Cosmic Dust in Suzhou A-Type Granite  

作　　者：王尔康 万玉秋 朱政 胡中为 林承毅 周剑雄 倪邦发 

机构地区：[1]Department of Earth Sciences, Nanjing University, Nanjing 210008, PRC [2]Department of Astronomy, Nanjing University, Nanjing 210008, PRC [3]Centre for Modern Analysis, Nanjing University, Nanjing 210008, PRC [4]Geological Academy of China, Beijing 100037, PRC [5]Institute of Atomic Energy of China, Beijing 102413, PRC

出　　处：《Science China Chemistry》1994年第9期1119-1129,共11页中国科学（化学英文版）

基　　金：the National Natural Science Foundation of China

摘　　要：A large number of microspherules have been extracted from Suzhou A-type granite bymeans of heavy placer.Both natural surfaces and part sections of 539 microspherules have been observed bySEM.457 microspherules have been determined by EDX,with some of them by EPMA,XRD and INAA.The results suggest these spherules are of ablated cosmic dust.Among them silicate glassy microspheruleshave been highly enriched in REE and other lithophile refractory trace elements,and REE abundance patternfavors a meteoritic origin as a roughly flat distribution.Ringwoodite has been first found in these glassy mi-crospherules.The composition of these iron spherules is similar to those of the ablated cosmic dust from deepsea and polar ice.Some Fe-Ni spherules and spherules composed of troilite have also been found.This isprobably the first report on various types of cosmic dust extracted from granite.A large number of microspherules have been extracted from Suzhou A-type granite by means of heavy placer.Both natural surfaces and part sections of 539 microspherules have been observed by SEM.457 microspherules have been determined by EDX,with some of them by EPMA,XRD and INAA. The results suggest these spherules are of ablated cosmic dust.Among them silicate glassy microspherules have been highly enriched in REE and other lithophile refractory trace elements,and REE abundance pattern favors a meteoritic origin as a roughly flat distribution.Ringwoodite has been first found in these glassy mi- crospherules.The composition of these iron spherules is similar to those of the ablated cosmic dust from deep sea and polar ice.Some Fe-Ni spherules and spherules composed of troilite have also been found.This is probably the first report on various types of cosmic dust extracted from granite.

关 键 词：COSMIC DUST MICROSPHERULE GRANITE SUZHOU 

分 类 号：P588.1[天文地球—岩石学]