3D Geological Modeling and New Understanding of Ore-controlling Tectonic Evolution of the Hongnipo Copper Deposit in Sichuan Province

doi:10.19657/j.geoscience.1000-8527.2020.03.16

Abstract

Abstract:

The Hongnipo copper deposit is a newly discovered large copper deposit in the Lala region of Sichuan Province, which contains reserves of 642,000 tons Cu with an average grade of 1.31%. Ore bodies are hosted in the Proterozoic fold basement Hekou Group and they have a temporal association with gabbro intrusions, the host rocks have a generally sodic alteration. In this paper, a three-dimensional model of ore bodies and strata is constructed using 224 boreholes and 23 cross sections in the study area. The 3D geological model can delineate fine geological structure of the deposit and explain the regional metallogenesis and tectonic evolution: the early N-S principal stress in the mining area caused the Hekou Group to form a large syncline near E-W direction. On the basis of the reconstruction of the early fold basement, an axial NNE synclinorium superposed on it was formed under the late E-W principal stress. After two-stage major tectonic movements, the area has formed an overlay frame of NNE-SSW and NWW-SEE structures. This study provides new ideas for the research of mineral deposits in the Lala region, and can provide scientific guidance for mineral exploration in the region.

Key words: the Hongnipo copper deposit, 3D geological modeling, tectonic evolution, structural grid, mineral exploration

CLC Number:

P618.41
P624

YANG Wangdong, GAO Fulei, WANG Gongwen, PANG Zhenshan, SHEN Heming, GONG Lingming, SHEN Hongtao, ZHANG Zhiqiang, LIU Xiaoning. 3D Geological Modeling and New Understanding of Ore-controlling Tectonic Evolution of the Hongnipo Copper Deposit in Sichuan Province[J]. Geoscience, 2020, 34(03): 598-608.

Figures/Tables 11

Fig.1 Simplified tectonic map showing the study area in the Yangze Block(a) and regional geological map of the Kangdian copper belt showing the distribution of the major Cu-Fe deposits(b) (modified after Chen and Zhou[14],2012 )

Fig.2 Regional geological map of the Lala ore camp

Fig.3 Stratigraphic column of the Hekou Group (after Chen Hui,unpublished data)

Fig.4 Geological map of the Hongnipo mining area(a) and profile of the prospect line P-3(b)

Fig.5 Distribution of the prospect lines on the surface(a) and 3D model of the surface and drill holes of the Hongnipo mining area(b)

Fig.6 3D model of geological bodies of the Hongnipo mining area

Fig.7 3D stratigraphic model of the Hongnipo mining area

Fig.8 Fine stratigraphic model of the Hongnipo mining area

Fig.9 3D model of AMT of the Lala ore camp

Fig.10 Tectonic frame of the Lala ore camp (modified after Zhou et al.[16],2008)

Fig.11 Stratigraphic evolution map of the Hongnipo area

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