發(fā)布時間：2018-01-23 08:33

  本文關(guān)鍵詞： 水槽實驗 正牽引構(gòu)造 沖積扇 沉積過程 沉積構(gòu)型　出處：《地學(xué)前緣》2017年06期 　論文類型：期刊論文

【摘要】：逆斷層正牽引構(gòu)造廣泛發(fā)育于擠壓盆地邊緣,伴隨逆斷層的幕式活動而生成,并影響山前沖積扇沉積過程與沉積構(gòu)型。為進一步認識這種特殊的凸起構(gòu)造對沖積扇沉積過程及其內(nèi)部構(gòu)型的控制作用,利用水槽實驗對正牽引構(gòu)造發(fā)育背景下的沖積扇沉積過程進行模擬與觀測。研究表明,攜帶大量沉積物的碎屑流沖出供水槽后很快受到正牽引構(gòu)造的阻擋,大量的粗粒沉積物快速卸載在正牽引構(gòu)造的迎水面,形成一個砂礫壩,同時水流被分成兩股分支水流。由于較粗粒的沉積物快速在迎水面卸載,砂礫壩迎著水流逐步向物源方向生長,形成逆向(生長)砂礫壩。分支水流繞過正牽引構(gòu)造后形成兩個新的次級物源,在次級物源持續(xù)供給下,形成兩個由多期碎屑流朵體復(fù)合而成的次級扇。受控于正牽引構(gòu)造的阻擋,沖積扇表面不同位置的沉積物卸載過程差異較大,相較于正常沖積扇沉積體,砂礫壩沉積物偏粗、分選更差,而次級扇沉積物粒度偏細、分選更好;正牽引構(gòu)造凸起幅度高低也會影響沖積扇沉積構(gòu)型,凸起幅度越高,正牽引構(gòu)造對水流的阻擋作用越強、越持久,逆向砂礫壩和次級扇的規(guī)模越大、空間結(jié)構(gòu)也越復(fù)雜。正牽引構(gòu)造完全被沉積物覆蓋后,扇面沉積特征與一般沖積扇無異。受控于正牽引構(gòu)造的沖積扇與一般沖積扇的內(nèi)部構(gòu)型存在較大差異,在順物源剖面上前者依次發(fā)育碎屑流朵體、逆向砂礫壩及次級扇,而后者則整體以碎屑流朵體為主;在由近端至遠端的切物源剖面上,前者依次以碎屑流朵體主控、逆向砂礫壩主控及次級扇主控,而后者則均以碎屑流朵體主控為主。
[Abstract]:The normal traction structure of the reverse fault is widely developed in the margin of the compressional basin and is formed along with the episodic movement of the thrust fault. It also affects the deposition process and sedimentary configuration of alluvial fan in front of mountains. In order to further understand the control effect of this special uplift structure on the sedimentary process and internal configuration of alluvial fan. The sedimentation process of alluvial fan in the background of positive traction structure is simulated and observed by flume experiment. The results show that the debris flow carrying a large amount of sediment is quickly blocked by the positive traction structure after it is washed out of the supply tank. A large amount of coarse sediment is rapidly unloaded on the front surface of the positive traction structure, forming a gravel dam, and the flow is divided into two streams of water flow. The gravel-gravel dam gradually grows toward the material source and forms the reverse (growth) sand gravel dam. After the branch water flows around the positive traction structure two new secondary material sources are formed under the continuous supply of the secondary material source. Two secondary fans composed of multi-stage clastic flow are formed. Controlled by the blocking of positive traction structure, the process of sediment unloading at different positions on the surface of alluvial fan is quite different, which is different from that of normal alluvial fan. The gravel-dam sediments are coarse and worse, while the secondary fan sediments are finer in size and better in sorting. The higher the uplift amplitude of the positive traction structure is, the greater the sedimentary configuration of alluvial fan is. The higher the uplift amplitude is, the stronger the blocking effect of the positive traction structure is on the flow of water, the longer the duration is, the larger the scale of the reverse gravel dam and secondary fan is. The more complex the spatial structure is, the more the sedimentary characteristics of the fan are similar to those of the general alluvial fan after the positive traction structure is completely covered by the sediment. The internal configuration of the alluvial fan controlled by the normal traction structure is different from that of the general alluvial fan. The former developed debris flow flower body, the reverse sand gravel dam and secondary fan in sequence, while the latter developed debris flow flower body as a whole. In the cutting source profile from the proximal end to the distal end, the former is controlled by the debris flow, the reverse sand dam and the secondary fan, while the latter is dominated by the debris flow.
【作者單位】： 中國石油大學(xué)(北京)地球科學(xué)學(xué)院;油氣資源與探測國家重點實驗室;長江大學(xué)地球科學(xué)學(xué)院;中國石油勘探開發(fā)研究院鄂爾多斯分院;中國石油新疆油田分公司;
【基金】：國家自然科學(xué)基金項目(41372116)
【分類號】：P542;P618.13
【正文快照】： 2.長江大學(xué)地球科學(xué)學(xué)院,湖北武漢4301003.中國石油勘探開發(fā)研究院鄂爾多斯分院,北京1000834.中國石油新疆油田分公司,新疆克拉瑪依834000FENG Wenjie1,2,WU Shenghe1,*,LIU Zhongbao2,XIA Qinyu1,3,ZHANG Ke1,XU Zhenhua1,XIANG Xianpeng41.College of Geosciences,China Uni，

本文編號：1457191