Elemental Geochemistry of Sedimentary Rocks at Yellowknife Bay, Gale Crater, Mars
Elemental Geochemistry of Sedimentary Rocks at Yellowknife Bay, Gale Crater, Mars
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DOI：
10.1126/science.1244734
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发表时间：
2014-01-24
期刊：
影响因子：
56.9
通讯作者：
Yingst, R. A.
中科院分区：
文献类型：
--
作者：
McLennan, S. M.;Anderson, R. B.;Yingst, R. A.
在火星的耶洛奈夫湾，Currency探测器探测到的沉积岩，其来源是从近似平均的火星地壳成分演变成受碱性玄武岩影响的成分。没有保留化学风化的证据，表明干旱（可能是寒冷）的古气候以及快速的侵蚀和沉积。预测的地球化学变化的情况下，磁铁矿和层状硅酸盐形成的低温，近中性的pH值，岩石为主的水的条件下的成岩作用。在高空间分辨率的成岩特征（包括结核，隆起的脊，和骨折）的分析表明，它们是由富铁和卤素的组件，镁-铁-氯丰富的组件，和水合硫酸钙，分别。横切岩脉状特征的组成与沉积侵入体一致。这些沉积岩的地球化学为火星早期历史上不同的沉积和成岩沉积环境提供了进一步的证据。
Sedimentary rocks examined by the Curiosity rover at Yellowknife Bay, Mars, were derived from sources that evolved from an approximately average martian crustal composition to one influenced by alkaline basalts. No evidence of chemical weathering is preserved, indicating arid, possibly cold, paleoclimates and rapid erosion and deposition. The absence of predicted geochemical variations indicates that magnetite and phyllosilicates formed by diagenesis under low-temperature, circumneutral pH, rock-dominated aqueous conditions. Analyses of diagenetic features (including concretions, raised ridges, and fractures) at high spatial resolution indicate that they are composed of iron-and halogen-rich components, magnesium-iron-chlorine-rich components, and hydrated calcium sulfates, respectively. Composition of a cross-cutting dike-like feature is consistent with sedimentary intrusion. The geochemistry of these sedimentary rocks provides further evidence for diverse depositional and diagenetic sedimentary environments during the early history of Mars.