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The DRIAR Project: Dry-Rifting In the Albertine-Rhino Graben, Uganda
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  • D. Sarah Stamps,
  • Estella Atekwana,
  • Eliot Atekwana,
  • Suzan van der Lee,
  • Michael Taylor,
  • Andrew Katumwehe,
  • Rob Evans,
  • Fred Tugume,
  • Kevin Aanyu,
  • Stewart Fishwick,
  • Peter Barry,
  • Saemundur Halldorsson,
  • Folarin Kolawole,
  • Georg Rumpker,
  • Asenath Kwagalakwe,
  • Daniel Mongovin,
  • Hillary Mwongyera,
  • Igor Jose Eufrasio de Oliveira,
  • Esha Islam,
  • Richard Birungi,
  • Emmanuel Njinju
D. Sarah Stamps
Virginia Polytechnic Institute and State University

Corresponding Author:[email protected]

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Estella Atekwana
University of California Davis
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Eliot Atekwana
University of California Davis
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Suzan van der Lee
Northwestern Univ
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Michael Taylor
University of Kansas
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Andrew Katumwehe
Midwestern State University
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Rob Evans
Woods Hole Oceanographic Institution
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Fred Tugume
Geological Survey Department
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Kevin Aanyu
Department of Geology and Petroleum Studies, College of Natural Sciences, Makerere University
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Stewart Fishwick
University of Leicester
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Peter Barry
Woods Hole Oceanographic Institution
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Saemundur Halldorsson
SIO-UCSD
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Folarin Kolawole
BP America
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Georg Rumpker
Goethe University Frankfurt
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Asenath Kwagalakwe
Virginia Polytechnic Institute and State University
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Daniel Mongovin
University of Kansas
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Hillary Mwongyera
University of Kansas
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Igor Jose Eufrasio de Oliveira
Northwestern University
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Esha Islam
Virginia Polytechnic Institute and State University
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Richard Birungi
Midwestern State University
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Emmanuel Njinju
Virginia Polytechnic Institute and State University
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Abstract

Continental rifting is a critical component of the plate tectonic paradigm, and occurs in more than one mode, phase, or stage. While rifting is typically facilitated by abundant magmatism, some rifting is not. We aim to develop a better understanding of the fundamental processes associated with magma-poor (dry) rifting. Here, we provide an overview of the NSF-funded Dry Rifting In the Albertine-Rhino graben (DRIAR) project, Uganda. The project goal is to apply geophysical, geological, geochemical, and geodynamic techniques to investigate the Northern Western Branch of the East African Rift System in Uganda. We test three hypotheses: (1) in magma-rich rifts, strain is accommodated through lithospheric weakening from melt, (2) in magma-poor rifts, melt is present below the surface and weakens the lithosphere such that strain is accommodated during upper crustal extension, and (3) in magma-poor rifts, there is no melt at depth and strain is accommodated along pre-existing structures such as inherited compositional, structural, and rheological lithospheric heterogeneities. Observational methods in this project include: passive seismic to constrain lithospheric structure and asthenospheric flow patterns; gravity to constrain variations in crustal and lithospheric thickness; magnetics to constrain the thermal structure of the upper crust; magnetotellurics to constrain lithospheric thickness and the presence of melt; GNSS to constrain surface motions, extension rates, and help characterize mantle flow; geologic mapping to document the geometry and kinematics of active faults; seismic reflection analyses of intra-rift faults to document temporal strain migration; geochemistry to identify and quantify mantle-derived fluids in hot springs and soil gases; and geodynamic modeling to develop new models of magma-poor rifting processes. Fieldwork will begin in January 2022 and the first DRIAR field school is planned for summer 2022. Geodynamic modeling work and morphometric analyses are already underway.