Next Article in Journal
Sustainable Reuse of Mine Tailings and Waste Rock as Water-Balance Covers
Next Article in Special Issue
Contrasting Surficial Composition of Native Gold from Two Different Types of Gold Ore Deposits
Previous Article in Journal
The Effect of Conditioning on the Flotation of Pyrrhotite in the Presence of Chlorite
Article Menu
Issue 7 (July) cover image

Export Article

Open AccessArticle
Minerals 2017, 7(7), 127; https://doi.org/10.3390/min7070127

Hydrothermal Alteration in the Main Sulfide Zone at Unki Mine, Shurugwi Subchamber of the Great Dyke, Zimbabwe: Evidence from Petrography and Silicates Mineral Chemistry

Department of Geology and Geography, University of North Carolina–Pembroke, 211 Old Main, 1 University Dr., Pembroke, NC 28372, USA
Received: 24 May 2017 / Revised: 30 June 2017 / Accepted: 14 July 2017 / Published: 22 July 2017
(This article belongs to the Special Issue Geochemistry and Mineralogy of Hydrothermal Metallic Mineral Deposits)
Full-Text   |   PDF [31899 KB, uploaded 25 July 2017]   |  

Abstract

The main platinum-group element (PGE) occurrence in the Great Dyke of Zimbabwe, the Main Sulfide Zone (MSZ), is a tabular stratabound layer hosted in pyroxenites. A petrographic and silicate composition study across the MSZ at Unki Mine in the Shurugwi Subchamber was conducted to help place some constrains on the origin of the mineralization. The PGE-enriched zone at Unki Mine is a ~10 m thick package of rocks ranging from gabbronorites, a chromitite stringer, plagioclase websterite, plagioclase pyroxenite (pegmatitic in one narrow zone), a base metal sulfide zone and it is largely located below the contact of the Mafic and Ultramafic Sequences. Pyroxenes have been partially hydrothermally altered to amphibole and chlorite in most lithologies. In addition, sulfides tend to occur as cumulus phases or as inclusions in all the silicate phases. Two generations of sulfide mineralization likely occurred at Unki Mine with primary sulfides occurring in association with cumulus phases, and the relatively finer-grained, often lath-like, sulfides that occur in association with alteration phases of chlorite and amphibole that were likely formed later during hydrothermal alteration. Chlorite thermometry yields temperatures ranging from 241 to 390 °C, and from 491 to 640 °C, and they are interpreted to be temperatures recording the hydrothermal event(s) of magmatic origin which affected the mineralization at Unki Mine. Two-pyroxene thermometry yields temperatures that range from 850 to 981 °C, and these temperatures are interpreted to indicate a hydrothermal imprint on the minerals that constitute the MSZ. View Full-Text
Keywords: layered intrusions; Great Dyke; Main Sulfide Zone; mineral chemistry; hydrothermal alteration layered intrusions; Great Dyke; Main Sulfide Zone; mineral chemistry; hydrothermal alteration
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).

Supplementary material

SciFeed

Share & Cite This Article

MDPI and ACS Style

Chaumba, J.B. Hydrothermal Alteration in the Main Sulfide Zone at Unki Mine, Shurugwi Subchamber of the Great Dyke, Zimbabwe: Evidence from Petrography and Silicates Mineral Chemistry. Minerals 2017, 7, 127.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Minerals EISSN 2075-163X Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top