THE CHARACTERISTICS OF ORE-BODIES,TAM-KALANFU LEAD-ZINC DEPOSITS, ARKETAO COUNTY,XINJIANG
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The lead-zinc deposits occur in the margin carbonate rocks, formed from low temperature hydrothermal. The deposits are located in three paleoaquifer that consist of sandstone and overlying carbonate rocks. Ore-bodies are all found in the breccia-rocks which contain lead-zinc minerals, and the ore-bodies and breccia-rocks are of complex shape, and occurred as no regular. The rich bodies are often found in the middle of breccia-rock. The major factor affecting the shape of ore-body are the interface between sandstone and carbonate rocks, faults, alterated by low temperature hydrothermal, and the property of wall-rocks. The lead-zinc, copper and iron mineralizations in this area are all in one ore-forming system. The wall-rock of zinc(lead) deposits mostly is carbonate rocks, that of copper is amaranth sandstone and carbonate rocks, and that of lead is grey sandstone. The studies on the ore deposits geology show that there are enormous exploring foreground in this area and in the deep of deposits.Keywords:
Breccia
Wall rock
Carbonate minerals
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Deposits of copper and zinc at Johnson, Arizona, occur in metamorphosed Paleozoic limestone near a quartz monzonite stock probably of late Cretaceous or early Tertiary age. The metallic mineralization was preceded by a stage of thermal metamorphism during which pure carbonate beds were recrystallized and impure carbonate beds were altered to garnet, diopside, and other contact-metamorphic silicates. Silicate formation, which involved loss of carbon dioxide, was accompanied by shrinkage that reached a maximum of 30 percent. In the following metallic mineralization, the metamorphic rock was replaced by copper and zinc sulfides associated with some chlorite and other relatively low temperature gangue minerals. Nearly all the ore occurs as tabular masses and chimneys in particular beds in the Abrigo formation of Cambrian age.The recently discovered Moore ore body is a lenticular mass in the Abrigo formation about 400 feet below the present surface. Faulted and fractured limestone and dolomite beds of the Escabrosa limestone (Mississippian) crop out above the ore body. Local copper stains, which are abundant in the district, and a greater-than-average amount of faulting are somewhat meager geological evidence for the presence of ore.To determine if there was any geochemical evidence for the proximity of ore, outcrops of the Escabrosa limestone and part of the underlying Martin formation (Devonian), the fault zones, and soils were sampled both over the ore and in the adjoining area, and the samples were analyzed for traces of the ore metals.The ore-metal content varies widely and is determined in part by stratigraphy and structure. Large areas abnormally high in ore metal are indicated by samples from the fault zones. Composite chip samples of the rock between the faults show small high areas within the high areas indicated by the fault-zone samples. One of the chip-sample anomalies is over the Moore ore body but displaced somewhat to one side of the center of the body. Two other anomalies are over unexplored ground some distance from the ore body. Soil samples collected on low ridges, where contamination is unlikely, show the same general anomalies as the rock samples.A genetic relationship between the Moore ore body and the nearby geochemical anomaly is suggested by its proximity and by the presence in the anomaly area of fault zones which carry concentrations of ore metal and project toward the ore. Diamond drilling and further geochemical studies are suggested as possible means of checking the inferred relationship. At present, geochemical studies give promise of becoming a valuable adjunct of geology in prospecting the Johnson district and similar areas elsewhere.
Prospecting
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Breccia
Ore genesis
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The Journal of the Japanese Association of Mineralogists Petrologists and Economic Geologists (1959)
The copper deposit of the Hamanaka area is located in the southern part of East Hokkaido. This ore deposit was discovered in the outer zone of Kuril arc, and is considered to be originated by the igneous activies of alkaline basic rocks. It must be a remarkable thing. The geological complex developed in the neighbourhood of this ore deposit are the Hamanaka formation with alkaline rocks of upper Cretaceous and some deposits of Quaternary age. The ore deposit is generally observed as massive or stratified bodies in the alternation member of black mudstone and tuffaceous sandstone, and these ore bodies consist of yellowish massive ore and dark gray Kuroko-like ore. The important minerals are pyrite and chalcopyrite, with minor quantities of sphalerite, galena, marcasite, quartz, and rarely calcite and barite. After all, this ore deposit is considered to be a cupriferous iron sulfide deposit from its geological situation, occurrence of ore bodies, and its distinctive character of ore. And it is an ore deposit that have been replaced by hydrothermal solutions.
Marcasite
Polymetallic replacement deposit
Ore genesis
Hypogene
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The Journal of the Japanese Association of Mineralogists Petrologists and Economic Geologists (1964)
In the Miocene formations distributed in the east and the north of the Iide mountainland there occur many black-ore type deposits which are mainly composed of gypsum containing pyrite, chalcopyrite, galena, sphalerite, anhydrite, barite and calcite. These ore-deposits can be found in several formations and they clearly cross the bedding plane. Moreover, the structures of mother rocks are sometimes left in the massive alabaster ore body. In the rhyolite covering the upper part of the deposits, network ore-vein and impregnated ore can sometimes be found. From these facts it is considered that the gypsum ore deposits in this area may be formed by the hydrothermal solution genetically related to the igneous action which occurred after the country rocks had been formed.
Anhydrite
Supergene (geology)
Ore genesis
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Lithology
Devonian
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The Zn-Pb ore deposit in the vicinity of Chrzanow consists of about 90 ore bodies of varied size. Mineralization occurs within the Middle Triassic dolomites in form of bed-shape sphalerite concentrations, replacing the host rocks and various aggregates of sphalerite and galena, infilling their voids. Ore distribution within the rock massif is determined by lithology of the Triassic deposits and by tectonic structures but also an influence of paleohydrological factor on are body origin is assumed. The effect of these factors operation is the ore concentration in some beds, named “ore horizons” and resulted the tabular form of ore bodies and their position concordant with bedding of surrounding rocks. The influence of tectonic factor also determinates internal variability of are bodies, The described here deposit development could be assumed as typical for a part of the Silesian-Cracow ore province, located within the Upper Silesian Trough.
Massif
Lithology
Polymetallic replacement deposit
Prospecting
Bedding
Ore genesis
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Aguilar deposit, in northern Argentina, is a hypothermal lead, zinc, silver replacement in Cambrian calcareous quartzite. The rocks had previously been altered to tactite by a granite stock whose contact is from 150 to 250 m. from the ore bodies. The deposit lies between the granite and a post-tactite, pre-mineral fault of some 3,000 m. displacement. The fault provided the ore channel and also prepared favorable areas for later ore deposition by shearing the calcareous and tactite rocks. Both bedded and shear-zone deposits are present. The granite and the mineralization are believed to be of late Tertiary age.
Lead (geology)
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Bornite
Covellite
Chalcocite
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Breccia
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This paper discusses the manner in which Upper Silesian zinc-lead ores of Mississippi Valley type were introduced into, and deposited within, the ore-bearing dolomite, the host rock of the ores. The ore-bearing dolomite is a neosome developed in Triassic carbonates through dolomitization of limestones and recrystallization of primary or early diagenetic dolomites. It contains three types of ore: (1) ore deposited in rock openings; (2) metasomatically emplaced ore; and (3) ore that crystallized in disaggregated, i.e., delithified, dolomite. The ores were emplaced by mineralizing solutions circulating through an aquifer(s) in lithified rocks. The action of these solutions, combined with that of mobilized ground waters, accounts for the formation of the ore-bearing dolomite. The sulfide ores definitely are epigenetic in relation to their host rocks, and there is no evidence that they were ever part of primary bottom sediments. Further, no evidence is known to us of lateral deposition within the Triassic strata. Mineralization worked outward from those rock volumes that contained the greatest abundance of solution voids. Ample geologic evidence, discussed in this paper, confirmed by measurements of temperature ranges for sulfide precipitation, clearly points to ascending hydrothermal solutions as the progenitors of the ore mineralization. These solutions are thought to be responsible for the formation of conspicuous mineralized karst structures (hydrothermal karsts) that are among the most important ore hosts in the Upper Silesian ore district.The geologic evidence (as detailed in this paper) also indicates that the hydrothermal ore-bearing solutions rose on a broad front along the northeastern margin of the Silesian basin and, after gaining access to the Triassic aquifer, spread laterally to the south and southwest.
Dolomitization
Ore genesis
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