Persistent Link:
http://hdl.handle.net/10150/305792
Title:
Supergene Copper Enrichment at Hanover Mountain, New Mexico
Author:
Duke, Jessica Carey
Issue Date:
2001
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Hanover Mountain is a supergene enriched chalcocite deposit located in the Central Mining district, southwest New Mexico, near Silver City. The Central Mining district is a complex, polymetallic district from which Cu, Fe, Zn, Pb, and Ag have been mined. Deposit types present in the district include porphyry, skarn and vein deposits. Primary mineralization in the district is Laramide in age. Hanover Mountain is near, but separate from other deposits in the district, but is believed to be a part of a larger hypogene system related to igneous intrusion. Detailed surface mapping of Hanover Mountain and measurement of preferred structural orientations, leached capping and alteration were completed as part of this research project. Hanover Mountain is somewhat unusual compared to the other deposits because the mineralization is located in the Colorado Formation, an Upper Cretaceous, heterolithic sedimentary unit composed of shale, siltstone, and sandstone. The Colorado Formation was deposited during a regressive period and ranges from shallow marine to fluvial in origin. In the study area the Colorado Formation has a weak metamorphic overprint. Some of the heterogeneity in the Colorado Formation at Hanover Mountain has been interpreted as facies changes. Rocks on the south side of the mountain are more sandy and silicified. Finer-grained facies predominate on the north side of the mountain and at lower elevations. The predominant structural grains at Hanover Mountain are N-S, NE and ENE. The mountain is bounded on the southeast by the Barringer fault, a NE-striking, district-scale fault with approximately 1500' of displacement. The Barringer Fault drops sediments down to the northwest, juxtaposing Cretaceous clastic rocks with Paleozoic limestone. Two types of dikes crop out on the surface of Hanover Mountain. Early, mafic plagioclase-hornblende porphyry dikes occupy E-W structures; younger granodiorite porphyry dikes are found in N-S structures. The leached cap on Hanover Mountain is dominantly goethitic and ranges from 20-200' thick. Mapping of the distribution of hematite, goethite, and limonite indicates the existence of at least one previous enrichment blanket. In the study area the Colorado Formation is pervasively sericitized. The enrichment blanket is up to about 100' thick and mimics topography. Relict primary pyrite and chalcopyrite incompletely replaced by chalcocite indicate an immature enrichment blanket.
Type:
text; Electronic Thesis
Degree Name:
M.S.
Degree Level:
masters
Degree Program:
Graduate College; Geoscience
Degree Grantor:
University of Arizona
Advisor:
Titley, Spencer

Full metadata record

DC FieldValue Language
dc.language.isoen_USen_US
dc.titleSupergene Copper Enrichment at Hanover Mountain, New Mexicoen_US
dc.creatorDuke, Jessica Careyen_US
dc.contributor.authorDuke, Jessica Careyen_US
dc.date.issued2001-
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractHanover Mountain is a supergene enriched chalcocite deposit located in the Central Mining district, southwest New Mexico, near Silver City. The Central Mining district is a complex, polymetallic district from which Cu, Fe, Zn, Pb, and Ag have been mined. Deposit types present in the district include porphyry, skarn and vein deposits. Primary mineralization in the district is Laramide in age. Hanover Mountain is near, but separate from other deposits in the district, but is believed to be a part of a larger hypogene system related to igneous intrusion. Detailed surface mapping of Hanover Mountain and measurement of preferred structural orientations, leached capping and alteration were completed as part of this research project. Hanover Mountain is somewhat unusual compared to the other deposits because the mineralization is located in the Colorado Formation, an Upper Cretaceous, heterolithic sedimentary unit composed of shale, siltstone, and sandstone. The Colorado Formation was deposited during a regressive period and ranges from shallow marine to fluvial in origin. In the study area the Colorado Formation has a weak metamorphic overprint. Some of the heterogeneity in the Colorado Formation at Hanover Mountain has been interpreted as facies changes. Rocks on the south side of the mountain are more sandy and silicified. Finer-grained facies predominate on the north side of the mountain and at lower elevations. The predominant structural grains at Hanover Mountain are N-S, NE and ENE. The mountain is bounded on the southeast by the Barringer fault, a NE-striking, district-scale fault with approximately 1500' of displacement. The Barringer Fault drops sediments down to the northwest, juxtaposing Cretaceous clastic rocks with Paleozoic limestone. Two types of dikes crop out on the surface of Hanover Mountain. Early, mafic plagioclase-hornblende porphyry dikes occupy E-W structures; younger granodiorite porphyry dikes are found in N-S structures. The leached cap on Hanover Mountain is dominantly goethitic and ranges from 20-200' thick. Mapping of the distribution of hematite, goethite, and limonite indicates the existence of at least one previous enrichment blanket. In the study area the Colorado Formation is pervasively sericitized. The enrichment blanket is up to about 100' thick and mimics topography. Relict primary pyrite and chalcopyrite incompletely replaced by chalcocite indicate an immature enrichment blanket.en_US
dc.typetexten_US
dc.typeElectronic Thesisen_US
thesis.degree.nameM.S.en_US
thesis.degree.levelmastersen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineGeoscienceen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorTitley, Spenceren_US
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