Magmatic activity across the East African North Tanzanian Divergence Zone

Sara Mana, Tanya Furman, Brent D. Turrin, Mark D. Feigenson, Carl C. Swisher

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

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 40Ar/39Ar ages, new 40Ar/39Ar 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.

Original languageEnglish (US)
Pages (from-to)368-389
Number of pages22
JournalJournal of the Geological Society
Volume172
DOIs
StatePublished - Mar 19 2015

Fingerprint

divergence
volcanism
garnet
amphibole
rifting
lithosphere
volcanic rock
rare earth element
volcano
plume
melting
Miocene
melt
mantle
tectonics
fluid

All Science Journal Classification (ASJC) codes

  • Geology

Cite this

Mana, Sara ; Furman, Tanya ; Turrin, Brent D. ; Feigenson, Mark D. ; Swisher, Carl C. / Magmatic activity across the East African North Tanzanian Divergence Zone. In: Journal of the Geological Society. 2015 ; Vol. 172. pp. 368-389.
@article{585792e4733a486690e5430e7e0238b3,
title = "Magmatic activity across the East African North Tanzanian Divergence Zone",
abstract = "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 40Ar/39Ar ages, new 40Ar/39Ar 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.",
author = "Sara Mana and Tanya Furman and Turrin, {Brent D.} and Feigenson, {Mark D.} and Swisher, {Carl C.}",
year = "2015",
month = "3",
day = "19",
doi = "10.1144/jgs2014-072",
language = "English (US)",
volume = "172",
pages = "368--389",
journal = "Journal of the Geological Society",
issn = "0016-7649",
publisher = "Geological Society of London",

}

Magmatic activity across the East African North Tanzanian Divergence Zone. / Mana, Sara; Furman, Tanya; Turrin, Brent D.; Feigenson, Mark D.; Swisher, Carl C.

In: Journal of the Geological Society, Vol. 172, 19.03.2015, p. 368-389.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Magmatic activity across the East African North Tanzanian Divergence Zone

AU - Mana, Sara

AU - Furman, Tanya

AU - Turrin, Brent D.

AU - Feigenson, Mark D.

AU - Swisher, Carl C.

PY - 2015/3/19

Y1 - 2015/3/19

N2 - 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 40Ar/39Ar ages, new 40Ar/39Ar 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.

AB - 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 40Ar/39Ar ages, new 40Ar/39Ar 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.

UR - http://www.scopus.com/inward/record.url?scp=84928888312&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84928888312&partnerID=8YFLogxK

U2 - 10.1144/jgs2014-072

DO - 10.1144/jgs2014-072

M3 - Article

AN - SCOPUS:84928888312

VL - 172

SP - 368

EP - 389

JO - Journal of the Geological Society

JF - Journal of the Geological Society

SN - 0016-7649

ER -