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GEOREF RECORD

The Anarraaq Zn-Pb-Ag and barite deposit, Northern Alaska; evidence for replacement of carbonate by barite and sulfides

Karen D. Kelley, Julie A. Dumoulin and Scott Jennings
The Anarraaq Zn-Pb-Ag and barite deposit, Northern Alaska; evidence for replacement of carbonate by barite and sulfides (in Barite and Zn-Pb-Ag deposits in the Red Dog District, western Brooks Range, Northern Alaska, Karen D. Kelley (editor) and Scott Jennings (editor))
Economic Geology and the Bulletin of the Society of Economic Geologists (November 2004) 99 (7): 1577-1591

Abstract

The Anarraaq deposit in N Alaska consists of a barite body, estimated at 1 billion metric tons, and a Zn-Pb-Ag massive sulphide zone with an estimated resource of about 18 Mt at 18 percent Zn, 5.4 percent Pb, and 85 g/t Ag. The barite and sulphide minerals are hosted by the uppermost part of the Mississippian Kuna Formation (Ikalukrok unit) that consists of carbonaceous and siliceous mudstone or shale interbedded with carbonate. The amount of interbedded carbonate in the Anarraaq deposit is atypical of the district as a whole, comprising as much as one third of the section. The total thickness of the Ikalukrok unit is considerably greater in the area of the deposit (210 to almost 350 m) than to the N and S (maximum of 164 m). The mineralized zone at Anarraaq is lens shaped and has a relatively flat top and a convex base. It also ranges greatly in thickness, from a few metres to more than 100 m. Textures of some of the carbonate layers are distinctive, consisting of nodules within siliceous mudstone or layers interbedded with shale. Many of the layers contain calcitized sponge spicules or radiolarians in a carbonate matrix. Textures of barite and sulphide minerals mimic those of carbonate and provide unequivocal evidence that replacement of precursor carbonate was an important process. Barite and sulphide textures include either nodular, bladed grains of various sizes that resemble spicules (observed only with iron sulphides) or well-rounded forms that are replaced radiolarians. Mineralization at Anarraaq probably occurred in a fault-bounded Carboniferous basin during early diagenesis in the shallow subsurface.


ISSN: 0361-0128
EISSN: 1554-0774
Coden: ECGLAL
Serial Title: Economic Geology and the Bulletin of the Society of Economic Geologists
Serial Volume: 99
Serial Issue: 7
Title: The Anarraaq Zn-Pb-Ag and barite deposit, Northern Alaska; evidence for replacement of carbonate by barite and sulfides
Title: Barite and Zn-Pb-Ag deposits in the Red Dog District, western Brooks Range, Northern Alaska
Author(s): Kelley, Karen D.Dumoulin, Julie A.Jennings, Scott
Author(s): Kelley, Karen D.editor
Author(s): Jennings, Scotteditor
Affiliation: U. S. Geological Survey, Denver, CO, United States
Affiliation: U. S. Geological Survey, Denver, CO, United States
Pages: 1577-1591
Published: 200411
Text Language: English
Publisher: Economic Geology Publishing Company, Lancaster, PA, United States
References: 42
Accession Number: 2005-010425
Categories: Economic geology, geology of ore deposits
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sect., sketch map
N60°04'60" - N68°04'60", W163°00'00" - W163°00'00"
Secondary Affiliation: Teck Cominco American, USA, United StatesTeck Cominco American, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2018, American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
Update Code: 200505
Program Name: USGSOPNon-USGS publications with USGS authors
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