【摘要】：柴達(dá)木盆地是我國西部三大含油氣盆地之一,經(jīng)歷了多期疊加與改造。盆地構(gòu)造-熱演化史研究一方面對分析柴達(dá)木盆地的構(gòu)造成因,揭示青藏高原的形成機(jī)制和隆升歷史有重要的意義,另一方面為盆地進(jìn)行油氣資源評價(jià)提供科學(xué)依據(jù)。采用平衡剖面技術(shù)、磷灰石裂變徑跡年齡分布特征定性分析與徑跡長度分布數(shù)據(jù)定量模擬相結(jié)合的方法,分析了柴達(dá)木盆地東部古生代以來的構(gòu)造演化過程,研究表明:柴達(dá)木盆地東部在侏羅紀(jì)早期構(gòu)造活動強(qiáng)烈,導(dǎo)致了石炭系抬升、剝蝕;白堊紀(jì)末期構(gòu)造運(yùn)動相對較弱,表現(xiàn)為早期的弱伸展與晚期北東-南西向的擠壓;喜山運(yùn)動在該區(qū)域多期發(fā)育,主要為喜山運(yùn)動早期(41.1~33.6Ma)、喜山運(yùn)動晚期(9.6~7.1 Ma,2.9~1.8 Ma),其中晚喜山運(yùn)動造成了先存斷裂的再次活化。在埋藏史重建的基礎(chǔ)上,對柴達(dá)木盆地東部熱歷史進(jìn)行了恢復(fù),結(jié)果表明柴達(dá)木盆地東部熱歷史總體變現(xiàn)為緩慢降低的特征,古生代末期柴達(dá)木盆地東部古地溫梯度為38~41.5℃/km,地溫梯度平均值為39℃/km;古近紀(jì)早期地溫梯度降為29~35.2℃/km,平均值為約33.0℃/km,古近紀(jì)末地溫梯度有所變大,新近紀(jì)末趨于現(xiàn)今的熱狀態(tài)。柴達(dá)木盆地東部古生代以來構(gòu)造-熱演化特征主要受控于研究區(qū)巖漿熱事件發(fā)育與構(gòu)造活動的特征。
[Abstract]:Qaidam basin is one of the three major petroliferous basins in western China, which has undergone multi-stage superposition and transformation. On the one hand, the study of tectonic-thermal evolution history of the basin is of great significance for analyzing the tectonic origin of Qaidam basin and revealing the formation mechanism and uplift history of the Qinghai-Tibet Plateau. On the other hand, it provides a scientific basis for the evaluation of oil and gas resources in the basin. By means of balanced section technique, qualitative analysis of apatite fission track age distribution characteristics and quantitative simulation of track length distribution data, the tectonic evolution process since Paleozoic in eastern Qaidam Basin is analyzed. The results show that the eastern Qaidam basin has strong tectonic activity in the early Jurassic, which led to the Carboniferous uplift and denudation. The tectonic movement in the late Cretaceous is relatively weak, which is characterized by the weak extension in the early stage and the compression in the NE-SW direction in the late stage. The Himalayan movement developed in many stages in this area, mainly in the early Himalayan movement (41.1~33.6Ma) and the late Himalayan movement (9.6 Ma,2.9~1.8 Ma), in which the late Himalayan movement resulted in the re-activation of the pre-existing faults. Based on the reconstruction of burial history, the thermal history in the eastern Qaidam basin is restored. The results show that the thermal history in the eastern Qaidam basin is gradually decreasing. The paleogeothermal gradient of the eastern Qaidam basin in the late Palaeozoic era is 38 ~ 41.5 鈩，

本文編號：2442153