An Epsilon-Type Structure with Westward Convex Frontal Arc $$$$ ' The Jishui Epsilon-Type Structure'

摘要

The "Jishui epsilon-type Structure" on the east side of the Ganjiang River is located in Fengcheng, Xingan, Xiajiang, Yongfeng, Jishui and Ji'an Counties, extending for 150 km in length from latitude 27° 48' in the north to 26° 40' N in the south and spreading for 70 km in width from longitude 115° 09' E in the west to 115° 48' E in the east. Running from Liuyuan of Xiajiang County southward through Baiwuling, Luxiling and Qiubei area of Jishui County, and with its apex lying in Jishui County town, the frontal arc is formed by the Wangyuan-Fengping anticline, the Shuikou anticline, and a series of compression fractures(mostly thrust faults) that parallel with the strata in strike. The Wangyuan-Fengping anticline is an arcuate fold 50 km long along strike; with the Wujiang River as a dividing line, the north section strikes from ENE through NE to NNE from north to south, while the south section plunges southeastery around Yuanjiafang of Jishui County; the core consists of the lower part while the limbs are composed of the upper part of Sinian strata; the strata generally dip at angles of 30° -50° ; the axial plane is vertical but dips to south locally; the two limbs are about 10 km in width. The Shuikou anticline strikes NW-NNW plunging northwesterly, and is made up also of Sinian strata; the core and the limbs are similar to those of the Wangyuan-Fengping anticline in lithologies; strata in the two limbs dip at angles of 30° -50° ; the axial plane is vertical but dips to south locally; the two limbs are about 10 km in width.