雷琼地区湛江组、北海组的古地磁学研究

对雷琼地区几个剖面的北海组、湛江组地层及其火山熔岩夹层进行了古地磁学研究，对这些火山岩夹层还进行了Ｋ－Ａｒ同位素年代测定。研究结果表明，湛江组地层的剩余磁性以反极性为主，其磁性序列特征类似于松山反极性时中、晚期的地磁场特征；火山岩夹层的剩余磁性特征以及它们的Ｋ－Ａｒ同位素年代测定值则肯定了这些火山岩生成于松山反极性时中、晚期。北海组地层岩石剩余磁性表明，其生成于松山反极性时末期至布容正极性时早期。由古地磁和岩石同位素年代学研究确定了湛江组地层时代为早更新世；北海组地层时代为早更新世晚期至中更新世早期。

PALEOMAGNETISM OF BEIHAL AND ZHANJIANG FORMATIONS IN LEI-QIONG REGION Ge Tongming

Samples of Beihai and Zhanjiang Formations,collected from some sections in Lei-Qiong region,were paleomagnetically studied.Some volcanic-rock samples collectedfrom Beihai and Zhanjiang Formations were measured by K-Ar method.The resultsshow that most of the samples from Zhanjiang Formation have reverse remanence andthe magnetic succession in the formation seems to be similar to the sequence of the geo-magnetic field of the middle-late stage in Matuyama Chron,The feature of the rema-nence in Beihai Formation is the same as that of the geomagnetic field in late Matuyamaand early Brunhes Chron,The isotopic ages of the volcanic rocks indicate the same re-sults.Paleomagnetism and isotopic studies have prove that Zhanjiang Formation is EarlyPleistocene in age,and Beihai Formation is late Early Pleistocene-early Mid Pleis-tocene.