位于川西高原东南部边界带内侧的沪定大渡河西岸海于坪，分布着一套厚度颇大的昔格达组河一湖相地层，为我国西南地区广布的昔格达组出露厚度最大的地点之一。海子坪湾湾头一于海于剖面，出露的晚新生代地层厚度大于441m，底部为厚约30m的角砾层，上覆昔格达组，岩性为粘土、粉 Located in the southeast of the western Sichuan Plateau southeast of the border zone of the Shanghai Daduhehai Haipu Ping, a set of thickness of the Xigeda He Yi Lake phase strata, for the extensive distribution of Xigeda Southwest China group thickness One of the largest locations. Haizi Pingwan Bay first in the sea in the profile, exposed Late Cenozoic strata thickness greater than 441m, the bottom of the thick 30m thick breccia, overlying the Xigeda group, lithology clay, powder