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Origin of the Powai ankaramite, and the composition, P-T conditions of equilibration and evolution of the primary magmas of the Deccan tholeiites

DSpace at IIT Bombay

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Title Origin of the Powai ankaramite, and the composition, P-T conditions of equilibration and evolution of the primary magmas of the Deccan tholeiites
 
Creator CHATTERJEE, N
SHETH, H
 
Subject PARTIAL MELT COMPOSITIONS
FLOOD-BASALT VOLCANISM
MIDOCEAN RIDGE BASALTS
DEPLETED PERIDOTITE
MANTLE SOURCES
TRACE-ELEMENT
WESTERN INDIA
GEOCHEMICAL STRATIGRAPHY
EXPERIMENTAL PETROLOGY
CRUSTAL CONTAMINATION
Deccan Traps
Ankaramite
Tholeiite
Primary magma
Thermobarometry
Mantle melting
 
Description The Powai ankaramite flow from Mumbai, western Deccan Traps, contains abundant crystals of augite (En(59-47)Fs(10-14)Wo(27-42), 22-40 modal %, 3-5 mm) and olivine (Fo(84-74), 11-16 modal %, 1-2 mm), and minor plagioclase (An(71), similar to 0.5 mm) embedded in a fine-grained matrix. Minor orthopyroxene (En(79-77)Fs(16-19)Wo(5-4)) with irregular and embayed margins is mantled by thick augite overgrowth rims. The Fe-Mg distribution between the large crystals and bulk rock shows disequilibrium, indicating that the ankaramite is a cumulate rock. The ankaramite probably formed by the intrusion of tholeiitic melt into a cumulate pile with olivine, augite, and orthopyroxene left by the crystallization of earlier magmas, resulting in orthopyroxene dissolution and subsequent precipitation of augite. Olivine-hosted melt inclusions and melts represented by the ankaramite groundmass and some associated tholeiitic dikes are multiply saturated with olivine + plagioclase + clinopyroxene at
 
Publisher SPRINGER
 
Date 2016-01-14T10:58:08Z
2016-01-14T10:58:08Z
2015
 
Type Article
 
Identifier CONTRIBUTIONS TO MINERALOGY AND PETROLOGY, 169(3)
0010-7999
1432-0967
http://dx.doi.org/10.1007/s00410-015-1125-8
http://dspace.library.iitb.ac.in/jspui/handle/100/17417
 
Language en