Banded iron formation bifassociated gold deposits, a subtype of orogenic lode gold deposits, are structurally controlled at all scales, ranging from the distribution of deposits along major structures to the internal textures and structures of the ore. The saramacca gold deposit, a new orogenic gold discovery in the guiana shield amec round up 2018, vancouver l tsx. Some of the properties are available for option from prospectors or as joint ventures with junior mining companies. Cassidy proterozoic lode gold and ironcopper gold deposits. Composition and origin of fluids associated with lode gold deposits. The country rocks hosting the deposits are predominantly of devonian age with low. Neighbouring orogenic gold deposits may be the products of. A scaleintegrated exploration model for orogenic gold deposits. Gold has historically been a key strategic commodity, and the study of gold deposit formation has long been investigated. A proposed classification in the context of their crustal distribution and relationship to other gold deposit types, authordavid i. The key parameters accounting for their formation remain under discussion.
Orogenic gold, or gold deposits in metamorphic rocks, and associated placer deposits, comprise about 6575 percent of this endowment, with lodes existing as structurallyhosted vein and or disseminated orebodies. It originated as late toniancryogenian island arcs on the site of the mozambique. Models and exploration methods for major gold deposit types. Phillips, 20, continues largely because it is difficult to reliably identify the source of gold. The late timing of orogenic gold deposits within the structural evolution of the host orogen. Trace element compositions of pyrites can be used to effectively discriminate orogenic gold and vhms deposit signatures during exploration. Orogenic gold deposits have become attractive exploration targets because of the potential for relatively high grades. Rethinking deposit models for phanerozoic orogenic gold. Orogenic gold deposits of all ages, from paleoarchean to tertiary, show consistency in. Distribution of orogenic gold deposits in relation to.
In both types of orogen, hydrated marine sedimentary and volcanic rocks have been added to continental margins during tens to some 100. Prospectivity analysis of orogenic gold deposits in saqez. Orogenic gold deposits in the superior province of manitoba. This setting contrasts with the majority of orogenic lode gold deposits worldwide, which are. Anderson mineral deposits geologist manitoba geological survey scott d. These are dominated by orogenic gold deposits that were put in place during the major orogenies.
Orogenic gold short course manitoba mining and minerals convention 2008. A proposed classification in the context of their crustal distribution and relationship to other gold deposit types. These were first filtered to remove duplicates and non gold occurrences. Scribd is the worlds largest social reading and publishing site. Orogenic gold deposits, or gold deposits in metamorphic rocks, are the spatially and temporally most widespread gold deposit type, defining important exploration targets in precambrian shields and in phanerozoic orogen ic belts. Metallogenesis of mesozoic orogenic gold deposit in. A peculiar feature of these deposits is the association of gold with a variety of copper sulfides and the rare copper arsenides domeykite and koutekite which is atypical for orogenic type gold deposits. This au ore upgrading model, referred to as aseismic refinement, provides a new insight for the genesis of ultrarich au mineralization and, based on textures reported from many au deposits, may be a globally significant component in the formation of orogenic au deposits. Good science, good exploration, can find new deposits eg.
Sedimenthosted gold deposits of the worlddatabase and grade. On the source of orogenic gold geology geoscienceworld. The socalled mesothermal gold deposits are associated with reginally metamorphosed terranes of all ages. In the context of this ongoing debate, the jurassic danba gold deposit of the northwestern yangtze craton, as described below, is potentially critical as it is a very rare phanerozoic orogenic deposit with typical hypozonal. Structural and lithological controls on bifassociated. Structural geometry of orogenic gold deposits sga student.
For orogenic gold deposits at deeper crustal levels, oreforming fluids are commonly focused along. This deposit is a classic example of a lowsulfide turbidityhosted orogenic gold quartz deposit sulfide less than 25% located in the folds of sandstoneshale rock as a saddle reef and as discordant veins and stockwork, predominantly in the anticlinal domes. Developing predictive capacity through good science boosts confidence, helps overcome investment notions that victorian gold is maybe too hard. Schematic cross secti on showing the key geologic elements of the main gold systems and their crustal depths of emplacement. The distribution of au and associated trace elements in pyrite and arsenopyrite from late archean hutti and hirabuddini orogenic gold deposits, eastern dharwar craton, southern india was investigated by laser ablationinductively coupled plasmamass spectrometry.
Pdf exploration targeting for orogenic gold deposits in. Epithermal gold deposits part ii geology and gold deposits of the oatman district, northwestern arizona by ed dewitt, jon p. Pdf parameters for the formation of orogenic gold deposits. The saramacca gold deposit, a new orogenic gold discovery. Hydrothermal gold deposits epithermal, carlintype, and orogenic have accounted for 75% of lode gold production. Orogenic gold deposits are the main source of gold for humanity. These deposits formed from the archaean to phanerozoic at crustal depths of. These gold deposits, combined with gold panning and artisanal mining, underscore the highly m pro ising character of the area. The deposit is hosted by a secondorder ductile shear zone of the cadillaclarder lake fault zone cllfz. Mcqueen crc leme, australian national university, canberra, act 0200 and school of rehs, university of canberra, act 2601. This study presents data on the geological setting and ore mineralogy of these deposits.
Introduction to orogenic gold deposits investing news network november 23rd, 2014 orogenic deposits are the source of much of the worlds gold. These deposits formed from the archaean to phanerozoic at crustal depths of more than 4 km. Ores were formed during compressional to transpressional deformation processes at convergent plate margins in accretionary and collisional orogens. Orogenic gold deposits archaean greenstonehosted deposits. In contrast to typical orogenic gold deposits displaying textures indicating brittle ductile deformation and recrystallization, those of grass valley only display minor brittle fracturing of quartz and pyrite. Existing published models for orogenic gold deposits are based heavily on the worldclass late archean deposits, especially those in the abitibi belt in canada and the yilgarn province in southwest australia.
The archean orogenic new celebration gold deposit, located in the kalgoorlie terrane of the eastern goldfields province, western australia, is hosted within the western segment of the firstorder boulder lefroy fault zone blfz. For orogenic gold deposits at deeper crustal levels, oreforming fluids are. Four eagles, and can help brownfields deliver fosterville, costerfield, ararat. Following the first discovery in 1890, gold mining has taken place almost continuously in manitoba for over 100 years. Such an assumption is valid because this deposit type is, by far, the most dominant gold deposit type in the studied craton. Detailed material for this globally important deposit type will be provided on tectonic and structural controls. The approach to modelling these systems is based on the following assumptions about orogenic gold systems at the deposit to camp scale. Models and exploration methods for major gold deposit types robert, f. Mineralogical association of tourmalinepyrite in orogenic gold deposits, val dor mining district, quebec, canada. Predictive targeting in australian orogenicgold systems. Timing, nature and characteristics of orogenic gold. The shangxu gold deposit is a medium size deposit with average grade of 6. In mali, a less developed country, gold export has substantially increased in the 1990s 1. The wasamac deposit is an example of archean greenstonehosted gold deposit located in the abitibi belt, 15 km southwest of rouynnoranda.
Mesothermal gold deposits form half way up through the rise of the melt from the deep crust to the surface usually at a depth of less than 10 km but greater than 1 km. Common or evolving fluid and metal sources through. Orogenictype coppergoldarsenicbismuth mineralization. Phillips and powell 2011 either as the erosion of primary gold deposits or from hydrothermal. Parameters for the formation of orogenic gold deposits. Numerous and diverse gold deposit types formed during the cenozoic era include epithermal, porphyry, skarn and carlintype deposits. These deposits formed from the archaean to phanerozoic at crustal depths of more than 4. A carbonaceous sedimentary sourcerock model for carlin. Pyrite compositions from vhms and orogenic au deposits in. Mineralogical association of tourmalinepyrite in orogenic. The nubian shield is a large region of juvenile neoproterozoic rocks that, together with its counterpart in the arabian shield, is part of a major accretionary orogen.
If all orogenic gold deposits define a coherent mineral system, there are only. Importantly, the lodes may be located on one side of a cross fault, but not consistently displaced to the other side of the fault. Ontario geological survey openfile report, 5524 1984, p. The abundance of orogenic gold deposits reflects paleozoic to triassic. The orogenic gold deposits are confined to this jog and are sited in a number of d2 shear zones at, or close to, their intersection with the crossfault arrays. Debate on the genesis of socalled orogenic gold deposits 75% of gold recovered through history. Although these deposits form in distinctly different geologic settings and by. Orogenic gold deposits of china society of economic. Mali suffers from artisanal and smallscale mining formalization problem as other mineral rich countries in the region2. The term mesothermal veins is really a sack term, referring simply to the depth formation. Pdf from intrusionrelated to orogenic mineralization. Dr richard goldfarb is a world expert on orogenic gold deposits. Mineral system analysis, targeting model and prospectivity analysis.
Crowe a comparison of australian and global examples. Gold in 2000 contents gold in 2000an introduction s. Gold has been produced from quartzcarbonate vein orogenic deposits and as byproduct from volcanogenic massive sulphide vms deposits. These gold deposits performance as same geological characteristics as that typical orogenic gold deposit, which confirm that an important orogenic gold mineralization event existed in the bangongnujiang suture belt. Mesothermal and greenstone gold deposits aka orogenic. In rare examples where phanerozoic orogenic gold deposits are hosted in precambrian. Knoxrobinson, 2000 and are sited in accretionary or collisional orogens of all ages. Aseismic refinement of orogenic gold systems economic. Orogenic gold short course orogenic gold deposits in the superior province of manitoba orogenic gold deposits in the superior province of manitoba scott d. A rare phanerozoic amphibolitehosted gold deposit at.
Traceelement geochemistry of pyrite and arsenopyrite. Exploration targeting for orogenic gold deposits in the granitestanami orogen. The vast array of ore deposit types and their particular. Hydrothermal evolution of two stages of gold mineralization at the. He explains how orogenic gold formed during plate tectonic collisions and. This paper presents evidence and arguments that carbonaceous sedimentary rocks were a source for au and as in sedimenthosted orogenic and carlintype gold deposits and develops a. Gold deposits in polydeformed metasedimentary rocks. Gold deposits free download as powerpoint presentation. Both deposits share the main characteristics of orogenic gold deposits.
1368 624 1525 991 302 1235 1390 1504 278 870 421 1250 719 824 518 387 1300 921 1444 197 609 573 1257 1092 1033 715 1550 1369 1296 51 1490 957 223 6 64 1234 1326 60 56 1139 662 840 1050 765 1424