Formation of iddingsite veins in the martian crust by centripetal replacement of olivine: Evidence from the nakhlite meteorite Lafayette
Formation of iddingsite veins in the martian crust by centripetal replacement of olivine: Evidence from the nakhlite meteorite Lafayette
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橄榄石的向心置换在火星地壳中形成伊丁矿脉：来自钠辉石陨石拉斐特的证据
DOI：
10.1016/j.gca.2015.01.022
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发表时间：
2015
影响因子：
5
通讯作者：
Lee M
中科院分区：
文献类型：
--
作者：
Lee M
拉斐特陨石是一种橄榄石斜辉石岩，大约13亿年前在火星上的熔岩流或浅岩中结晶。大约7亿年后，液态水进入这片火成岩，产生了一套次生矿物，统称为“iddingsite”，它们以脉状出现在奥辉岩和橄榄石的颗粒中。次生矿物中水的氘氢比表明，水溶液来源于一个或多个近地表储层。通过其宽度、形状和晶体取向的不同，可以识别出几种岩石学上截然不同的脉型。奥辉石和橄榄石均含有极细晶粒的富铁和富镁水合硅酸盐脉，脉宽约1-2 μm，缺乏任何优选的晶体取向。这些狭窄的静脉是由破裂形成的孔隙空间胶结形成的，可能是对冲击的反应。轴线平行于（0 ~ 0 ~ 1）的橄榄石矿脉亚群，其壁面呈锯齿状，是由界面溶蚀-沉淀耦合作用使窄矿脉变宽而形成的。铁-镁硅酸盐取代了狭窄的前体脉壁，从而开始变宽，而溶解-降水锋面轨迹的结晶学控制产生了微米尺度的{11 11}锯齿。许多细锯齿状脉的壁随后被菱铁矿取代，造成橄榄石碳酸化的溶液也使硅酸铁镁部分再结晶。蒙脱石是最后形成并取代菱铁矿生长的矿物。该成矿序列表明，Lafayette暴露于两个离散的水溶液脉冲中，第一个脉冲形成了Fe-Mg硅酸盐，第二次脉冲介导了菱铁矿和蒙脱石对脉壁的取代。拉斐特陨石和陆相玄武岩中溶蚀脉在大小、形状和晶体取向上的相似性表明，火星和地球之间的水-矿物相互作用具有共同的微观结构控制，表明先前的冲击变形不是火星地壳水蚀变的先决条件。
The Lafayette meteorite is an olivine clinopyroxenite that crystallized on Mars ∼1300 million years ago within a lava flow or shallow sill. Liquid water entered this igneous rock ∼700 million years later to produce a suite of secondary minerals, collectively called ‘iddingsite’, that occur as veins within grains of augite and olivine. The deuterium/hydrogen ratio of water within these secondary minerals shows that the aqueous solutions were sourced from one or more near-surface reservoirs. Several petrographically distinct types of veins can be recognised by differences in their width, shape, and crystallographic orientation. Augite and olivine both contain veins of a very fine grained hydrous Fe- and Mg-rich silicate that are ∼1–2 μm in width and lack any preferred crystallographic orientation. These narrow veins formed by cementation of pore spaces that had been opened by fracturing and probably in response to shock. The subset of olivine-hosted veins whose axes lie parallel to (0 0 1) have serrated walls, and formed by widening of the narrow veins by interface coupled dissolution–precipitation. Widening started by replacement of the walls of the narrow precursor veins by Fe–Mg silicate, and a crystallographic control on the trajectory of the dissolution–precipitation front created micrometre-scale {1 1 1} serrations. The walls of many of the finely serrated veins were subsequently replaced by siderite, and the solutions responsible for carbonation of olivine also partially recrystallized the Fe–Mg silicate. Smectite was the last mineral to form and grew by replacement of siderite. This mineralization sequence shows that Lafayette was exposed to two discrete pulses of aqueous solutions, the first of which formed the Fe–Mg silicate, and the second mediated replacement of vein walls by siderite and smectite. The similarity in size, shape and crystallographic orientation of iddingsite veins in the Lafayette meteorite and in terrestrial basalts demonstrates a common microstructural control on water–mineral interaction between Mars and Earth, and indicates that prior shock deformation was not a prerequisite for aqueous alteration of the martian crust.
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NAKHLITES 第二部分：地点、时间和方式
DOI：
10.1111/j.1945-5100.1975.tb01188.x
发表时间：
1975
期刊：
Meteoritics
影响因子：
--
作者：
A. Reid;T. Bunch
通讯作者：
T. Bunch
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影响因子：
--
作者：
A. Treiman;D. Lindstrom
通讯作者：
D. Lindstrom
影响因子：
3.1
作者：
Martin R. Lee;David J. Brown;Caroline L. Smith;M. Hodson;M. Mackenzie;R. Hellmann
通讯作者：
Martin R. Lee;David J. Brown;Caroline L. Smith;M. Hodson;M. Mackenzie;R. Hellmann
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DOI：
--
发表时间：
2006
期刊：
影响因子：
--
作者：
L. Leshin;E. Vicenzi
通讯作者：
E. Vicenzi
影响因子：
5.8
作者：
Plumper, Oliver;Royne, Anja;Jamtveit, Bjorn
通讯作者：
Jamtveit, Bjorn