Multi-scale exploration of giant Qulong porphyry deposit in a collisional setting

With the increasing demand for copper resources, exploration methods based on the discovered porphyry Cu deposits (PCDs) to target concealed orebodies are of greater importance. Single parameter is no longer sufficiently effective against concealed deposit exploration, and different combinations of survey techniques are required. The Qulong porphyry Cu-Mo deposit is the largest collisional PCD found in China. Here we evaluated the relationship between variations in multiple parameters and alteration to define exploration footprints around the porphyry Cu centers. In order to improve the exploration efficiency and accuracy, we combined geophysical (magnetic susceptibility and resistivity) and popular geochemical exploration methods (i.e., short wavelength infrared spectroscopy-SWIR, portable X-ray fluorescence-pXRF, and indicator minerals) to the drill hole ZK005 of Qulong PCD in southern Tibet seeking for a firm interpretation. Four orebody indicators were established in study of Qulong deposit, which are: (i) the fluctuations of Ca/K, Mg/Fe, Sr/Ti, and Si/Al ratios, (ii) long wavelength white mica (2207-2214 nm) and short-wavelength chlorite (2247-2253 nm), (iii) sub-high magnetic susceptibility and (iv) low resistivity. Multi-scale prospecting methods can improve prospecting efficiency and narrow down the target area. Based on the local environment, selecting an appropriate combination of methods can improve exploration efficiency in the brownfields at a lower cost.