Das Süd-Altiplano-Becken (Bolivien) im Tertiär: Sedimentäre Entwicklung und tektonische Implikationen
Das Süd-Altiplano-Becken (Bolivien) im Tertiär: Sedimentäre Entwicklung und tektonische Implikationen
复制标题
Das Süd-Altiplano-Becken（玻利维亚）第三次：沉积物开发和技术应用
DOI：
10.17169/refubium-5301
复制
发表时间：
2004
影响因子：
4.9
通讯作者：
Patricio Silva González
中科院分区：
文献类型：
--
作者：
Patricio Silva González
分析了玻利维亚南高原盆地第三纪沉积物及其沉积环境。在此基础上，进行了地层学、岩相学、物源和沉降分析，建立了盆地模式。该盆地见证了沉积物积累的变化，中部含有7500米，东部高达4500米厚的新生代沉积物。这些沉积物分为埃尔莫利诺、圣卢西亚、卡亚拉、波托科、圣维森特和乔卡亚组。埃尔莫利诺组是在古近纪-第三纪界线期间大面积沉积的。在埃尔莫利诺组之上，第三纪大陆沉积物堆积在南部高原盆地。南高原盆地的发育始于古新世。西缘由白垩纪-第三纪岩浆弧形成。盆地向东延伸至Camargo盆地，向北延伸至南部Altiplano盆地，南部Altiplano盆地是中部和北方Altiplano盆地的一部分，向南延伸至与阿根廷西北部共同沉积区的一部分。在这个盆地中沉积了埃尔莫利诺和圣卢西亚地层的沉积物。在古新世末期，随着原始东科迪勒拉山脉的发展和南部高原盆地从原始东科迪勒拉山脉的山间盆地中分离出来，一个新的盆地格局开始形成。组成成熟和河流Cayara组沉积在前陆盆地位于西部的最初形成的原始东科迪勒拉。在始新世，南部高原基底是一个远源沉积区。构造活动集中在盆地边缘。印支期，西部弧后盆地反转，发育前陆盆地。在南部高原盆地的中部，Potoco组的一部分来自西部。东部的原东科迪勒拉变形前缘向西扩展，形成前陆盆地和阿托查背驮式盆地。由古生界和白垩系岩石组成的隆起区是Potoco组的烃源岩。在盆地东部，Potoco组由干盐湖、河流和冲积层组成。在这个相对的构造平静阶段，只有南部高原盆地的中部是从上始新世受伸展构造活动的影响。这种伸展活动并没有在地表产生主要断层，而是导致了细粒的普拉亚波托科组的沉积。这些沉积物来自南部高原盆地边缘。在此期间，南部高原盆地边缘的东部和西部都形成了前陆盆地，而中部的地堑构造则受到圣克里斯托瓦尔断层的限制。从下渐新世到上渐新世的过渡见证了剧烈的构造变化。二叠系、结晶岩和第三系是南高原盆地西部渐新世-中新世沉积物的烃源岩。西部渐新世-中新世圣维森特组烃源岩近期未出露地表，但可根据圣维森特组岩相学资料予以支持。在渐新世晚期，一个新的火山弧开始并到达原始东科迪勒拉山脉的西缘。同时粗粒和火山碎屑沉积物沉积在圣维森特组。沉积物来源于南部高原盆地的西部、中部和东部。在下渐新世向上渐新世的过渡时期，南高原盆地中部发育了一个由北向南的弧内盆地。在中新世弧内盆地反转期间，一个新的变形前缘向东扩展。同构造层序在反转活动期间沉积在圣维森特组中，底部和顶部由渐进不整合面界定。这些层序沉积于反转断层的上盘和下盘。在南部高原盆地的东缘，变形前缘继续向西扩展，在圣维森特组中沉积了同构造层序。南高原盆地边缘在构造活动的作用下发生了隆升，同时盆地也经历了强烈的沉降。南部高原盆地的构造活动在7 ~ 10 Ma之间。
The Tertiary sediments of the Southern Altiplano Basin, Bolivia, and the depositional setting were analised. This study was made based on stratigraphy, facies, petrography, provenance and subsidence analysis, and a basin model was developed. The basin witnessed variation in sediment accumulation, with the central part containing 7500 m and the eastern part up to 4500 m thick cenozoic sediments. These sediments are classified in the El Molino, Santa Lucía, Cayara, Potoco, San Vicente and Chocaya formations. The El Molino Formation was deposited in a wide area during the Cretaceous-Tertiary boundary. Above the El Molino Formation Tertiary continental sediments were accumulated in the Southern Altiplano Basin. The development of the Southern Altiplano Basin begann in the Paleocene. The western margin was formed by the Cretaceous-Tertiary magmatic arc. To the east, the basin extent into the Camargo basin while to the north, the Southern Altiplano Basin was part of the Central and Northern Altiplano basin.To the south, the basin was part of a common depositional area with NW-Argentina. In this basin the sediments of the El Molino and Santa Lucía formations were deposited. At the end of the Paleocene, a new basin configuration commenced with the development of the Proto-Eastern Cordillera and separation of the Southern Altiplano Basin from the intramontane basins in the Proto-Eastern Cordillera. The compositional mature and fluvial Cayara Formation was deposited in a foreland basin located in the west of the initially formed Proto-Eastern Cordillera. During the Eocene the Southern Altiplano Basis was a distal depositional area. The tectonic activity was concentrated in the basin margins. During the Incaic phase the back arc basin in the west was inverted and a foreland basin developed. In the central part of the Southern Altiplano Basins part of the Potoco Formation was sourced from the west. The deformation front of the Proto-Eastern Cordillera in the east propagated to the west, forming a foreland basin and the Atocha piggy-back basin. The uplifted area consisting of Paleozoic and Cretaceous rocks was the source rocks of the Potoco Formation. In the eastern part of the basin, the Potoco Formation consists of playa-, fluvialand alluvial deposits. In this relative tectonically quiesence phase, only the central part of the Southern Altiplano Basin was from the Upper Eocene influenced by an extensional tectonic activity. This extensional activity which did not create major faults at the surface, led to the deposition of the fine-grained playa Potoco Formation. These sediments were sourced from the Southern Altiplano Basin margins. During this time, both the eastern and western parts of the Southern Altiplano Basin margins formed a foreland basin, while a graben structure in the central part was limited by the San Cristobal fault. The transition from Lower to Upper Oligocene witnessed a drastic tectonic change. Permian, crystalline and Tertiary rocks are the source rocks of the Oligocene-Miocene sediments in the western part of the Southern Altiplano Basin. The western source rocks of the Oligocene-Miocene San Vicente Formation recent does not outcroped on the surface, but can be supported based an the petrography of the San Vicente Formation. In the Upper Oligocene a new volcanic arc began and reached the western margin of the Proto-Eastern Cordillera. Simultaneously coarse-grained and volcaniclastics sediments were deposited in the San Vicente Formation. The sediments were sourced from the west, central and east of the Southern Altiplano Basin. Also during the transition from Lower to Upper Oligocene a north to south oriented intra-arc basin developed as a subordinate structure in the central part of the Southern Altiplano Basin. During the Miocene inversion of the intra-arc basin, a new deformation front developed propagating to the east. Syntectonic sequences were deposited in the San Vicente Formation during this inversional activity, being delimited at the base and top by progressive discordances. These sequences were deposited in the hangingand footwall of the inverted faults. In the eastern margin of the Southern Altiplano Basin, the deformation front continued to prograde to the west, depositing syntectonical sequences in the San Vicente Formation. The margins of the Southern Altiplano Basin were uplifted by tectonic activity, at the same time the basin witnessed high subsidence. The Southern Altiplano Basin is between 7 to 10 Ma tectonically inactive.