滇中禄丰地区侏罗系磁性地层学研究

Magnetostratigraphy of the Jurassic in Lufeng, central Yunnan

通过云南中部禄丰地区侏罗系磁性地层学研究,建立了滇中侏罗系磁极性地层柱,为国内及该地区侏罗系地层单元的时代划分与对比提供了基础资料。依据磁性地层学研究的结果,修订了滇中侏罗系的顶界和上、中侏罗统的界线,建立了中、下侏罗统和侏罗系—三叠系界线数据。经对比发现,滇中侏罗系古地磁极与扬子地块侏罗系古地磁参考极之间有较大差异,反映滇中地块自侏罗纪以来曾向南发生了明显移动,产生过顺时针旋转。

A Jurassic magnetic polarity column was established in Lufeng, central Yunnan, southwest China, on the basis of a magnetostratigraphic study of the Jurassic. It provides basic data for the stratigraphic classification and correlation of the Jurassic in the area as well as China. According to the results of the magnetostratigraphic study, the authors revise the upper boundary of the Jurassic and the boundary between the Upper and Middle Jurassic in central Yunnan and establish the database of the boundaries between the Middle and Lower Jurassic and between the Jurassic and Triassic in the area. Correlation reveals that there are appreciable differences between the Jurassic paleomagnetic poles in central Yunnan and the Jurassic reference paleopoles of the Yangtze block, suggesting that the central Yunnan block is very likely to have experienced a southward motion and a clockwise rotation relative to the Earth rotation axis since the Jurassic.