本文選題：青藏高原東北緣S波速度結(jié)構(gòu)　切入點：接收函數(shù)　出處：《中國地質(zhì)大學(xué)(北京)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：青藏高原東北緣作為整個高原向內(nèi)陸延伸的最前緣部分,是研究高原隆升和變形機制的關(guān)鍵區(qū)域。本文研究區(qū)域包括西秦嶺、祁連、東昆侖造山帶,柴達(dá)木盆地和阿拉善、松潘-甘孜以及羌塘塊體。通過收集研究區(qū)域內(nèi)223個臺站記錄的2007-2010年的遠(yuǎn)震波形數(shù)據(jù),首先利用遠(yuǎn)震P波接收函數(shù)對研究區(qū)域殼幔界面進行成像研究。接收函數(shù)結(jié)果顯示:柴達(dá)木盆地地殼厚度約為50-55 km;松潘-甘孜塊體的地殼厚度自西向東從65-75 km降低到~50 km;西北祁連造山帶地殼厚度約為60-65 km;東南祁連造山帶和西秦嶺造山帶的地殼厚度約為50-55km。Vp/Vs值在松潘甘孜塊體西部、羌塘塊體約為1.8,而其余地區(qū)Vp/Vs均值約為1.75。然后利用遠(yuǎn)震雙平面波成像法提取研究區(qū)域25-111 s的瑞利波相速度分布,利用背景噪聲成像方法獲取10-40 s的瑞利波相速度分布。聯(lián)合接收函數(shù)、背景噪聲和雙平面波法的面波頻散結(jié)果,反演獲得了研究區(qū)域地表至地下150km的S波速度結(jié)構(gòu)。S波速度結(jié)果表明:(1)松潘-甘孜塊體、羌塘塊體西部和東昆侖斷層的中地殼到140 km范圍存在連續(xù)的低速帶。(2)祁連造山帶下方的速度分布特征存在著明顯的橫向各向異性。西北祁連造山帶的中下地殼表現(xiàn)為明顯的低速特征,而在東南祁連造山帶下方并未觀測到低速的中下地殼。西北祁連造山帶的地殼厚度約為60-65 km,其中下地殼范圍內(nèi)的低速帶很可能與該區(qū)域的地殼增厚相關(guān)。而在具有較薄地殼(50~55 km)的西秦嶺造山帶和東南祁連造山帶的地殼內(nèi)沒有觀測到低速帶,這說明地殼流模型可能并不是青藏高原東北緣生長變形的主要機制。
[Abstract]:The front part of the northeastern margin of the Tibetan Plateau as the whole plateau extends inland, is the key area of plateau uplift and deformation mechanism. The research areas include Qilian, West Qinling Mountains, East Kunlun orogenic belt, Qaidam Basin and Alashan, Songpan - Ganzi and Qiangtang block. By Teleseismic waveform data collected for 2007-2010 years in the study area were recorded at 223 stations, first using teleseismic P wave receiver function of regional crust mantle interface imaging. The receiver function results show that the crustal thickness in this basin is about 50-55 km; the Songpan - Ganzi block of the crustal thickness from west to East, reduced from 65-75 km to ~50 km; the thickness of the crust in northwestern Qilian orogenic belt is about 60-65 km; the thickness of the crust in Southeast Qilian orogenic belt and the West Qinling Mountains orogenic belt is about 50-55km.Vp/Vs in Songpan Ganzi west block, the Qiangtang block is about 1.8, while the rest were Vp/Vs About 1.75. and then using teleseismic double plane wave imaging method of Rayleigh wave extraction in the research area of 25-111 S phase velocity distribution, using the method of background noise imaging to obtain 10-40 s Rayleigh wave phase velocity distribution. Combined receiver function, background noise scattered results and double plane wave method of surface wave frequency, S wave velocity inversion the structure of.S wave velocity results of regional surface to underground 150km showed that: (1) Songpan - Ganzi block, crust in the Qiangtang block in the West and the East Kunlun fault to the range of 140 km with low speed continuous. (2) under the Qilian orogenic belt, the velocity distribution characteristics are transverse anisotropy northwest of the Qilian orogenic belt. The lower crust showed low speed characteristics, and in the southeast of Qilian orogenic belt is not observed at low speed. The lower crust in northwestern Qilian orogenic belt of crustal thickness is about 60-65 km, of which the lower crust in the range of The low velocity zone may be related to crustal thickening in the region. But in having a relatively thin crust (50~55 km) were observed in the low velocity zone of the crust in Western Qinling Mountains orogenic belt and the East Qilian orogenic belt, which shows that the main mechanism of the crustal flow model may not be the growth of the northeastern margin of the Tibetan Plateau deformation.

【學(xué)位授予單位】：中國地質(zhì)大學(xué)(北京)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：P315.2

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相關(guān)期刊論文 前1條

1 王椿鏞;常利軍;呂智勇;秦嘉政;蘇偉;Paul Silver;Lucy Flesch;;青藏高原東部上地幔各向異性及相關(guān)的殼幔耦合型式[J];中國科學(xué)(D輯:地球科學(xué));2007年04期

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本文編號：1561213