Contamination of mafic magma by partial melting of dolomitic xenoliths
Details
Serval ID
serval:BIB_CFB00B3AB65E
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Contamination of mafic magma by partial melting of dolomitic xenoliths
Journal
Terra Nova
ISSN-L
0954-4879
Publication state
Published
Issued date
2001
Peer-reviewed
Oui
Volume
13
Pages
197-202
Language
english
Abstract
Mg-skarns enclosed in dunite cumulates of the Neo-Proterozoic
loko-Dovyren intrusion (northern Baikal region, Russia) can be traced to
silica-poor dolomitic host rock layers. The dominant minerals of the
skarns are brucite (pseudomorph after periclase), forsterite and Cr-poor
spinel. Rapid heating of quartz-poor dolomitic xenoliths led to the
formation of minor olivine, followed by the breakdown of dolomite to
calcite and periclase. Xenoliths were partially melted upon further
heating resulting in a calcite melt. This low-density melt was
quantitatively squeezed out, mixed with the surrounding mafic magma and
left behind periclase and olivine. This caused the crystallization of
new olivine with elevated CaO contents in zones above skarn-bearing
horizons. Mixing of calcite melt with the surrounding mafic magma also
resulted in the crystallization of Cats-rich clinopyroxene instead of
plagioclase. The mineralogy of contaminated dunite cumulates is
consistent with assimilation of approximately 4wt% CaO by the
loko-Dovyren mafic magma.
loko-Dovyren intrusion (northern Baikal region, Russia) can be traced to
silica-poor dolomitic host rock layers. The dominant minerals of the
skarns are brucite (pseudomorph after periclase), forsterite and Cr-poor
spinel. Rapid heating of quartz-poor dolomitic xenoliths led to the
formation of minor olivine, followed by the breakdown of dolomite to
calcite and periclase. Xenoliths were partially melted upon further
heating resulting in a calcite melt. This low-density melt was
quantitatively squeezed out, mixed with the surrounding mafic magma and
left behind periclase and olivine. This caused the crystallization of
new olivine with elevated CaO contents in zones above skarn-bearing
horizons. Mixing of calcite melt with the surrounding mafic magma also
resulted in the crystallization of Cats-rich clinopyroxene instead of
plagioclase. The mineralogy of contaminated dunite cumulates is
consistent with assimilation of approximately 4wt% CaO by the
loko-Dovyren mafic magma.
Create date
02/10/2012 20:34
Last modification date
20/08/2019 16:50