用MT资料解释苏北地区海相残留地层展布

Interpretation of the distribution of residual marine strata in the north part of Jiangsu province using magnetotelluric sounding data

在江苏苏北地区开展了以中、古生界为主要对象的大地电磁测深勘探 (MT) ,并进行了综合地质解释。以二维剖面解释为依据 ,探讨了苏北盆地建湖隆起及以北地区的现今构造区划和海相残留地层展布。资料表明 ,海相中、上古生界地层主要残存在该区的东部 ,西部仅残存下古生界地层 ,印支 -燕山中期发育于阜宁凹陷南界的NE向逆冲断层和一系列NW向正断层控制了海相地层残存。

The magnetotelluric sounding exploration for the Mesozoic and Paleozoic formations has been carried out in the recent years in the north part of Jiangsu province. The stratum columnar section consists of six electrical layers, among which three layers are low-resistance ones and three high-resistance. Comprehensive geologic interpretation is performed on data after field preprocessing, cleaning-up of static displacement, and 2D inversion. Based on interpretation of magnetotelluric sounding data, we infer the classification of structures and the distribution of residual marine strata in Jianghu Buildup and the north in the north part of Jiangsu province. Results show the marine middle and upper Paleozoic residual strata mainly locate in the east part of the survey area, and the lower Paleozoic residual strata locate only in the west part. The residual marine strata are controlled by the reverse thrust of NE direction that was developed from the south end of Funing sag in the middle of Indo-chinese and Yanshanian epoch and a series of normal faults of NW direction.