume such as the Galapagos. Instead we propose that multiple oceanic intraplate igneous structures, such as plateaus and hotspot tracks, were accumulated through the subduction process. The igneous structures could be remnants of the earlier history of the Galapagos hotspot, making it one of the oldest active hotspots on Earth. Alternatively they could have been derived from several spatially distinct mantle-melting events that sampled similar source material, e.g., oceanic lithosphere of similar age.