Alunitic alteration at Marysvale, Utah

Abstract

Deposits of alunite in the J.farysvale region, Utah, are nearly all confined to the Bullion Canyon Volcanics of Tertiary age. The deposita consist of two types, alunite veinB and iegular alunite replacement bodies. Tile vein deposits are restricted to the vicinity of Alunite Ridge southwest of l1arysvale in the Tushar !bmtains, and the repla,..ement bodies are distributed circumferentially about a quartz monzonite etock in the Antelope Ranee northeast of the village.The wall rock alteration that borders the alunite veins has been divic'ed into three phases . In order of their zonal distribut ion toward the vein, the phases are the feeble phase, the moderate phase, and the intense phase. Feeble phase alteration is characterized by illite-montrnorillonite mixed lattice clay, kaolinite and minor quartz t-thich were formed at thv expense of carbcnate, seritized plagioclase and some of ((? the chlorite of the re 1 ional.ly al tcred Bullion Canyon volcanics.Alteration of the moderate phase is represented by tm assemblage, alunite, kaolinite and quartz which were produced in part from the mixed lattice clay am chlorite of the feeble phase. Strongly alunitized am silicified rock adjacent to the vein represents the intense phase of alteration.Alteration in the replacement deposits is represented by the feeble and moderate phases. The alunite bodies represent the moJerate phase of alterat.ion, and those bodies that are sharply defined are surro~"'lded by an envelope of feeble phase alteration. The mineralogy of the corresponding alteration phases of t he vein and replacement deposits is the S<L'1'18e c ?7

Thermochemistry of jarosite-alunite and natrojarosite-natroalunite solid solutions

“…Deficiencies in iron and aluminum have been reported (Hendricks, 1937;Parker, 1954;Ripmeester et al, 1986;. Charge neutrality for such nonstoichiometric samples is conserved by protonation of hydroxyl groups in the structure, leading to structural water molecules (Ripmeester et al, 1986).…”