Microtektites and Glassy Microspherules in Loess: Their Discoveries and Implications  

作　　者：李春来 欧阳自远 刘东生 安芷生 

机构地区：[1]Institute of Geology, Academia Sinica, Beijing 100101, PRC [2]Laboratory of Loess and Quaternary Geology at Xi'an, Academia Sinica, Xi'an 710061, PRC

出　　处：《Science China Chemistry》1993年第9期1141-1153,共13页中国科学（化学英文版）

基　　金：Project supported by the National Natural Science Foundation of China, and Lab of Loess and Quaternary Geology at Xi'an, Academia Sinica.

摘　　要：It is first in continental sediment-loess that 16 microtektites and 3 ablated glassy Si-Mg microspherules were found. They occur only in the upper layer of L8, a 40—70-cm horizon above the B/M boundary. The age of deposition is about 0.72 Ma. Microtektites in loess are usually sphere, speroid, kidney-form, tear-drop and irregular debris in shape. They are transparent and translucent, and some have the shade of green, amber and yellow in color. Their sizes range from 65 to 220μm. Most of microtektites were badly pitted and corroded, but there remain bubbles, cavities and scorious and flow microstructure in some ones. On the basis of their major oxide compositions, microtektites in loess may be divided into three chemical groups that are described as normal, bottle-green and high-aluminium microtektite. They are similar in chemical composition to microtektites in deep-sea cores. Geochemistry of trace elements show that the origin of microtektite is very complicated and their parent materials are from multiple sources. On the basis of geographical location, deposition age, stratigraphic occurrence, physical property and chemical composition, microtektites found in loess at Luochuan may fall into the Australia-Southeast Asian tektite strewn field.It is first in continental sediment-loess that 16 microtektites and 3 ablated glassy Si-Mg microspherules were found. They occur only in the upper layer of L8, a 40—70-cm horizon above the B/M boundary. The age of deposition is about 0.72 Ma. Microtektites in loess are usually sphere, speroid, kidney-form, tear-drop and irregular debris in shape. They are transparent and translucent, and some have the shade of green, amber and yellow in color. Their sizes range from 65 to 220μm. Most of microtektites were badly pitted and corroded, but there remain bubbles, cavities and scorious and flow microstructure in some ones. On the basis of their major oxide compositions, microtektites in loess may be divided into three chemical groups that are described as normal, bottle-green and high-aluminium microtektite. They are similar in chemical composition to microtektites in deep-sea cores. Geochemistry of trace elements show that the origin of microtektite is very complicated and their parent materials are from

关 键 词：LOESS microtektite mierospherule impact. 

分 类 号：O6[理学—化学]