Mineralization Based on CSAMT and SIP Sounding Data: A Case Study on the Hadamengou Gold Deposit in Inner Mongolia

Abstract

The Hadamengou deposit is the largest gold deposit in Inner Mongolia. However, given that the sources of ore-forming alkaline magmatic hydrothermal solutions and ore-controlling structures are still controversial, the theories behind the genesis of the deposit have been controversial. In this study, four controlled-source audio magnetotellurics (CSAMT) and spectral induced polarization (SIP) profiles in the mining area were used to obtain the underground resistivity model and the pseudo section map of the apparent frequency dispersivity based on fine inversion. In the resistivity model, there are two high-resistivity blocks with resistivity greater than 3000 Ω m and three low-resistivity channels with resistivity less than 50 Ω m. Combined with the regional geological and drilling data, it is inferred that the high-resistance bodies, R4 and R5, may be alkaline magmatic intrusions related to multiple stages of magmatic hydrothermal activities, ranging from the Precambrian to Yanshanian periods. The highly conductive channels, C3, C5, and C4, may represent the Baotou-Hohhot fault, secondary faults, and ductile shear zone, respectively, which were formed in the Precambrian era and underwent multiple activations during the Hercynian to Yanshanian period. According to the spatial relationship, it is inferred that the ductile shear zone is an important ore-controlling and ore-hosting structure. However, the Baotou–Hohhot fault may be a pre-metallogenic fault rather than an ore-controlling fault. By comparing the resistivity model with the pseudo section of the apparent frequency dispersivity, it was found that all the known gold veins are located in the superimposed area of low resistivity and high-frequency dispersivity. It is speculated that the ductile shear zone outside the alkaline magmatic rock with the superimposed characteristics of low resistivity and high-frequency dispersivity is the favorable area for mineralization.

Deep Structure of Epithermal Deposits in Youxi Area: Insights from CSAMT and Dual-Frequency IP Data

“…Minerals 2024, 14, 27 6 o source interference. Thus, these frequencies were cutoff and only data in the range of 2 Hz to 8192 Hz were utilized for the inversion process.…”

“…Particularly noteworthy is the controlled-source audiofrequency magnetotelluric method (CSAMT), which offers advantages such as greater exploration depth and a wider range of parameters compared to conventional electrical methods. CSAMT, employing artificial sources, exhibits high signal-to-noise ratios and efficient data acquisition, making it a widely utilized tool for the exploration of ore deposits [25][26][27].…”

Cu-Polymetallic Deposit Exploration under Thick Cover in Gucheng-Yaxi Area Using Audio Magnetotelluric and Spread Spectrum Induced Polarization

“…Electromagnetic (EM) and electrical geophysical methods have been extensively applied successfully in the study and discovery of new mineral deposits [12][13][14][15]. For instance, controlled source magnetotelluric (CSAMT), audio magnetotelluric (AMT) and induced polarization are been applied to study shallow part of a deeper mineralization [16][17][18][19]. The magnetotelluric (MT) sounding and the wide-field electromagnetic (WFEM) method are gaining application to meet the demands for deep resource exploration [20][21][22].…”

Coupling Mechanism of the Concealed Rock Body and Metallogenic Structure of the Sarakan Gold Deposit in Laos Investigated Using Magnetic and Electrical Methods

“…In recent years, magnetic methods have been widely used to detect concealed rock bodies, orebodies, and underground structures [1][2][3][4]. Further, the induced polarization (IP) method is a relatively mature geophysical exploration method for finding sulfide mineral deposits [5,6]. It has a high working efficiency, fast surface-sweeping speed, and is relatively unaffected by topography [7][8][9].…”