Journal
GONDWANA RESEARCH
Volume 16, Issue 2, Pages 227-242Publisher
ELSEVIER
DOI: 10.1016/j.gr.2009.04.004
Keywords
Ore-bearing porphyry; Geochemistry; Sr-Nd isotopes; Baogutu porphyry copper belt; Darbut arc; Western Junggar
Categories
Ask authors/readers for more resources
The Baogutu porphyry copper belt lies in the Darbut transitional island arc of the western Junggar, in the western section of the Central Asian Orogenic Belt in NW China. Our new petrographic results for the ore-bearing porphyry stocks in the Baogutu porphyry copper belt recognize them as diorite porphyry stocks rather than the granodiorite porphyry stocks as previously identified. The copper mineralization is hosted in the diorite, diorite porphyries and related breccias of the diorite porphyry stocks. Geochemical data indicate that the ore-bearing porphyries have a predominantly intermediate composition with a transitional character from tholeiite to calc-alkaline, and are enriched in large ion lithophile elements (LILE) and depleted in high field strength elements (HFSE) with a clear negative Nb anomaly. REE patterns show distinct enrichments in LREE relative to HREE. The rocks also exhibit high initial epsilon(Nd)(t) (+2.7 to +6.3) ratios and low initial Sr-87/Sr-86 values (0.70359-0.70397). Many samples are chemically similar to adakites (e. g. Yb< 1.9 ppm, Y< 18 ppm, Sr/Yb>20, Sr-87/Sr-86<0.7045). These data are consistent with a transitional island arc from immature arc to mature arc and suggest that the ore-bearing porphyry system was derived from the partial melting of multiple sources including oceanic crust and a subduction-modified mantle wedge, with melts undergoing significant crystal fractionation during convergence between the paleo-Junggar ocean and the Darbut arc. (c) 2009 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available