Thus, for example, the most prevalent types of alteration in acidic rocks are sericitization, argillization, silicification and pyriti zation. 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. The two leaves of cavity walls can be of equal thickness if it is non load bearing wall. Low sulphidation epithermal auag deposits are characterised by neutral wall rock alteration assemblages dominated by illitic clays, although acidic waters collapsing. Supertopos climbing discussion forum is the worlds most popular community discussion forum for people who actively climb outdoors. About 10 types are being named as under though numerous permutations and combinations often tend to produce mixed variables. Wall rock is the rock that constitutes the wall of an area undergoing geologic activity. It also occurs as a minor component of wallrock alteration of mafic rocks, and replacing biotite in the outer zone of alteration associated with vein deposits lindgren and ransome, 1906. These are described in order from innermost to outermost alteration. Miguel island and includes a fumarolic field with multiple discharge points, closely associated with a mud pool. Wall rock country rock alteration is found in all hard rock mining districts and has been caused by hydrothermal solutions in the past history of the region. Winner of the standing ovation award for best powerpoint templates from presentations magazine.
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. Aubearing magmatic fluids are usually neutral or slightly alkaline. 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. Pat shanks iii 11 of 21 volcanogenic massive sulfide occurrence model scientific investigations report 20105070c. Mineral deposit geology wall rock alteration alteration halo eg garnet cannington agpbzn plate tectonics and the global distribution of ore deposits metallogenic. Worlds best powerpoint templates crystalgraphics offers more powerpoint templates than anyone else in the world, with over 4 million to choose from.
Hydrothermal fluid flow is controlled initially by structure then permeable lithologies as well as phreatomagmatic diatreme breccia pipes. The large mining companies of the world are focused in big deposits and the small deposits are attractive for small miners and perhaps their. The changes in rock and fluid compositions causes several alteration zones to form around the igneous rock. Wallrock petrology and geochemistry in alteration halos associated with mesothermal gold mineralization, central victoria, australia article in economic geology 952. This may occur without much hydrothermal fluid flow. Now coming to the exact question raised, the types are varied and manifold. The caldeiras da ribeira grande site is placed at the northeastern side of the ribeira grande geothermal system s. Our new crystalgraphics chart and diagram slides for powerpoint is a collection of over impressively designed datadriven chart and editable diagram s guaranteed to impress any audience. Sheet pilling walls are flexible bulkheads and used in soft soil and tight spaces.
Wallrock country rock alteration is found in all hardrock mining districts and has been caused by hydrothermal solutions in the past history of the region. It can arise also from calculations or by comparisons with similar build. Towards the sericite zone feldspars are totally obliterated, whereas towards the outer fringe they have generally survived complete alteration, being attacked only along grain. Influence of wall rock alteration and fluid mixing mechanisms in the chemistry of thermal fluids and mudpool sediments at caldeiras da ribeira grande s. The spencer method of slope stability analysis was used to assess the stability of the wall using the same rock mass parameters as in the udec analysis. Barnes hl ed geochemistry of hydrothermal ore deposits, 1st edn. Pdf influence of wallrock alteration and fluid mixing. Wallrock alteration article about wallrock alteration by. Presentation porphyry igneous rock rock geology free.
Yager chapter e3 of integrated investigations of environmental effects of historical mining in the animas river watershed, san juan county. Types of wallrock alteration associated with the askot. The zones of alteration have a bearing on where one might drill for ore bodies. Wallrock alteration alteration of wall rocks produces gradual and generally simple and regular changes in rock lithology, mineralogy, and chemistry. Major styles of mineralization and hydrothermal alteration. A free powerpoint ppt presentation displayed as a flash slide show on id. Some may form an envelope a few feet in thickness along the walls of a vein. A retaining wall refers to a structure that is designed and built up to defend the lateral pressure of soil, when any alteration occurs in ground elevation that surpasses the angle of repose of the soil.
Wall rock alteration is progressive, with some minerals reacting and being altered more rapidly than others. Ductile shear zones generally record a noncoaxial deformation. The background to a project in brazil is described that has found promising concentrations of platinum group elements pges in phoscoritecarbonatite complexes. Apr 30, 2015 types of wall rock alteration now coming to the exact question raised, the types are varied and manifold. In 1993 the system was updated to include more than cases grimstad and barton, 1993.
For masonry retaining wall, the depth of wall is raised along with height as masonry withstands the lateral pressure by its weight. Types of wall rock alteration types of wall rock alteration 1. If youre still not convinced that opile systems are superior to other sheet pile or concrete options. The intermediate wall rock alteration zone 3050 mt wide is easily distinguished because the sericitization is less intense than in the nearest wall rock alteration. Ppt mining geology 405 geological logging powerpoint. Carbonate alteration associated with lamprophyres and. Influence of wallrock alteration and fluid mixing mechanisms in the chemistry of thermal fluids and mudpool sediments at caldeiras da ribeira grande s. Geochemistry, paragenesis, and wallrock alteration of the. Structure, tectonics and surface weathering play a vital role over geological time as a passage for hydrothermal flow of mineralized fluids, accumulate and concentrate at suitable location. The wellestablished industrial demand and current level of prices for the platinum group metals have encouraged the exploration.
Some of the elements in these associations are not the direct target of exploration and discovery, but they can provide very useful path. Wallrock alteration article about wallrock alteration. The f ormation of a ductile shear zone is commonly associated with a drastic reduction of grain size and the development of a wellbanded and lineated rock called mylonite. D data for biotite in both assemblages suggest a magmatic fluid source that has evolved through extensive wall rock interaction and quartz precipitation gregory, 2012, 2017. Similar to metamorphic reactions wall rock alteration depends on a.
May 07, 2015 structural control ore deposits structure, tectonics and surface weathering play a vital role over geological time as a passage for hydrothermal flow of mineralized fluids, accumulate and concentrate at suitable location, remobilize and reorientate as postgenetic activity. Theyll give your presentations a professional, memorable appearance the kind of sophisticated look that todays audiences expect. Inrnooucrron professor kerr is one of the foremost students of hydrothermal wall rock alteration and has long shown friendly and helpful interest in anacondas study of the ore deposit at butte, montana. Causes of rock deformation stress pressure placed on rocks strain deformation of the rock strength rock resistance to deformation brittle deformation the rocks break or fracture. Further geochemical and mineralogical research is underway to determine their potential as ore deposits. Gravity walls cantilever wall sheet piling walls diagrams from.
To add challenge to this pose, lift the sole of the right foot and bring the outer edge of the foot to rest on the top of the left thigh. The magnetite ores occurred as layered to massive bodies, with lesser amounts of disseminated magnetite and hematitebearing veins. Charles meyers of the staff of the anaconda copper co. Alteration phenomena occur in various rock types, but are perhaps most effectively studied when found in igneous masses. Petrology of ore deposits university of south alabama. There are three types of brick partition walls which include plain brick partition wall, reinforced brick partition wall, and brick nogging partition wall. Areas of alteration which contain clay vary widely in their dimensions. Geology, hydrology, geochemistry, and biology of mine sites. Other secondary minerals include sericite and biotite. Gooseberry mine, storey county, nevada thesis submitted in partial ful 1 fi 11. The zonal sequence from fresh through bleached, softened rock to silicified rock adj acent to the vein is common, but the widths of the altered rock sheath and of individual zones in the.
To add challenge to this pose, lift the sole of the right foot and bring the. Types of wallrock alteration associated with the askot sulfide orebody the most prominent features indicative of rock alteration in the vicinity of the sulfide orebody at barigaon near askote are bleaching, softening, reduction in grain size, and a yellow or brown discoloration of the country rocks. Geology, hydrology, geochemistry, and biology of mine sites geologic aspects. Thus, for example, the most prevalent types of alteration in acidic rocks are sericitization, argillization, silicification and pyriti. 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 in volcanoes, wall rock can often become broken off the wall and incorporated into the erupted volcanic rock as. Retaining wall construction retaining wall excel spreadsheet. 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 alteration, where it may form a dense massive rock.
C spring water, allowing the accumulation of diluted thermal fluid and mud. Sulfide minerals precipitated late in the alteration event at temperatures between. Adjacent to the fluid conduits, the wall rock has been extensively altered. Eart4002 lect3 mineral exploration authorstream presentation. There are of course exceptions, but certain generalizations can be made. The qatruyeh iron deposits, located on the eastern border of the nwse trending sanandajsirjan metamorphic zone, southwest of iran, are hosted by a late proterozoic to early paleozoic sequence dominated by metamorphosed carbonate rocks. Prospecting and exploration that is a search for precious metals deposits is not a simple process because big deposits were discovered a long time ago.
Cantilever walls are with reinforced concrete base and designed to resist lateral and hydrostatic pressure. Displaying types of retaining wall powerpoint presentations if youre still not convinced that opile systems are superior to ppt presentation summary. Geochemistry, alteration, and genesis of gold mineralization. This alteration is especially obvious in greenschist and the altered rock has a pale creamy colour due to the replacement of various metamorphic phases epidote, chlorite, actinolite mostly by febearing carbonate and phyllosilicates.
Introduction alteration is a complex process of ion exchange whereby some constituents are removed, others are added and still others. React with wallrocks to alter wall rocks via replacement, exchange, and destruction reactions. There are several places with important content of precious metals waiting for skill prospectors. It is constructed from plain bricks, and it is common and cost effective. The major discharge is artificially confined to a tank, also fed by a cold. Fluids cool enroute to surface via conductive cooling. Metals tend to concentrate in the most intensely altered rocks. Others may comprise areas traceable for thousands of feet or even miles.
Take the right heel up to the calf, keeping the toes on the ground for balance. Ore deposits formed by lateral secretion are formed by metamorphic reactions during shearing, which liberate mineral constituents such as quartz, sulfides, gold, carbonates, and oxides from deforming rocks, and focus these constituents into zones of reduced pressure or dilation such as faults. Influence of wallrock alteration and fluid mixing mechanisms. Whereas the reinforced concrete retaining wall withstands the lateral pressure by structural action like. Major styles of mineralization and hydrothermal alteration and related solid and aqueousphase geochemical signatures by dana j. The laboratory at butte has also contributed to alteration studies through the development of an improved technique in the cutting of thin sections of alteration materials. Secondary alteration of rocks and their contained first step in that process. Wall rock alteration along veins in the central cityidaho springs region, gilpin and clear creek counties, colorado, superficially resembles alteration around similar basemetal sulfide deposits, but differs in some details. 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.
The wall rock alterations have often been used as a guide to orefinding for where weathering has removed the top of the orebody, these alteration haloes serve as indicator of hidden orebodies. A cavity wall has two separate walls constructed with a gap in between the two walls. A rock is a naturally occurring solid mixture of one or more minerals, or organic matter rocks are classified by how they are formed, their composition, and texture rocks change over time through the rock cycle igneous rock begins as magma. Wallrock petrology and geochemistry in alteration halos. Chart and diagram slides for powerpoint beautifully designed chart and diagram s for powerpoint with visually stunning graphics and animation effects. The geochemical features of hydrothermalpneumatolytic rare element deposits are discussed on the basis of a natural connection between. The results of the analysis with critical failure surfaces through the rock mass show that the wall is stable and estimates the factor of safety to be 2. Ppt shear walls powerpoint presentation free to download.
Primary and secondary mineralogy of ore deposits introduction our society and civilization is built upon resources of all kinds, also earth. Chondritenormalized ree patterns of samples show hree enrichments in metagabbro, a flat pattern with a positive. The bricks are laid as stretchers in cement mortar. Occasionally rock alteration leads to misidentification of lithology as in studies of the amulet rhyolite in the noranda. Take the right sole and place it below the knee, pressing up against the calf. Typical element associations for a range of deposit types are listed in table 1. Hydrothermal processes and wall rock alteration springerlink.
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