TY - JOUR
T1 - Permian, rifting related fayalite syenite in the Panxi region, SW China
AU - Shellnutt, J. Gregory
AU - Zhou, Mei Fu
N1 - Funding Information:
This study is supported by grants from the Research Grant Council of Hong Kong, SAR (HKU7056/03P and HKU7057/05P). The authors would like to thank Professor Ma Yuxiao and Mr. Zhao Hao from Chengdu University of Science and Technology for their logistics support. We are grateful to Haixia Brother Industrial Company Limited for access to their quarry and Xiao Fu and Liang Qi for helping with XRF and ICP-MS analyses, respectively. The reviews by Drs. R.B. Frost, Andre Lalonde, an anonymous reviewer and Christina Yan Wang greatly improve an earlier draft of this paper.
PY - 2008/2
Y1 - 2008/2
N2 - Within the Panxi rift of the Permian Emeishan large igneous province (ELIP), SW China, a 20 km2 quartz-bearing fayalite syenitic pluton intrudes the 260 Ma Baima igneous complex (BIC). The fayalite syenite is dated using SHRIMP zircon U-Pb techniques at 252 ± 2.5 Ma. The Panxi fayalite syenite is mainly composed of alkali feldspar, ferroan augite, fayalite, quartz and Fe-Ti oxides and contains 61.8-63.7 wt.% SiO2, 5.0-7.3 wt.% Fe2O3t and 9.9-12.1 wt.% total alkalis, belonging to an A-type variety of ferroan alkalic metaluminous granitoids. The fayalite syenite displays positive Eu anomalies (Eu/Eu* = 0.9-8.9) and is enriched in LREE [(La/Yb)N =6.6-11.5]. The e{open}Nd values and (87Sr/86Sr)initial ratios of the fayalite syenite range from + 1.3 to + 1.9 and from 0.7035 to 0.7068, respectively. The fayalite syenite and the BIC had the same mantle source; however the 8 myr age gap between them suggests the fayalite syenite formed by remelting of underplated mafic magmas injected into the crust during ELIP magmatism. The ages of the fayalite syenite and BIC are coincident with two Permian mass extinction events and suggest that ELIP may have influenced both.
AB - Within the Panxi rift of the Permian Emeishan large igneous province (ELIP), SW China, a 20 km2 quartz-bearing fayalite syenitic pluton intrudes the 260 Ma Baima igneous complex (BIC). The fayalite syenite is dated using SHRIMP zircon U-Pb techniques at 252 ± 2.5 Ma. The Panxi fayalite syenite is mainly composed of alkali feldspar, ferroan augite, fayalite, quartz and Fe-Ti oxides and contains 61.8-63.7 wt.% SiO2, 5.0-7.3 wt.% Fe2O3t and 9.9-12.1 wt.% total alkalis, belonging to an A-type variety of ferroan alkalic metaluminous granitoids. The fayalite syenite displays positive Eu anomalies (Eu/Eu* = 0.9-8.9) and is enriched in LREE [(La/Yb)N =6.6-11.5]. The e{open}Nd values and (87Sr/86Sr)initial ratios of the fayalite syenite range from + 1.3 to + 1.9 and from 0.7035 to 0.7068, respectively. The fayalite syenite and the BIC had the same mantle source; however the 8 myr age gap between them suggests the fayalite syenite formed by remelting of underplated mafic magmas injected into the crust during ELIP magmatism. The ages of the fayalite syenite and BIC are coincident with two Permian mass extinction events and suggest that ELIP may have influenced both.
KW - A-type
KW - Emeishan large igneous province
KW - Fayalite
KW - SHRIMP zircon dating
KW - Syenite
UR - https://www.scopus.com/pages/publications/38949098133
UR - https://www.scopus.com/pages/publications/38949098133#tab=citedBy
U2 - 10.1016/j.lithos.2007.07.007
DO - 10.1016/j.lithos.2007.07.007
M3 - Article
AN - SCOPUS:38949098133
SN - 0024-4937
VL - 101
SP - 54
EP - 73
JO - Lithos
JF - Lithos
IS - 1-2
ER -