Geochemical characteristics of the alteration of volcanic and volcaniclastic rocks in the feres basin, thrace, ne greece. Extensive hydrothermal alteration is observed around volcanogenic massive sulfide deposits. The rhyolitic tuffs, which host most of the kaolinized bodies, were deposited on top of the. Classification of altered volcanic island arc rocks using immobile trace elements. For altered rocks, the old schemes proposed by floyd and winchester 1975, 1978 and winchester and floyd 1976, 1977 cannot be used, because the highmg rock names were not included by these authors and the iugs criteria for subdivision of highmg and common altered. Volcanic rock diagenesis and characteristics analysis of. The geochemistry of altered volcanic rocks at matagami. Major and traceelement mobility in altered volcanic. These two alteration processes were contemporaneous events, which shared a common aqueous fluid, developed within cooling submarine volcanic rocks shortly after the extrusion of rhyolite, and terminated prior to extrusion of succeeding units. Altered volcanic rocks utas eprints university of tasmania. Many attempts have been made to define mineralogy, chemistry and chemical changes of hydrothermally altered footwall and hanging wall in several vms deposits around. The veins are integral parts of high to intermediate sulfidation epithermal mineralized centers in northern greece e. Volcanic rock diagenesis can be divided into constructive and destructive diagenesis according to its contribution to volcanic rock reservoir.
In volcanic rocks quartzchloritepyritechalcopyrite veins are superimposed on earlier biotitization and crosscut stage i quartz sulfide veins. This book is about the processes and products of alteration in submarine volcanic successions. The prime example of this style of mineralization is the giant kidd creek deposit, where most mineralization occurred below the seafloor in permeable, fragmental felsic volcanic. Epithermally altered volcanic rocks in greece host amethystbearing veins in association with various silicates, carbonates, oxides and sulfides. Numerical simulations of amethyst geode cavity formation by. Andesite on mars was an unexpected find as volcanoes are rare on the red planet. Geochemistry of hydrothermal alteration in volcanic rocks 43 whereas in the equivocada mine, kaolinite is associated with dickite and traces of alunite without pyrophyllite marfil et al. Clay minerals in hydrothermally altered rocks 197 groundmass or both. These deposits are related to late cretaceous volcanism in various parts of the eastern pontide province. This book will help to equip geologists working in altered and deformed successions with the skill and confidence to interpret the original volcanic facies and encourage the use of altered rocks as. Altered volcanic rocks is a practical guide for systematically describing and interpreting. The aim of this study is to devise a diagram to classify altered volcanic arc lavas on the same basis as the k 2 osio 2 diagram and to apply it to the jamaican samples. All structured data from the file and property namespaces is available under the creative commons cc0 license.
A layered bimodal sequence lbs was recently recognized in the canyon domain in the central grenville province, and inferred to be the extrusive products of riftrelated magmatism at 1. Altered volcanic rocks free ebook download as pdf file. Postage and handling charges must be paid as part of the order. Hydrothermally altered volcanic rocks metamorphosed at granulitefacies conditions. The zonal pattern of alteration revealed in the drill cores is similar to that associated with epithermal ore deposits in volcanic rocks at. Altered volcanic rocks is principally for handson geologists who practise in mineral explorationand mining geology, and the students who may in the future play in those professional fields. Articles about volcanoes, volcanic hazards and eruptions past and present. Igneous rocks pictures of intrusive and extrusive rock types. Ultramafic rocks also contain elevated amounts of chromium and nickel which may be toxic to plants. Numerical simulations of amethyst geode cavity formation. Altered volcanic rockshzs two main themes, which are organised into eight chapters.
Pdf clay minerals in hydrothermally altered volcanic rocks. Wood2 mining college, akita university, akita, japan 2 wairakei research centre, igns, taupo, nz summary the central taupo volcanic zone tvz of new zealand is one of the most active areas of rhyolite. Application to clay mineral detection and understanding aqueous environments on mars b. Altered volcanic rocks is designed to be a practical guide for systematically describing and interpreting altered volcanic rocks, and determining their significance in terms of mineral deposit prospectivity. Wood2 mining college, akita university, akita, japan 2 wairakei research centre, igns, taupo, nz summary the central taupo volcanic zone tvz of new zealand is one of. This leads to the use of e values of mudstone for the warm, altered basalt as a novel procedure in numerical simulations. Centre for ore deposit research, 2005 hydrothermal alteration 275 pages. Mean major and trace elements content of volcanic rocks of the georoc database, including values for several alteration indices and mass. The quartz magmatic crystals, from volcanic rocks without alteration, show cl sem spectra with emission bands at around 400, 430440, and 480nm. Mineralogical and compositional variations in hydrothermally altered country rocks 3. The behaviour of socalled immobile elements in hydrothermally altered rocks associated with volcanogenic submarineexhalative ore deposits. Evidence from mineral chemistry of jurassic lavas in northern chile, and tectonic implications pablo rossela,1, veronica oliverosa. The geochemistry of the garon lake rhyolite and underlying basalt are examined in detail.
Altered volcanic rocks sedimentary rock clastic rock. Evidence is available that some elements, notably zr, tio2, y, sc, ce and nb are largely immobile during the alteration of volcanic rocks owing to metamorphism, hydrothermal events and weathering e. Petrophysical alteration of volcanic rocks in hydrothermal systems of the kuril kamchatka island arc. False pyroclastic textures in altered silicic lavas, with. Altered volcanic rocks is a practical guide for systematically describing and interpreting altered volcanic rocks, and determining their significance in terms of mineral deposit prospectivity. The lbs consists of alternating felsic and mafic rocks with, locally, premetamorphic hydrothermally altered zones haz, and were metamorphosed to midp granulitefacies conditions during the. Geology and metamorphic petrology of variably altered volcanic rocks in the southern reindeer lake area, northern saskatchewan donald m wright 1, kevin m ansdell 1, david corrigan 2, and ralf 0. Geochemistry of hydrothermal alteration in volcanic rocks. Because of the scarcity of ferromagnesian minerals in the silicic rocks their alteration products are not important and, there fore, have been omitted in figs. Igneous rocks are formed from the solidification of molten rock material. The advance we have made in altered volcanic rocks is to integrate observations and data on volcanic facies and textures with alteration mineralogy and geochemistry at both regional and local scales in order to provide a multidisciplinary method for the study and discrimination of different alteration types. Identification and discrimination of altered and metamorphosed volcanic rocks using immobile elements. Altered silicic volcanic rocks with the appearance of welded and nonwelded pyroclastic flow deposits, volcaniclastic debris flows, and massive to thinbedded tuffaceous rocks form a major component of a silurian succession that hosts zncupb massive sulfide deposits at benambra, southeastern australia.
Altered and metamorphosed volcanic suites can be characterized in terms of magma series alkaline, subalkaline and degree of differentiation basaltic, andesitic, etc. Industrially, the common acid solutions used during acid well stimulation are hcl 10% and a mixture of hcl 10% and hf 5%. Pdf petrophysical alteration of volcanic rocks in hydrothermal. Across and along arc geochemical variations in altered. Clay minerals in hydrothermally altered volcanic rocks, eastern pontides, turkey. Files are available under licenses specified on their description page. Many diagrams conventionally used to classify igneous rocks utilize mobile elements, which commonly renders them unreliable for classifying rocks from the geological record.
This thesis is a petrographic and geochemical study of these rocks, and provides new insights on the protoliths, the hydrothermal alteration, and the subsequent metamorphic overprint. Pdf the geochemical behavior of altered igneous rocks in the. In the haz, characteristic felsic rocks are pink and white gneisses, grading into varieties of aluminous gneisses and garnetites. Altered volcanic rocks sedimentary rock clastic rock scribd. On points of similarity between zeolitic and siliceous. Major and traceelement mobilities have been investigated in hydrothermally altered zones of miocene volcanic rocks on the island lesbos. Pdf geochemical characteristics of the alteration of. Geology and metamorphic petrology of variably altered. Amethyst occurrences in tertiary volcanic rocks of greece. Clay minerals in hydrothermally altered volcanic rocks. Compositional variation of hydrothermally altered volcanic.
The age of the volcanic rocks in the woo dale borehole, derbyshire sir the highly altered character of the volcanic rocks which were encountered in the lower part of the woo dale borehole cope, 1973, situated about 5 km e of buxton in north derbyshire, has until recently defied attempts to obtain a meaningful radiometric age for these rocks. Three types of alteration have been recognized, and are characterized by the mineralogical composition. Altered volcanic rocks is designed to be a practical guide for systematically describing and interpreting altered volcanic rocks, and determining their significance in. Major and traceelement mobility in altered volcanic rocks. The major mineralogical components of igneous rocks can be divided into two groups.
Pdf classification of altered volcanic island arc rocks. Altered volcanic rockshzs two main themes, which are organised valuable basemetal, gold and silver deposits exist into eight chapters. Serpentine soil is a magnesium rich, calcium, potassium and phosphorus poor soil that develops on the regolith derived from ultramafic rocks. Across and along arc geochemical variations in altered volcanic rocks. Hydrothermal alteration of volcanic host rocks involves the replacement of primary igneous glass and minerals pla gioclase, orthoclase, quartz, biotite, muscovite, amphibole, pyroxene, titanomagnetite with alteration minerals stable at the conditions of alteration, generally in the temperate range of 150400 c. The boulderstudded landing site was interpreted as the site of catastrophic floods. However, it is shown, by reference to analyses of rocks from the environment of five volcanogenic massive sulphide bodies, that while zr, tio2 and ce. The causes for these differences in the features and the mechanism of gold deposition are discussed here, based primarily on the chemical compositions of the altered rocks andesite hosting the deposits. The age of the volcanic rocks in the woo dale borehole. Hydrothermal alteration of igneous rocks gsa bulletin. Nearby volcanic rocks, beyond the mine wedge, range from basalt to rhyolite.
It discusses the processes and products of the common alteration styles in submarine volcanic settings, including diagenetic alteration, burial metamorphism, hydrothermal alteration and. Geochemical characteristics of the alteration of volcanic and volcaniclastic rocks in the feres basin, thrace, ne greece article pdf available in clay minerals 434. Alteration and geochemistry of tertiary volcanic rocks in parts of. Petrography and geochemistry of hydrothermally altered. The mineralized rocks are, therefore, liable to ballooning. It discusses the processes and products of the common alteration styles in submarine volcanic settings. This page was last edited on december 2019, at 21. The constructive diagenesis can form primary, secondary pore, fracture, which can improve reservoir porosity and permeability, thus form favorable volcanic rock reservoir. Mineralogy and chemistry of altered icelandic basalts. It discusses the processes and products of the common alteration styles in submarine volcanic settings, including diagenetic alteration, burial metamorphism.
This volume is a comprehensive guide to alteration, primarily in submarine volcanic successions and in relation to volcanic rockhosted massive sulfide vhms deposits. Both belts consist of volcanic rocks, altered volcanic rocks, and associated sediments. Hydrothermally altered volcanic rocks metamorphosed at. The felsic minerals include quartz, tridymite, cristobalite, feldspars plagioclase and alkali feldspar, feldspathoids nepheline and leucite, muscovite, and corundum. On points of similarity between zeolitic and siliceous incrustations of recent formation by thermal springs, and those observed in amygdaloids and other altered volcanic rocks. Hastie 1 school of earth, ocean and planetary sciences, cardiff university, main building, park place, cardiff cf10 3ye, uk. Geochemistry of hydrothermally altered rocks at the horne mine. This book will help to equip geologists working in altered and deformed successions with the skill and confidence to interpret the original volcanic facies. Mineral assemblages resulting from alteration consist of mostly clay minerals and silica polymorphs, some sulfate minerals, and scarce zeolite minerals.
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