Chemistry and accretion history of Mars
Chemistry and accretion history of Mars
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DOI：
10.1098/rsta.1994.0132
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发表时间：
1994-11
期刊：
影响因子：
--
通讯作者：
H. Wänke;G. Dreibus
中科院分区：
文献类型：
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作者：
H. Wänke;G. Dreibus
利用在 SNC 陨石中观察到的元素相关性和一般宇宙化学约束，Wänke 和 Dreibus (1988) 估计了火星的总体成分。火星地幔中中等挥发性元素 Na、P、K、F 和 Rb 以及大多数挥发性元素（如 Cl、Br 和 I）的平均丰度值比陆地值高出约两倍。所有具有亲铜特性的元素（Cu、Co、Ni等）的显着消耗表明，与地球相反，火星是均匀吸积的，这也解释了水和碳丰度明显较低的原因。 SNC陨石，特别是shergottites是非常干燥的岩石，它们也含有很少的碳，而氯，尤其是硫的浓度比陆地岩石中的浓度高。因此，我们预计 SO2 和 HC1 将成为火星火山气体中最丰富的化合物。这或许可以解释维京土壤中硫和氯的主导地位。反过来，SO2 作为一种极好的温室气体，可能对古代火星历史上的温暖和潮湿时期具有重要意义。如本文所述，由火山侵入引发的火星风化层中液体或固体二氧化硫表中储存的大量二氧化硫的间歇性释放可能会导致数百年数量级的大量温暖和潮湿的气候时期，并被以水冰和固体二氧化硫液体为特征的更长的寒冷时期所中断。硫（FeS）可能也控制着火星表面岩石的氧逸度。
Using element correlations observed in SNC meteorites and general cosmochemical constraints, Wänke & Dreibus (1988) have estimated the bulk composition of Mars. The mean abundance value for moderately volatile elements Na, P, K, F, and Rb and most of the volatile elements like Cl, Br, and I in the Martian mantle exceed the terrestrial values by about a factor of two. The striking depletion of all elements with chalcophile character (Cu, Co, Ni, etc.) indicates that Mars, contrary to the Earth, accreted homogeneously, which also explains the obvious low abundance of water and carbon. SNC meteorites and especially the shergottites are very dry rocks, they also contain very little carbon, while the concentrations of chlorine and especially sulphur are higher than those in terrestrial rocks. As a consequence we should expect SO2 and HC1 to be the most abundant compounds in Martian volcanic gases. This might explain the dominance of sulphur and chlorine in the Viking soils. In turn SO2, being an excellent greenhouse gas, may have been of major importance for the warm and wet period in the ancient Martian history. Episodic release of larger quantities of SO2 stored in liquid or solid SO2 tables in the Martian regolith triggered by volcanic intrusions as suggested here could lead to a large number of warm and wet climate periods of the order of a hundred years, interrupted by much longer cold periods characterized by water ice and liquid of solid SO2. Sulphur (FeS) probably also governs the oxygen fugacity of the Martian surface rocks.