Petrology of Mineralized and Non-Mineralized Samples from the Railroad District within the Carlin Trend, Elko, NV

Mineralized and non-mineralized samples of Paleozoic rocks from the RailroadDistrict were analyzed using standard petrography, Environmental Scanning ElectronMicroscope (ESEM), and cathodoluminescence to identify the relationship betweenhost rock and gold mineralization fluids. The Railroad District, southwest of Elko,Nevada, is part of the Carlin Trend, an area known from submicroscopic gold deposition.Samples consisted of mineralized and non-mineralized limestone (Devonian DevilsGate Formation), mudstone (Mississippian Webb Formation), sandstone (MississippianChainman Formation), and fault breccias.Areas of highest mineralization are the Chainman Formation and fault brecciascontaining high amounts of Webb Formation, where two or more mieralization idicativephases were observed. Mineralized Chainman samples have stilpnomelane, Fe-richpyrite, barite, and andalusite porphyroblasts. Gold concentrations within mineralizedsamples range from 2-5 wt. % in the Chainman Formationand 2-8 wt. % in the faultbreccias. An apparent bimodal distribution of Au was found which reflects the mediadensity that contains it (Fe-rich pyrite vs. quartz).Elemental (Si, S, Te, Ca, Fe, As, Au, Ag, Ba, Al, K, Na, and Ti) data gatheredwas used for mean weight percents and correlation coefficients calculations for both mineralized and non-mineralized samples. Mineralized samples had high correlationsbetween (Fe-S), (Au-Ag), and (Ti-Ba), whereas non-mineralized had low correlations.Both mineralized and non-mineralized samples had low mean arsenic. Little correlationwas found between As and S in the mineralized and the non-mineralized samples. Cathodoluminescence microphotographs defined differences between mineralizedand non-mineralized samples. The presence of [RGB 79 132 169] Marina -colored bariteand [RGB 210 115 143] Chateau Rose-colored quartz. Mineralized samples were morevibrant than non-mineralized samples, making them easier to identify.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Geology

Grantor dc:publisher

University of Akron

Year dc:date

2013

Author dc:creator

• Dvorak, Katherine A.

Contributors dc:contributor

• Friberg, LaVerne

• Chemistry
• Geological
• Mineralogy
• Petrology
• Calrin depsoits
• gold
• Railroad District
• mineralization
• hydrothermal
• fluids
• Nevada

Statement dc:rights

• unrestricted
• This thesis or dissertation is protected by copyright: some rights reserved. It is licensed for use under a Creative Commons license. Specific terms and permissions are available from this document's record in the OhioLINK ETD Center.

Language dc:language

English

Repository record dc:identifier

http://rave.ohiolink.edu/etdc/view?acc_num=akron1363176129

OAI identifier oai:identifier

oai:etd.ohiolink.edu:akron1363176129