Hydrothermal processes and wall rock alteration request pdf. Crystallization and alteration of quartz monzonite, iron springs mining district, utah. Read the geochemistry of wall rock alteration in turbiditehosted gold vein deposits, central victoria, australia, journal of geochemical exploration on deepdyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips. Crystallization and alteration of quartz monzonite, iron. Wholerock geochemical analyses and calculated metasomatic reactions indicate the addition of k, al, s, as, au, ag, and ni during hydrothermal alteration. Roy a l l e n a thesis submitted in p a r t i a l ed.
Pyrite is the most widespread and predominant sulfide in stage 6 fig. Read wall rock alteration, atud gold mine, eastern desert, egypt. The different wall rock alteration mineral assem blages can be compared with metamorphic facies as, like these, they are formed in response to various pressure, temperature and compositional changes. Superimposed on the reginal alteration, the orerelated alteration is seen along veins, and this alteration was studied in the fujihonpi vein area. Pdf wallrock alteration, atud gold mine, eastern desert.
Kelly 1987 quaternary geology of willow creek and some age constraints on prehistoric faulting, lost. Wallrock alteration and hydrothermal flow paths about the. Zone 1 is an irregular, heterogeneous, borderzone whose chemistry resembles the lowtiquartznormative type ltq ena diabase but is interpreted as an alteration product. Detailed field mapping of wallrock alteration, veinlets, and sulfides, combined with petrographic, mineral composition, and fluid inclusion studies, has led to an assessment of temperatures, salinities, origins and flow paths of hydrothermal fluids through time and space. Geology and geochemistry of wallrock alteration at the. This may be caused by a greater degree of fluidrock interaction at depth, a smaller magmatic component, or a distinct magmatic component. Hydrothermal processes and wall rock alteration springerlink. Fractionation, hydrothermal alteration, and wallrock. Harraz and others published wall rock alteration, atud gold mine, eastern desert, egypt. A new zonation type of wmobearing altered biotite hornfels at the tyrnyauz deposit is reported. Geology and wall rock alteration at the hercynian draa sfar zn pbcu massive sulphide deposit, morocco a. Wallrock alteration of biotite hornfels at the tyrnyauz. Now coming to the exact question raised, the types are varied and manifold. The qsystem for rock mass classification, developed at the norwegian geotechnical institute ngi in 1974, originally included a little more than 200 tunnel case histories, mainly from scandinavia barton et al.
Wall rock alteration studies in four structurally controlled, epigenetic metalliferous belts in india indicate that the process, by the successive influx of solutions of varying composition, rich in metals, nonmetals, and volatiles, extended over a wide range of conditions, viz. Breccia, hydrothermal alteration and structural geology of. However, these processes assist in mineral alteration. Inrnooucrron professor kerr is one of the foremost students of hydrothermal wallrock alteration and has long shown friendly and helpful interest in anacondas study of. Requirements f o r the degree of the u n i v e r s i t y of b r i t i s h columbia. Cline, jean schroeder 1986 the sixteentoone epithermal silvergold deposit, esmeralda county, nevada. Wallrock alteration in the goldfield district, nevada. Implications for a hydrothermalmetasomatic genetic model. Pdf gold at the sheba gold mine is found in a variety of rocks, the most important being the schists and chert of the zwartkoppie formation. The archean amphibolite facies coolgardie goldfield. A wall rock alteration and fluid inclusion study m. Relationship of fluid inclusion geochemistry to wallrock.
Orebearing samples were not found, so that the 1 manuscript received november 26, 1962. Rose department of geosciences, pennsylvania state university, university park, pennsylvania 16802 abstract the carlin disseminated gold deposit occurs in an autochthonous sequence of paleozoic. Based on the mineral assemblages, the wall rock alteration around this vein is divided into three zones, a, b and c, from the vein side outwards. Wallrock petrology and geochemistry in alteration halos associated with mesothermal gold mineralization, central victoria, australia f. Alteration and clay filling have a negative effect on friction between joint surfaces.
Pdf wallrock alteration as a guide to goldbearing fracture zones. Gold fieldscale variations in the gangue and ore mineralogy of zoned wallrock alteration assemblages around lodes, the ore geochemistry, and the isotope chemistry of vein minerals at coolgardie are correlated with planview distance from the calooli monzogranite. T h e deposit c o n s i s t s o f s e v e r a l sub p a r a. Major styles of mineralization and hydrothermal alteration. The paper discusses the implications of wall rock alteration as a guide to exploration.
In this paper, four alteration zones are established, based on the mineral assemblage of clay minerals in volcanic rocks and relationship between formation of hydrothermal clay minerals and temperature in active geothermal systems. Emerald mineralization and amphibolite wallrock alteration at the khaltaro pegmatitehydrothermal vein system, haramosh mountains, northern pakistan. In 1993 the system was updated to include more than cases grimstad and barton, 1993. Compositional variations in hydrothermal white mica and. Kfeldspar alteration is mainly in the upper part of this zone, pervasively distributed in the amphibole trachyandesite, making the wall rock purplered fig. Secondary alteration of rocks and their contained first step in that process. In contrast, geothermal liquids are relatively reduced, near neutral ph, and their sulfidation state remains low to intermediate r. The geological characteristics, geochemical signature and. These wall rocks are more or less suffered from hydrothermal alteration in the vicinity of the vein systems. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. The main features of zonation are similar to those in acid leaching columns. The tonalites were emplaced along the contact between the andesitic volcaniclastic rocks and quartz diorite intrusives.
Altered wall rocks along vein deposits in the central cityidaho springs region, colorado 1 by e. In porphyry systems, there exists a close spatial and temporal link between. Copper and gold mineralisation is directly related to quartz veining and wall rock alteration that developed with multiple tonalite porphyry intrusions. Detailed field mapping of wall rock alteration, veinlets, and sulfides, combined with petrographic, mineral composition, and fluid inclusion studies, has led to an assessment of temperatures, salinities, origins and flow paths of hydrothermal fluids through time and space. Geology and geochemistry of wallrock alteration at the carlin gold deposit, nevada c. Wallrock petrology and geochemistry in alteration halos. Throughgoing carbonate veinlets, above and peripheral to altered. Diagrammatic compilation of data obtained in wairakei drillhole 71 showing stratigraphic sequence, faults, fresh rock, hydrothermal mineral distribution, temperature variations, and lithostatic and watervapour pressures. Pdf isotope wallrock alteration associated with hypogene. Barnes hl ed geochemistry of hydrothermal ore deposits, 1st edn. Nature and significance of wall rock alterations in some. The wall rock alteration around the hydrothermal aubearing quartz veins and lodes of the eastern.
Some minerals are members of a solid solution series and are samples of a range of compositional changes in a continuum, and thus are not mineral alteration products. Mississippi valleytype pbzn deposits models 32a, b. Nature of uranium mineralization and associated wall rock. They are not, however, generally referred to as alteration facies but as types of wall rock alteration. Multispectral analysis from airborne or satellite images may be able to detect wall rock alteration, obviously low sulfidation epithermal veins with their limited wall rock alteration will not be found like this but its a valuable tool for high sulfidation epithermals. Isotope wallrock alteration associated with hypogene karst of the crimean piedmont, ukraine. I begin by describing the main components of a hydrothermal system and models of magmaticrelated hydrothermal processes. Clay minerals in hydrothermally altered rocks 195 fig. These effects may develop in conjunction with silicification and dolomitization and constitute the major form of wallrock alteration in mvt districts. Hypogene alter ation is caused by ascending hydrothermal solu. Compositional variations in hydrothermal white mica and chlorite from wallrock alteration at the annmason porphyry copper deposit, nevada public deposited.
Pdf onzonkanbani gold deposits located in thabeikkyin township, mandalay region, central myanmar. The ore fluids were derived from oxidized magmatic source initially contaminated by reduced basement rocks. The intensity of such wall rock alteration differs from one deposit to another. Propylitic, sodic, sodiccalcic characteristics albite alteration is generally distributed along fracture and vein envelopes, typically becoming more pervasive toward the centre of the zone of. Major styles of mineralization and hydrothermal alteration and related solid and aqueousphase geochemical signatures by dana j. Wall rock alteration, atud gold mine, eastern desert.
Request pdf hydrothermal processes and wall rock alteration in this chapter, i discuss the effects that hydrothermal fluids derived from internal processes have on the ambient lithologies. Geochemistry, paragenesis, and wallrock alteration of the qatruyeh iron deposits, southwest of iran. Harraz department of geology, faculty of science, tanta university, tanta, egypt abstractthe atud gold mine, central eastern desert of egypt, is located in an intrusive. Geology and wall rock alteration at the hercynian draa. Pdf mineralogy, wall rock alteration, and geochemistry. Discontinuous calcite hydrocarbon veinlets predate hydrothermal alteration. Relationships of intrusion, wallrock alteration and. Occasionally rock alteration leads to misidentification of lithology as in studies of the amulet rhyolite in the noranda. Theses and dissertations department of geosciences. Yager chapter e3 of integrated investigations of environmental effects of historical mining in the animas river watershed, san juan county. Geological survey, denver, colorado abstract wallrock alteration along veins in the central cityidaho springs region, gilpin and. Wall rock is the rock that constitutes the wall of an area undergoing geologic activity. Carbonate alteration assemblages in the mafic metavolcanic host rocks, pro ceeding inward from background greenschist facies rocks to alteration envel opes enclosing individual veins, consist of. Mineral alteration is distinctly different than the rock alteration process metamorphism.
Wallrock alteration patterns are also well developed around the ore zone. Zinc, mn, co and ni are depleted in altered rock above the ore zone and redistributed upward and. Laurel hill, an almost completely exposed early jurassic volcanic neck, consisting of three concentric zones whose diverse chemical composition overlaps each of the major eastern north american ena jurassic diabase types. Geochemistry, paragenesis, and wallrock alteration of the. Hematite occurs as disseminated patches in stage 3 wall. Mineralization at zakanaka is characterized by a broad wall rock alteration halo of biotiteamphibole, and zoned quartzcalc silicate veins proximal to ore. The baker agau mine f o r m e r l y t h e chappelle deposit i s i n t h e toodoggone river area, n o r t h c e n t r a l b. The wall rock altered by kfeldspar show that finegrained kfeldspar in the groundmass of the amphibole trachyandesite typically have a secondary overgrowth texture fig. In this chapter, i discuss the effects that hydrothermal fluids derived from internal processes have on the ambient lithologies. Sandy particles, clay free disintegrated rock, etc. Examples are the rock along the neck of a volcano, on the edge of a pluton that is being emplaced, along a fault plane, enclosing a mineral deposit, or where a vein or dike is being emplaced. There are two main divisions of wall rock alter ation. Introduction alteration is a complex process of ion exchange whereby some constituents are removed, others are added and still others.