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Schematic illustration of alteration zoning and overprinting relationships in a porphyry system (modified after Holliday and Cooke 2007; Cooke et al. 2014). Lithocaps can overlie and partially overprint porphyry-style mineralisation associated with shallowcrustal hydrous intrusive complexes. They may host high sulfidation-state mineralisation and can cover intermediate sulfidation state epithermal veins. The lithocaps will overprint and be surrounded by propylitic alteration assemblages that vary from high to low temperature alteration subfacies (i.e., actinolite, epidote and chlorite subfacies) as a function of proximity to the intrusive source. The roots of the lithocap lie within the pyrite halo of the porphyry system. The degree of superposition of the lithocap into the porphyry system is contingent on uplift and erosion rates at the time of mineralization, and will vary from province to province, and from district to district. Abbreviations: ab-albite; act-actinolite; anh-anhydrite; Au-gold; bi-biotite; bn-bornite; cb-carbonate; chl-chlorite; cp-chalcopyrite; epi-epidote; gt-garnet; hm-hematite; Kf-K-feldspar; mt-magnetite; py-pyrite; qz-quartz.
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Lithocaps are subsurface, broadly stratabound alteration domains that are laterally and vertically extensive. They form when acidic magmatic-hydrothermal fluids react with wallrocks during ascent towards the paleosurface. Although lithocaps typically have steeplydipping structural roots, there is a significant component of lateral fluid flow involv...
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... The Guihu deposit is located at the center of a large lithocap (>30 km 2 ). High-temperature K-silicate alteration zones (with andalusite and corundum) in lithocaps (e.g., El Salvador; Gustafson and Hunt, 1975) may be spatially related to concealed porphyry (Sillitoe, 1995;Cooke et al., 2017). In the middle-lower parts of drill-hole ZK502 and ZK503, the quartz + pyrophyllite + alunite ± corundum assemblage was observed. ...
... i. Hypogene AA alteration environment This environment is formed by hypogene acidsulfate-chloride condensates separated from a mixture of vapor and hypersaline liquid at depth from a shallow intrusion source, generating a highly acidic fluid (pH < 1.5) that forms the lithocap in the upper portions of porphyry copper systems (Sillitoe 1995(Sillitoe , 2010Hedenquist and Arribas 2021). The study area surface shows sulfate-rich mineral assemblages consisting mainly of quartz-alunite-kaolinite that typically develop in the upper parts of these systems (Sillitoe 2010; Hedenquist and Taran 2013; Cooke et al. 2017). There is a core of silicified rock with restricted residual quartz zones at the upper areas of the Coya hill in which fractures, feeders, and veins are flanked by host rocks containing quartz-alunite ± kaolinite or quartz-kaolinite (or dickite) mineral assemblages, which grade laterally and downward, to clay minerals, mainly kaolinite-smectite ± illite/smectite (Fig. 3a, b). ...
Advanced argillic (AA) alteration produced by hydrothermal activity and subsequent supergene alteration in the Potrerillos district, Atacama Desert, Chile, includes sulfate-bearing and aluminosilicate alteration minerals. These alterations commonly contain alunite supergroup minerals (e.g., alunite, jarosite, and aluminum-phosphate-sulfate (APS) minerals) of both hypogene and supergene origin. In this contribution, we investigate the mineralogical and geochemical characteristics of these minerals, to decipher the physicochemical parameters of formation, as well as the composition, source, and evolution of the fluids that produced the AA alteration in the area. Field observations, optical microscopy, and geochemical analyses provide insights into the geochemical evolution of the hydrothermal system and its later supergene weathering. Three precipitation environments with different sulfur sources and characteristics of alunite group minerals have been defined at Potrerillos as follows: (i) hypogene environment with sulfur originating from H2S disproportionation and tabular alunite (> 200 µm); (ii) steam-heated environment with sulfur from oxidation of distilled H2S above the water table, tabular alunite (< 100 µm), and pseudocubic APS; and (iii) supergene environment with sulfur from the oxidation of hydrothermal sulfides and dissolution of alunite and APS in the vadose zone represented by pseudocubic alunite, jarosite (≤ 5 µm) and APS minerals. Hydrothermal and supergene minerals have endmember and intermediate compositions in the alunite-jarosite solid solution series, respectively. Divalent exchange in alunite and jarosite, and the precipitation of APS minerals reflect variations in the redox and pH conditions, chemical composition, and elemental concentration in the supergene fluids, these variations also were observed to a lesser extent in steam-heated solutions. The temperature of hypogene alteration is estimated to range from to 120 to 200 °C; lower temperatures are possible for the steam-heated environment.
... Combining VNIR-SWIR and LA-ICP-MS can obtain spectral parameters and chemical parameters that vary systematically with the spatial change of physicochemical conditions. Mineral exploration indicators (MEIs) can be established after extracting those parameters comprehensively, which is an effective tool for predicting mineralization centers and locating blind ore bodies [10,[12][13][14][15][16]. ...
Establishing exploration vectors to infer the properties of ore-forming fluids, locate blind ore bodies with the aid of visible to near-infrared (VNIR) and short-wave infrared (SWIR) spectroscopy, and infer the chemistry of minerals, is a new research interest for economic geology. Common alterations and clay minerals, including sericite, chlorite, epidote, alunite, kaolinite, tourmaline, etc., are ideal objects for the study of exploration indicators due to their sensitivity to variations in the nature of hydrothermal fluid. The diagnostic spectral feature and chemistry vary spatially and systematically with physicochemical change. VNIR spectroscopy can characterize the REE-bearing clay minerals directly. Obtaining spectral or chemical parameters with the aid of VNIR-SWIR spectroscopy, electron probe micro-analyzer (EPMA) or laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) can help to establish exploration vectors. This paper systematically summarizes recent advances in mineral exploration indicators (MEIs) of VNIR-SWIR spectroscopy and chemistry, and compares them in different regions or deposits. We found that some MEI spatial variation trends are random, even the same type of deposit can show an opposite trend. The controlling factors that limit the application of the established MEIs are vague. Conducting further research on petrology and mineralogy with the aids of observation under microscopy, X-ray diffraction (XRD), TESCAN Integrated Mineral Analyzer (TIMA), and EPMA are suggested to discover alteration mineral assemblage, alteration stages, and behaviors of “the pathfinder elements” related to mineralization. Based on the above research, the physicochemical properties of ore-forming fluids and their control over MEIs can be inferred. Refining the theoretical basis is critical to understanding and popularization of spectral and chemical MEIs.
... The lithocap, first defined by Sillitoe (1995), is a volumetrically significant domain of pyrite-rich rocks with extensive hypogene silicic, advanced argillic, and argillic alterations that formed between a paleosurface and a shallow-crustal intrusion. It is helpful for the finding of underlain porphyry mineralization by a lithocap due to its prominence on the surface (Sillitoe, 1995(Sillitoe, , 2000Hedenquist et al., 1998;Cook et al., 2017). However, the presence of a large lithocap (up to tens of square kilometers) maybe hinder the work of finely alteration zoning to further pinpoint the location of the underlying intrusive center. ...
... Intense volcanic activities are accompanied by mineralization, which is characterized by plentiful non-metallic alteration and mineralization, such as alunite, pyrophyllite, dickite, and illite. The non-metallic mineralization is supposed to have an affinity with Au-Cu-Mo polymetallic deposits and is an indicator of the blind metallic ore most of the time (Sillitoe, 2010;Chang et al., 2011;Hedenquist and Taran, 2013;Cook et al., 2017;Chen et al., 2019). The Guihu pyrophyllite deposit and the Fanshan alunite deposit are the representative non-metallic deposits in the area. ...
... According to the updated model (Sillitoe, 1995(Sillitoe, , 2000(Sillitoe, , 2010Hedenquist and Taran, 2013), magmatic fluid exsolved from water-rich intrusions in the shallow crust, forming supercritical fluid. The supercritical fluid underwent phase separation due to the decrease of pressure as it goes up, forming a huge volume of vapor and a relatively small volume of brine (Bodnar et al., 1985;Hedenquist et al., 1998;Cook et al., 2017). Some gas may escape from the volcanic vent, but most of the vapor carrying a large amount of acid-rich volatile (HCl and SO 2 ) condensed and reacted with the surrounding rock, producing advanced argillic alteration. ...
The Fanshan alunite deposit, located in Cangnan County, Zhejiang Province, is the largest alunite deposit in China, which developed a lithocap with an extensive advanced argillic alteration. Surface alteration mapping, through field geology and shortwave infrared (SWIR) spectroscopy analyses, has defined three alteration zones including Na-alunite-dickite-pyrophyllite-topaz alteration, K-alunite-pyrophyllite-phengitic muscovite alteration, and chlorite-illite alteration from center to margin. Alunite varies from K-rich to Na-rich and has different paragenesis and texture. Na-alunite, with quartz, pyrophyllite, dickite, and topaz, mainly developed in Pingpengling area of Fanshan, forming a typical advanced argillic alteration. The wavelength position of the alunite -OH spectral absorption feature at ∼1,480 nm (Pos1480) varies from 1478 nm to 1492 nm with increasing content of Na in alunite. There exists a positive correlation between Na/K ratio value and Pos1480 of alunite.
The TESCAN Integrated Mineral Analyzer (TIMA), coupled with LA-ICP-MS analyses of alunite has been conducted, aiming to systematically characterize the texture and mineral chemistry of alunite. Fanshan alunite is rich in Ga, V, rare earth elements (REEs), and large ion lithophile elements (LILEs). Na-alunite has higher LILEs and light rare earth elements (LREEs) than K-alunite. Thorium, U, Li, and B, vary greatly in the Na-alunite and K-alunite. The ratio of Na/K in alunite, together with Pos1480 has been used to vector the magmatic-hydrothermal center. Furthermore, the content of Pb and ratios of Rb/Sr*1000, Sr/Pb, La/Pb, have illustrated the consistent results as Na/K and Pos1480. Based on the spatial distribution of these vectors in conjunction with the occurrence of Na-alunite, we concluded that Pingpengling area is the most proximal area to the magmatic-hydrothermal center, which may imply a possible causative intrusion underneath. Further exploration is suggested to be conducted under Pingpengling to verify if there is porphyry Cu(-Au-Mo) mineralization.
... At a first order of approximation, these RTE anomalies may be explained by the Imbanguila Dacite which is more magnetic (low RTE anomalies) vis-à-vis the less magnetic, hydrothermally-altered surrounding rocks (high RTE anomalies). In addition, the presence of alunite in Mohong Hill is consistent with a lithocap (Chang et al., 2011) which could possibly overlie an associated porphyry copper deposit at depth (e.g., Sillitoe, 1983;Sillitoe, 2010;Cooke et al., 2017). ...
Ground magnetic surveys conducted in Suyoc, Mankayan, Benguet led to the delineation of features related to epithermal and porphyry copper targets in the area. High reduced to equator (RTE) anomalies are observed in areas with epithermal mineralization. The high RTE anomalies are attributed to hydrothermally altered rock with quartz veins. The previously recognized porphyry copper prospect in Palasaan (Mohong Hill) is characterized by low RTE anomaly surrounded by a high RTE anomaly. One explanation for this signature is the possible presence of a magnetic core and the destruction or absence of magnetite in the alteration haloes at the periphery of a porphyry prospect. Areas such as Mangga and Liten exhibit the same magnetic signatures. This distinct magnetic pattern coupled with observed alteration and mineralization signatures led to the interpretation of prospective blind porphyry deposits in these localities. Results of the study reveal the applicability of ground magnetic data in characterizing and extracting a potential area of mineralized zones at a regional scale. The first ground magnetic surveys conducted in Suyoc, Mankayan, Benguet led to the delineation of features related to epithermal and porphyry copper targets in the area. Results of this study reveal magnetic anomalies which may be used in characterizing and determining mineralized areas at a regional scale.
... Epithermal deposits provide challenges for explorers as they tend to have large and lateral zonation patterns defined by clay minerals, which are difficult to determine. HS and IS epithermal deposits are commonly associated with zones that are characterized by two main hypogene alterations: silicic (dominated by residual quartz) with advanced argillic halos (dominated by alunite, pyrophyllite, and dickite) alteration (Hedenquist, 2018;Hedenquist and Henley, 1985;Heinrich et al., 2004;Melfos et al., 2019;Sillitoe, 1977Sillitoe, , 1993Sillitoe and Thompson, 1998;White, 1955;White and Hedenquist, 1995;Chang et al., 2011;Cooke et al., 2017;Henley, 1991;Lindgren, 1933). ...
The Svetloye epithermal district (SED) is located within the Okhotsk-Chukotka volcanic belt (OCVB), 220 km southwest of Okhotsk. The OCVB, which formed during the Cretaceous with ore potential, is a large marginal volcanic rock belt associated with continental subduction. Svetloye occupies two volcanic edifices of different ages – the northwestern volcanic center (including the Emmy deposit) consists of basaltic-andesite of the Khetanian suite (Coniacian-Santonian time (K2), and the southeastern volcanic center (hosts the Elena, Tamara, Lyudmila, and Larisa deposits) comprises the dacite-rhyolite-leucogranite formation of the Urak suite (Campanian-Maastrichtian time (K2). Distinct host rocks and different levels of erosion in the two edifices of Svetloye led to various altered rocks, mineral assemblages, and diverse types of gold mineralization. The alteration halo of the Emmy deposit contains vuggy residual quartz, with Au-Ag-telluride and Au-Ag mineralization plus other tellurium-bearing minerals (goldfieldite, kawazulite, coloradoite, melonite, altaite, tellurobismuthite, tellurantimony, and native tellurium). Altered rocks of the other deposits are characterized by variable halos, including vuggy residual quartz, alunite, dickite, quartz-alunite-dickite, illite-chlorite, illite, illite-smectite, smectite, quartz-carbonate, and quartz-white mica alteration, hypogene and supergene processes. The hydrothermal (hypogene) and supergene ore processes within the SED occurred in 3 stages: leaching and barren quartz-rutile-pyrite zone with halos of quartz-alunite-dickite-pyrite (or quartz-illite-chlorite-calcite-pyrite), then quartz-pyrite with polysulfides and gold, gold-silver telluride, and finally supergene with 'mustard' gold. The alteration halo, epithermal ore bodies as hydrothermal veins and breccias with vug infill, colloform, and crustiform textures, hypogene sulfide assemblage represented by galena, sphalerite, tennantite-tetraedrite, and chalcopyrite of SED are typical of epithermal styles with an high-intermediate sulfidation signature, possibly indicates a porphyry deposit at depth. The lack of high-sulfidation-state sulfides such as hypogene covellite, enargite, famatinite, luzonite in the residual quartz may be due to their erosion at shallower paleodepth, and/or to their supergene oxidation below the present day surface.
... A lithocap is a type of alteration system that has undergone advanced argillic and argillic alteration and is mainly composed of acidsulfate alteration minerals characterized by alunite-kaolinite-dickite-quartz ± pyrite (Rye et al., 1992;Sillitoe, 1995). Lithocaps generally occur in island arc settings above convergent plate boundaries (Sillitoe et al., 1998;Cooke and Simmons, 2000;Sillitoe, 2010;Xu et al., 2010;Richards, 2011) and are hosted in volcanic strata along well-permeated or fractured structures (Sillitoe, 1995;Cooke et al., 2017b). A lithocap is generally related to porphyry intrusions (Steven and Ratte, 1960;Cooke et al., 2014Cooke et al., , 2017a and have long been for exploration. ...
Lithocaps in island-arc settings are genetically related to porphyry-epithermal systems and can be used to guide exploration for porphyry deposits. The Fanshan area of the Luzong basin in the eastern China, hosts a large lithocap but no porphyry or epithermal deposits have been found. The Fanshan lithocap in the Luzong basin is centred on the Dafanshan alunite mining district with vuggy quartz–alunite–pyrite, quartz–dickite–kaolinite ± alunite, quartz–kaolinite and kaolinite–illite ± smectite from northeast to southeast. The alteration zoning reflects the gradual decrease in the temperatures and acidities of the fluids. Four types of alunite including bladed alunite, needle alunite, granular alunite, and powdery alunite suggest that the Fanshan lithocap formed in the magmatic-hydrothermal and supergene environment. From the southwest to the northeast of the Dafanshan district, Pb and 10⁶Pb/(Na + K) in the alunite samples gradually decrease, Au content gradually increases, but the Cu content does not change significantly. The peak positions at 1480 nm and the Na content of the magmatic-hydrothermal alunite gradually increase, whereas Pb and 10⁶Pb/(Na + K) in the alunite minerals gradually decrease. This suggests that the source of the hydrothermal fluids and a potential zone of precious metal mineralization area may be in the northeast of the Dafanshan district, and the potential area of copper mineralization may be in the Huangtun area northeast of the Luzong basin.
... The recognition of fertile belts of igneous intrusions and prospective areas of hydrothermal alteration can now be assisted through the use of porphyry indicator minerals (PIMs) such as zircon, plagioclase, apatite, magnetite and tourmaline (Dupuis & Beaudoin 2011;Dilles et al. 2015;Shen et al. 2015;Bouzari et al. 2016;Williamson et al. 2016)such minerals can help to identify the geochemical 'fingerprint' of a porphyry deposit and discriminate it from other deposit styles and background rocks. At the district scale, far-field detection of concealed mineralized centres in porphyry districts has been enabled through the application of porphyry vectoring and fertility tools (PVFTs), which involves detection of low-level geochemical anomalies preserved in hydrothermal alteration minerals such as epidote, chlorite or alunite (Chang et al. 2011;Cooke et al. 2014aCooke et al. , 2015Cooke et al. , 2017Wilkinson et al. 2015Wilkinson et al. , 2017Baker et al. 2017;Xiao et al. 2018). This new generation of geochemical exploration tools have been created due to advances in laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and hyperspectral analytical techniques. ...
... Lithocaps may form between the mineralizing intrusive complex and the paleosurface (Fig. 2). Lithocaps are large, stratabound domains of silicic, advanced argillic and argillic alteration assemblages that can exceed dimensions of 10 × 10 km laterally and may be more than 1 km thick (Sillitoe 1995;Chang et al. 2011;Cooke et al. 2017). Lithocaps typically have structural roots, with advanced argillic assemblages transitioning downwards from quartz alunitepyrite to quartzdickitepyrophyllitepyrite and then into phyllic-altered roots (i.e. ...
... quartzmuscovitepyrite; Sillitoe 1999). Lithocaps provide significant challenges for explorers because they have very broad, difficult to detect lateral alteration zonation patterns defined by clay minerals (Chang et al. 2011;Cooke et al. 2017). ...
In the past decade, significant research efforts have been devoted to mineral chemistry studies to assist porphyry exploration. These activities can be divided into two major fields of research: (1) porphyry indicator minerals (PIMs), which are used to identify the presence of, or potential for, porphyry-style mineralization based on the chemistry of magmatic minerals such as zircon, plagioclase and apatite, or resistate hydrothermal minerals such as magnetite; and (2) porphyry vectoring and fertility tools (PVFTs), which use the chemical compositions of hydrothermal minerals such as epidote, chlorite and alunite to predict the likely direction and distance to mineralized centers, and the potential metal endowment of a mineral district. This new generation of exploration tools has been enabled by advances in and increased access to laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS), short wavelength infrared (SWIR), visible near-infrared (VNIR) and hyperspectral technologies.
PIMs and PVFTs show considerable promise for exploration and are starting to be applied to the diversity of environments that host porphyry and epithermal deposits globally. Industry has consistently supported development of these tools, in the case of PVFTs encouraged by several successful blind tests where deposit centers have successfully been predicted from distal propylitic settings. Industry adoption is steadily increasing but is restrained by a lack of the necessary analytical equipment and expertise in commercial laboratories, and also by the on-going reliance on wellestablished geochemical exploration techniques (e.g., sediment, soil and rock-chip sampling) that have aided the discovery of near-surface resources over many decades, but are now proving less effective in the search for deeply buried mineral resources, and for those concealed under cover.
... In many districts, pre-ore alteration is associated with the development of laterally continuous lithocaps of often lithologically controlled blankets or ledges of advanced argillic alteration, representing the upper expressions of magmatichydrothermal systems ( Fig. 2; Sillitoe, 1995Sillitoe, , 2010Hedenquist et al., 2000;Cooke et al., 2017;John et al., 2018). Extensive lithocaps, with their surrounding argillic alteration, can obscure areas of underlying blind mineralization (Teal and Benavides, 2010;Cooke et al., 2017;Fig. ...
... In many districts, pre-ore alteration is associated with the development of laterally continuous lithocaps of often lithologically controlled blankets or ledges of advanced argillic alteration, representing the upper expressions of magmatichydrothermal systems ( Fig. 2; Sillitoe, 1995Sillitoe, , 2010Hedenquist et al., 2000;Cooke et al., 2017;John et al., 2018). Extensive lithocaps, with their surrounding argillic alteration, can obscure areas of underlying blind mineralization (Teal and Benavides, 2010;Cooke et al., 2017;Fig. 29A). ...
... Large, disseminated high-sulfidation epithermal deposits often occur in lithocap environments, as exemplified by Pascua, Veladero, Tambo (Chile), Yanacocha, Lagunas Norte/ Alto Chicama (Peru), Mulatos-La India (Mexico), Paradise Peak (Nevada), and several deposits on the Biga Peninsula of Turkey (Sillitoe, 1999;Bissig et al., 2015;Sanchez et al., 2016). Paleoupflow zones within the lithocap can be inferred from the distribution of zones of strong silicification and residual quartz alteration, which often are preserved as topographic highs due to preferential erosion of surrounding argillic steam-heated alteration (Fig. 29D, E; Vikre, 1989;Cooke et al., 2017). Fault-controlled paleoupflow zones may be indicated by thickening of silicified zones within the lithocap (Fig. 29B), forming resistant, linear anomalies and ore zones ( Fig. 29C; Harlan et al., 2005;Teal and Benavides, 2010). ...
... The recognition of fertile belts of igneous intrusions and prospective areas of hydrothermal alteration can now be assisted through the use of porphyry indicator minerals (PIMS) such as zircon, plagioclase, apatite, magnetite and tourmaline (Dupuis and Beaudoin, 2011;Dilles et al., 2015;Shen et al., 2015;Williamson et al., 2016;Bouzari et al., 2016). At the district scale, far-field detection of concealed mineralized centres in porphyry districts can now be enabled through the application of porphyry vectoring and fertility tools (PVFTS), which involves detection of low-level geochemical anomalies preserved in hydrothermal alteration minerals such as epidote, chlorite or alunite (Chang et al., 2011;Cooke et al., 2014aCooke et al., , 2015Cooke et al., , 2017Wilkinson et al., , 2017Baker et al., 2017;Xiao et al., 2017). This new generation of geochemical exploration tools has arisen thanks to advances in laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) analytical techniques. ...
... These subzones essentially map the actinolite and epidote isograds (Figure 3), and represent decreasing fluid temperatures and oxygen fugacity away from the intrusive complex (Cooke et al., 2014a). Magnetite and Figure 3: Schematic illustration of alteration zoning and overprinting relationships in a porphyry system (modified after Holliday and Cooke 2007;Cooke et al. 2014bCooke et al. , 2017. The multiphase intrusive complex at the centre of porphyry deposits typically has potassic alteration developed within and around it. ...
... Lithocaps may form between the mineralizing intrusive complex and the paleosurface (Figure 3). Lithocaps are large, stratabound domains of silicic, advanced argillic and argillic alteration assemblages that can exceed dimensions of 10 x 10 km laterally and may be more than 1 km thick (Sillitoe, 1995;Chang et al., 2011;Cooke et al., 2017). Lithocaps typically have structural roots, with advanced argillic assemblages transitioning downwards from quartzalunitepyrite to quartzdickitepyrophyllitepyrite and then into phyllic-altered roots (i.e., quartzmuscovitepyrite; Sillitoe, 1999). ...
In the past decade, significant research efforts have been devoted to mineral chemistry studies to assist porphyry exploration. These activities can be divided into two major fields of research: (1) porphyry indicator minerals (PIMS), which aims to identify the presence of, or potential for, porphyry-style mineralization based on the chemistry of magmatic minerals such as plagioclase, zircon and apatite, or resistate hydrothermal minerals such as magnetite; and (2) porphyry vectoring and fertility tools (PVFTS), which use the chemical compositions of hydrothermal minerals such as epidote, chlorite and alunite to predict the likely direction and distance to mineralized centres, and the potential metal endowment of a mineral district. This new generation of exploration tools has been enabled by advances in laser ablation-inductively coupled plasma mass spectrometry, short wave length infrared data acquisition and data processing, and the increased availability of microanalytical techniques such as cathodoluminescence. PVFTS and PIMS show considerable promise for porphyry exploration, and are starting to be applied to the diversity of environments that host porphyry and epithermal deposits around the circum-Pacific region. Industry has consistently supported development of these tools, in the case of PVFTS encouraged by several successful “blind tests” where deposit centres have successfully been predicted from distal propylitic settings. Industry adoption is steadily increasing but is restrained by a lack of the necessary analytical equipment and expertise in commercial laboratories.
