甘肃平凉“崆峒山砾岩”地层时代的商榷

出露于甘肃省平凉市崆峒山国家地质公园的＂崆峒山砾岩＂岩性特殊,厚度巨大。但是其地层时代的归属问题60多年来一直存在着各种不同的认识。作者根据野外观察,结合区域地质构造研究后初步认为,＂崆峒山砾岩＂可与陕西省千阳县出露的芬芳河组对比,两者是同一套地层,时代应属晚侏罗世。并进一步推测＂崆峒山砾岩＂和鄂尔多斯盆地内部的安定组可能是同期异相沉积,前者是山麓洪积扇堆积,后者是河流—湖泊相沉积。

DISCUSSION ON GEOLOGICAL AGE OF KONGTONGSHAN CONGLOMERATE IN PINGLIANG CITY, GANSU PROVINCE

Kongtongshan Conglomerate with special lithology and great thickness is exposed at Kongtongshan National Geopark in Pingliang city, Gansu Province. Since 1944 while the name of Kongtongshan Conglomerate created, the issue on stratigraphic age has not reached a common understanding. According to field observation and research of regional tectonics, it is suggested that Kongtongshan Conglomerate may be the same strata as Fenfanghe Formation in Qianyang County of Shanxi Province, and divided into the late Jurassic Epoch by correlation with it. Furthermore supposing, Kongtongshan Conglomerate and Anding Formation withir, Erduosi Basin may be the deposits with different facies, but in the same age, late Jurassic Epoch, the former is the piedmont alluvial and pluvial facies deposit, and the latter is the fluvial and lake facies deposits.