TY - JOUR
T1 - Geochronologic-petrochemical studies of the Hongshishan mafic-ultramafic intrusion, Beishan area, Xinjiang (NW China)
T2 - Petrogenesis and tectonic implications
AU - Su, Benxun
AU - Qin, Kezhang
AU - Sakyi, Patrick Asamoah
AU - Tang, Dongmei
AU - Liu, Pingping
AU - Malaviarachchi, Sanjeewa P.K.
AU - Xiao, Qinghua
AU - Sun, He
PY - 2012/2/1
Y1 - 2012/2/1
N2 - The Hongshishan mafic-ultramafic intrusion (SIMS zircon U-Pb age 286.4 ± 2.8Ma) consists of dunite, clinopyroxene peridotite, troctolite, and gabbro. Major elements display systematic correlations. Trace elements have identical distribution patterns, including flat rare-earth element (REE) patterns with positive Eu anomalies and enrichments in large ion lithophile elements (LILE) but depletions in Nb and Ta, indicating fractional crystallization as a key factor in magmatic evolution. Petrologic and geochemical variations in drill core samples demonstrate that minor assimilation and progressive magma injections were closely associated with Ni-Cu mineralization. Mass balance estimates and Sr-Nd isotopes reveal that the Hongshishan parental magmas were high-Mg and low-Ti tholeiitic basalts and were derived from a lithospheric mantle source that had been modified by subducted slab metasomatism before partial melting. Southward subduction of the Palaeo-Tianshan-Junggar Ocean is further constrained by a compilation of inferred, subduction-induced modifications of mantle sources in mafic-ultramafic intrusions distributed in the eastern Tianshan-Beishan area. Integrating the regional positive εNd(t) granites, high-Mg and low-Ti basaltic magmas (mafic-ultramafic intrusions), and slightly later high-Ti basalts in NW China suggests that their petrogenesis could be attributed to Permian mantle plume activities.
AB - The Hongshishan mafic-ultramafic intrusion (SIMS zircon U-Pb age 286.4 ± 2.8Ma) consists of dunite, clinopyroxene peridotite, troctolite, and gabbro. Major elements display systematic correlations. Trace elements have identical distribution patterns, including flat rare-earth element (REE) patterns with positive Eu anomalies and enrichments in large ion lithophile elements (LILE) but depletions in Nb and Ta, indicating fractional crystallization as a key factor in magmatic evolution. Petrologic and geochemical variations in drill core samples demonstrate that minor assimilation and progressive magma injections were closely associated with Ni-Cu mineralization. Mass balance estimates and Sr-Nd isotopes reveal that the Hongshishan parental magmas were high-Mg and low-Ti tholeiitic basalts and were derived from a lithospheric mantle source that had been modified by subducted slab metasomatism before partial melting. Southward subduction of the Palaeo-Tianshan-Junggar Ocean is further constrained by a compilation of inferred, subduction-induced modifications of mantle sources in mafic-ultramafic intrusions distributed in the eastern Tianshan-Beishan area. Integrating the regional positive εNd(t) granites, high-Mg and low-Ti basaltic magmas (mafic-ultramafic intrusions), and slightly later high-Ti basalts in NW China suggests that their petrogenesis could be attributed to Permian mantle plume activities.
KW - Beishan
KW - eastern Tianshan
KW - fractional crystallization
KW - mafic-ultramafic intrusions
KW - mantle plume
UR - http://www.scopus.com/inward/record.url?scp=84863395324&partnerID=8YFLogxK
U2 - 10.1080/00206814.2010.543011
DO - 10.1080/00206814.2010.543011
M3 - Review article
AN - SCOPUS:84863395324
SN - 0020-6814
VL - 54
SP - 270
EP - 289
JO - International Geology Review
JF - International Geology Review
IS - 3
ER -