Numerous gold prospects however were recently discovered in association with metamorphic rocks This paper focuses on metamorphic rock hosted gold mineralization in Eastern Indonesia in
A TRIASSIC OROGENIC GOLD MINERALIZATION EVENT IN THE PALEOPROTEROZOIC METAMORPHIC ROCKS EVIDENCE FROM TWO TYPES OF RUTILE IN THE BAIYUN GOLD DEPOSIT LIAODONG PENINSULA NORTH CHINA CRATON Rutile grains often occur in different types of gold deposits and their U Pb ages have been widely
Orogenic gold deposits that are hosted in high grade rocks often present challenging exploration targets as their depositional histories are commonly obscured by ductile deformation and metamorphic overprints Knight et al 2000 Groves et al 2003 Heiligmann et al 2008 Disseminated gold mineralization and ore bodies such as those at the
Deposits are also found in higher grade metamorphic rocks known as hypozonal gold deposits These deposits are mostly hosted in amphibolite facies rocks in greenstone belts and are characterized by high temperature alteration assemblages such as garnet diopside hornblende and K feldspar and ore forming temperatures as high as
The northern margin of the NCC Fig 1 A is separated from the Central Asian Orogenic Belt CAOB by the regional scale Junggar Hegen fault metamorphic basement of this region consists mainly of Archean high grade metamorphic basement rocks middle to low grade metamorphic granite greenstone belts and Paleoproterozoic
The study area is found the placer and primary gold hosted by metamorphic rocks The gold is evidently derived from gold bearing quartz veins hosted by Pompangeo Metamorphic Complex PMC These
According to Large et al 2011 most of orogenic gold deposits across the globe are commonly associated with processes of metamorphism usually with the formation of the ore minerals in terranes of low metamorphic grade The main orogenic gold deposits are strongly related to deformed metamorphic terranes with gold commonly related to
For many decades gold exploration in Indonesia was focused on volcanic rock hosted deposits Present day gold exploration activities are more emphasized on the metamorphic rock hosted deposits
1 In weathered plutonic and metamorphic rocks areas because rock outcrops are rare due to the extensive regolith cover geological mapping is largely based on the interpretation of airborne data and imagery aerial photographs satellite images airborne geophysics when available etc In the sub Saharan Africa numerous village water supply campaigns were
Common metamorphic rocks at various degrees of metamorphism Pictures & Descriptions of Metamorphic Rock Types There are so many types of metamorphic rocks that it can be hard to keep track of them all but thankfully things are made a little easier by dividing them into two general groups foliated and non foliated or granular
Many workers accept a metamorphic model for orogenic gold ore formation where a gold bearing aqueous carbonic fluid is an inherent product of devolatilization across the greenschist amphibolite boundary with the majority of deposits formed within the seismogenic zone at depths of 6 12 km Fertile oceanic rocks that source fluid and metal may be heated
Metamorphic processes have been implicated in the genesis of many of the world s major gold deposits including gold in slate belts the Witwatersrand goldfields of South Africa Carlin deposits of Nevada and—of primary interest here—gold in Archaean greenstone belts Fig 1 This grouping is referred to as gold only using the term in order to differentiate
Uplift of the Otago Schist from metamorphic depths occurred in the Jurassic and early Cretaceous Harper and Landis 1967 Little et al lower greenschist facies rocks which host the Macraes gold deposit were uplifted through Rb/Sr and K/Ar system closure temperatures between 160 and 130 Ma Fig 2; Adams and Graham 1997 These radiometric
GOLD IN METAMORPHIC ROCKS FACTS AND FANCY Fig 1 A possible fractal like classification of mineral deposits in which the shear zone related ores have a symmetrical position to the intermediate ore deposits such as porphyry coppers or massive sulfide deposits acc to Uduba¿a et al 1998
The North China Craton NCC contains more than 7000 metric tons of gold arguably forming the third largest gold province in the world Deng and Wang 2016 Song et al 2018 Zhu et al 2015 Gold mineralization occurred mainly in the 130 120 Ma interval and is variably hosted in Neoarchean to Paleoproterozoic metamorphic rocks late Paleoproterozoic
The term initially coined by Bohlke 1982 has been broadened to characterize all quartz carbonate lode gold deposits hosted by metamorphic rocks Also and Tomkins 2013 have posited that
Gold mobilization during metamorphic devolatilization of Archean and Paleoproterozoic metavolcanic rocks Patten; Volcanic rocks in Archean and Paleoproterozoic greenstone belts are abundant and have been suggested as a potential Au source for orogenic Au deposits The behavior of Au during metamorphism of these rocks is
Gold Ag As Sb Hg Mo and W were found to have significantly lower concentrations in higher grade metamorphic rocks compared to unmetamorphosed protolith samples
Metamorphism derived from the Greek meta meaning change and morphe meaning form is the process by which a rock responds to variations in ambient physical chemical conditions while remaining in a more or less solid state These changing conditions within the Earth may either be intensive mass independent variables such as pressure P and
As a model for progressive metamorphism petrologists consider different metamorphic facies series the sequences of metamorphic rocks that would form in different metamorphic environments The PT diagram in Figure shows the most important of these series Rocks undergoing contact metamorphism experience only low pressure
Metamorphic Rocks Fool s Gold in the Making 1 What are Metamorphic Rocks Sculptures and Monuments Metamorphic rocks have been used for centuries to create sculptures and monuments The durability and beauty of these rocks make them ideal for creating lasting works of art that can withstand the test of time Examples of famous sculptures
The source of the auriferous fluid is from the metamorphism of thousands of km 3 of rock in response to elevated temperature Some sequences such as altered basaltic rocks and greywacke have hydrous minerals carbonates and minor sulfide that react to produce a supercritical H 2 O CO 2 H 2 S fluid that dissolves nanometric gold at the time of fluid formation
Southern Chile placer gold deposits have been known and exploited since Spanish colonial times Despite this precise knowledge about their origin is scarce This work aims to identify possible primary sources of the gold in the Pureo placers by studying the morphological and chemical characteristics of gold particles according to their spatial
Orogenic Gold Deposit in Metamorphic Rocks Minerals and Structural Control at Rarowatu Area Southeastern Arm of Sulawesi Indonesia February 2023 DOI / 2023 2 10
