Figure 1 - Lithocaps – characteristics, origins and significance for porphyry and epithermal exploration

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 – characteristics, origins and significance for porphyry and epithermal exploration - Scientific Figure on ResearchGate. Available from: https://www.researchgate.net/figure/Schematic-illustration-of-alteration-zoning-and-overprinting-relationships-in-a-porphyry_fig1_322087357 [accessed 31 Mar, 2023]

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Figure 1. 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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<a href="https://www.researchgate.net/figure/Schematic-illustration-of-alteration-zoning-and-overprinting-relationships-in-a-porphyry_fig1_322087357"><img src="https://www.researchgate.net/profile/Zhaoshan-Chang/publication/322087357/figure/fig1/AS:576555862552576@1514473037108/Schematic-illustration-of-alteration-zoning-and-overprinting-relationships-in-a-porphyry.png" alt="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."/></a>