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dc.contributor.authorWilson, E.D.
dc.date.accessioned2018-09-29T02:13:38Z
dc.date.available2018-09-29T02:13:38Z
dc.date.issued1961
dc.identifier.urihttp://hdl.handle.net/10150/629779
dc.descriptionGold placers, or deposits such as gravel and sand which contain notable concentrations of gold, all result from the slow milling and concentration processes incident to natural erosion of pre-existing gold-bearing rocks. The origin of many gold placers is traceable directly to auriferous veins, lodes, or replacement deposits which, in most instances, were not of high grade. According to Emmons, placers are not apt to form from goldbearing outcrops that contain abundant manganese, iron sulphides, and chlorides, unless precipitating agents such as calcite, siderite, rhodochrosite, pyrrhotite, chalcocite, nepheline, olivine, or leucite are abundant, or unless erosion is very rapid. In other words, the gold may be dissolved and carried below by means of natural chlorination processes that are established when solutions containing chlorides, together with sulphuric acid from the oxidation of iron sulphides, act upon manganese dioxide; but this process is neutralized if precipitating agents are present, and may be ineffective if erosion is very rapid
dc.language.isoen
dc.relation.ispartofseriesBulletin 168
dc.relation.urlhttp://repository.azgs.az.gov/uri_gin/azgs/dlio/70
dc.rightsArizona Geological Survey. All rights reserved.
dc.subjectArizona Geological Survey Bulletins
dc.subjectYuma
dc.subjectYavapai
dc.subjectArizona Counties
dc.subjectPima
dc.subjectOatman
dc.subjectGreaterville
dc.subjectArizona
dc.subjectplacer equipment
dc.subjectprospecting
dc.subjectsedimentation
dc.subjectplacers
dc.subjectmining districts
dc.subjectheavy minerals
dc.subjectgold
dc.subjecteconomic mineralogy
dc.titleGold Placers and Placering in Arizona
csdgm.bounding.west-114.829
csdgm.bounding.east-108.984
csdgm.bounding.north36.985
csdgm.bounding.south31.3161
dc.description.noteOriginally published in 1961, reprinted in 1981.
dc.description.collectioninformationDocuments in the AZGS Document Repository collection are made available by the Arizona Geological Survey (AZGS) and the University Libraries at the University of Arizona. For more information about items in this collection, please contact azgs-info@email.arizona.edu.
refterms.dateFOA2018-09-29T02:13:38Z


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