May 9, 2023 · Propylitic alteration is a type of hydrothermal alteration that occurs in volcanic and plutonic rocks. It is characterized by the alteration of primary minerals, such as feldspar and quartz, to secondary minerals, such as chlorite, epidote, and sericite.

regional propylitic alteration that predated the mineralizing episodes by 5–15 million years. Combined geologic and aqueous geochemical studies within these five areas have led to a better understanding of the major sources of anthropogenic and natural acidity and metals in the watershed. Detailed geologic mapping has shown

sericite-chlorite, quartz-chlorite, and finally quartz-sulfide (Zierenberg and others, 1988). The completely silicified rocks were originally mapped as “chert exhalite,” but careful mineralogical, geochemical, and isotopic studies showed the presence of relict igneous chromium spinel, proving massive hydrothermal replacement.

The early stage of the hydrothermal activity has produced extensive propylitisation and potassic alteration (orthoclase, biotite, sericite) associated with the central part of the quartz-micromonzodioritic porphyry stock.

May 20, 2013 · Hematization is an alteration style caused by oxidizing fluids. It results in the formation of hematite and some potassium-feldspar, sericite, chlorite and epidote. Hematization is associated with magmatic-hydrothermal environments …

Apr 30, 2015 · Phyllic (or sericitic) alteration. ØThis alteration style is the most common in a variety of hydrothermal ore deposits and forms over a wide temperature range by hydrolysis of feldspars to form sericite (fine-grained white mica), with …

Hydrothermal alteration includes silicification, argillic, propylitic, and phyllic alterations; and ore mineralogy consists of stibnite, cinnabar, pyrite, chalcopyrite, sphalerite, covellite,...

Phyllic Zone (Sericitic Zone) Characteristics: Minerals: Sericite (fine-grained muscovite) Quartz Pyrite Formation: Forms at intermediate temperatures (300–400°C) as acidic hydrothermal fluids alter the rocks. It often occurs adjacent to or overlapping the potassic zone.

Nov 8, 2023 · Chlorite-sericite alteration contains muscovite, chlorite and epidote (Fig. 3e–f), and overprints preexisting potassic alteration assemblages. Propylitic alteration is characterized by extensive disseminations, veinlets or aggregates of chlorite, epidote, and actinolite (Fig. 3g–h). Argillic alteration is only developed locally in the ...

Jan 1, 2022 · The alteration index (AI) and chlorite-carbonate-pyrite index (CCPI) reveal that argillic, sericitic, and propylitic alteration types are the main zones of alteration surrounding ore veins indicating that AI increases and CCPI decreases toward more proximal to the structures linked to these ore systems.