塔里木盆地石炭系卡拉沙依组的厘定

REVISION OF THE CARBONIFEROUS KALASHAYI FORMATION OF THE TARIM BASIN

长期以来 ,塔里木盆地石炭系卡拉沙依组存在多种划分方案。根据巴楚组的原始定义及井下化石特征 ,结合前人研究成果及对卡拉沙依组的习惯用法 ,厘定了卡拉沙依组 ,将底界放在生屑灰岩段与中泥岩段之间 ,顶界放在顶灰岩段与含灰岩段之间 ,厘定后的卡拉沙依组自上而下可进一步划分为“含灰岩段、砂泥岩段、上泥岩段、标准灰岩段、中泥岩段”五段。塔中 4 0 1井卡拉沙依组发育全 ,岩性段划分清楚 ,生物发育 ,地层时代确定 ,被指定为卡拉沙依组次层型。

Now, based on the original definition of the Bachu Formation and the characters of the fossils from the boreholes, and combined with the results of previous researches and the common usage of the former Kalashayi Formation, the basal boundary of the revised Kalashayi Formation is put between the Bioclastic Limestone Member and the Middle Mudstone Member and the top boundary is placed between the Top Limestone Member and Limestone-bearing Member. The revised Kalashayi Formation may be descending subdivided into five members, namely the Limestone-bearing Member, Sandy Mudstone Member, Upper Mudstone Member, Typical Limestone Member and Middle Mudstone Member. The Kalshayi Formation in the Tazhong 401 borehole with distinct lithologic members, developed organisms, and precise stratigraphic age, is well developed organisms, and precise stratigraphic age, is well developed, and is de- signated as the hypostratotype of the Kalashayi Formation.