Collaborative Research: Interactions Between Incipient Continental Rifting, Fluvial Systems, and Regional Climate in Southern Africa: The Okavango-Makgadikgadi Complex, Botswana

在非洲南部博茨瓦纳北部，奥卡万戈裂谷带（ORZ）和三角洲（OD）以及Makgadikgadi古巨湖（MPL）形成了构造活动、气候变化、沉积、植被、动物和人类影响在不同时空尺度上相互作用的动力系统。该奖项为ORZ-OD-MPL复合体中早期大陆裂谷、排水模式和新近纪/第四纪区域气候之间的相互作用和反馈的多学科研究提供了支持。目标是发展：(i) ORZ-OD的结构和构造模型；（ii） MPL的OD和填充阶段的演变年表；（iii） OD-MPL中复杂气候/植被的流域扩张和收缩的历史，以及ORZ、OD和MPL之间的联系或缺乏联系。首要的科学问题是：在ORZ-MPL系统中，构造与地表过程和气候的相互作用在多大程度上？中新世以来，这种相互作用涉及哪些反馈回路，以控制中非南部的环境演变？pi将结合地震学和沉积物岩心来观察裂谷断层和沉积物填充的几何形状。岩心的材料还将用于确定沉积物的来源和建立气候记录。来自岩心的这两个数据集将用于评估气候（通过可变侵蚀）与构造控制（河流迁移/捕获等）对沉积物供应的相对重要性。一个二维数值模型将整合这些数据，以探索盆地不对称和泥沙加载的影响，以及这些影响如何通过加载和应变局部化反馈到盆地发育中。

The Okavango Rift Zone (ORZ) and Delta (OD), and the Makgadikgadi Paleo-Megalake (MPL) form adynamic system in northern Botswana, southern Africa, where tectonic activity, climate change,sedimentation, vegetation, fauna, and human influences interact with each other at various spatial andtemporal scales. This award provides support for a multidisciplinary study of the interactions and feedbacks between incipient continental rifting, drainage patterns, and Neogene/Quaternary regional climate in the ORZ-OD-MPL complex. The objectives are to develop: (i) a structural and tectonic model of the ORZ-OD; (ii) chronologies for the evolution of the OD and infilling phases of the MPL; and (iii) histories of drainage basin expansions and contractions of the complex climate/vegetation in the OD-MPL, and the links, or lack thereof, between the ORZ, OD, and MPL. The overarching scientific question is: to what degree tectonics interacted with surface processes and climate in the ORZ-MPL system, and what feedback loops were involved in this interaction to control the environmental evolution of central southern Africa since the Miocene?The PIs will use a combination of seismology and sediment cores to look at the geometry of the rift faults and sediment fill. The material from the cores will additionally be used to establish provenance of the sediment and build climate records. These two datasets from the cores will be used to assess the relative importance of climate (via variable erosion) versus tectonic control (river migration/capture, etc.) on sediment supply. A 2D numerical model will integrate these data to explore the effect of basin asymmetry and sediment loading and how these feedback into basin development via loading and strain localization.