Cenozoic stratigraphy and structure in the Central Andes

安第斯山脉中部新生代地层和结构

• 批准号: 31844394
• 负责人: Dr. Cornelius Eji Uba
• 金额: --
• 依托单位: Institut für Geowissenschaften
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2006
• 资助国家: 德国
• 起止时间: 2005-12-31 至 2008-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/31844394?language=en
• 关键词: Cenozoic; stratigraphy; structure; Central; Andes

The central Andes, an integral part of the Cenozoic non-collisional orogenic belt parallel to the South American/Nazca plate boundary, is characterized by high elevation, high relief contrasts, and internally drained areas of low relief. The tectonic processes that led to the development of this orogen, which may have commenced during Cretaceous-Eocene time are well reflected in the foreland basin sequence in Bolivia. These sedimentary rocks represent a unique archive providing constraints on the geometry, rates, and history of orogenic and foreland basin evolution. Although thin-skinned horizontal shortening has been proposed as the main mechanism responsible for the Andean uplift in this region, the timing and magnitude of deformation and the effect of the pre-Mesozoic Izozog High on the Andean orogen make an unambiguous assessment of the tectonic evolution of the Andean foreland region difficult. These various uncertainties bring to question previous models for the late Cenozoic evolution of the southern central Andes. I propose in this project a multidisciplinary study that focuses to resolve the inconsistencies in (1) magnitude, timing, and geometry of the Andean deformation, (2) evolution of the Alto de Izozog structural high and its impact on foreland basin evolution, (3) Cenozoic sediment budget estimates and climate forcing parameters, thereby permitting reconstruction of the paleogeomophologic, paleoecologic, and tectonic evolution of the Andes. These objectives are best achieved through combining sedimentological, seismic stratigraphical, and geochronological analyses of the up to 7.5-km-thick Cenozoic strata in the Inter- and Subandean zones and the Chaco plain.

中部安第斯山脉是新生代非碰撞造山带的一个组成部分，平行于南美洲/纳斯卡板块边界，其特征是高海拔、高地形对比和低地形的内部排水区。导致该造山带发展的构造过程，可能始于白垩纪-始新世，在玻利维亚的前陆盆地序列中得到了很好的反映。这些沉积岩代表了一个独特的档案，提供了对造山和前陆盆地演化的几何形状、速率和历史的限制。虽然薄皮水平缩短已被提出的主要机制负责安第斯隆起在这一地区，变形的时间和规模和影响的前中生代伊佐佐格高安第斯造山带作出明确的评估安第斯前陆地区的构造演化困难。这些不同的不确定性使人们对安第斯山脉中南部晚新生代演化的先前模型提出了质疑。我在这个项目中提出了一个多学科的研究，重点解决的不一致性（1）规模，时间，和安第斯山脉变形的几何形状，（2）的Alto de Izozog构造高的演变及其对前陆盆地演化的影响，（3）新生代沉积物的预算估计和气候强迫参数，从而允许重建的古地貌，古生态和构造演化的安第斯山脉。通过对Inter-和Subandean带以及查科平原中厚达7.5公里的新生代地层进行沉积学、地震地层学和地质年代学分析，可以最好地实现这些目标。