以火山岩层序剖面K-Ar测年确定辽西四合屯古生物化石地层的年代

Constrain the time of the paleocoenosis fossil stratum by K-Ar age of Sihetun volcanic rock sequence.

从系统剖面连续测年的角度,利用K-Ar年代学方法并结合前人工作,确定了辽西四合屯剖面的六个火山活动期和含古生物化石的湖相沉积地层的顶底时间界限。六期火山活动分别为133．6～133．1Ma、129．3～129．2Ma、～126．1Ma、125．1～124．2Ma、～122Ma和～113Ma。其中第四期活动最为强烈。侵入含古生物化石的湖相沉积层的火山岩的年龄为124．4Ma,其上覆火山岩年龄为124．2Ma,下伏火山岩的年龄为124．6～125．1Ma,因此,该湖相沉积地层的持续时间应为大约1Ma。

The age of volcanic rock and the lacustrine stratigraphy with paleontologic fossil from a systemic section in Sihetun （ west Liaoning Province） are dated by K-Ar chronology method. The results and other results suggest six episodic volcano activity occurred at 133. 6-133. 1Ma, 129. 3-129. 2Ma,-126.1Ma, 125.1 - 124. 2Ma, -122Ma and -113Ma respectively, and the fourth one is the strongest. The age of volcanic rock which intrude into the stratigraphy with Rehe biota is 124. 4Ma, and the age of both the volcanic rocks overlap the strata and the basement of the strata is 124. 2Ma and 124. 6 -125.1Ma respectively, so that, the sustained depesitional time of the sediment with Rehe biota should be about 1Ma.