冀北-辽西地区侏罗纪土城子组的时代归属

CHRONOSTRATIGRAPHY OF THE JURASSIC TUCHENGZI FORMATION IN NORTHERN HEBEI AND WESTERN LIAONING, CHINA

摘要: 土城子组的时代归属存有分歧.目前主要有5种观点：①中侏罗世晚期-晚侏罗世早期；②晚侏罗世早期；③晚侏罗世；④晚侏罗世-早白垩世；⑤早白垩世.根据侏罗纪年代地层学的研究现状，综合生物地层、磁性地层及同位素年代学的资料，认为土城子组的时代应为中侏罗世晚期-晚侏罗世早期（Callovian-Oxfordian）.土城子组的同位素年龄在147~136 Ma之间.

Abstract: The age of the Tuchengzi formation in Northern Hebei and Western Liaoning provinces has long been disputed. There are mainly five viewpoints: 1) late Middle Jurassic to early Late Jurassic; 2) early Late Jurassic; 3) Late Jurassic; 4) Late Jurassic to Early Cretaceous; and 5) Early Cretaceous. Based on biostratigraphy, magnetostratigraphy, isotopic dating as well as current situation of the Jurassic chronostratigraphic studies, the age of the volcanic rocks of Tuchengzi formation is dated 147 -136 Ma, i.e. the late of Middle Jurassic to the early of Late Jurassic (CallovianOxfordian).