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Speleology in Kazakhstan

Shakalov on 04 Jul, 2018
Hello everyone!   I pleased to invite you to the official site of Central Asian Karstic-Speleological commission ("Kaspeko")   There, we regularly publish reports about our expeditions, articles and reports on speleotopics, lecture course for instructors, photos etc. ...

New publications on hypogene speleogenesis

Klimchouk on 26 Mar, 2012
Dear Colleagues, This is to draw your attention to several recent publications added to KarstBase, relevant to hypogenic karst/speleogenesis: Corrosion of limestone tablets in sulfidic ground-water: measurements and speleogenetic implications Galdenzi,

The deepest terrestrial animal

Klimchouk on 23 Feb, 2012
A recent publication of Spanish researchers describes the biology of Krubera Cave, including the deepest terrestrial animal ever found: Jordana, Rafael; Baquero, Enrique; Reboleira, Sofía and Sendra, Alberto. ...

Caves - landscapes without light

akop on 05 Feb, 2012
Exhibition dedicated to caves is taking place in the Vienna Natural History Museum   The exhibition at the Natural History Museum presents the surprising variety of caves and cave formations such as stalactites and various crystals. ...

Did you know?

That consequent river is a river flowing down the original slope of geologic beds or general slope of topography [16].?

Checkout all 2699 terms in the KarstBase Glossary of Karst and Cave Terms


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Chemistry and Karst, White, William B.
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Karst environment, Culver D.C.
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Calculating flux to predict future cave radon concentrations, Rowberry, Matt; Marti, Xavi; Frontera, Carlos; Van De Wiel, Marco; Briestensky, Milos
Microbial mediation of complex subterranean mineral structures, Tirato, Nicola; Torriano, Stefano F.F;, Monteux, Sylvain; Sauro, Francesco; De Waele, Jo; Lavagna, Maria Luisa; D’Angeli, Ilenia Maria; Chailloux, Daniel; Renda, Michel; Eglinton, Timothy I.; Bontognali, Tomaso Renzo Rezio
Evidence of a plate-wide tectonic pressure pulse provided by extensometric monitoring in the Balkan Mountains (Bulgaria), Briestensky, Milos; Rowberry, Matt; Stemberk, Josef; Stefanov, Petar; Vozar, Jozef; Sebela, Stanka; Petro, Lubomir; Bella, Pavel; Gaal, Ludovit; Ormukov, Cholponbek;
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Your search for gold (Keyword) returned 42 results for the whole karstbase:
Showing 16 to 30 of 42
SEDIMENT-HOSTED GOLD MINERALIZATION IN THE RATATOTOK DISTRICT, NORTH SULAWESI, INDONESIA, 1994,
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Turner S. J. , Flindell P. A. , Hendri D. , Hardjana I. , Lauricella P. F. , Lindsay R. P. , Marpaung B. , White G. P. ,
The Ratatotok district in the Minahasa Regency of North Sulawesi, Indonesia is an area of significant gold mineralisation. Gold has been mined in the district since at least the 1850s, and intensively by the Dutch between 1900 and 1921 with a recorded production of 5,060 kg of gold. Newmont began exploring the district in 1986, and has delineated a major sediment-hosted replacement-style deposit at Mesel, and other smaller deposits in an 8 X 5 km area. A total drill-indicated resource of over 60 metric tonnes of gold ( 2 Moz) is reported for Mesel, and three of the smaller deposits. Approximately 80% of this resource is refractory. Silver grades are usually low (< 10 g/t). The Mesel deposit is similar to many Carlin-type deposits in carbonate hostrocks, alteration, geochemical signature and ore mineralogy, but is distinct in tectonic setting. The discovery of replacement-style mineralisation at Mesel, in an impure limestone within a Tertiary island arc environment, demonstrates that deposits with outward characteristics similar to Carlin-type mineralisation are not restricted to a continental setting. Carbonate sediments in the Ratatotok district were deposited in a Late Miocene restricted basin. Later compressional tectonics caused uplift that resulted in karst development in the limestone and erosion of the adjacent volcanic arc with deposition of a thick epiclastic unit. This was followed by intrusion of shallow level pre-mineral andesite into the sequence. Mineralisation at Mesel, and probably elsewhere in the district, is synchronous with the late-stage reactivation of strike-slip faults. Mineralising fluids at Mesel were focussed along steep structures sympathetic to these faults, and trapped below a relatively impermeable andesite cap rock. Hydrothermal fluids caused decalcification of the silty, more permeable carbonate units with the formation of secondary dolomite, deposition of fine arsenian pyrite, silica veinlets and gold. Volume loss due to decalcification and dolomite formation caused collapse brecciation which enhanced fluid flow and further mineralisation. This locally culminated in total decarbonation and deposition of massive silica. Late-stage stibnite occurs in structural zones within the ore deposit, whereas arsenic (as realgar and orpiment) and mercury (as cinnabar) are concentrated on the periphery. Elsewhere in the Ratatotok district, gold mineralisation is restricted to replacement-style mineralisation in permeable zones along limestone-andesite contacts, open-space-filling quartz-calcite veins and stockworks, and residual quartz-clay breccias. The residual breccias are developed in-situ, and are interpreted to form by dissolution of the wallrock limestone from around pre-existing mineralisation. This has resulted in widespread eluvial gold occurrences

A combined continuum and discrete network reactive transport model for the simulation of karst development, 1996,
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Clemens T Huckinhaus D. , Sauter M. , Liedl R. , Teutsch G.

Funde von gediegen Gold in der Dachstein-Mammuthhle., 1998,
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Arthofer P. , Thaler H.
[(1547/9)]

Did the Argonauts of Greek myth go underground in the Slovene karst?, 1998,
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Shaw Trevor R. , Macqueen James G.

Lazius's maps of Carniola, the first of which was printed in 1545, have a note at Vrhnika, where the Ljubljanica rises from its subterranean course, saying that the Argonauts of the Greek golden fleece myth went underground there on their way from the Black Sea to the Adriatic. The original Greek sources describe only a surface route, either following a branch of the Sava running west to the sea, or requiring their ship to be carried overland for this part of the journey. Elsewhere, though, it was said that fish pass from one sea to the other by underground channels. The subterranean variant of the Argonaut story has not been traced before Lazius, though he may have got the idea from another mapmaker, Hirschvogel, who had lived in Ljubljana. Münster's map of 1550 implies the existence of an underground river between Vrhnika and the Mirna river in Istria, but it does not associate it with the Argonaut story. The idea seems to have arisen just when maps were showing that hills formed a barrier between the east-flowing Sava and the rivers of the Adriatic basin, and when the existence of caves and underground rivers was becoming more widely known.


Funde von gediegen Gold in der Dachstein-Mammuthhle, 1998,
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Arthofer P. , Thaler H.

Sinkholes in karst mining areas in China and some methods of prevention, 1999,
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Li G. Y. , Zhou W. F. ,
Mining of coal, lead and zinc, gold, and iron ore deposits in karst areas has been closely associated with sinkholes in China. Surface collapse causes an increase in mine water drainage and the possibility of major water inflow from karst aquifers, which threatens the environment in mining areas and endangers the mine safety. A combination of factors including soil weight, buoyancy, suffusion process and vacuum suction can contribute to the sinkhole formation. The key measures to prevent sinkholes in mining areas are to control the amount of mine drainage, reduce water level fluctuation, seal-off karst conduits and subsurface cavities in the overlying soil, prevent water inflow, and/or to increase gas pressure in the karst conduits. (C) 1999 Elsevier Science B.V. All rights reserved

Organic geochemistry of paleokarst-hosted uranium deposits, South China, 2000,
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Min M. Z. , Meng Z. W. , Sheng G. Y. , Min Y. S. , Liu X. ,
The paleokarst-hosted uranium deposits in organic-matter, clay-rich Devonian-Carboniferous carbonates are an economically important, new type of uranium deposit in China. The organic matter intimately associated with the uranium mineralization in this type of deposit has been characterized by petrographic, isotopic, gas chromatographic, pyrolysis-gas chromatographic, infrared spectroscopic and elemental geochemical methods. Comparing genetic types of the organic matter in unmineralized and mineralized samples indicates that no fundamental differences are found. The organic matter is chiefly of marine origin and contains a minor terrestrial component. The immature nature of the indigenous organic matter in the unmineralized samples shows generally a low-temperature history (less than or equal to max. 65 degrees C), and geologic data show a shallow maximal burial depth. By combining the organic geochemistry with the geological data, U-Pb dating and temperature determinations, an overall formation process for this type of uranium deposit is deduced. The formation of the paleokarst-hosted uranium deposits in South China is the result of: (1) repeated paleokarstifications of the Devonian and Carboniferous organic, clay-rich carbonate along the faults and unconformities between different strata because of the Hercynian and Yanshanian regional tectonism, and extensive formation of solution-collapse, solution-fault breccias; (2) accumulation of organic matter and clays in the paleocaverns and matrix of the breccias, fixation and adsorption of uranium by the organic matter and clays from the paleokarst waterflows that leached metals from the uranium-bearing host carbonates during their passage towards the karst zones, (3) reduction of uranium by the organic matter and formation of protore and low-grade ore; (4) circulation of heated formational waters and deep circulating, uraniferous meteoric waters by tectonic pumping, reworking the uranium-rich, paleocave-fillings, protore and low-grade ore, reduction and formation of primary uranium minerals (uraninite and coffinite) because of the reducing environment resulting from organic matter and sulfide. (C) 2000 Elsevier Science B.V. Ail rights reserved

Geochemical and mineralogical characteristics of Fe-Ni- and bauxitic-laterite deposits of Greece, 2000,
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Eliopoulos Dg, Economoueliopoulos M,
Contiguous vertical sample profiles from Ni-laterite deposits with in situ features (Kastoria, Profitis Ilias, and Tsouka) and allochthonous Ni- and bauxitic-laterite deposits in contact with basement limestone (Nissi) and bauxitic-laterites lying on peridorite (Parhari) were analyzed for major, trace (including Tn and U), rare earth and platinum-group elements (REE and PGE, respectively). In addition, minerals with emphasis to chromite grains found as residual components in these laterites, inherited from the ophiolitic parent rocks, were analyzed by microprobe. Low Al2O3, TiO2, REE, Th and U contents are common features of the Kastoria, Bitincka and Tsouka deposits. Tn contrast, elevated REE contents are present in the karst-type bauxitic- and Ni-laterite ores of Nissi and bauxitic-laterites of Parhari. The bauxitic-laterite deposit of Nissi attains REE contents of thousands parts per million in samples from the contact between the lowest part of the bauxitic-laterite and the footwall limestone. Highest contents of Th and U are found in the bauxitic-laterites, with Th ranging from 4 to 28 ppm and U from 4 to 66 ppm. In general, increasing Al contents are accompanied by elevated Ti, REE, Tn and U contents at the Parhari and Nissi laterite deposits. Goethite, is the dominant mineral in all Ni-laterite profiles studied, while boehmite co-existing with goethite is common in the bauxitic-laterites at Nissi and Parhari. Goethite exhibits variable Al contents, while the Al/Fe ratio increases towards the top of the profiles. The PGE concentrations are generally low, ranging from less than 100 ppb to a few hundred parts per billion. The lowest values - lower than in the bedrock - were recorded in the saprolite zone. A certain enrichment in Pt (up to 48 ppb), Pd (7 ppb), and Au (16 ppb) is recorded in the reddish altered peridotite overlying the saprolite zone at Profitis Ilias. The Fe-Ni ore overlying the reddish altered peridotite has the highest Os values (14 ppb), Ir (32 ppb), Ru (66 ppb), Rh (20 ppb), Pt (86 ppb), and Pd (186 ppb). Gold contents are below 36 ppb. An increasing Pt/Pd ratio from 3.0 in Fe-Ni-laterites to 6.0 in bauxitic-laterites is apparent. Both whole rock compositions and mineral chemistry of laterites indicate that major controlling factors of the composition of the bauxitic-laterites are the conditions during transportation/deposition of the weathered material and during diagenesis/metadiagenesis stage rather than parent mafic ophiolitic rocks. The comparison between the primary composition of chromite in the saprolite zone and the overlying Fe-Ni ore may provide evidence for the discrimination between Fe-Ni ore linked to in situ weathering and ore derived by transportation to some extent of elastic and chemical material. (C) 2000 Elsevier Science B.V. All rights reserved

The occurrence of sinkholes and subsidence depressions in the far west Rand and Gauteng Province, South Africa, and their engineering implications, 2001,
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De Bruyn Ia, Bell Fg,
Dewatering associated with mining in the gold-bearing reefs of the Far West Rand, which underlie dolomite and unconsolidated deposits, led to the formation of sinkholes and subsidence depressions. Hence, certain areas became unsafe for occupation and were evacuated. Although sinkholes were initially noticed in the 1950s, the seriousness of the situation was highlighted in December 1962 when a sinkhole engulfed a three-story crusher plant at West Driefontein Mine. Consequently, it became a matter of urgency that the areas at risk of subsidence and the occurrence of sinkholes were delineated. Sink-holes formed concurrently with the lowering of the water table in areas which formerly had been relatively free of sinkholes. In addition, subsidence occurred as a consequence of consolidation taking place in the unconsolidated deposits as the water table was lowered. In the latter case, the degree of subsidence which occurred reflected the thickness and original density of the unconsolidated deposits which were consolidated. These deposits vary laterally in thickness and thereby gave rise to differential subsidence. Subsidence also occurred due to the closure of dewatered voids at the rock-soil interface. The risk of sinkhole and subsidence occurrence is increased by urban development, since interrupted natural surface drainage, increased runoff, and leakage from water-bearing utilities can result in the concentrated ingress of water into the ground. Where the surficial deposits are less permeable, the risk of instability is reduced. In the area underlain by dolomite, which extends around Johannesburg and Pretoria, these problem have been more notable in recent years because of housing development, both low-cost and up-market, and the growth of informal settlements. Residential densities may be very high, especially for low-cost housing, the development of which frequently has proceeded without recognition of the risk posed by karst-related ground instability. The appearance of significant numbers of small sinkholes has been associated with dolomite at shallow depth, that is, occurring at less than 15 m beneath the ground surface. The vulnerability of an area overlying dolomite bedrock at shallow depth is largely dependent on the spacing, width and continuity of grikes. When dolomite is located at depths greater than 15 m, the sinkholes which appear at the surface usually are larger in diameter. The risk of sinkhole occurrence in areas of shallow dolomite in general, may be greater, although the hazard itself is less severe. A classification system for the evaluation of dolomitic land based on the risk of formation of certain sized sinkholes has enabled such land to be zoned for appropriate development. Ongoing monitoring and maintenance of water bearing services, and the implementation of precautionary measures relating to drainage and infiltration of surface water are regarded as essential in developed areas underlain by dolomite. Special types of foundation construction for structures are frequently necessary

Origin of atoll lagoons, 2001,
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Purdy Edward G. , Winterer Edward L. ,
A database of 301 atolls from the Pacific, Indian, and Atlantic Oceans has been analyzed with respect to factors governing maximum atoll lagoon depth. Statistically significant correlations between maximum atoll lagoon depth and both atoll area and present-day rainfall are viewed as the combined effect of paleorainfall precipitation and catchment area in contributing to overall atoll morphology. This interpretation is supported by the gross saucer-shaped morphology of several of the Lau group of the Fiji Islands, and the subsurface Cretaceous Golden Lane atoll of Mexico, where evidence of reef rim construction is lacking but evidence for significant solution relief is compelling. The contribution of reefs to atoll rim construction appears to be limited generally to [~]10 m, leaving more than 20 m of relief to be explained at most atolls. At a number of these, the last interglacial highstand surface is [~]15-20 m beneath Holocene rim sediments. Subsidence rates of even 5 cm/ k.y. do not suffice to explain the subsea depth of this unconformity, suggesting the dominating influence of solution on relief expression. Calculations of solution rates relative to the residence time of sea level below given depths during the past 700 k.y. suggest that the observed atoll relief is in part inherited from more than one Pleistocene, or perhaps earlier, glacial stage. Whatever the precise time of origin, the data available strongly suggest that atoll morphology is solution determined rather than growth predicated

Central Aldan gold deposits, 2002,
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Vetluzhskikh V. G. , Kazansky V. I. , Kochetkov A. Y. , Yanovsky V. M. ,
The Central Aldan ore district stands out in many features against the other gold districts within the Aldan Shield. The gold, uranium, and other mineral deposits are located at a junction of regional structures, they originated within a relatively short time interval of about 100 Ma, the ore mineralization is closely spatially and genetically related to alkaline magmatism, the igneous rocks and related ore deposits are located within a concentric-radial structure, and the host rocks consist of basement and sedimentary cover contrasting in physicochemical properties. All these features allow us to consider the Central Aldan district as an endogenous ore-magmatic system. The Aldan complex of primarily ore-bearing alkaline basaltic crustal-mantle volcanic and plutonic rocks originated during four to five stages and numerous intrusive phases and extensive magma differentiation in mature continental crust including thin horizontally heterogeneous platform cover. Some facts considered in this paper allowed us, however, to comprise the whole series of Central Aldan gold deposits as an endogenous-exogenous ore-forming system characteristic of the tectonically activated regions of ancient platforms. The evolution of the Central Aldan district in the Jurassic, Cretaceous, and Cenozoic developed during the tectonic activation of Precembrian structures, oxidation of primary ores and weathering crust formation, and exposure of the Lebedinsk-, Kuranakh-, Ryabinovsk-, and Samolazovsk-type gold deposits to the erosion level. The formation of underground and surficial karst systems was initiated during the Jurassic weathering of carbonate rocks of the platform cover in subaerial environments. The endogenous stage of ore concentration was here directly followed by an exogenous stage with the formation of weathered rocks and gold placers in various morphostructural local environments, e.g., horsts, grabens, and graben valleys. Specific features of the placer structures and gold, quality in various placer types are related with hypogene ore bodies and elements of ore-controlling structures and zones of primary disseminated mineralization. The ore bodies of the Kuranakh and Samolazovskoe deposits actually belong to new types of endogenous-exogenous deposits. The gold dispersion and concentration related to karst formation are also significant in this ore district. Thus, Central Aldan is also an ore-placer district with specific features

Origin and Significance of Postore Dissolution Collapse Breccias Cemented with Calcite and Barite at the Meikle Gold Deposit, Northern Carlin Trend, Nevada, 2003,
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Emsbo P, Hofstra Ah,
The final event in a complicated hydrothermal history at the Meikle gold deposit was gold deficient but caused extensive postore dissolution of carbonate, collapse brecciation, and precipitation of calcite and barite crystals in the resulting cavities. Although previously interpreted to be part of the Carlin-type hydrothermal system, crosscutting relationships and U-Th-Pb geochronology constrain this hydrothermal event to late Pliocene time (ca. 2 Ma), nearly 36 Ma after ore formation. Mineralogic, fluid inclusion, and stable isotope data indicate that postore hydrothermal fluids were reduced, H2S-rich, unevolved meteoric waters ({delta}18O = -17{per thousand}) of low temperature (ca. 65{degrees}C). The{delta} 18O values of barite and calcite indicate that these minerals were in isotopic equilibrium, requiring that barite SO4 was derived from the oxidation of reduced sulfur; however, preexisting sulfides in breccia cavities were not oxidized. The{delta} 34S (15{per thousand}) values of barite are higher than those of local bulk sulfide and supergene alunite indicating that SO4 was not derived from supergene oxidation of local sulfide minerals. The 15 per mil {delta}34S value suggests that the H2S in the fluids may have been leached from sulfur-rich organic matter in the local carbonaceous sedimentary rocks. A reduced H2S-rich fluid is also supported by the bright cathodoluminescence of calcite which indicates that it is Mn rich and Fe poor. Calcite has a narrow range of {delta}13C values (0.3-1.8{per thousand}) that are indistinguishable from those of the host Bootstrap limestone, indicating that CO2 in the fluid was from dissolution of the local limestone. These data suggest that dissolution and brecciation of the Bootstrap limestone occurred where H2S-rich fluids encountered more oxidizing fluids and formed sulfuric acid (H2SO4). Intense fracturing in the mine area by previous structural and hydrothermal events probably provided conduits for the descent of oxidized surface water which mixed with the underlying H2S-rich waters to form the dissolving acid. The surface-derived fluid apparently contained sufficient oxygen to produce H2SO4 from H2S but not enough to alter pyrite to Fe oxide. Although H2S is an important gold-transporting ligand, the temperature was too low to transport a significant amount of gold. The presence of analogous calcite- and barite-lined cavities in other Carlin-type deposits suggests that the generation (and oxidation) of H2S-rich meteoric waters was a common phenomenon in north-central Nevada. Previous sulfur isotope studies have also shown that the Paleozoic sedimentary rocks were the principal source of H2S in Devonian sedimentary exhalative-type, Jurassic intrusion-related, Eocene Carlin-type, and Miocene low-sulfidation gold deposits in the region. The similar sulfur source in all of these systems suggests that basin brines, magmatic fluids, and meteoric waters all evolved to be H2S-rich ore fluids by circulation through Paleozoic sedimentary rocks. Thus, although not directly related to gold mineralization, the recent hydrologic history of the deposit provides important clues to earlier ore-forming processes that were responsible for gold mineralization

Alligator Ridge District, East-Central Nevada: Carlin-Type Gold Mineralization at Shallow Depths, 2003,
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Nutt Constance J. , Hofstra Albert H. ,
Carlin-type deposits in the Alligator Ridge mining district are present sporadically for 40 km along the north-striking Mooney Basin fault system but are restricted to a 250-m interval of Devonian to Mississippian strata. Their age is bracketed between silicified ca. 45 Ma sedimentary rocks and unaltered 36.5 to 34 Ma volcanic rocks. The silicification is linked to the deposits by its continuity with ore-grade silicification in Devonian-Mississippian strata and by its similar{delta} 18O values (~17{per thousand}) and trace element signature (As, Sb, Tl, Hg). Eocene reconstruction indicates that the deposits formed at depths of <300 to 800 m. In comparison to most Carlin-type gold deposits, they have lower Au/Ag, Au grades, and contained Au, more abundant jasperoid, and textural evidence for deposition of an amorphous silica precursor in jasperoid. These differences most likely result from their shallow depth of formation. The peak fluid temperature (~230{degrees}C) and large{delta} 18OH2O value shift from the meteroric water line (~20{per thousand}) suggest that ore fluids were derived from depths of 8 km or more. A magnetotelluric survey indicates that the Mooney Basin fault system penetrates to mid-crustal depths. Deep circulation of meteoric water along the Mooney Basin fault system may have been in response to initial uplift of the East Humboldt-Ruby Mountains metamorphic core complex; convection also may have been promoted by increased heat flow associated with large magnitude extension in the core complex and regional magmatism. Ore fluids ascended along the fault system until they encountered impermeable Devonian and Mississippian shales, at which point they moved laterally through permeable strata in the Devonian Guilmette Formation, Devonian-Mississippian Pilot Shale, Mississippian Joana Limestone, and Mississippian Chainman Shale toward erosional windows where they ascended into Eocene fluvial conglomerates and lake sediments. Most gold precipitated by sulfidation of host-rock Fe and mixing with local ground water in zones of lateral fluid flow in reactive strata, such as the Lower Devonian-Mississippian Pilot Shale

The future of the dolomitic springs after mine closure on the Far West Rand, Gauteng, RSA, 2003,
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Swart C. J. U. , James A. R. , Kleywegt R. J. , Stoch E. J. ,
Approximately 1.2 km of dolomitic limestone overlies the Far West Rand gold reefs southwest of Johannesburg, South Africa. This karst aquifer is partitioned into several groundwater compartments by predominantly north-south trending syenite dykes. Prior to mining, the primary water flow was westwards, decanting over dyke boundaries as a succession of springs along the Lower Wonderfontein Spruit. Dewatering of the overlying dolomitic aquifer for safety and economic reasons by deep gold mining operations, caused the water levels of four compartments to drop and their respective springs to dry up. By perforating dykes, formerly separated aquifers were hydraulically interconnected by mining. Using historical and recent data of water flow-surface and groundwater-and pumping rates, a geohydrological model is presented. The results suggest that the water tables will rise to their pre-mining levels within 30 years after mining ceases and that the dry springs will flow again, despite the compartments being connected by the extensive mining operations

Geochemical exploration for gold in Jamaica: a comparison of stream sediment and soil surveys, 2004,
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Garrett Rg, Lalor Gc, Vutchkov M,
The geology of Jamaica is reviewed with reference to gold. Two geochemical surveys, one employing stream sediments for mineral exploration in selected regions of Jamaica considered a priori to have greater mineral potential, and the other an island-wide low-density soil survey to meet agro-environmental objectives, were undertaken in 1986 and 1988, respectively. The paper presents an interpretation of the previously unpublished soil data for gold, and undertakes a comparison of the two surveys in terms of their effectiveness for gold exploration. The stream sediment survey (1 site per 1 km2) led to the discovery of three new gold occurrences, one of which became a producing mine in 2001, and the recognition of two previously known auriferous districts. The low-density soil survey (1 site per 64 km2) identified the host rocks of three of these auriferous districts as having gold potential, including those of the producing mine, demonstrating its value as a broad-scale regional mineral reconnaissance tool. Geochemical studies of gold in Jamaica are complicated by the presence of transported palaeo-anomalies, related to Miocene ash-falls, in terra rossa soils in karst terrain. The Fe/Na ratio is an index of soil maturity and increases over two-and-a-half orders of magnitude with increasing soil age and mature. The plotting of Au versus the Fe/Na ratio in soils offers a simple procedure for identifying samples most likely to be related to gold occurrences in bedrock, i.e. high Au and low Fe/Na ratio. It is concluded that in the specific instance of Jamaica's high relief terrain and the apparent limitation of gold occurrences to the Cretaceous Inliers and Eocene Wagwater Trough underlying those high relief areas, stream sediment sampling is the most effective mineral exploration tool

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