【摘要】：蘭坪—思茅(盆地)內(nèi)部發(fā)育的一系列褶皺和逆沖斷層組成了顯著的弧形構(gòu)造,其中部呈現(xiàn)反S形構(gòu)造形態(tài)。該地區(qū)地殼構(gòu)造變形方式及其演化過程與青藏高原東南緣地殼物質(zhì)新生代側(cè)向擠出逃逸密切相關(guān),對其開展地殼構(gòu)造變形方式的定量分析,具有重要的意義。本文通過蘭坪—思茅盆地中部反S形構(gòu)造區(qū)域四條白堊紀(jì)紅層剖面的巖石磁學(xué)和古地磁學(xué)研究,獲得南澗牛街地區(qū)早白堊世LN-a和LN-b剖面的特征剩磁方向分別為D_s=244.7°,I_s=-47.3°,Ks=31.6,α_(95)=16.6°(K_1j~1),和D_s=245.4°,I_s=-46.4°,K_s=52.2,α_(95)=9.4°(K_1n~2),兩剖面在99%置信度下通過了Mc Fadden(1990)褶皺檢驗(yàn);小灣鎮(zhèn)地區(qū)早白堊世NX-a和NX-b剖面(兩套地層分屬軸向不同的兩褶皺)特征剩磁方向分別為D_s=244.9°,I_s=-40.2°,K_s=1067.5,α_(95)=2.3°(K_1j~1)和D_s=182.6°,I_s=-42.1°,K_s=335.2,α_(95)=3.7°(K_1j~2)。結(jié)合前人在蘭坪—思茅地體中部獲得的可靠古地磁數(shù)據(jù)及青藏高原東南緣區(qū)域新生代斷裂活動演化過程的分析,指出蘭坪—思茅盆地中部弧形反S形構(gòu)造的形成和演化,以及蘭坪—思茅盆地構(gòu)造區(qū)內(nèi)部差異性旋轉(zhuǎn)變形作用主要受控于新生代時期青藏高原東南緣地殼塊體側(cè)向旋轉(zhuǎn)擠出過程中的相互擠壓作用和臨滄花崗巖基對蘭坪—思茅地體側(cè)向順時針旋轉(zhuǎn)擠出運(yùn)動的阻擋等一系列構(gòu)造因素。
[Abstract]:A series of folds and thrust faults developed in Lanping-Simao (basin) form a significant arc structure, and the middle part of the basin presents an anti-S-shaped structure. The crustal tectonic deformation pattern and its evolution process in this area are closely related to the Cenozoic lateral extrusion escape of crustal material in the southeast margin of Qinghai-Xizang Plateau. It is of great significance to carry out the quantitative analysis of crustal tectonic deformation mode. In this paper, the petromagnetism and paleomagnetism of four Cretaceous red bed sections in the anti-S-shaped structural area in the central Lanping-Simao Basin are studied. The characteristic remanence directions of early Cretaceous LN-a and LN-b profiles in Nanjian Niujie area are D_s=244.7 擄, I_s=-47.3 擄, Ks=31.6, 偽 _ (95) = 16.6 擄(K_1j~1) and D_s=245.4 擄, respectively. I_s=-46.4 擄, K 鈮，

本文編號：2488141