Dissertation/Thesis Abstract

Diffusion of oxygen and lithium isotopes at a contact between the Bushveld Complex and metasedimentary rock: Implications for the timescale of Phepane Dome diapirism
by Potter, Rachel H., M.S., University of Maryland, College Park, 2009, 126; 1465548
Abstract (Summary)

Within the Eastern Lobe of the Bushveld Complex, the Phepane Dome is a circular structure of metasedimentary rock hypothesized to have formed as a wallrock diapir. To constrain the duration of Phepane Dome formation using one-dimensional diffusion models of oxygen and lithium exchange between the Bushveld Complex and the Phepane Dome, samples taken across the contact between these two lithologies were measured for their O and Li isotopic compositions and Li concentrations. Models of O and Li diffusion through melt and through aqueous fluid were fit to the data, resulting in a diffusive distance of 1.0 m for oxygen and 14.1 m for lithium. Using experimentally constrained parameters for O and Li diffusion, a range of 2 kyrs to 2 Myrs was calculated from the diffusive distances. This is consistent with previous studies of the time for crystallization of the Bushveld Complex and a model of Phepane diapir development.

Indexing (document details)
Advisor: Penniston-Dorland, Sarah
Commitee: Farquhar, James, Rudnick, Roberta
School: University of Maryland, College Park
Department: Geology
School Location: United States -- Maryland
Source: MAI 47/06M, Masters Abstracts International
Subjects: Geology, Geochemistry
Keywords: Bushveld Complex, Diapirism, Diffusion, Lithium, Oxygen isotopes, Phepane Dome
Publication Number: 1465548
ISBN: 9781109220346