摘要
本文对四川北部旺苍-南江地区晚侏罗世蓬莱镇组进行了较为详细的岩石磁学和古地磁学研究．逐步热退磁揭示出蓬莱镇组岩石所携带的剩磁由两个分量组成，其中低温组分（次生剩磁）的解阻温度低于420℃;高温组分（特征分量）可通过褶皱及倒转检验，由此求得磁偏角和磁倾角分别为18．4°和29．3°（构造校正后），95％置信回（α95）为8．5°，对应的古地磁极经纬度分别为236．4°E和66．6°N．基于古地磁结果，并结合已有的地质证据，提出根据古地磁学确定的扬子地块晚侏罗世古纬度偏低的原因可能是由真极移造成的．
Penglaizheng Formation has been paleomagnetically studied to understand the Mesozoic tectonic history of China. Progressive thermal demagnehzahon has successfully resolved two magnetization components from this Formation. One component with lower unblocking temperature is overprint other component with higher unblocking temperature and passing the fold and reverse test is characterishc remanence. The overall mean declination and inclination of the characteristic component is 18.4 and 29.3 respechvely with 95% confidence (α95) 8.5,cormsponding to paleopole position of the Late Jurassic at 66.6 N, 236.4 E for Yangtze block. It is worth to point out that paleolatitude of the Late Jurassic is abnormally lower than that determined by other geological evidence, we Propose that the low latitude phenomenon be caused by the true polar wander which took place in the Late Jurassic.
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
1998年第3期324-331,共8页
Chinese Journal of Geophysics
基金
国家自然基金!"八五"重点资助
49334050
关键词
旺苍-南江地区
古地磁
晚侏罗世
真极移
Wangcang-Nanjian, Paleomagnetism, Late Jurassic, True polar wander.
