前言西藏东北部系指东径90°—96°,北纬29°—32°范围,东北角部分跨入青海省(图1)。本区在1975年以前,未进行过系统的区域地质调查。1975—1977年由西藏地质局综合普查大队进行了1:100万拉萨幅(H—46)编测工作,笔者随队参加了三年野外工作, 同时还在东巧、切里湖一带进行了较详细的区域地质研究,完成纪路通—通麦、索县—嘉黎、下秋卡—麦底卡和江索—冷青拉一带四条较系统的路线地质调查工作,横穿了该区东 Preface The northeastern Tibet refers to a region with an east diameter of 90 ° -96 ° and a latitude of 29 ° -32 ° and a part of the northeast corner into Qinghai Province (Figure 1). Before 1975, there was no systematic regional geological survey conducted in this area. From 1975 to 1977, a 1: 1 million lasagna (H-46) survey was conducted by the General Census Brigade of the Tibet Bureau of Geology. The author participated in the field work for three years with the team, and also conducted work in Dongqiao and Lake Cherihu In a more detailed regional geological study, four more systematic geological surveys of Jilu Tong - Tongmai, Suoxian - Jiali, Qiuqika - Maiqiaka and Jiangsuo - Lengqingla were completed, crossing the area east