10.6084/m9.figshare.3453908.v1
Sara Mana
Sara
Mana
Tanya Furman
Tanya
Furman
Brent D. Turrin
Brent D.
Turrin
Mark D. Feigenson
Mark D.
Feigenson
Carl C. Swisher III
Carl
C. Swisher III
Magmatic activity across the East African North Tanzanian Divergence Zone
Geological Society of London
2016
garnet content
tectonic scenarios
North Tanzanian Divergence Zone
Magmatic activity
REE data
metasomatic events
Rift System
involvement
North Tanzanian Divergence Zone Volcanism
rifting event
2.3 Ma
NTD
metasomatized subcontinental lithospheric mantle
geochemical variations
data show
Ar
Geology
2016-06-21 11:45:40
Dataset
https://geolsoc.figshare.com/articles/dataset/Magmatic_activity_across_the_East_African_North_Tanzanian_Divergence_Zone/3453908
<p>Volcanism across the North Tanzanian Divergence Zone (NTD), part of the East African Rift System, occurred episodically from
the late Miocene to Recent. Here, we present a summary of previously published K–Ar and <sup>40</sup>Ar/<sup>39</sup>Ar ages, new <sup>40</sup>Ar/<sup>39</sup>Ar ages, and geochemical and Sr–Nd–Pb isotopic analyses on samples collected from several volcanoes distributed across the
NTD: Burko, Monduli, Tarosero, Ketumbeine, Gelai, Kerimasi and Meru. The locus of volcanism over this period progressed from
the southwestern portion of the NTD to the north and east, with a main pulse occurring at about 2.3 Ma, possibly marking the
inception of a main rifting event. We model the source of the NTD volcanic rocks as a metasomatized subcontinental lithospheric
mantle that includes minor and variable amounts of garnet and amphibole. REE data indicate variations in residual garnet content,
consistent with varying depth of melt separation. Radiogenic isotopic data show systematic variations requiring the involvement
of up to three components. Two alternative but not exclusive tectonic scenarios are proposed: one requiring the involvement
of contributions from recent plume-related fluids, and one explaining the observed geochemical variations by melting of a
lithosphere layered by multiple metasomatic events.
</p>