漠河盆地沉积充填与热构造研究

发布时间：2018-08-12 10:41

【摘要】：漠河盆地位于我国最北端，其与俄罗斯境内的乌舒蒙盆地相连为一个统一的盆地，其北为“蒙-鄂造山带”。研究漠河盆地的沉积体系和构造背景,并将漠河盆地成因机制与“蒙-鄂造山带”联系起来,将为“蒙-鄂带”造山过程甚至重建中生代东亚汇聚提供依据，且对盆地油气的进一步勘探有一定的指导意义。通过分析该区地球物理物性样品数据的分析得出，该区主要存在三个主要的密度物性界面，四个密度层；两个主要的磁性物性界，三个磁性层。该区重磁异常以近北西向异常为主，存在两个近北西向重力高值异常区，且东北部重力高值异常更加明显，自西向东表现出低-高-低-高的特点；五个磁力异常区（两个强磁异常区，三个弱磁异常区），北西部北西向高值异常表现明显，总体表现出西高东低的特点。综合分析重磁、野外地质现象及地震资料，识别出断裂共75条，其中I级断裂11条，II级断裂11条，III级断裂53条；近EW向断裂20条NE、NEE向断裂25条，NW、NWW向断裂23条，近SN向断裂7条。其中近EW走向断裂既有逆断裂，也有正断裂。其中逆断裂形成于晚侏罗纪。NE、NW、 SN向断裂多为正断层，主要形成于早白垩纪。且近EW向及个别近NE向、NW向的控盆断裂活动性最强。根据重磁资料解释，将漠河盆地划分为六个一级构造单元（两隆四拗）、十二个二级构造单元（6凹6凸），总体表现出西部地区相对较深，一般为3000m，东部地区略浅，一般为2500m，最深部位于盆地中部的长缨地区，达9000m。受近东西向的断裂控制，盆地的主体凹陷呈东西向。后期的北东-北北东向断裂对原来的近东西向构造造成了破坏和改造，并在其上叠加了北东-北北东向的断陷。综合测井、岩心观察及野外地质剖面，共识别出该区主要发育三种沉积相（冲积扇相、扇三角洲相及湖泊相），盆地总体表现出北部水体较深向南逐渐变浅，由北向南沉积相表现出半深湖-滨浅湖-前扇三角洲-扇三角洲前缘-扇三角洲平原-冲积扇相的规律。从秀峰组到二十二站组为正旋回，底部发育砾岩；二十二站组到额木尔河组为反旋回，顶部发育砾岩,表现出挤压性盆地的沉积特征。漠河盆地晚侏系纪整体上表现为，下部为一段的正旋回，上部为一大段的反旋回。而早白垩系整体上表现为，下部（塔木兰沟组）为一段的正旋回，上部（伊列克得组）为反旋回。漠河盆地靠近“蒙古-鄂造山带”一侧沉积相随鄂霍茨克缝合带走向展布，且由于鄂霍茨克海关闭的挤压作用，盆地的沉积中心存在向南迁移的现象。通过对该区28个磷灰石裂变径迹年龄的研究得出，样品年龄主要分布在137-110Ma、218-164Ma、326-299Ma三个区段中，漠河盆地基底在三叠纪-早中侏罗纪快速隆升，在晚侏罗纪-早白垩纪隆升较慢，最后在晚白垩纪-现今再次较快速的隆升。三叠纪-早中侏罗纪为沉积岩源区的隆升阶段，之后遭受剥蚀-搬运-沉积，形成晚侏罗纪盆地沉积岩盖层，，并在120Ma-0Ma（早白垩纪-现今）再次隆升遭受剥蚀。蒙古-鄂霍茨克海关闭始于三叠纪，结束于晚侏罗末到早白垩纪初期。在此过程中形成了漠河-乌舒蒙前陆盆地。三叠纪由于弧-陆碰撞形成弧后小洋盆—乌舒蒙盆地，因而乌舒蒙盆地发育三叠纪海相地层，三叠纪时期乌舒蒙盆地为弧后前陆盆地；随着挤压碰撞造山的进行（陆-陆碰撞），盆地横剖面进一步扩展，在晚侏罗纪中国境内的漠河盆地开始发育陆相地层，在晚侏罗纪漠河-乌舒蒙盆地为周缘前陆盆地。到早白垩纪由于蒙古－鄂霍茨克洋的关闭和造山后垮塌和古太平洋板块俯冲的远程效应的综合作用，漠河盆地白垩纪以来整体处于伸展状态，为分割的断陷湖盆。
[Abstract]:The Mohe Basin is located in the northernmost part of China. It is a unified basin connected with the Wushumeng Basin in Russia. The northern part of the basin is the "Mongolia-Hubei orogenic belt". The study of the sedimentary system and tectonic setting of the Mohe Basin will link the genetic mechanism of the Mohe Basin with the "Mongolia-Hubei orogenic belt" and even reconstruct the "Mongolia-Hubei belt" orogenic process. Mesozoic East Asia convergence provides a basis, and has a certain guiding significance for further exploration of oil and gas in the basin.
The analysis of geophysical data shows that there are three main density-physical interfaces, four density layers, two main magnetic property boundaries and three magnetic layers in this area. The anomaly is more obvious, showing the characteristics of low-high-low-high from west to east; five magnetic anomaly areas (two strong magnetic anomaly areas, three weak magnetic anomaly areas), the NW-trending high-value anomaly in the northwest is obvious, showing the characteristics of high-value anomaly in the West and low-value in the east.
Seventy-five faults were identified by comprehensive analysis of gravity and magnetic, field geological phenomena and seismic data, including 11 faults of grade I, 11 faults of grade II and 53 faults of grade III, 20 faults of NE, 25 faults of NEE, 23 faults of NW and NWW, and 7 faults of SN. Jurassic. NE, NW, SN faults are mostly normal faults, mainly formed in the early Cretaceous, and near EW and some near NE, NW-trending basin-controlling faults have the strongest activity.
According to the interpretation of gravity and magnetic data, the Mohe Basin is divided into six first-order tectonic units (two uplifts and four depressions) and twelve second-order tectonic units (six concave and six convex). Generally speaking, the western part is relatively deep, generally 3000 m, the eastern part is slightly shallow, generally 2500 m, and the deepest part of the Mohe Basin is located in the Changluo area of the central part of the basin, up to 9000 M. The main depression of the basin is E-W trending, and the NE-NE trending faults in the later period destroyed and reformed the original E-W trending structures, and superimposed the NE-NE trending faults on it.
Three main sedimentary facies (alluvial fan facies, fan delta facies and lacustrine facies) were identified by comprehensive logging, core observation and field geological profiles. The basin shows that the northern water body gradually becomes shallow from deep to south, and the sedimentary facies from north to South shows semi-deep lake-shore shallow lake-front fan delta-fan Delta front-fan Delta plain-fan Delta plain. From Xiufeng Formation to the 22nd Station Formation, conglomerate is normal cycle and developed at the bottom; from the 22nd Station Formation to the Emuerhe Formation, conglomerate is developed at the top, showing sedimentary characteristics of compressive basin. On the whole, the Cretaceous is characterized by a positive cycle in the lower part (Tamulangou Formation) and a reverse cycle in the upper part (Elikode Formation). The sedimentary facies along the direction of the Okhotsk suture zone in the Mohe Basin near the "Mongolia-E Orogenic Belt" are distributed along with the movement of the Okhotsk suture zone, and the sedimentary center of the basin migrates southward due to the compression of the closure of the Okhotsk Customs.
According to the study of 28 apatite fission track ages in this area, the sample ages are mainly distributed in 137-110Ma, 218-164Ma, 326-299Ma. The basement of Mohe Basin uplifted rapidly from Triassic to Early-Middle Jurassic, uplifted slowly from Late Jurassic to Early Cretaceous, and uplifted rapidly again from Late Cretaceous to present. The early and middle Jurassic was the uplift stage of sedimentary source area, and then was eroded, transported and deposited, forming the sedimentary rock caprock of the late Jurassic basin, and uplifted and eroded again at 120Ma-0Ma (Early Cretaceous-present).
The Mongolian-Okhotsk Customs closure began in the Triassic and ended in the late Late Jurassic to the early Early Cretaceous, during which the Mohe-Wushumen foreland basin was formed. Continental basin; with the development of compressional collision orogeny (continental-continental collision), the transverse section of the basin expanded further. continental strata began to develop in the Mohe basin in late Jurassic China, and the Mohe-Wushumeng basin was a peripheral foreland basin in late Jurassic. By the early Cretaceous, due to the closure of the Mongolia-Okhotsk Ocean and post-orogenic collapse and Paleo-Archean. The comprehensive effect of the long-range subduction of the Pacific Plate makes the Mohe Basin in an extensional state since Cretaceous, which is a faulted lake basin.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P512.2;P548

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