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Wang G.,China University of Geosciences | Pang Z.,Technical Guidance Center for Mineral Resources Exploration | Boisvert J.B.,University of Alberta | Hao Y.,China University of Geosciences | And 2 more authors.
Journal of Geochemical Exploration

Three-dimensional (3D) geological, geostatistical, and fractal/multifractal modeling are combined for the identification of new exploration targets in the Tongshan porphyry Cu deposit (China): (1) A 3D geological model of the deposit includes the strata, faults, altered rocks, intrusive bodies, and three orebodies using geological map, cross-sections, borehole dataset, and magnetic inversion; (2) geostatistical analysis involves omnidirectional and vertical semi-variogram calculations of the orebody, ordinary kriging interpolation of the orebody and 3D trend modeling using the assay data; (3) fractal models consisting of Hurst exponent estimation of the continuity of vertical mineralization and its concentration-volume (C-V) fractal model separation mineralized zones in a 3D block model; and (4) interpretation and validation: magnetic inversion was utilized to constrain intrusive rock shape between cross-sections and additional interpret orebody geometry model by ordinary kriging interpolation method using Tongshan borehole dataset. The results indicate that (a) the Hurst exponent is useful for identifying the vertical continuity of mineralization (with the range between 0 and 1200. m), (b) the C-V fractal model is useful for identifying thresholds of Cu values in oxidation-type, skarn-type, and magmatic-type orebodies in the Tongshan deposit, and (c) the 3D geological and trend model can be combined to recognize potential subsurface targets in the Tongshan deposit. The methods can be applied to estimate mineral resources through district-scale exploration. © 2013 Elsevier B.V. Source

Xie B.,China University of Geosciences | Zhou S.,China University of Geosciences | Zhou S.,China University of Gosciences | Xie G.,Development Research Center | And 3 more authors.
Acta Petrologica Sinica

This study reports the whofe-rock geochemical and zircon U-Pb geochronofogical data of Linzizong Vofcanic Succesion (LVS) outcropped in Konglong-Dingrenle region of the middle Gangdese belt. Zircon U-Pb dating results indicate that acidic detritus crystal ignimbrite (LZ06022-2) coflected Irom bottom layer of the Nianbo Formation yields an age of 59.64 ±0. 72Ma, and that andesitic crystal tuff ( LZ06017-) sampled Irom bottom layer of the Dianzhong Formation was emplaced around 69. 97 ±0. 72Ma. This is the ofdest age lor LVS. Combing with previously reported vofcanism, geochemical and chronofogical date, it is revealed that the vofcanic activity characteristics are different lrom early to late and east to west of the Gangdese. First, the eruptive patterns of vofcanism of Linzizong vofcanic successions mainly include extrusive and explosive lacies. The vofcanic explosivity index is getting weaker lrom early to late, which means the eruptive patterns change lrom explosion lacies-dominated of the early Dianzhong Fromation to extrusion lacies of the late Pana Formation. Second, under the time evofution the vofcanic activity changes lrom intensive to weak. In the early , the east area is more intensive than the middle and west area. But , in the interim , the west area is more intensive than the other. To the late stage , the vofcanic activity of whofe Gangdese is weak. The vofcanism of the Nianbo Formation is the most intensive , lrequent and long lasting in the middle belt of LVS. The early stage of LVS is mainly basic , middle stage and late stage is prevailed by neutral and acidic rock types. Respectively , the total alkali content is increasing , and the rock series also change lrom calc-alkaline to high potassic calc-alkali to shoshonite. Third , LVS has the characteristics of epicontinental arc vofcanic rocks , and it is the product of India-Asian continent coUision. The starting time of coUision lor the west , middle and east area is different. In the contrast , the middle belt is slightly earlier than that of the eastern and western part. Source

Jia D.L.,China University of Geosciences | Jia D.L.,Technical Guidance Center for Mineral Resources Exploration | Yan G.S.,Technical Guidance Center for Mineral Resources Exploration | Ye T.Z.,Technical Guidance Center for Mineral Resources Exploration | And 5 more authors.
Acta Petrologica Sinica

The Guangshan granitic complex consists of two granitoids, the medium-grain alkali feldspar granite and the fine-grain alkali feldspar granite that intruded into the former. LA-MC-ICP-MS zircon U-Pb dating shows that they formed in Yanshanian (162.4 ±0.9Ma and 156.3 ±0.7Ma), indicating that Guangshan intrusion is the product of two cycles of magmatic activities at least. The compositions of these two period granites fall into the calc-alkaline category, with an A/CNK ratio of 0.95 ∼ 1.05. They have moderate REE and strong Eu depletion with a slightly right inclined sea-gull shaped REE pattern, and all belonging to A2 -type granite. Zircon εHf(t) values of the granites are negative (-4.35 to 0), and two-stage Hf model ages (tHf2) range from 1219Ma to 1478Ma, suggesting that these granites are originated from remelting of the Mesoproterozoic crustal materials. Combined with previous results, we infer that the late Early Yanshanian A-type granites in South China were formed in a post-orogenic extension environment. Source

Tao W.,China University of Geosciences | Tao W.,Technical Guidance Center for Mineral Resources Exploration | Yi C.R.,Technical Guidance Center for Mineral Resources Exploration | Zhong H.J.,China University of Geosciences | Long S.C.,China University of Geosciences
Proceedings of the 3rd Academic Conference of Geology Resource Management and Sustainable Development, GRMSD 2015

The H-O isotopic data of the quartz and the S-Pb isotopic data of the pyrites have been analyzed at HuaJian gold deposit on the basis of the geological setting and the geology of the deposit. The isotopic compositions of H and O suggest that the ore-forming fluids during the mineralization were primary magmatic fluids that over time became increasingly mixed with meteoric and hydrothermal water. Furthermore, the characteristics of the S and Pb isotopic compositions indicate that metallogenic metal materials are related to magmatic processes. Consequently, these results suggest that the ore-forming fluids and materials were derived from the crust in depth which is closely tied to magmatic intrusion. Source

Du Z.-Z.,China University of Geosciences | Du Z.-Z.,Technical Guidance Center for Mineral Resources Exploration | Du Z.-Z.,Development and Research Center | Ye T.-Z.,Technical Guidance Center for Mineral Resources Exploration | And 16 more authors.
Geological Bulletin of China

The ferriferous silicalites in the Zheyaoshan ore district occur in sedimentary discontinuity interface between the ore-bearing rock series (quartz keratophyre taff) and the upper rock system, and are composed mainly of fine-crystalline quartz and hematite, which account for more than 90%, with a small amount of silk mica, feldspar, sodium chlorite etc. The ferriferous silicalites are characterized by low TiO2 and A12O3 as well as high ore-forming elements (Fe, Cu, Pb, Zn). Through the calculation of Al/(Al+Fe+Mn) ratio, the characteristics of hydrothermal sedimentary rock were displayed. In the Fe-Mn-Al triangular diagram, Fe-Mn-(Cu+Co+Ni)×10 triangular diagram and Zr-Cr diagram, the ferriferous silicalites in this area are located in the hydrothermal sedimentary rock area, the total REE of ferriferous silicalites is very low, and the north American shale standardization distribution pattern is a right oblique curve with weak negative Eu anomaly or positive Eu anomaly as well as weak negative Ce anomaly. The ω(MnO)/ω (TiO2) ratio of part of the samples is somewhat smaller, U/Th ratio is larger, Al2O3 content is higher, with a negative Eu anomaly, indicating that the addition of normal sedimentary silicalite ingredients. Combined with the geological background of ferriferous silicalites and rare earth elements of ore-bearing rock series (quartz keratophyre tuff) and mineralized quartz, the authors hold that the provenance of ferriferous silicalites was mainly derived from quartz keratophyre tuff and belonged to the abiogenic type related to volcanism, and this can be regarded as an important prospecting criterion in the orefield. Source

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