TY  - JOUR
ID  - epprod382
UR  - http://dx.doi.org/10.1016/j.chemgeo.2006.03.010
IS  - 3-4
A1  - Kamenetsky, VS
A1  - Elburg, MA
A1  - Arculus, RJ
A1  - Thomas, R
Y1  - 2006/10//
N2  - Unravelling the origin of different components contributing to subduction-related magmas is a prerequisite to understanding the sources and processes involved in their origins. Mafic, high-Ca subduction-related magmas from geographically-diverse areas (Indonesia, Solomon Islands, Kamchatka, Valu Fa Ridge) contain two populations of olivine crystals, of which only the high-Ca population (CaO = 0.3-0.5 wt.%) crystallized from the melt that dominantly contributed to the whole rock composition. Forsterite-rich (Fo90-94), low-Ca (CaO < 0.15 wt.%), high-Ni (NiO > 0.3 wt.%) olivine crystals, which constitute 16-37 vol.% of total olivine population, are generally interpreted as mantle or lithospheric xenocrysts. However, in these samples, the olivine shape and chemical zoning, the composition of included minerals (orthopyroxene, clinoenstatite and Cr-spinel) and presence of melt inclusions, are indications that these crystals are phenocrysts from a mafic magma with high silica and low calcium contents. The coexistence of contrasting magmas (mafic high-Ca silica-poor versus low-Ca silica-rich) within a number of arc systems and their mixing may not be a rare event, and should be taken into account when developing models of arc petrogenesis.
JF  - Chemical Geology
VL  - 233
KW  - Island-arc magmas; Picrites; Olivine; Clinoenstatite; Magmatic inclusions; Xenocrysts; Mantle
TI  - Magmatic origin of low-Ca olivine in subduction-related magmas: Co-existence of contrasting magmas
SP  - 346
AV  - restricted
EP  - 357
ER  -