豫西的上前寒武系及其对比关系

自从1924年李四光等在长江峡东区和1934年高振西等在河北蓟县各自建立震旦系的划分系统以后,一般就把这两个地区的剖面看成为同时代。

ON THE UPPER PRE-CAMBRIAN OF WESTERN HENAN AND ITS SIGNIFICANCE IN STRATIGRAPHICAL CORRELATION

The Upper Sinian Luoquan formation occurring in western Henan is composed of a tillite in the lower part and variegated shales in the upper. The tillite may be correlated with the Nantuo tillite of South China. The Luoquan formation rests uncomformably on the underlying strata of various ages and is separated discom-formably from the overlying Lower Cambrian. Below the Luoquan formation are the Wufushan group (upper) and the Xiyanghe group (lower). K-Ar age measurements made on glauconite from the Wufushan group and its equivalents yield ages of 844, 972, 1120 and 1149 m.y. Thus the Wufushan group is older than the Sinian of the Yangtze gorge, and the Lower Sinian is probably absent in Henan. The Wufushan group and its equivalents may, therefore, be correlated with the sequence ranging from the Dahongyu formation to the Tieling formation of Yenshan, and also with the Shennongjia group of Hubei.