The axi lowsulfidation ls epithermal deposit in northwestern china is the result of geological controls on hydrothermal fluid flow through strikeslip faults. Geological survey, mail stop 901, 345 middlefield road, menlo park, california 94025 abstract. Andrew mitchell, in geological belts, plate boundaries, and mineral deposits in myanmar, 2018. Adulariasericite auag or low sulfidation 2 and agznpb intermediate sulfidation epithermal deposits are located schematically in the low temperature, periphery of the mineral system, with porphyry cuaumo and pyrophyllitekaolinite high sulfidation or acidsulfate aucu epithermal systems more proximal to intrusive bodies. This below is an image of a simple low sulfidation vein system, with all its. For example, the characteristic form of these two styles of epithermal deposit is different table 2.
Selenium in some epithermal deposits of antimony, mercury. Purnama, baskara, kejora and gerhana and one lowsulfidation epithermal goldsilver deposit, pelangi. The martabe gold district, situated on the northwest coast of sumatra, indonesia, consists of four highsulfidation epithermal goldsilver deposits over an 8 km strike length. Other studies on midmiocene northern nevada lowsulfidation epithermal auag deposits have reported general conditions for deposition or have focused on rhyolitichosted ores. Evidence for transients in sulfidation state, due to boiling, local wall rock influence, or other factors, exists in all three types of epithermal deposits. Miocene and early pliocene epithermal goldsilver deposits in. The epithermal deposits of the yanacocha district are classified as highsulfidation or acidsulfate epithermal deposits e. They mainly occur in distal volcanic settings and their relationship to magmatism, apart from the common volcanic host rocks, is mostly speculative.
Epithermal deposits are now subdivided into low, intermediate and highsulfidation. High sulfidation acid sulfate type low sulfidation adulariasericite type disseminated misalnya pada epithermal agsnpbzn. Epithermal systems of the seongsan district, south korea. Contoh endapan epithermal low sulfidation endapan au ton umur lihir 924 quat porgera 600 mp round mountain 443 mp baguio district 300 quat hishikari 250 quat pacucha 200 mp kelian 180 mp gunung pongkor 175 mp dukat 150 cret cerro korikollo 147 mp cerro vanguardia 100 jura. The kencana auag low sulfidation epithermal deposit, situated in the neogene magmatic arc of halmahera, eastern indonesia, has an estimated resource of 4. Most low sulfidation deposits consist of cavityfilling veins with sharp boundaries, or. These studies lack in situ trace and majorelement analysis in order to provide a high precision model on midmiocene lowsulfidation, epithermal auag deposits. Models and exploration methods for major gold deposit types.
Exploration for epithermal gold deposits gold in 2000. The secondary classification of magmatic arc epithermal gold deposits is between high and low. Epithermal veins tend not to have great vertical continuity, but many are exceedingly rich and deserving of the term bonanza. Fundamental difference between high sulphidation epithermal deposits and low sulfidation deposits is the amount and degree of interaction between the magmatic fluid, groundwater and host rocks. Thompson, mineralogical association of canada short course vol. Society of economic geologists, economic geology v100 pp463490 8 the pascua hse system model shows preservation of the gold poor steam heated alteration cap overlying the concealed 27 moz aueq mineralization hosted by vuggy. Characteristics of high sulfidation epithermal deposits, and their relation to magmatic fluid. High sulfurmetal ratio enargite, luzonite, covellite. Other studies on midmiocene northern nevada low sulfidation epithermal auag deposits have reported general conditions for deposition or have focused on rhyolitichosted ores. Low salinity but variable high gases particularly h2s strong faultrelated permeability, episodic opening lowsulfidation epithermal au veins. Low sulfidation deposits have been wellrecognised for a long time. Purnama, baskara, kejora and gerhana and one low sulfidation epithermal goldsilver deposit, pelangi.
The high and low sulphidation epithermal deposits associated with blue coloured belts are late mesozoic and cenozoic in age generally pdf. Fluid inclusion gas analysis was also done in some samples and indicates that h2o accounts for 99. Although they are a product of the same igneous system, low sulfidation epithermals gold deposits are very different from high sulfidation. Riftrelated geothermal activity and epithermal gold veins. The high sulfidation epithermal deposits, mostly hosted by volcanic rocks, include largetonnage low grade deposits e. First order genetic classification of epithermal deposits, based on alteration and mineralogy. Characteristics of the geology, vein stratigraphy, mineralogy, and metal zoning at kencana were combined to develop an ore genesis model, which can be used to generate new targets in the gosowong goldfield and other lowsulfidation epithermal districts. In low sulfidation the main control for gold deposition, is fluid boiling caused by a drop in the confining pressures the fluid approaches the surface. The term intermediatesulfidation epithermal deposits has been used for nearly two decades. Unfortunately, the tonnage of ore in epithermal veins is typically small compared with other types of lower grade gold deposits. Epithermal goldsilver and porphyry coppergold exploration. Origin of basalthosted epithermal goldsilver mineralization. A dapted from corbett 2001 and corbett and leach 1998.
Smith2 abstract mines in the oatman mineralized district, near oatman in northwestern arizona, have produced more than 1. Epithermal gold for explorationists paper 200201, april 2002 4 figure 3. Low sulfidation ls epithermal deposits appear to be distinct and show little variation from low and intermediate sulfidation states. Generalized sketches showing the relation of fluid types to alteration zoning in the two styles of epithermal deposits. The axi low sulfidation ls epithermal deposit in northwestern china is the result of geological controls on hydrothermal fluid flow through strikeslip faults. The term epithermal is derived from the latin for shallow heat reflecting the shallow crustal environment in which they form.
Controls to low sulphidation epithermal auag mineralisation. Guanajuato, mexico, epithermal deposits, intermediate sulfidation, low sulfidation, rbsr ages, illite, arar ages, adularia. Resources have been estimated for the three principal known deposits, purnama, baskara and pelangi. In some classic localities, low sulfidation epithermal deposits crosscut or telescope earlier formed porphyry.
The wunthobanmauk segment of the arc contains numerous low sulfidation or quartzadularia type vein prospects and workings, most of which are hosted in the basaltic and andesitic mawgyi volcanics. These studies lack in situ trace and majorelement analysis in order to provide a high precision model on midmiocene low sulfidation, epithermal auag deposits. Much of the mineralisation in low sulphidation epithermal vein deposits occurs within ore shoots which are best developed at the coincidence of several controls described below. Epithermal systems of the seongsan district, south korea an investigation on the geological setting and spatial and temporal relationships between high and low sulfidation systems thesis submitted by christopher david bowden, bsc hons, jcunq for the degree of doctor of philosophy in the school of earth sciences at. The martabe auag highsulfidation epithermal deposits. Epithermal deposits are now subdivided into low, intermediate and high sulfidation. The martabe gold district, situated on the northwest coast of sumatra, indonesia, consists of four high sulfidation epithermal goldsilver deposits over an 8 km strike length. Selenium in some epithermal deposits of antimony, mercury and silver and gold by d. Other types of globally important gold deposit include low and intermediatesulfidation epithermal, carlin, aurich vms, and witwatersrand type deposits figure 1. I i e n os short note geochronology of mexican mineral. The vertical interval of low sulfidation ore zones typically averages about 300 m buchanan, 1981, but may be as large as 600 to 800 m for intermediate sulfidation state deposits fig.
Lowsulphidation epithermal systems silicon dioxide. Lowsulphidation epithermal systems free download as powerpoint presentation. Epithermal deposits are classed as high, low or intermediate sulphidation based on mineral assemblage and the pheh of mineralizing fluids. Geology and genesis of the multistage high sulfidation epithermal pascua auagcu deposit, chile and argentina. Characteristics, distribution, and relationship to magmatism david a. Advanced argillic assemblage, dominated by alunite and pyrophyllite at deeper levels. Short note geochronology of mexican mineral deposits. Pdf characteristics of highsulfidation epithermal deposits.
Pdf geophysical exploration for epithermal gold deposits. There are characteristic mineral textures and assemblages associated with epithermal deposits and, coupled with fluid inclusion data, they indicate that most lowsulfidation and highsulfidation deposits form in a temperature range of about 160 to 270c. Chapter 18 linkages between volcanotectonic settings, ore. However, it is first interesting to consider the fluids which form many veins. Endapan epithermal karakteristik suhu relatif rendah 50250c terbentuk pada kedalaman dangkal 1 km klasifikasi. Jul 12, 20 epithermal gold deposits are among the richest gold deposits in the world with some bonanza grade ore shoots containing more than gt gold, or in other words, a kilogram of gold for every tonne of rock mined. Characteristics of high sulphidation epithermal gold deposits. Other articles where epithermal deposit is discussed.
In contrast to high and intermediate sulfidation deposits, exploration for low sulfidation au deposits, even where exposed, may be hampered by the visually subtle nature of. Characteristics of high sulphidation epithermal gold. They have characteristic textures and mineralogy, relatively short vein lengths, and mostly low fluid salinities and temperatures. Derivation of low and high sulphidation fluids including arc and rift low sulphidation. Now lets quickly cover the last of the broad groups, the intermediate sulfidation epithermal. Such controls occur commonly in ls epithermal deposits worldwide, but unfortunately, these have not been quantitatively analyzed to determine their spatial relationships with gold distribution and further guide mineral prospecting. Mineral resources department, geological survey of japan, 1 higashi, tsukuba 305, japan. The vertical interval of lowsulfidation ore zones typically averages about 300 m buchanan, 1981, but may be as large as 600 to 800 m for intermediate sulfidationstate deposits fig. Model to account for varying hydrothermal fluids which contribute towards the. Epithermal gold deposits part ii geology and gold deposits of the oatman district, northwestern arizona by ed dewitt, jon p. They contain economic concentrations from a precious metal such as gold and silver, and in some cases base metals such as copper, lead, iron ore and. The high and low sulphidation epithermal deposits associated with blue coloured belts are late mesozoic and cenozoic in age generally deposits located in the middle of plates grey coloured belts or metallogenic provinces are associated with paleozoic age ca. Other types of globally important gold deposit include low and intermediate sulfidation epithermal, carlin, aurich vms, and witwatersrand type deposits figure 1. This below is an image of a simple low sulfidation vein system, with all its components preserved.