Premium
Geochronology, Geochemistry and Petrogenesis of Diabase Dyke Swarms in East Tianshan, Xinjiang, NW China
Author(s) -
Zuoheng ZHANG,
Fengmei CHAI,
Tuanhua WANG,
Yanbo CHENG,
Lingang XU,
Shunda YUAN
Publication year - 2012
Publication title -
acta geologica sinica ‐ english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 61
eISSN - 1755-6724
pISSN - 1000-9515
DOI - 10.1111/1755-6724.12018
Subject(s) - petrogenesis , geology , geochemistry , zircon , magmatism , mantle (geology) , geochronology , asthenosphere , rift , permian , lithosphere , partial melting , petrology , tectonics , geomorphology , seismology , structural basin
Diabase dyke swarms are widespread in the East Tianshan and Beishan regions. LA‐ICP‐MS zircon U‐Pb ages of these diabase vary from 305 Ma to 278 Ma, showing that these dykes were formed during Late Carboniferous‐Early Permian magmatism. All diabase samples are subalkali calc‐alkali, characterized by slight LREE and LILEs enrichment, and weak negative Ti, Nb and Ta anomalies. The diabase samples have positive ε Nd ( t ) values (>+3), high Sr isotopic compositions (initial 87 Sr/ 86 Sr values=0.7030–0.7097), and large variation of Pb isotopic compositions, indicating they were derived from a deplete mantle source. Regional geology and geochemistry evidences indicate that these diabase dyke swarms were generated in a lithosphere extensional setting and had the same magma sources. Initial magmas may be a mixture of depleted asthenosphere mantle and enriched lithospheric mantle during rapid magma ascending.