Bleached-spot formation in Fe-oxide-rich rock by inorganic process
Bleached-spot formation in Fe-oxide-rich rock by inorganic process
复制标题
无机过程在富铁氧化物岩石中形成漂白斑
DOI：
10.1016/j.chemgeo.2022.121049
复制
发表时间：
2022
期刊：
影响因子：
3.9
通讯作者：
Umemura Ayako
中科院分区：
文献类型：
--
作者：
Kawahara Hirokazu;Yoshida Hidekazu;Nishimoto Shoji;Kouketsu Yui;Katsuta Nagayoshi;Umemura Ayako
在富含氧化铁的沉积岩中，如红层中，经常观察到不含氧化铁矿物的白色漂白斑点。斑点的形成被解释为与有机物质有关的局部还原反应，如烃类流体和有机碎屑作为前体，最近主要流行的方法是沉积物中的微生物活动。然而，很少发现斑点内微生物活动的证据，并且整个斑点是否都是微生物起源仍然存在争议。我们在澳大利亚北部的沉积岩斑马岩中发现了具有节律性铁氧化物带的漂白斑点，并解释了这些斑点是由原生黄铁矿分解引起的pH变化形成的。综合岩石学研究进一步表明，这些斑点是在酸性流体渗透过程中形成的，与铁氧化物带的形成有关，而作为前驱体的原生黄铁矿目前以赤铁矿和针铁矿的盘状和聚集组成的伪形态保存下来。这项研究表明斑马岩中的白斑是由无机化学反应形成的，这表明其他研究中提出的这种白斑可以作为在火星上发现生命的生物标志物的建议并不总是可行的。
In sedimentary rocks rich in Fe-oxide, such as red beds, white bleached spots that are free of Fe-oxide minerals are often observed. The spot formation has been explained by localized reduction reactions in relation to organic substances, such as fluids including hydrocarbon and organic debris as a precursor, and the recent major prevalent approach is the microbial activity in sediments. However, the evidence for microbial activities within the spots is rarely found, and it remains debatable whether the entire spots are of microorganism origin. We discovered bleached spots in zebra rock, which is the sedimentary rock from northern Australia with rhythmic Fe-oxide bands, and explained that the spots were formed by pH changes induced by the decomposition of primary pyrite. Our comprehensive petrological studies further demonstrate that the spots developed during the infiltration of the acidic fluid in relation to the Fe-oxide band formation, and the primary pyrite as a precursor is currently preserved as a pseudomorph composed of dickite and aggregation of hematite and goethite. This study demonstrates that the bleached spots in zebra rock were formed by inorganic chemical reactions, indicating that the proposal in other studies that spots of this kind can be used as a biomarker to find life on Mars is not always available.
登录
查看更多内容
西澳大利亚东金伯利地区“斑马岩”的成分和起源
影响因子：
1.2
作者：
F. Loughnan;F. I. Roberts
通讯作者：
F. I. Roberts
宏观铁成液晶决定金伯利斑马岩的结构
DOI：
--
发表时间：
2003
期刊：
--
影响因子：
--
作者：
E. Mattievich;J. Chadwick;J. Cashion;J. F. Boas;M. J. Clark;R. Mackie
通讯作者：
R. Mackie
西澳大利亚北部斑马岩中铁氧化物带的热液形成
影响因子：
3.9
作者：
Kawahara Hirokazu;Yoshida Hidekazu;Yamamoto Koshi;Katsuta Nagayoshi;Nishimoto Shoji;Umemura Ayako;Kuma Ryusei
通讯作者：
Kuma Ryusei
沃里克郡石炭系/二叠系红层还原斑的形成机制
影响因子：
2.3
作者：
H. Mykura;B. Hampton
通讯作者：
B. Hampton
影响因子：
1.8
作者：
HOFMANN, BA
通讯作者：
HOFMANN, BA