青海达日—久治地区巴颜喀拉盆地研究进展     

杨欣德  鄢犀利 《地质力学学报》2011,17(1):79-90

建立了测区三叠系巴颜喀拉山群地层格架,恢复了盆地充填序列和大地构造背景,系统总结了盆地基本层序类型,分析了盆地沉积旋回和海平面变化规律; 新发现深水风暴岩沉积; 取得了较老的锆石年龄数据,认为巴颜喀拉盆地存在硬基底; 发现三条大型韧脆性剪切带,探讨了区域隆升历史; 进行了大比例尺南水北调西线工程环境地质研究。   相似文献   

Mesozoic syncollision siliciclastic sediments of the Bols’shoi Lyakhov Island (New Siberian Islands)     

A. B. Kyzs’michev  A. V. Soloviev  V. E. Gonikberg  M. N. Shapiro  O. V. Zamzhitskii 《Stratigraphy and Geological Correlation》2006,14(1):30-48

Graywackes and shales of the Bols’shoi Lyakhov Island originally attributed to the Mesozoic were subsequently considered based on microfossils as the Late Proterozoic in age. At present, these sediments in the greater part of the island are dated back to the Permian based on palynological assemblages. In the examined area of the island, this siliciclastic complex is intensely deformed and tectonically juxtaposed with blocks of oceanic and island-arc rocks exhumed along the South Anyui suture. The complex is largely composed of turbidites with members displaying hummocky cross-stratification. The studied mineral and geochemical characteristics of the rocks defined three provenances of clastic material: volcanic island arc, sedimentary cover and/or basement of the ancient platform, and exotic blocks of oceanic and island-arc rocks such as serpentinites and amphibolites. All the rock associations represent elements of an orogenic structure that originated by collision of the New Siberian continental block with the Anyui-Svyatoi Nos island arc. Flyschoid sediments accumulated in a foredeep in front of the latter structure in the course of collision. The Late Jurassic volcanics belonging to the Anyui-Svyatoi Nos island arc determine the lower age limit of syncollision siliciclastic rocks. Presence of Late Jurassic zircons in sandstones of the flyschoid sequence in Bols’shoi Lyakhov Island is confirmed by the fission-track dating. The upper age limit is determined by the Aptian-Albian postcollision granites and diorites intruding the siliciclastic complex. Consequently, the flyschoid sequence is within stratigraphic range from the terminal Late Jurassic to Neocomian. It appears that Permian age of sediments suggested earlier is based on redeposited organic remains. The same Late Jurassic-Neocomian age and lithology are characteristic of fossiliferous siliciclastic sequences of the Stolbovoi and Malyi Lyakhov islands, the New Siberian Archipelago, and of graywackes in the South Anyui area in Chukchi Peninsula. All these sediments accumulated in a spacious foredeep that formed in the course the late Cimmerian orogeny along the southern margin of the Arctic continental block.  相似文献   

川西复理石区填图方法的新进展     

范晓  游再平 《四川地质学报》2000,20(1):29-34

四川区调队在近年的区调中,应用基本层序、层序地层、海底浊积扇等理论和方法,对川西松潘－甘孜造山带复理石区的填图方法进行了新的探索。本文对其进行了初步总结。  相似文献   

大别山北麓石炭纪盆地沉积和构造研究   总被引：18，自引：0，他引：18  

李宝芳  马文璞  张惠良  赵志根  李贵东 《地学前缘》2000,7(3):153-167

大别山加里东构造带北麓的石炭系为残留海盆地沉积 ,分布限制在潢川—固始—肥中断裂以南和信阳—商城—金寨—舒城断裂以北 ,保存在南翼向南倒转并有逆冲推覆构造的复式向斜中 ,中部被燕山期花岗岩侵入体破坏。排除构造重复 ,石炭系总厚 >2 0 0 9m (掩盖部分未计 ) ,按岩石地层单元分 5个组 ,各组之间均为断层接触。自下而上花园墙组为以复理石为代表的深水浊积扇和具有向上变细序列的陡坡扇沉积 ;杨山组为辫状河和滨岸辫状三角洲含煤沉积 ;道人冲组为辫状河、辫状三角洲、扇三角洲及滨浅海沉积 ;胡油坊组分布最广 ,为微咸水盆地陡坡扇、浊积扇沉积 ,有特征的复理石和滑塌沉积 ;杨小庄组为碎屑海岸含煤沉积。下统和上统的界限位于道人冲组中下部厚层砾岩的底部。古水流方向以自南指向北占优势 ,物源主要来自南侧的大别山区。石炭系下统砾岩为远源硅质正砾岩 ,含大量脉石英砾石 ,母岩为岩浆热液成因 ,现已无保存 ;上统砾岩为近源陡坡环境形成的复成分、多杂基的副砾岩 ,为浊积砾岩 ,其中脉石英砾石明显减少 ,含千枚岩和沉积岩砾石 ,母岩主要来自南侧的信阳群 /佛子岭群等。复理石、滑塌、浊积砾岩的存在表明石炭系具陡坡陆缘海活动大陆边缘的沉积特征 ,并发现有少量火山岩碎屑 ,可能形成于弧后盆地。稀?  相似文献