3D computational shape- and cooling process-modeling of magmatic intrusion and its implication for genesis and exploration of intrusion-related ore deposits: An example from the Yueshan intrusion in Anqing, China

Computational modeling is a promising method for investigating the spatial, topographic characteristics and geodynamic processes of complex geological systems involving irregularly-shaped geological bodies. The ore deposits in the Anqing orefield are of skarn type and show close association with the cooling process of the irregularly shaped intrusion, Yueshan intrusion. In this paper, we apply the methods of 3D geometric shape and geodynamic process modeling to investigate the Yueshan intrusion-related mineralization systems in the Anqing orefield, China. We have developed a C++ program to transform a 3D geometric solid model to the 3D geodynamic discrete model for simulating the geodynamic process of irregular geological bodies. The 3D geometric shape modeling is used to simulate the spatial and topographic features of the Yueshan intrusion and its association with the Cu orebodies, while the geodynamic modeling is used to reconstruct the cooling process of the intrusion and to investigate the controlling mechanism of intrusion on orebodies. The modeling results demonstrate that the orebodies are located in some specific places where the intrusion boundary is concave and in contact with its carbonate rocks. These mineralized zones are also the high dilation zones where the fluids from different sources are focused, as a result of the coupled mechano-thermo-hydrological (MTH) processes during the syn-extensional cooling of the intrusion. The modeling results provide a useful guide for selecting further exploration targets, which has led to the discovery of a new mineralization zone in dilation zones close to the intrusion contact. ► 3D modeling is used to reveal structure and dynamic process of an intrusion-related ore system. ► Ore locations are found to be associated with geometric shape of the intrusion. ► Temporal–spatial variation of temperature, fluid flow and strain in model controls ore location. ► Exploration tests show modeling to be effective for selecting targets of hidden orebodies.