Stratigraphic Evolution of the Turkana Basin, Kenya and Ethiopia

肯尼亚和埃塞俄比亚的图尔卡纳盆地长期以来一直被认为是了解东非脊椎动物进化的关键地点。盆地的地质记录范围很广，包括白垩纪到全新世的夹层火山岩沉积。白垩纪到渐新世的历史尚未确定，但中新世到全新世的地层是众所周知的。它们记录了盆地的地层演化，从火山活动的局部沉积圈闭，到具有周期性湖相的综合河流盆地，最后到构造控制的裂谷盆地。过去十年对该盆地脊椎动物进化背景的研究极大地改变了我们对该区域历史和东非裂谷发展的看法。在为脊椎动物研究建立的地层和时间框架内，现在可以从火山、构造和沉积史的角度详细研究该区域的演化，并重新评估非洲这一地区的地质过程历史。我们打算把我们的注意力集中在图尔卡纳盆地未被研究的南部，并调查洛伊扬加拉尼地区，查尔比沙漠，在山上的暴露。库拉尔，以及苏古塔和凯里奥山谷。了解这些地区的地质记录对于评估盆地中主要地质事件的历史至关重要，包括盆地整合、水文连接和构造发展。

The Turkana Basin of Kenya and Ethiopia has long been known as a critical locality for the understanding of vertebrate evolution in East Africa. The geologic record of the basin spans a broad range, including Cretaceous through Holocene sediments with intercalated volcanics. Cretaceous through Oligocene history has yet to be characterized, but Miocene to Holocene strata are well- known. They record the stratigraphic evolution of the basin from a volcanically active, localized sediment trap, to an integrated fluvial basin with periodic lacustrine phases, and finally to a structurally-controlled rift basin. Research over the past decade on the context of vertebrate evolution in the basin has greatly altered our perspective on the history of the region and development of the East African Rift. Within the stratigraphic and temporal framework established for vertebrate studies, it is now possible to examine in detail the evolution of the region in terms of its volcanic, tectonic and sedimentary history, and to reevaluate the history of geologic processes in this portion of Africa. We intend to focus our attention on the unstudied southern portion of the Turkana Basin, and to investigate exposures in the Loiyengalani region, the Chalbi Desert, on Mt. Kulal, and in the Suguta and Kerio Valleys. Understanding of the geologic record from these regions is critical to evaluating the history of major geologic events in the basin, including basin integration, hydrographic connections, and structural development.