Exploration and Mining
Keytash Moshtaghian; Seyed Mohammad Abtahi Forooshani; Hooshang Asadi Harooni; Mohammad Hajheidari; Ghazal Janghorban
Abstract
The Dalli porphyry Copper-Gold deposit consists of two northern and southern indexes located on the Urmia-Dokhtar Volcanic Belt in Markazi province. Due to the presence of magnetite beneath the potassic alteration zone in the center of porphyry mineralization, a magnetometric survey was performed ...
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The Dalli porphyry Copper-Gold deposit consists of two northern and southern indexes located on the Urmia-Dokhtar Volcanic Belt in Markazi province. Due to the presence of magnetite beneath the potassic alteration zone in the center of porphyry mineralization, a magnetometric survey was performed in the region. In the current study in the northern index, first, we extracted the local anomaly via removing the regional and aliasing effects from the magnetic data. Then, using three-dimensional inverse modeling of the reducted data illustrates the presence of a body with high magnetic susceptibility, in the depth range of 40 to 640 meters of the study area. A comparison between geochemical analysis of two exploratory core drilling with the depth variational model of the estimated magnetic susceptibility in the study area indicates a spatial correlation between increases in the grades of copper and gold and large variations of the magnetic susceptibility. Also, comparison between the magnetic susceptibility model and resistivity and chargeability models estimated from IP/RS data of three parallel profiles indicates a relation between sulfidic and altered mineralized zones and magnetic susceptibility variations. Therefore, the current study shows a high potential for the copper-gold mineralization in the northern Dalli index.
B. Oskooi; G.A. Fanaee-Kheirabad
Abstract
Geothermal energy is playing a large role as an alternative energy source for both electricity generation and space heating. Sabalan is a high temperature geothermal region in Ardabil province northwestern of Iran. In this study the conductivity structure of the top crust (depth lower than 2 kilometers) ...
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Geothermal energy is playing a large role as an alternative energy source for both electricity generation and space heating. Sabalan is a high temperature geothermal region in Ardabil province northwestern of Iran. In this study the conductivity structure of the top crust (depth lower than 2 kilometers) is examined using data from collected 212 magnetotelluric (MT) and time-domain electromagnetic (TDEM) soundings across the Sabalan volcano in 1998. The MT data collected between 1-8192 Hz is of useful quality and provides good control on the surface layers in majority of sites. The MT data were corrected for static shift effect using TDEM data. The TDEM data and MT data were jointly inverted to yield 1D and 2D models. In practice for geothermal investigation, measured MT data are never entirely 1D and diagonal elements of the impedance tensor are always non-zero. However, in many cases the Earth response is dominated by an overall 2D structure, permitting data analysis within these lower dimensions. In this study, in order to have the best possible interpretation we used two modes MT data in 2D inversion. Static shift correction and inversion approach accomplished by using WinGlink software. We choose three intersect profiles with 54 MT sites along with, to show resistivity distribution around Sabalan and try to predict the main intrusive magma chamber position as the heat source of the system. MT resistivity images confirmed the findings of previous surveys and the reported geological features in the Sabalan field. To have a better view about resistivity distribution, we combine the 2D models at the intersection points to obtain a 2.5D view about the resistivity in the area. The resulting models reveal the extension of the high conductivity anomalies in the western and southwestern parts of the area that most probably is related to the main heat source of the geothermal system at shallow depths.