The study area covers major parts of the worlds largest. Jul 10, 2019 the ahafo mine is composed of three orogenic gold deposits that have oxide and primary mineralization. The focus of the mining operation is a model, which is often based on incomplete or flawed data. Aspects of resource geology in archaean orogenic gold deposits. This class of gold deposit is characteristically associated with deformed and metamorphosed midcrustal blocks, particularly in spatial association with major crustal structures.
On the basis of predecessors study, this paper found that outbreak frequency of mantle plume is increase, while scale is reduce. Debate on the genesis of socalled orogenic gold deposits 75% of gold recovered through history. A tentative study of relationship between mantle plumes. Ore deposits as guides to geologic history of the earth. This research was funded through natural environment research council grant nej0218221 and the apc was paid through the rcuk oa block grant. Aspects of resource geology in archaean orogenic gold. The ones marked may be different from the article in the profile. Diversity of gold deposits, geodynamics and conditions of. Selected reference materials western mining services. Temporal relations between mineral deposits and global. The massawa gold deposit, eastern senegal, west africa.
The large finnish suurikuusikko orogenic gold deposit is in cluded for comparison with the younger swedish deposits. An orebody is commonly a poorly understood geological entity, and the resource model is generated from samples taken from this orebody. The paper presents analysis of the distribution of the principal parameters of mineralizing fluids depending on the age of the mineralization. Phillips, 20, continues largely because it is difficult to reliably identify the source of gold.
A geologic time scale 2004 why, how and where next. The koka gold deposit is located in the elababu shear zone between the nakfa terrane and the adobha abiy terrane, nw eritrea. Goldfarb et al orogenic gold and geologic time a global. Gardol, s 2001 orogenic metallic concentrations in surrounding rocks is gold and geologic time.
Orogenic gold mineralization in the qolqoleh deposit. Pdf a proposed revision of the orogenic gold class, based on. Orogenic gold deposits and prospects of the savransinitsovska area dniestrboug domain, ukrainian shield are hosted in archaean granulitefacies metamorphic rocks and have undergone a retrograde amphibolitefacies metamorphic overprint during the paleoproterozoic. On the source of orogenic gold geology geoscienceworld. The giant zaozigou ausb deposit in west qinling, china. Geological survey collaborated with international colleagues to assess undiscovered resources in porphyry copper deposits in the central asian orogenic belt and eastern tethysides. In the last decade, significant progress has been made in the definition, classification, characterization, thereby aiding understanding of the main gold deposit types. Pdf late palaeozoic orogenic goldantimony deposits from. Early synsedimentary or synvolcanic models and hydrothermal meteoricfluid models are now invalid. Orogenic gold deposits have formed over more than 3 billion years of earths history, episodically during the middle archean to younger precambrian, and continuously throughout the phanerozoic.
The geology of gold a collection of articles on the geology, mining, prospecting and history of gold. Metamorphic belts are complex regions where accretion or collision has added to, or thickened, continental crust. The term orogenic gold deposit, as defined by groves et al. Gold has historically been a key strategic commodity, and the study of gold deposit formation has long been investigated. Pacific region, australian journal of earth science, v.
Since it is the exchange of femg that is crucial table 1 mined orogenic gold deposits in the gold line and skellefte district, and some prospects presently under evaluation. H characteristics and controls of the largest porphyry copper. The savran ore field of the dniestrboug domain, ukrainian. Stephen gardoll senior project geologist selfemployed. As with the other gold deposit types above, all worldclass to. Pdf distinguishing intrusionrelated from orogenic gold. Porphyry copper assessment of the central asian orogenic. These areas host 20 known porphyry copper deposits, including the world class oyu tolgoi deposit in mongolia that was discovered in the late 1990s.
Within the mining industry, all phases of the operation are dependent on the resource model. As all of the deposits studied in this thesis are classified as archaean orogenic. Based on a paragenetic study, two main stages of gold mineralization were identified in the koka gold deposit. The geologic time scale gts is a system of chronological dating that relates geological strata. West africa, with presently an approximate 10,000metric ton t gold endowment, is one of the worlds great gold provinces and the largest paleoproterozoic gold producing region. After the discovery of the new world, colombia was the most. Gold mineralization in the qolqoleh deposit is almost entirely confined to a series of steeply dipping ductilebrittle shear zones generated during late cretaceoustertiary continental collision between the afro. Magmatichydrothermal models fail because of the lack of consistent spatially associated granitic intrusions and inconsistent temporal relationships. Minerals free fulltext physicochemical parameters and. Supercontinent is the movement of upper crust that could be cause by. Gold rich deposits can be formed at all stages of orogen evolution, so that evolving metamorphic belts contain diverse gold deposit types that may be juxtaposed or overprint each other. Distinguishing intrusionrelated from orogenic gold systems.
This cited by count includes citations to the following articles in scholar. In 1841 john phillips published the first global geologic time scale based on the types of fossils found in each era. The term orogenic gold deposits has been widely accepted, but there has been continuing debate on their genesis. Geology, fluid inclusion, and isotope constraints on ore. The present work aims to provide an update on the current state of knowledge on the different types of gold deposits models, geodynamics, their mode of formation and. Gold prospecting some history, geography and geology of gold prospecting by usgs. Pdf orogenic gold deposits in midto subgreenschist facies metamorphic belts of the neoarchean. A holistic model for the origin of orogenic gold deposits.
Scribd is the worlds largest social reading and publishing site. The mantle plume provides oreforming minerals to orogenic gold deposits, as well as affords force to supercontinent formation and decomposition, for the more controls the global tectonic. The inherent variation caused by geological complexity within the. Gsf giant gold provinces sga student chapter prague. Groves di, goldfarb rj, robert f, hart cj 2003 gold deposits in metamorphic belts. The qolqoleh gold deposit is located in the northwestern part of the sanandai. Based on the above discussions and comparisons of geological and geochemical characteristics with typical orogenic gold deposits, we propose that the yuka gold deposit has features similar to those of typical orogenic type gold deposits 1, 6, 7, 81, 88. Santoshb,c,d, acentre for exploration targeting, uwa, crawley 6009, wa, australia b centre for tectonics resources and exploration, department of earth sciences, university of adelaide, sa 5005, australia c state key laboratory of geological processes and mineral. Fluid inclusion and hospb isotope geochemistry of the. Goldfarb et al orogenic gold and geologic time a global synthesis ogr 2001 free download as pdf file.
Gold occurs in a wide range of deposit types and settings. Understanding the relationship between mineral occurrences and host granitic rocks can be controversial. This partly explains the high level of controversy on the origin of some deposit types. The geological society of america geologic time scale. The third global episode of orogenic gold vein formation occurred at ca. Goldfarb rj, groves di, gardoll s 2001 orogenic gold and geologic time. The gold resources are concentrated within the 2250 to 2000 ma greenstone belts of the manleo shield, forming the southern part of the west africa craton. Groves di, goldfarb rj, gebremariam m, hagemann sg, robert f 1998 orogenic gold deposits.
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