Olorgesailie, Kenya: A Million Years in the Life of a Rift Basin
Published:January 01, 2002
Anna K. Behrensmeyer, Richard Potts, Alan Deino, Peter Ditchfield, 2002. "Olorgesailie, Kenya: A Million Years in the Life of a Rift Basin", Sedimentation in Continental Rifts, Robin W. Renaut, Gail M. Ashley
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A sequence of lacustrine, volcaniclastic, and alluvial sedimentary deposits that record the past million years of the history in the Olorgesailie Basin, southern Kenya, provide an example of how tectonics, climate, and volcanism affect sedimentation in a rift valley. A series of radiometric dates on volcanic materials through this sequence permits relatively fine-scale calibration of the timing and duration of volcanic input to the depositional system, transgressive-regressive cycles of the lake, and intervals of valley cutting and filling. The Olorgesailie Formation, accumulated between 0.992 and 0.493 Ma, consists of relatively pure diatomites, reworked diatomites, primary volcanic and reworked volcaniclastic...
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Sedimentation in Continental Rifts
Continental rift basins have long been of interest to sedimentologists. Of all the terrestrial settings, rift basins typically provide the greatest accommodation space, and consequently have some of the longest records of continental sedimentation. These records are a product of a complex interplay between several factors that include geological structure and tectonic activity, volcanism, climate and its temporal variability, hydrology, biology and time. Sedimentation in Continental Rifts is a timely update on this exciting interdisciplinary field and presents new approaches and insights into tectonic and structural controls of sedimentation. Other topics included are lacustrine and fluviatile depositional environments and some lesser-known settings, such as springs, wetlands, and paleosols. Several papers consider the behavior of silica in rift lakes, particularly the roles of microorganisms in silica precipitation, whereas others examine the paleoenvironmental importance of freshwater carbonates. The contents of the volume show that sedimentological research in rift basins has progressed beyond basic facies description and general models, and is now focused on understanding the integrative effects of physical, chemical and biological processes in rifts.