formation of gold deposits

Formation of gold deposits: Review and evaluation of the The continuum model differs from alternative genetic models for Archaean greenstone gold in that it po formation of gold deposits

formation of gold deposits

  • Formation of gold deposits: Review and evaluation of the

    The continuum model differs from alternative genetic models for Archaean greenstone gold in that it postulates the formation of gold deposits anywhere from prehnite–pumpelleyite to granulite facies conditions, and over an interval of 20–25 km vertically through the crust ()Explicit in the model is that many deposits formed at the peak of metamorphism (Fig 3, Fig 4; eg Groves, 1993The continuum model is reviewed at this stage because we believe that it does not successfully account for many aspects of gold deposit formation The most obvious shortcoming is in considering ore deposits found in rocks of uppermost amphibolite and granulite facies domains where temperatures were appropriate for partial meltingFormation of gold deposits: Review and evaluation of theFormation of Gold Deposits This book addresses the origin of gold deposits to answer questions of science and curiosity These answers contribute in turn to the improved exploration and mining of gold Initially there is a summary of the methods used to address the genesis of gold deposits including some of the essential science and conceptsFormation of Gold Deposits | Neil Phillips | Springer

  • (PDF) Formation of gold deposits: a metamorphic

    Formation of gold deposits: a metamorphic devolatilization model G N P H I L L I P S 1 , 2 A N D R P O W E L L 1 1 School of Earth Sciences, The University of Melbourne, Melbourne, VicThe correlation of major gold deposits with rock type, even when the gold is primarily in veins, argues for rockdominated depositional systems, not fluiddominated ones As a consequence, a general role in gold deposition for fluid mixing, temperature decrease and/or fluid pressure decrease and boiling is unlikely, although such effects may beFormation of gold deposits: a metamorphicThe correlation of major gold deposits with rock type, even when the gold is primarily in veins, argues for rock‐dominated depositional systems, not fluid‐dominated ones As a consequence, a general role in gold deposition for fluid mixing, temperature decrease and/or fluid pressure decrease and boiling is unlikely, although such effectsFormation of gold deposits: a metamorphic

  • Formation of gold deposits: Review and evaluation of the

    The hypozonal gold deposits occur mainly in Archean terranes (Groves, 1993;Knight et al, 1993), such as Challenger gold deposit in Southern Australia (Tomkins et al, 2004), Big Bell gold depositAbstract The continuum model has been one of the more widely advocated genetic models for ‘goldonly’ deposits such as those found in Archaean greenstone belts It postulates that hydrothermal gold deposits were formed throughout a 20–25 km vertical crustal profile, from temperatures above 700 °C to below 180 °C, and that the deposition occurred synchronous with the peak of metamorphismFormation of gold deposits: Review and evaluation of theOrogenic gold deposits account for an estimated 75% of the gold extracted by humans (Phillips 2013), including the tonnage of Witwatersrand, the world’s largest district (∼30% of gold extracted: Phillips and Powell (2011) – either as the erosion of primary gold deposits or from hydrothermal accumulation Such deposits are thus the largestParameters for the formation of orogenic gold deposits

  • Introduction to Geology and Resources of Gold, and

    A14 Gold solubility versus oxygen activity diagram showing solution path during oxidation A22 TABLES Al Temperatures of formation and salinities for selected epithermal precious metal deposits All A2 Summary of gold contents for selected rock types A14 A3 Partial list of aqueous gold species occurring in natural systems A16 IV ContentsThe correlation of major gold deposits with rock type, even when the gold is primarily in veins, argues for rock‐dominated depositional systems, not fluid‐dominated ones As a consequence, a general role in gold deposition for fluid mixing, temperature decrease and/or fluid pressure decrease and boiling is unlikely, although such effectsFormation of gold deposits: a metamorphicAbstract The continuum model has been one of the more widely advocated genetic models for ‘goldonly’ deposits such as those found in Archaean greenstone belts It postulates that hydrothermal gold deposits were formed throughout a 20–25 km vertical crustal profile, from temperatures above 700 °C to below 180 °C, and that the deposition occurred synchronous with the peak of metamorphismFormation of gold deposits: Review and evaluation of the

  • Formation of gold deposits: a metamorphic

    Formation of gold deposits: a metamorphic devolatilization model Formation of gold deposits: a metamorphic devolatilization model PHILLIPS, G N; POWELL, R 00:00:00 A metamorphic devolatilization model can explain the enrichment, segregation, timing, distribution and character of many goldfields such as those found in Archean greenstone belts, slate‐belts and otherThe continuum model has been one of the more widely advocated genetic models for 'goldonly' deposits such as those found in Archaean greenstone belts It postulates that hydrothermal gold deposits were formed throughout a 2025 km vertical crustal profile, from temperatures above 700 °C to below 180 °C, and that the deposition occurred synchronous with the peak of metamorphismFormation of gold deposits: Review and evaluation of theThe formation of gold deposits in South Africa 20 April 2017 The left picture shows uraninite (uranium ore) that surrounds gold In the right picture, a computerThe formation of gold deposits in South Africa

  • Gold Deposits | Goldfo

    Gold Deposits in Small Concentrations Gold is one of the most valuable and at the same time rarest metals on earth It is estimated that up to now only 150,000 tonnes have been extracted worldwide Indeed gold is present everywhere in the 16 kilometre thickMuch of global gold production has come from deposits with uneconomic concentrations of base metals, such as copper, lead and zinc These 'goldonly' deposits are thought to have formed from hot, aqueous fluids rich in carbon dioxide, but only minor significance has been attached to the role of the CO2 in the process of gold transportRole of CO2 in the formation of gold depositsOrogenic gold deposits account for an estimated 75% of the gold extracted by humans (Phillips 2013), including the tonnage of Witwatersrand, the world’s largest district (∼30% of gold extracted: Phillips and Powell (2011) – either as the erosion of primary gold deposits or from hydrothermal accumulation Such deposits are thus the largestParameters for the formation of orogenic gold deposits

  • Gold Deposits and Their Geological Classification

    A rational geological classification of the commonly recognized lode gold deposits is feasible if it is based on the geological settings of the deposits, host rocks, nature of mineralization and geoche mical signature Sixteen common types of bedrock gold deposits are distinguished from one another and their main geological attributes areThe major gold deposits in East China are characterized by their occurrence in preCambrian host metamorphic rocks, restriction in some specific stratigraphicstructural terranes, tendentious localization in ductile or ductilebrittle shear zones, association with the syntexistype granitoids, and significant remobilization, superimposition and enrichment by the laterstage Mesozoic tectonoImportant geological factors controlling the formation ofGoldladen water heated by magmamolten rockin Earth's shallow crust forms a variety of lode gold deposits Hydrothermalhot waterfluids rich in sulfur form gold ores in rocks of active volcanoes The deposits of Summitville, Colorado, are an example 3 Gold minerals form in hot rocks in and around volcanoesForming Deposits | AMNH

  • Formation of gold deposits: a metamorphic

    Formation of gold deposits: a metamorphic devolatilization model Formation of gold deposits: a metamorphic devolatilization model PHILLIPS, G N; POWELL, R 00:00:00 A metamorphic devolatilization model can explain the enrichment, segregation, timing, distribution and character of many goldfields such as those found in Archean greenstone belts, slate‐belts and otherThe continuum model has been one of the more widely advocated genetic models for 'goldonly' deposits such as those found in Archaean greenstone belts It postulates that hydrothermal gold deposits were formed throughout a 2025 km vertical crustal profile, from temperatures above 700 °C to below 180 °C, and that the deposition occurred synchronous with the peak of metamorphismFormation of gold deposits: Review and evaluation of theThe formation of gold deposits in South Africa 20 April 2017 The left picture shows uraninite (uranium ore) that surrounds gold In the right picture, a computerThe formation of gold deposits in South Africa

  • The formation of gold deposits in South Africa GEOMAR

    20 April 2017/Kiel The Witwatersrand basin in South Africa hosts the largest known gold repository on Earth – but how was it formed? Scientists of the GEOMAR Helmholtz Centre of Ocean Research Kiel and Canadian research institutes were able to figure out how parts of the Earth’s largest gold deposits formed about three billion years agoA rational geological classification of the commonly recognized lode gold deposits is feasible if it is based on the geological settings of the deposits, host rocks, nature of mineralization and geoche mical signature Sixteen common types of bedrock gold deposits are distinguished from one another and their main geological attributes areGold Deposits and Their Geological ClassificationThese 'goldonly' deposits are thought to have formed from hot, aqueous fluids rich in carbon dioxide, but only minor significance has been attached to the role of the CO2 in the process of gold transport This is because chemical bonding between gold ions and CO2 species is not strong, and so it is unlikely that CO2 has a direct role in goldRole of CO2 in the formation of gold deposits 百度学术

  • The formation of gold‐rich seafloor sulfide deposits

    Similar to other highgold midocean ridge vent sites, it does not share recognized characteristics with highgold VMS deposits in the geological record where the auriferous deposits are generally associated with an arc setting, bimodality in hostThe major gold deposits in East China are characterized by their occurrence in preCambrian host metamorphic rocks, restriction in some specific stratigraphicstructural terranes, tendentious localization in ductile or ductilebrittle shear zones, association with the syntexistype granitoids, and significant remobilization, superimposition and enrichment by the laterstage Mesozoic tectonoImportant geological factors controlling the formation ofexample of this is the Shuangwang gold deposit (Fan, SC and Jin, QH, 1994), which is a large Carlintype gold deposit in the Qinling area, hosted by stratabound breccia bodies (fig 29), and located in Devonian age Xinhongpu Formation rocks, whichGEOLOGY OF SEDIMENTARY ROCKHOSTED GOLD