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Abstract
This paper introduces the application of the pyrite thermoelectric property measurements in gold exploration of the Shihu gold deposit. Pyrite is the main gold-carrying mineral. Four gold mineralization stages may be distinguished. The thermoelectric type assemblage of pyrite is P<N⇒P≥N⇒P>N⇒P≤N from mineralization stages I to IV. In the mineralization area, from the top downward when (P and P% decrease, (N and N% increase, which in the main coincides with the results of mineralogical mapping by using the distribution of pyrite type (P%) and the mean of the thermoelectric coefficient (P. Some typomorphic information such as formation temperatures of pyrite, relative burial depths of orebodies, characteristics of orebodies and prospects of the deep part may be obtained according to thermoelectric properties of pyrite.
... The properties of pyrite occurring in gold deposits have been widely studied including crystal structure (Li et al., 1996;Abraitis et al., 2004), chemical composition (Li et al., 1994(Li et al., , 1996Abraitis et al., 2004;Cook et al., 2009a;Yan et al., 2012Yan et al., , 2013, and thermoelectricity (Chen et al., 1987;Li et al., 1994Li et al., , 1996Li et al., , 2013Abraitis et al., 2004;Cao et al., 2008;Chen et al., 2010). However, as a common mineral in Ag-metallogenic deposits, its geochemical characteristics and implications on ore genesis are still unclear. ...
... Our results on the evolutionary trend of the thermoelectric coefficients of pyrite in the Jiawula deposit show a generally ascending trend and define a gradient from N-type to P-type. These trends are closely comparable with the thermoelectricity of gold deposits (Cao et al., 2008;Li et al., 2009Li et al., , 2013Chen et al., 2010;Zhang et al., 2010). According to previous research, N-type pyrite is related to sulfur deficiency, low (<2) S/Fe ratio, and low As content (Favorov et al., 1974;Schieck et al., 1990). ...
The Jiawula Ag-Pb-Zn deposit is located in the northern part of the Da Hinggan Mountains metallogenic belt in the eastern section of the Central Asian Orogenic Belt. Sphalerite, galena, pyrite, chalcopyrite, and arsenopyrite are the major sulfide minerals occurring in this deposit. Here we report results from electron probe micro-analysis (EPMA), thermoelectricity, and sulfur isotope studies of the constituent silver minerals and sulfide phases of the Jiawula deposit. Petrographic observations and EPMA study reveal abundant silver mineralization in the ore, especially within sphalerite and galena. Discrete grains of silver minerals (including argentite, pyrargyrite, and canfieldite) and isomorphism in silver-bearing sulfides are identified. Silver and tellurium contents in galena are relatively high and show interrelationship. Significant substitution of S by Te in the galena lattice facilitates silver entering the galena structure, which might have been promoted by relatively low lgfS2. The thermoelectric coefficient of pyrite shows a marked gradient from N-type to P-type from pre- to post-metallogenic stages. Pyrites in Jiawula are enriched in Co and As and in the absence of Ni, displaying features typical of epithermal deposits. The isotopic data present a close relationship between the sulfur source and magmatism.
... The mineral accounts for 85% of the major gold-bearing minerals in gold deposits (Gao et al., 2000;Palenova et al., 2015). The characteristics of pyrite including morphology (Abraitis et al., 2004;Koglin et al., 2010), chemical composition (Li et al., 1994(Li et al., , 1996Abraitis et al., 2004;Reich et al., 2005;Cook et al., 2009;Yan et al., 2012Yan et al., , 2013, thermoelectricity (Abraitis et al., 2004;Cao et al., https://doi.org/10.1016/j.oregeorev.2019.103008 Received 17 August 2018; Received in revised form 2 July 2019; Accepted 8 July 2019 2008; Chen et al., 2010;Li et al., 1994 reference with no printed form.]; ...
The Bagrote valley in North Pakistan, belonging to the Kohistan island arc, is well-known for regional placer gold mining. However, no economically feasible in situ hydrothermal gold deposits have been discovered in this region due to rugged terrain and remote nature of its location in the western Himalaya. The streams draining the Main Karakoram Thrust (MKT)/Shyoke suture zone carry placer gold in sediments as well as old river terraces, although the primary source remains unknown. In this paper, we employ a multiparametric approach including, X-ray Diffraction (XRD) analysis, thermoelectricity, major and trace element geochemistry and isotopic characteristics of pyrite associated with placer gold with a view to identify the nature of the unknown deposits and ore forming fluids on the catchment of the Bagrote valley. Pyrite in the Bagrote valley placers is euhedral to subhedral indicating the proximal gold sources. The high rate of occurrence of N-type thermoelectric coefficients (89%) with low P-type (11%) and crystallization temperature (290 °C−380 °C) combined with chemical features indicate that the pyrite was derived from porphyry or epithermal type of magmatic hydrothermal gold deposits from the hinterlands of the Bagrote valley. The X-Ray elemental maps show that Fe, As, Mo and Ni are homogenously distributed from core to rim suggesting stable crystallization condition without any alteration by later fluids. The calculated chemical formula of pyrite of our samples is [Au0.0006Fe] S2.004], plots of Au-As and Au-Fe shows that gold occurs in pyrite as micro to nano inclusion as Au⁰. The δ³⁴ SV-CDT values of pyrite range from – 0.6‰ to 0.9‰ with an average of −0.02‰, indicating the derivation of sulfur from a homogeneous magmatic source. The Pb isotope data indicates that the Pb was sourced from orogenic-type source, with minor contribution of lower crust. The narrow variations in ²⁰⁶Pb/²⁰⁴Pb and ²⁰⁸Pb/²⁰⁴Pb values suggest a single lead source. The low, medium and high Mo/Ni ratios reflect a mixed provenance for the auriferous pyrite. The average value of γ (71.8%), of pyrite computed from thermoelectric parameters (XnP), suggests that the dominant part of the primary source that contributes to the placers might have already been eroded. However, the proximal source and with high content of gold in the pyrite grains (up to 1160 ppm) suggest the possibility of significant economic mineralisation below the present erosion level of the deposits in the hinterlands of Bagrote Valley.
... The Shihu gold deposit has been explored for the last 30 years and has high metallogenic reserves. Previous studies have focused on the deposit's geochemistry (Liu, 2007;Niu et al., 2008), mineralogy (Cao et al., 2008(Cao et al., , 2009(Cao et al., , 2010, and fluid inclusions (Cao et al., 2012). However, the age and the source of ore-forming material of the deposit have not been studied and is not well understood. ...
The Early Cretaceous Shihu gold deposit is located in the northern segment of the Taihang Tectonic belt, which extends across the central part of the North China Craton. The deposit is hosted predominantly by the Archean metamorphic crystalline units, and is spatially and temporally related to quartz diorite porphyry present extensively throughout the gold deposit. We studied the geology, geochronology and stable isotopic geochemistry. Zircon U–Pb LA–ICP–MS ages of the quartz diorite porphyry at deposit range from 134 ± 1 to 131 ± 2 Ma, which are coeval and probably genetically related to the mineralization. The majority of the sulfides of the gold deposit have δ34S values ranging from −1 to 2‰, which suggest an homogeneous magmatic source. In addition, the isotopic compositions of δ18Ofluid and δ18Dfluid vary from 2.1 to 7.0‰ and −93 to −65‰, respectively, suggesting that the magmatic fluids mingled with meteoric water. The Pb isotopic analyses reveal that both the ore-forming materials and the quartz diorite porphyry originated from the lower crust and may have been mixed with mantle material. The 87Sr/86Sri and 143Nd/144Nd (143Nd/144Nd)i ratios for the quartz diorite porphyry demonstrate that there was mixing of two end-member (crust and the mantle) isotopic compositions. These results suggest that the ore-forming fluids and materials were derived from lower-crustal melting induced by mantle processes. Processes associated with the formation of the Shihu gold deposit differ significantly from those that characterize orogenic gold deposits, and instead are representative of formation in an intracontinental tectonic environment.
... Mesozoic mineralization and associated post-magmatic hydrothermal in the TTB are homologous and synchronous making the Shihu gold deposit ideal for investigating gold metallogenesis. However, some researchers have focus on geochemistry [1], mineralogy [2], and fluid inclusions [3]. The behavior of the elements during the alteration has not been studied and well understood, which is related to Au transfer and is helpful to the exploration. ...
The Shihu gold deposit is located in the northern Taihang Tectonic belt, which is a part of the North China Craton. The Shihu gold deposit is hosted by amphibolite to granulite facies rocks in the Archean Fuping Metamorphic Complex and defined as post-magmatic hydrothermal type of gold deposit. Hydrothermal alteration by means of isocon analysis shows that alkalic hydrothermal activity produces sericite alteration during the alteration. Chlorite alteration is not provided by the ore-forming fluid predominately but the metamorphic rocks. The multiple-metal enrichment gives an advantage of the forming polymetallic sulphides and gold ore bodies. Therefore, it can be a useful indicator for exploration in the Shihu gold deposit.
... Leinov et al. [2010] describe thermoelectric effects in brine-saturated sandstone in situ. The thermoelectric effect from ore minerals, for example from pyrite during computeraided resistivity surveys for gold (called pyrite-thermoelectric surveying), has also been described [Cao Ye et al. 2008, Zhang Yun-qiang et al. 2010], as has thermoelectricity from magnetite grains in the Earth's crust, and especially in the middle-lower crust [Junfeng Shen et al. 2010]. This widespread effect is similar to defect charging (described in the Defect charging subsection, above) in that both processes mobilize charge carriers and holes (acceptors), the one with a temperature gradient, the other with pressure. ...
Telluric currents are natural electrical phenomena in the Earth or its bodies of water. The strongest electric currents are related to lightning phenomena or space weather. Earth electricity can cause damage to structures, and may be useful for earthquake forecasting and other applications. Thirty-two distinct mechanisms that cause Earth electricity are described, and a broad selection of current research is highlighted. © 2013 by the Istituto Nazionale di Geofisica e Vulcanologia. All rights reserved.
... Gangue minerals are of variable distribution with different ore types. Quartz, feldspar, plagioclase, carbonate, biotite, sericite, and chlorite constitute characteristic gangue minerals for both ore types (Cao Ye et al., 2008). ...
The Shihu gold deposit is situated in the central shear zone of the Meso-Cenozoic Fuping metamorphic core complex in the middle-northern
part of the Taihang Mountains. This kind of gold deposits named after ‘Shihu type’ widely occurs in this region. Gold-bearing
quartz veins are their most important industrial orebodies. Detailed laser 40Ar/39Ar geochronology of the mineralized quartz veins in the study area reveals details of its tectono-magmatic history. The 40Ar/39Ar ages for the quartz are between 134.4 Ma and 155.9 Ma with a mean age of 141±4 Ma on the isochron line and 139±7 Ma on
the inverse isochron line, respectively, which is interpreted to be the best estimate of the crystalline age of the quartz
veins. The gold mineralization was most likely related to an underplating event that took place in the northern part of the
Taihang Mountain at ca. 140 Ma. The timing of gold mineralization in the area is similar to those observed in other major
gold-producing provinces in the NCC. This episode is simultaneous with those in the eastern NCC, indicative of a widespread
late Yanshanian metallogenic event that was a response either to the subduction of the Izanagi-Pacific plate beneath eastern
China or to the removal of the Early Cretaceous lithosphere in the eastern NCC. The ore-forming material sources may be the
Early Precambrian metamorphic basement, instead of intermediate-acid rock bodies and dykes.
Gold Mineralization of the Shihu deposit can be divided into 4 stages, pyrite-quartz stage, quartz-pyrite stage, polymetallic sulfide stage and quartz-carbonate stage. Cell parameters of pyrite and quartz from 4 stages were analyzed in this paper. The analytical results of pyrite indicated that the value of &Q and uo is minimum in UJ stage; the values of a- and u0 decrease as mineralization stage proceeds from I to IV and as the depth of ore-body increases from 560 to 180 meters. The analytical results of quartz indicated that the values of co and the Co/ao, ratios decrease as mineralization stage changes; the values of ao increase as the depth of ore-body increases; the values of Co and the C o/ao, ratios change rhythmically as the depth of ore-body increases. Results of cell parameters suggested that pyrites have high contents of Co, Ni and As, and have not undergone S depletion. Moreover, Al and Fe are the major replacement impurities in isomorphism of quartz. Gold-bearing pyrites are characterized by small ao , while gold-bearing quartz are characterized by big ao, small Co, and C o/ao ratio. The values of ao, of pyrite and the values of Co and Co/ao ratios of quartz are mostly larger than their ideal values. Therefore, denudation of the gold ore-body is slight, and potential value of this deposit is considerable.
Pyrite is one of the most important gold -bearing minerals, and its crystal forms and thermoelectricity have important implications to the prospecting and evaluation of gold deposits. Based on systematic sampling from drill holes ZK18, ZK30 and ZK40 in the Shuangwang brecciastype gold deposit, the authors mainly studied the crystal forms and thermoelectricity of pyrite, and have reached the following conclusions. The crystal forms of pyrite are fairly simple, comprising cube, octahedron, pentagonal dodecahedron and their composite combination, with the main crystal habit being {hkO}. Overall, the number of crystal forms is in decreasing order of {hkO}, {100}, {111}. The thermoelectric conductive type of pyrite is mainly NP type, with the thermoelectric coefficients of Ntype pyrite ranging from .0 to.7 and those of P-type pyrite ranging from 1.7 to 346.7 ß V-^C-1; the thermoelectric parameters of pyrite vary gready; the degree of denudation varies from 53.67% to 60.12%. All of the above data indicate a better exploration prospect at the depth of drill holes ZK18, ZK30 and ZK40 in No. 9 and No. 8 ore bodies.
A summary of elemental and isotopic compositions of the Mesozoic gabbros and Cenozoic basalts from the Taihang Mountains shows a remarkable difference in their mantle sources. Cenozoic basalts are mainly alkaline basalts with minor olivine tholeiites and originated from partial melting of asthenosphere with some involvements of old subcontinental lithospheric mantle. In contrast, the Mesozoic gabbros are high in SiO2 content, enriched in LREE and LILE (Ba, Th, U) and depleted in HFSE (Nb, Ta, Zr and Ti). They are also enriched in Sr-Nd isotopes (most 87Sr/86Sri > 0. 705, 143Nd/144 Ndi < 0.512) and depletion in Pb isotopes (206Pb/204Pbi <17.5, 207Pb/204Pbi < 15.5, 208Pb/204Pbi <38.0). These geochemical features indicate that these Mesozoic gabbros were generated from enriched old lithospheric mantle, which was greatly modified by silicate melt. Such a modification might be related to the Proterozoic subduction/collision during the formation of the Trans-North China Orogen. The old and isotopically enriched lithospheric mantle is existent till the Cenozoic, as recorded in mantle peridotitic xenoliths from Cenozoic basalts of the region.
The thermoelectric effect represents interactions between electrical and thermal transport, that is,a thermal gradient causing an electric field. As a typomorphic characteristic, thermoelectricity of metal-semiconducting minerals can denote the physical-chemical conditions of mineral formation,and therefore can be applied to the exploration and evaluation of ore deposits. In order to probe into the relation between the thermoelectric typomorphic characteristics and prospecting, the principle involved in the thermoelectric effect of minerals and the factors influencing the thermoelectric power are discussed,and the application.of thermoelectric typomorphic characteristics to prospecting is elucidated on the basis of the latest research on minerals from the land deposits and the Pacific Ocean respectively. It is shown that a database of information regarding the determination of basin paleotemperature, the estimation of mineralization, the prediction of concealed ore bodies, the study of metallogenetic zonation, and the evaluation of denudation extent of ore deposits can be obtained through characterizing the thermoelectric effect of minerals.
A summary of elemental and isotopic compositions of the Mesozoic gabbros and Cenozoic basalts from the Taihang Mountains shows a remarkable difference in their mantle sources. Cenozoic basalts are mainly alkaline basalts with minor olivine tholeiites and originated from partial melting of asthenosphere with some involvements of old subcontinental lithospheric mantle. In contrast, the Mesozoic gabbros are high in SiO2 content, enriched in LREE and LILE (Ba, Th, U) and depleted in HFSE (Nb, Ta, Zr and Ti). They are also enriched in Sr-Nd isotopes (most 87Sr/86Sri > 0. 705, 143Nd/144 Ndi < 0.512) and depletion in Pb isotopes (206Pb/204Pbi <17.5, 207Pb/204Pbi < 15.5, 208Pb/204Pbi <38.0). These geochemical features indicate that these Mesozoic gabbros were generated from enriched old lithospheric mantle, which was greatly modified by silicate melt. Such a modification might be related to the Proterozoic subduction/collision during the formation of the Trans-North China Orogen. The old and isotopically enriched lithospheric mantle is existent till the Cenozoic, as recorded in mantle peridotitic xenoliths from Cenozoic basalts of the region.