摘要
我国嫦娥五号任务在月球风暴洋北部采集到了迄今为止最年轻的月海玄武岩并成功返回.研究这些年轻月海玄武岩的岩相学特征和冷却速率对于揭示月球熔岩流的结构剖面和就位情况具有重要科学意义.本文利用扫描电子显微镜和电子探针技术对一个嫦娥五号玄武质岩屑(CE5C0800YJYX005GP)进行了详细的岩相学和矿物学研究,并利用晶体粒径分布和热力学模拟恢复了该样品的冷却速率.结果表明,该样品的辉石具有高和低切尔马克组分的两个成分分区,指示开始结晶时30~50℃的高过冷度条件;钛铁矿和斜长石的晶体粒径分布指示152~189℃/h的快速冷却条件和5.7~6.3 cm的埋藏深度,使得该样本成为迄今为止所报道的最快速冷却、最接近熔岩流表面的嫦娥五号玄武岩.结合先前对其他嫦娥五号样本的冷却速率研究,重建了嫦娥五号熔岩流的结构剖面和就位模型.该模型表明嫦娥五号玄武岩母岩浆比阿波罗玄武岩母岩浆的去气程度更低,有利于熔岩流热量的维持,从而有利于在月球表面形成超长月溪.
The quantitative effects of cooling kinetics on morphology and mineralogy of crystalline phases in natural basalts have been well recognized through microprobe analysis and crystallization experiments.For decades,our understanding of the crystallization and emplacement of lunar magmas has been greatly advanced through laboratory analysis of lunar mare basalts and basaltic meteorites,petrological experiments,and thermodynamic models.These investigations have revealed that the cooling rates of mare basalts can vary significantly,ranging from 0.001°C/h(Apollo-15 basalt 15058)to~1000°C/h(Apollo-15 basalt 15597)(e.g.,[1]).
作者
王子龙
田伟
王伟
马犇
刘平平
裴军令
陈振宇
吴江
魏春景
Zilong Wang;Wei Tian;Wei-(RZ)Wang;Ben Ma;Ping-Ping Liu;Junling Pei;Zhenyu Chen;Jiang Wu;Chunjing Wei(School of Earth and Space Sciences,Peking University,Beijing 100871,China;Key Laboratory of Paleomagnetism and Tectonic Reconstruction of Ministry of Natural Resources,Institute of Geomechanics,Chinese Academy of Geological Sciences,Beijing 100871,China;State Key Laboratory of Nuclear Resources and Environment,East China University of Technology,Nanchang 330013,China;Key Laboratory of Metallogeny and Mineral Assessment of Ministry of Natural Resources,Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037,China)
基金
supported by the National Natural Science Foundation of China(42272348 and 42172068)。
