山东章丘地区三叠纪地层研究新进展

NEW ADVANCES IN THE TRIASSIC STRATIGRAPHY OF THE ZHANGQIU AREA,SHANDONG PROVINCE

山东基岩区三叠系一直缺少化石依据(隐伏区已发现三叠纪化石),前人在该套地层底部发现了铱等元素异常,认为可作为划分三叠纪地层的时代依据。在1/25万《淄博市幅》区域地质调查中,于该地层中首次发现了孢粉化石,结合铱元素等异常特征,经区域对比确定其时代为早—中三叠世,认为区内原“孙家沟组”相当于华北地区的刘家沟组+和尚沟组,原“刘家沟组”则相当于二马营组。

Fossils are rare in the Triassic outcrops of Shandong Province,although the Triassic fossils have been found in drilling cores. Iridium anomalies have been previously identified near the base of the Triassic successions and these anomlies have been used as evidence for a Triassic age. We discovered sporopollen fossils from the Triassic outcrops in the Zhangqiu area during geological survey. The palynological data together with the iridium anomalies,suggest that the fossiliferous strata are early-middle Triassic in age. The former ‘Sunjiagou Formation＇ can he correlated with the Liujiagou and Heshanggou formations of North China,while the former ‘Liujiagou Formation＇ of this area can he correlated with the Er＇maying Formation.