Zhu Q.-Q.,Chinese Academy of Geological Sciences |
Zhu Q.-Q.,MRL Key Laboratory of Metallogeny and Mineral Assessment |
Xie G.-Q.,Chinese Academy of Geological Sciences |
Xie G.-Q.,MRL Key Laboratory of Metallogeny and Mineral Assessment |
And 4 more authors.
Geology in China | Year: 2014
This paper presents in situ microanalysis data of garnets form the Jinshandian iron skarn deposit, Hubei Province. Studies show that garnets from the Jinshandian iron skarn deposit can be divided into two stages, i.e., early Al-rich garnets mainly with grossular and grossular-andradite series, and late Fe-rich garnets dominated by andradite, with the variation implying the increase of the fluid oxidation. Compared with the early garnets, the late stage are rich in large ion lithophile elements and high field strength elements as well as REE. Early grossular shows typical HREE-enrichment and LREE-depletion features, while smaller fractionation between HREE and LREE characterizes grossular-andradite series. Total REE content, SEu and HREE/LREE fractionation degrees of Fe-rich garnet samples vary from sample to sample, and are even different in different parts of a single garnet grain, suggesting that the process of its formation was not stable, and fluid properties changed greatly, possibly due to the addition of evaporate minerals from the wall rocks. Garnet in situ microanalysis research also suggests that the evaporate minerals added into the Jinshandian skarn system had features of heterogeneity and periodicity.
Zhu Q.Q.,Chinese Academy of Geological Sciences |
Xie G.Q.,Chinese Academy of Geological Sciences |
Xie G.Q.,MRL Key Laboratory of Metallogeny and Mineral Assessment |
Jiang Z.S.,Chinese Academy of Geological Sciences |
And 2 more authors.
Acta Petrologica Sinica | Year: 2014
U-Pb ages and trace element compositions of two types of hydrothermal titanite from the Jinshandian iron skarn deposit, southeastern Hubei Province, have been successfully analyzed by laser ablation inductively coupled plasma mass spectrometry (LAICPMS). Compared to titanite from diopside and scapolite skarn, hydrothermal titanite from albite altered quartz diorite are characterized by lower REE, δ5Eu values, Th/U, Lu/Hf ratios and higher Hf component and LREE/HREE, suggesting they formed under different environment. The amount of Ti in the hydrothermal titanite probably resulted from the decomposition of Ti-bearing accessory minerals such as titanite, ilmenite and rutile from magma during the alteration. In situ U-Pb dating of titanite by LA-ICPMS shows that titanite from diopside + anhydrite + magnenite and scapolite + anhydrite + magnenite skarn sample yield a weighted mean 206Pb/ 238 U ages of 129. 5 ± 1. IMa and 130. 4 ± 1. 2Ma, respectively, while that of albite altered quartz diorite give 127 ± 12Ma. These ages might be considered to be the age of mineralization, consistent with crystallization age of phlogopite got by previous researcher, suggesting that Jinshandian iron skarn deposit formed associate with lithospheric thinning, similar to other skarn Cu-Fe deposits in the southeastern Hubei Province. Our study shows that in situ U-Pb dating of hydrothermal titanite by LA-ICPMS is a robust method for getting precise formation age of skarn iron deposit.
Li R.,Development of Geological and Research Center |
Zhu Q.,Chinese Academy of Geological Sciences |
Hou K.,Chinese Academy of Geological Sciences |
Hou K.,MRL Key Laboratory of Metallogeny and Mineral Assessment |
And 2 more authors.
Acta Petrologica Sinica | Year: 2012
The Jinniu basin located in Southeast Hubei ore cluster, is one of volcanic basins of the Middle-Lower Yangtze Reaches metallogenic belt. Compared with Nanjing-Wuhu basin and Lujing-Zongyang basin, new mineral deposits have not been discovered in the Jinniu basin in recent years. To date, no geochronological or geochemical studies have been undertaken to sub-volcanic rocks in the Jinniu basin. The zircon U-Pb dating of rhyolite porphyry yielded an age of 128 ± IMa in central of the Wubaihao area from Jinniu basin, its( 176Hf/177Hf)i and εHf(t) values are ranging from 0. 28247 to 0. 28262 and -2. 5 to -7. 7, respectively. The zircon U-Pb dating of granite porphyry yielded an age of 129 ± IMa, its (176Hf/177Hf)i and εHf(t) values are ranging from 0. 28239 to 0. 28259 and - 3. 6 to -10. 7. The ages of granite porphyry and rhyolite porphyry are 129 ∼ 128Ma, suggesting that they were developed during Early Cretaceous. The granite porphyry and rhyolite porphyry from Jingniu basin are derived from mixture enriched mantle and crustal. Both volcanic rocks and sub-volcanic rocks in the Jinniu basin were coeval with those in the Luzong, and Ningwu basins in the Middle-Lower Yangtze River Belt. The hydrothermal gold deposits and porphyry iron deposits have been played attention in the Jinniu Basin in the future.