Key Laboratory of Geological Process and Mineral Resource Survey of Guangdong Province

Guangzhou, China

Key Laboratory of Geological Process and Mineral Resource Survey of Guangdong Province

Guangzhou, China
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An Y.,Anhui University | An Y.,Key Laboratory of Geological Process and Mineral Resource Survey of Guangdong Province | Li X.,Key Laboratory of Geological Process and Mineral Resource Survey of Guangdong Province | Li X.,Sun Yat Sen University | And 7 more authors.
Yanshi Xuebao/Acta Petrologica Sinica | Year: 2017

The Pozaiying deposit is one of most significant deposits in southwestern section of Qinzhou-Hangzhou Belt. The deposit is of the central planar alteration type and ore bodies are composed of three types' veins of A, B and D. In order to deepen the understanding of the mineralization process, some pyrite samples among ore veins from Pozaiying deposits were retrieved to characterize the signature of microfabrics with SEM, XRD and Raman spectral analysis for reshaping the metallogenic process of thermodynamics and kinetics. The results of SEM show three points as follows: (1) pyrite with droplets-shaped microcrystalline on crystal face among A vein is rare, hypautomorphic-xenomorphic, and about 100 ∼200μm; (2) pyrite with oval-layered microcrystalline on crystal face among B vein is common, euhedral-hypautomorphic, and about 500 ∼ 1000μm; (3) pyrite with angular and linear microcrystalline on cubic crystal face among D vein is about 10 ∼ 20mm. Our analysis indicates that the size of pyrite particle increases and microcrystalline on crystal faces becomes more regular from A vein to B vein to D vein, which reveals that the crystallization rate of pyrite may be reduced and the crystallization environment tends to be stable from early to ate period. The results of XRD shows an obvious difference that the main peak is 28. 5° and the secondary peak is 37. 1° in A vein, and respectively, are 37. 1° and 33. 1° in B vein, and are 33. 1° and 56. 3° D vein were detected, although the outline of the curves look similar between each sample of pyrite in different veins. All the above evidences indicate that pyrite in A vein may consist of an octahedron enclosed with (111) crystal plane and pentagonal dodecahedron enclosed with (210) crystal plane, by which, we speculate at its formation temperatures should be higher than 3001. Samples in B vein should be made up of pentagonal dodecahedron enclosed with (2 10) crystal plane and cubic enclosed with (111) crystal plane, and its formation temperatures should be between 200 ∼300°C or higher. Samples in D vein mainly consist of cubic enclosed with (10 0) crystal plane and its formation temperatures should be less than 200°C. The Raman spectrum reveals that all the parameter of samples in A vein νEg = 348. 0 ∼ 350. 7cm-1, νAg = 385. 2 ∼ 386. 5cm-1 and νTg = 441. 9 ∼ 422. 8cm-1, compare with them, the corresponding value of B vein and D vein were shifting to low frequencies by 2 ∼6cm and 5 ∼ 14cm-1; the scattering intensity of sample in A vein IEg =388.8∼745.5, IAg =1532.8 ∼2071.8 and ITg =238.9∼254.4, while the corresponding scattering intensity of B vein and D vein are enhanced significantly. Comparative analysis shows that the characteristics of Raman spectrum shift towards low-frequencies from A to B to D indicating that the growth pressure of the three types of pyrite decreases gradually and the scattering ntensity ncreases from A to B to D also ndicates that the formation temperatures between the three gradually decreases. Thus, our studies suggest that the formation temperature and pressure of the vein from early to ate decrease in Pozaiying molybdenum deposit.


An Y.-F.,Sun Yat Sen University | An Y.-F.,Key Laboratory of Geological Process and Mineral Resource Survey of Guangdong Province | Zhong L.-L.,Sun Yat Sen University | Zhong L.-L.,Key Laboratory of Geological Process and Mineral Resource Survey of Guangdong Province | And 5 more authors.
Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis | Year: 2014

Some granite samples from Pozaiying molybdenite deposits in the west of Guangdong were retrieved to characterize the spectral signature of XRD, FT-NIR and Raman. The results show that compared to the Porphyry granite and granite in the far zone, the signal of XRD and Raman of granite in near zone is weaker while the signal of FT-NIR is stronger. The authors' analyses indicate that the FWHM of quartz (101) peak in XRD, Sericite peak (4 529 cm-1) in FT-NIR and quartz peak in Raman shift from the latter are higher than those of former two. Those spectral characteristics indicate that compared with other samples, the content of petrogenetic mineral in samples from near zone is lower while the content of alteration mineral is higher, and its crystallinity and crystallization temperatures are both lower. The authors' studies suggest that there may be an alteration zone, embracing the granite-porphyry, which comprised low temperature mineral. and the quartz-porphyry which related to molybdenite mineralization belongs to the zone near Guanshanzhang mass.

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