新疆北部下中泥盆统层序及其界线讨论

STRATIGRAPHIC SEQUENCES AND BOUNDARY DISCUSSIOU OF LOWER AND MIDDIE DEVONIAN IN NORTHERN .XINJIANG

新疆北部是中国北方下中泥盆统出露最全地区之一,1977年曾作为中国北方槽区典型剖面.笔者根据最新资料研究,重新选定了下中泥盆统标准层序(自下而上):下泥盆统:乌吐布拉克组、曼格尔组.芒克鲁组;中泥盆统:乌鲁苏巴斯套组、纸房组.并根据岩性变化及床板珊瑚化石资料,对乌吐布拉克组进行了重新审定,将原沙尔布尔提山剖面乌吐布拉克组下2层归入上志留统.重点讨论了下泥盆统的底界及下与中泥盆统间的界线.

The Lower and Middle Devonian strata in northern Xinjiang are well developed. They are the most complete sequences of Lower and Middle Devonian in the northern part of China. On the basis of study of recent materials, the author again selectes the stan- dard stratigraphic sequences of Lower and Middle Devonian in the Region. The Lower Devonian section is located at the Mangkelu Region of Sarburti Mountain in the Western Junggar of Xinjiang, from lower to upper: Utublake Formation, Mengeer Formation and Mangkelu Formation. The Section of Middle Devonian, is located at the Kaokesaiergai Region of the Eastern Junggar, from lower to upper: Wulusubasitaw Formation and Zhifang Formation. According to the Changes of the lithology and faunas, the author reexamines the Wutublake Formation of the Western Junggar putting the 1-2 beds of this section into Upper Silurian. At the same time, on the basis of various fauna assemblage character istics, the author also discusses the boundary between Upper Silurian and Lower Devonian, as well as between Lower, and Middle Devonian in the Mangkelu Region of Western Junggar.