Aeromagnetic identification and modeling of mafic-ultramafic complexes in the Huangshan-Turaergen Ni-Cu metallogenic belt in NW China: Magmatic and metallogenic implications

Abstract

Aeromagnetic and Bouguer gravity data are conducted to analyze the geological and metallogenic features of the Huangshan-Turaergen Ni-Cu polymetallic metallogenic belt in the Gobi Desert in Northwest China. The Ni-Cu deposits are generally located to the south of the high-amplitude gravity and magnetic gradient belt that marks the Kanggurtag fault zone. To analyze the prospecting potential of the complexes in the metallogenic belt, the model depths and shapes of the complexes are calculated via Euler deconvolution combined with three-dimensional (3D) inversion. The buried complexes occur at relatively shallow depths and have NE orientations. We use a method of lithology recognition based on 3D inversion modeling which enables the definition of two additional buried ultramafic complexes, namely the West Yaziquan (WY) and North Yaziquan (NY) complexes. Our results reveal that these complexes have ring-like shapes similar to most of the other known mafic-ultramafic complexes in this metallogenic belt. The upward continued Bouguer gravity and aeromagnetic data reveal highly consistent gravity and magnetic anomalies, which are explained as a regional magma chamber that is structurally controlled by the Kanggurtag fault zone. In order to determine the scale and shape of this regional magma chamber, 3D gravity and magnetic inversion was carried out for the entire region. According to models of the complexes and pluton, the source, driving mechanism, and evolution of the regional magma are analyzed, and the areas with mineralization and exploration potential are also discussed. This work can aid in the exploration of additional Ni-Cu deposits in Eastern Tianshan.