广东南雄盆地晚白垩系古地磁研究

A PALEOMAGNETIC STUDY ON LATE CRETACEOUS IN NANXIONG BASIN OF GUANGDONG PROVINCE

对广东南雄盆地大凤一河南街剖面和古城一坪岭剖面上白垩统南雄组（Ｋ２ｎ）２５个采点、古新统上湖组（Ｅ１ｓ）２个采点的古地磁研究，经系统热退磁及倒转检验，分析出南雄组的特征剩磁方向为Ｄ＝３２．７°，Ｉ＝２７．４°，Ｋ＝１６．１，α９５＝８．４°，Ｎ＝２０；显示晚白垩世时期华南大陆位于１４．５°Ｎ的位置，同时晚白垩世以后华南大陆可能曾发生较大规模的顺时针旋转。

aleomagnetic sites of Late Cretaceous Nanxiong Formation (K2n) and 2 sites of Paleocenb Shanghu Formation (Eis) in two profiles, Dafeng-Henanjie and GuchengPinling, are studied in this paper. All samples are systematically thermal demagnetized and met by reversal test. A Late Cretaceous paleomagnetic direction is obtained D32. 7°. I=27. 4°, K = 16. 1, a95=8. 4°,N=20. It suggests that the South China block was located at a 14. 5°N position in Late Cretaceous, and much possible a large clockwise rotation had occurred since Late Cretaceous.