The role of crustal contamination in the formation of Ni-Cu sulfide deposits in Eastern Tianshan, Xinjiang, Northwest China: Evidence from trace element geochemistry, Re-Os, Sr-Nd, zircon Hf-O, and sulfur isotopes

详细信息	查看全文 | 推荐本文 |

• 作者：Dong-Mei Tang^a ; ^{tdm@mail.iggcas.ac.cn} ; Ke-Zhang Qin^a ; ^{kzq@mail.iggcas.ac.cn} ; He Sun^a ; ^b ; Ben-Xun Su^a ; Qing-Hua Xiao^a
• 关键词：Eastern Tianshan ; Ni&ndash ; Cu sulfide deposits ; Re&ndash ; Os and S geochemistry ; Source characteristics ; Crustal contamination
• 刊名：Journal of Asian Earth Sciences
• 出版年：2012
• 期刊代码：40_13679120
• 类别：ear
• 出版时间：30 April, 2012
• 卷：49
• 期：Complete
• 页码：145-160
• 文件大小：2201 K

摘要

Tulaergen, Xiangshan, Huangshan, Tianyu, and Baishiquan magmatic Ni-Cu sulfide deposits, which are all located in the eastern part of the Central Asian Orogenic Belt, and associated with small mafic-ultramafic intrusions with high-grade Cu and Ni orebodies have similar ages of formation. Their magma sources are MORB-like and OIB-like depleted mantle. Modeling calculations of Sr-Nd and zircon Hf isotopic data show that about 10-15%of oceanic slab components are added into the source of Baishiquan and Tianyu intrusions, but only less than 5%are in the three other intrusions. The higher degree of subduction metasomatism in the Baishiquan and Tianyu magma sources is likely the result of the Paleozoic multiple-stage subduction. Moreover, the relative enrichment of LILE, depletion of HFSE, and lower Ce/Pb ratios indicate that these intrusions experienced crustal contaminations. The effects of crustal contamination are also identified in the magmatic sulfide deposits by the higher zircon 未¹⁸O, higher sulfide 纬Os, and 未³⁴S values observed. We propose a two-stage crustal contamination model of the Tulaergen, Xiangshan, Tianyu, and Baishiquan intrusions. However, the Huangshan intrusion, which has the highest degree of crustal contamination, likely experienced only single-stage upper crustal contamination (鈭?4.2%). The addition of crustal S appears to be directly related to triggering S saturation in these deposits. According to a simple S isotopic modeling calculation, 11%, 2.9%, 1.2%and 2.1%of the crustal sulfur addition into the parental magma would be required to form the Tianyu, Baishiquan, Xiangshan, and Tulaergen deposits, respectively.