Linked magma ocean solidification and atmospheric growth for Earth and Mars
Linked magma ocean solidification and atmospheric growth for Earth and Mars
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DOI：
10.1016/j.epsl.2008.03.062
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发表时间：
2008-07-15
影响因子：
5.3
通讯作者：
Elkins-Tanton, L. T.
中科院分区：
文献类型：
--
作者：
Elkins-Tanton, L. T.
在类地行星演化的早期，高能撞击、放射性衰变和地核形成可能创造了一个或多个全部或部分的硅酸盐地幔岩浆海洋。地幔凝固的时间，然后到地球表面条件允许液态水的时间，高度依赖于从行星表面通过不断增长的原始大气的热通量。在这里，我们模拟的时间，地球和火星上的整个和部分岩浆海洋的条件，以及由此产生的硅酸盐地幔挥发性成分。在我们的计算中包括水和二氧化碳之间的分配固化地幔堆积矿物组合，不断发展的液体成分，和不断增长的大气。我们发现，小的初始挥发分含量（0.05重量% H2O，0.01Wt-%CO2）可以产生超过100巴的大气，地幔凝固在不到500万年的时间内完成了98%，对于地球和火星上研究的所有岩浆海洋，不到100，000年的时间。随后的冷却到地球表面的条件发生在5到几十个Ma之间，强调了早期行星中连续岩浆海洋和间歇性地球表面条件的可能性。堆积地幔是挥发性的轴承和稳定的分层凝固后，抑制热对流的发生，但允许进一步的水和碳排放从火山，即使在没有板块构造。因此，模型为类地行星的地幔演化提供了一个新的假设起点。(C)2008 Elsevier B. V.保留所有权利。
Early in terrestrial planet evolution energetic impact, radiodecay, and core formation may have created one or more whole or partial silicate mantle magma oceans. The time to mantle solidification and then to clement surface conditions allowing liquid water is highly dependent upon heat flux from the planetary surface through a growing primitive atmosphere. Here we model the time to clement conditions for whole and partial magma oceans on the Earth and Mars, and the resulting silicate mantle volatile compositions. Included in our calculations are partitioning of water and carbon dioxide between solidifying mantle cumulate mineral assemblages, evolving liquid compositions, and a growing atmosphere. We find that small initial volatile contents (0.05 wt.% H2O, 0.01 Wt-% CO2) can produce atmospheres in excess of 100 bars, and that mantle solidification is 98% complete in less than 5 Myr for all magma oceans investigated on both Earth and Mars, and less than 100,000 yr for low-volatile magma oceans. Subsequent cooling to clement surface conditions occurs in five to tens of Ma, underscoring the likelihood of serial magma oceans and punctuated clement conditions in the early planets. Cumulate mantles are volatile-bearing and stably stratified following solidification, inhibiting the onset of thermal convection but allowing for further water and carbon emissions from volcanoes even in the absence of plate tectonics. Models thus produce a new hypothetical starting point for mantle evolution in the terrestrial planets. (C) 2008 Elsevier B.V. All rights reserved.