Tropical weathering has important linkages to global biogeochemistry and landscape evolution in the East African rift. We disentangle the influences of climate and terrestrial vegetation on chemical weathering intensity and erosion at Lake Malawi using a long sediment record. Fossil pollen, microcharcoal, particle size, and mineralogy data affirm that the detrital clays accumulating in deep water within the lake are controlled by feedbacks between climate and hinterland forest composition. Particle-size patterns are also best explained by vegetation, through feedbacks with lake levels, wildfires, and erosion. We develop a new source-to-sink framework that links lacustrine sedimentation to hinterland vegetation in tropical rifts. Our analysis suggests that climate-vegetation interactions and their coupling to weathering/erosion could threaten future food security and has implications for accurately predicting petroleum play elements in continental rift basins.
Bibliographical noteFunding Information:
We thank the U.S. National Science Foundation (grant EAR-0602404), the U.S. Geological Survey, and the American Chemical Society–Petroleum Research Fund program (54376-DNI8) for funding. Thanks to W. Benzel for analytical assistance, and LacCore at the University of Minnesota for core curation. We also thank the anonymous reviewers who helped improve this manuscript.
© 2017 Geological Society of America.
Copyright 2017 Elsevier B.V., All rights reserved.
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