四川九寨溝地區(qū)古應(yīng)力測量和分析

【摘要】 古應(yīng)力重建是研究區(qū)域構(gòu)造演化的一個重要方法。三清山地區(qū)位于秦嶺造山帶的南緣，先后受到秦嶺造山帶、龍門山和大巴山等構(gòu)造的控制。本文根據(jù)野外露頭，重點(diǎn)研究三清山地區(qū)發(fā)育的三大主要斷裂帶（大河－楊壩－竹壩斷裂、正源－水磨－上兩－官壩斷裂、牟家壩斷裂）,對斷層面的古應(yīng)力標(biāo)記、產(chǎn)狀進(jìn)行詳盡的觀測，并利用Angelier等提出的古應(yīng)力分析方法及相關(guān)的配套軟件對野外實(shí)測數(shù)據(jù)進(jìn)行分析，作出古應(yīng)力圖，恢復(fù)出該地區(qū)的構(gòu)造演化。結(jié)果顯示，本區(qū)發(fā)育三組不同性質(zhì)的斷裂。在印支-燕山期，本區(qū)主要是受到秦嶺巨型推覆構(gòu)造控制，在南北向擠壓應(yīng)力的作用下，發(fā)育了一組順層滑動的逆斷裂；在喜馬拉雅期，由于龍門山推覆構(gòu)造的影響，區(qū)域上受到北西-南東向的擠壓作用和北東-南西的拉伸作用而發(fā)育有一系列走滑斷層；最晚期的正斷裂體現(xiàn)出來的拉張作用推測與本區(qū)推覆構(gòu)造形成后期的滑脫作用有關(guān)。

【關(guān)鍵詞】 斷裂帶 野外測量  古應(yīng)力分析  三清山

【Abstract】 Paleostress reconstruction is an important way to research regional tectonic evolution. Micangshan locates at southern part of Qinling orogenic belt, and its tectonic frame is mainly controlled by Qinling orogenic belt, Longmenshan and Dabashan. This paper focus on three faults zones (i.e. Dahe-Yangba-Zhuba fault, Zhengyuan-Shuimo-Shangliang-Guanba fault and Mojiaba fault) in this area. Detailed paleostress measurement was done first in field work. The measured data were then processed and plotted following the paleostress analysis method given by Angelier. The results show that there are three groups of faults in this area. In Indosinian-Yanshan period, this area is mainly controlled by Qinling giant nappe structure and a group of inverse faults along the strata plane were formed under the SN strike stress. In Himalayan period, under the influence of Longmenshan nappe structure, a group of strike-slip faults was formed in this area. The last group of faults, which is also the latest, was supposed to be related to the decollement process of the nappe structure in this area.

【Keywords】 Fault Zone  Field Measurement  Paleostress Analysis  Sanqingshan
 
目錄
1 引言 1
1.1 研究的目的和意義 1
1.2 研究現(xiàn)狀 1
1.3 研究思路 1
2 區(qū)域地質(zhì)概況 1
2.1 地層 1
2.2 構(gòu)造背景 1
2.4 地質(zhì)發(fā)展史 2
3 古應(yīng)力恢復(fù)的原理和方法 2
3.1 斷層及其分類 2
3.2 斷層盤上的標(biāo)識 2
4 三清山地區(qū)古應(yīng)力測量及分析 3
4.1 野外工作概況和實(shí)測數(shù)據(jù) 3
4.2 古應(yīng)力分析 3
5 三清山地區(qū)古應(yīng)力測量分析所揭示的區(qū)域構(gòu)造意義 4
6 結(jié)論和建議 4
6.1 結(jié)論及認(rèn)識 4
6.2 工作建議 4
致謝 4
主要參考文獻(xiàn) i