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Magmatic evolution of the north Tanzanian divergence zone, East African rift system
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Mana, Sara. Magmatic evolution of the north Tanzanian divergence zone, East African rift system. Retrieved from https://doi.org/doi:10.7282/T3V40S7W

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TitleMagmatic evolution of the north Tanzanian divergence zone, East African rift system
NameMana, Sara (author); Swisher, Carl C. (chair); Carr, Michael J. (internal member); Feigenson, Mark D. (internal member); Furman, Tanya (outside member); Rutgers University; Graduate School - New Brunswick
Date Created2013
Other Date2013-10 (degree)
SubjectGeological Sciences, Rifts (Geology)--Tanzania, Magmatism--Tanzania
Extentxii, 139 p. : ill.
DescriptionMy study focuses on the magmatic evolution of the North Tanzanian Divergence zone (NTD). Using high precision 40Ar/39Ar geochronology I identify stages of magmatic activity and episodes of progressive magma migration. The newly developed temporal framework combined with elemental and isotopic geochemistry allows me to understand how the melting process has changed during the spatial and temporal evolution of the NTD. I use the abundances of key trace elements to identify the source mineralogy; including rare earth element (REE) modeling to constrain depths of melt separation. In addition, I employ radiogenic Sr-Nd-Pb isotope ratios to identify possible contributions from different mantle and crustal components. The NTD represents an example of an early stage continental rifting where lithospheric melts are generated during the interaction of a mantle plume and a heterogeneous metasomatized lithosphere. Melting occurs in the garnet stability zone. The first melt produced derives from fusible amphibole rich veins. Through the NTD rifting development, melting conditions change to generate alkali basalts with systematically different isotopic signatures. This episode of magmatism consists of an intense pulse, related to the inception of rifting, and characterized by melt separation occurring at shallower depths. The observed chemical signature can be explained either with the involvement of contributions from plume related fluids, or by melting of layered lithosphere. Subsequent volcanism has features consistent with mixing between the first two events. Through time we observe an eastwards migration of the magmatic activity consistent with the hypothesis of a fixed mantle plume and an overall westward migration of the African plate.
NotePh.D.
NoteIncludes bibliographical references
NoteIncludes vita
Noteby Sara Mana
Genretheses, ETD doctoral
Persistent URLhttps://doi.org/doi:10.7282/T3V40S7W
Languageeng
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.
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