Deep roots of the Messinian salinity crisis
Deep roots of the Messinian salinity crisis
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DOI：
10.1038/nature01553
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发表时间：
2003-04-10
期刊：
影响因子：
64.8
通讯作者：
Morgan, JP
中科院分区：
文献类型：
--
作者：
Duggen, S;Hoernle, K;Morgan, JP
梅西尼亚盐度危机--596万至533万年前地中海干涸(1)--是新生代地球上最具戏剧性的事件之一(2)。这是由于大西洋和地中海之间的海洋门户关闭造成的，其原因仍然是个谜。在这里，我们利用火山岩的年龄和成分重建了地中海最西端从中新世到更新世(约12.1-0.65Myr前)的地球动力学演化。我们的数据表明，地幔火山岩的地球化学发生了显著的转变，反映了从俯冲作用向板内型火山作用的转变，发生在6.3-4.8Myr之前，与梅西尼期的盐度危机基本同步。利用热力学模型，我们表明，俯冲的特提斯大洋岩石圈的西退和与之相关的软流圈上涌为产生岩浆化学迁移和必要的沿非洲和伊比利亚大陆边缘的抬升(类似于1公里)提供了一个可能的机制，从而关闭了中新世的海洋门户，从而导致了梅西纪的盐度危机。
The Messinian salinity crisis-the desiccation of the Mediterranean Sea between 5.96 and 5.33 million years (Myr) ago(1)-was one of the most dramatic events on Earth during the Cenozoic era(2). It resulted from the closure of marine gateways between the Atlantic Ocean and the Mediterranean Sea, the causes of which remain enigmatic. Here we use the age and composition of volcanic rocks to reconstruct the geodynamic evolution of the westernmost Mediterranean from the Middle Miocene epoch to the Pleistocene epoch (about 12.1-0.65 Myr ago). Our data show that a marked shift in the geochemistry of mantle-derived volcanic rocks, reflecting a change from subduction-related to intraplate-type volcanism, occurred between 6.3 and 4.8 Myr ago, largely synchronous with the Messinian salinity crisis. Using a thermomechanical model, we show that westward roll back of subducted Tethys oceanic lithosphere and associated asthenospheric upwelling provides a plausible mechanism for producing the shift in magma chemistry and the necessary uplift (similar to1 km) along the African and Iberian continental margins to close the Miocene marine gateways, thereby causing the Messinian salinity crisis.