Seismological constraints on core composition from Fe-O-S liquid immiscibility
Seismological constraints on core composition from Fe-O-S liquid immiscibility
复制标题
DOI：
10.1126/science.1101109
复制
发表时间：
2004-12-24
期刊：
影响因子：
56.9
通讯作者：
Kaneshima, S
中科院分区：
文献类型：
--
作者：
Helffrich, G;Kaneshima, S
地核主要由铁（Fe）和约10%的轻元素组成。随着内核冷却和内核结晶，较轻的元素在液态外核中逐渐富集。Fe-O-S液体的热力学模型表明，不混溶的液体可以存在于外核压力（136至330吉帕斯卡），温度低于5200开尔文，并导致分层的外核，如果轻元素的浓度足够高。我们没有发现分层的证据，在旅行时间和P4 KP地震波的波形，反映在核心内部的外部核心。因此，不存在层限制了Fe-O-S体系中的外芯组成不富含6 +/-1重量%（wt %）O和2至15重量% S。10.5 +/-3.5wt%S和1.5 +/-1.5wt%O的单芯液体组合物与整个外芯的波速和密度相容。
Earth's core is composed primarily of iron (Fe) with about 10% by weight of lighter elements. The lighter elements are progressively enriched in the liquid outer core as the core cools and the inner core crystallizes. Thermodynamic modeling of Fe-O-S liquids shows that immiscible liquids can exist at outer-core pressures (136 to 330 gigapascals) at temperatures below 5200 kelvin and lead to layering in the outer core if the concentrations of the lighter elements are high enough. We found no evidence for layering in the outer core in the travel times and wave forms of P4KP seismic waves that reflect internally in the core. The absence of layers therefore constrains outer-core compositions in the Fe-O-S system to be no richer than 6 +/- 1 weight % (wt %) 0 and 2 to 15 wt % S. A single core liquid composition of 10.5 +/- 3.5 wt % S and 1.5 +/- 1.5 wt % O is compatible with wave speeds and densities throughout the outer core.