当前位置: X-MOL 学术Nat. Astron. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Meteoritic evidence for a Ceres-sized water-rich carbonaceous chondrite parent asteroid
Nature Astronomy ( IF 14.1 ) Pub Date : 2020-12-21 , DOI: 10.1038/s41550-020-01274-z
V. E. Hamilton , C. A. Goodrich , A. H. Treiman , H. C. Connolly , M. E. Zolensky , M. H. Shaddad

Carbonaceous chondrite meteorites record the earliest stages of Solar System geological activities and provide insight into their parent bodies’ histories. Some carbonaceous chondrites are volumetrically dominated by hydrated minerals, providing evidence for low-temperature, low-pressure aqueous alteration1. Others are dominated by anhydrous minerals and textures that indicate high-temperature metamorphism in the absence of aqueous fluids1. Evidence of hydrous metamorphism at intermediate pressures and temperatures in carbonaceous chondrite parent bodies has been virtually absent. Here we show that an ungrouped, aqueously altered carbonaceous chondrite fragment (numbered 202) from the Almahata Sitta (AhS) meteorite contains an assemblage of minerals, including amphibole, that reflect fluid-assisted metamorphism at intermediate temperatures and pressures on the parent asteroid. Amphiboles are rare in carbonaceous chondrites, having only been identified previously as a trace component in Allende (CV3oxA) chondrules2. Formation of these minerals would require prolonged metamorphism in a large (about 640–1,800 kilometres in diameter) asteroid that is as yet unknown. Because Allende and AhS 202 represent different asteroidal parent bodies, intermediate conditions may have been more widespread in the early Solar System than is recognized from known carbonaceous chondrite meteorites, which are likely to represent a biased sampling.



中文翻译:

谷神星大小的富水碳质球粒母体小行星的气象学证据

碳质球粒陨石记录了太阳系地质活动的最早阶段,并提供了对其母体历史的了解。一些碳质球粒陨石在体积上受水合矿物的支配,为低温,低压水蚀作用提供了证据1。其他的则以无水矿物和质地为主,这些矿物和质地表明在没有水性液体的情况下会发生高温变质1。几乎没有碳质球粒陨石母体在中等压力和温度下发生含水变质的证据。在这里,我们显示了来自Almahata Sitta(AhS)陨石的未分组,含水改变的碳质球粒陨石碎片(编号202)包含多种矿物,包括闪石,这些矿物在中间温度和母体小行星上的压力下反映了流体辅助的变质作用。闪石在碳质球粒陨石中很少见,以前仅被鉴定为Allende(CV3 oxA)球粒陨石中的微量成分2。这些矿物的形成将需要在一个未知的大型(直径约640-1,800公里)小行星中进行长时间的变质作用。由于Allende和AhS 202代表着不同的小行星母体,因此中间条件在早期的太阳系中可能比从已知的碳质球粒陨石中识别出的更为普遍,后者可能代表有偏差的采样。

更新日期:2020-12-21
down
wechat
bug