摘要
位于湖北省西部的黄陵穹窿具有基底加盖层双层结构,其暴露的基底主要以黄陵花岗岩为代表。该穹窿对长江三峡的形成演化、四川—江汉盆地一带构造格局的形成,以及三峡大坝的安全性等方面均具有重要控制和影响作用。本文通过对黄陵花岗岩的裂变径迹特征分析,结合夷平面分析和野外实测阶地地貌数据,获得了黄陵穹窿自65Ma以来的隆升速率、隆升高度等方面的数据:①65～7Ma,隆升速率为24.6～7.4m/Ma,隆升高度为1426.8～429.2m;②7Ma至今,平均隆升速率为204.1m/Ma,隆升高度为1428.7m。其中7～0.73Ma,隆升速率由0.009～0.013m/ka增加至0.293～0.387m/ka;而0.73～0.01Ma以来隆升速率由0.058m/ka增加为1.033m/ka,平均隆升速率为0.134m/ka,显示出隆升早期较慢,后期加快的趋势。65Ma以来,总的剥蚀厚度至少为2455.5～1457.9m,其中7Ma以来剥蚀的厚度为1028.7m,剥蚀速率为0.147mm/a。研究结果表明,该区的隆升历史,与青藏高原的形成演化密切相关,同时约束了长江三峡的形成时间和过程,证实了三峡是一年轻的河谷;该区隆升所引发的地表活动也可能会对三峡大坝产生一定的影响。
Huangling Dome consists of base and cover rocks, which is located in the west edge of Hubei Province, with Hungling Granite being representive outcrop of the base. Huangling Dome is very important to the formation and evolution of the Yangtze Three Gorges, the formation of structural pattern of Sichuan and Jianghan Basins, and also has important effect on security of the Yangtze Three Gorges Dam. Based on fission track analysis of Hungling Granite, combing with research of planation surfaces and terraces characteristics in field, we obtain data of uplift velocity and uplift height of Huangling Dome since 65Ma： （1）65-7Ma, uplift velocity was 24.6--7.4m/Ma, and uplift height was 1426.8~429.2m; （2）7- 0Ma, uplift velocity was 204. lm/Ma, and uplift height was 1428.7m. Especially, uplift velocity increased from 0.009~0.013m/Ka to 0. 293~0. 387m/Ka during 7~0.73Ma, and increased from 0. 058m/Ka to 1. 033m/Ka in the course of 0.73Ma to 0.01Ma and mean velocity was 0. 134m/Ka, which showed that uplift velocity was slow in the early stage , but increased continuously from then on. Total denudation depth was 2455.5~1457.9m from 65Ma to now, and denudation depth was 1028.7m and mean denudation velocity was 0. 147mm/a from 7Ma to present. Research results reflect uplift history in this area has close relationship with formation and evolution of the Qinghai-Xizang Plateau, and also restrict formation time and process of the Yangtze Three Gorges, and prove the Three Gorges is a youthy river valley. On the other hand, surface geological activities aroused by uplift of Huangling Dome will have some effects on the Three-Gorges Dam.
出处
《地质学报》
EI
CAS
CSCD
北大核心
2009年第9期1247-1254,共8页
Acta Geologica Sinica
基金
国家自然科学基金项目(编号40602011)资助的成果
关键词
黄陵穹窿
新生代
隆升特征
三峡贯通
隆升原因
Hungling Dome
Cenozoic
uplift characteristics
formation of the Yangtze Three Gorges
uplift reason
