Wallrock alteration categories and their geochemical signatures in gold-bearing Neoproterozoic granitoids, Batouri gold district, southeastern Cameroon
Journal article
Authors / Editors
Research Areas
Publication Details
Subtitle: Wallrock alteration categories and their geochemical signatures in gold-bearing Neoproterozoic granitoids, Batouri gold district, southeastern Cameroon
Author list: Shemang, Elisha
Publisher: Geological Society
Publication year: 2018
Journal: Geochemistry: Exploration, Environment, Analysis (1467-7873)
ISSN: 1467-7873
eISSN: 2041-4943
Languages: English-United States (EN-US)
Abstract
Hydrothermally altered granitoids in the Batouri district host gold mineralization. Gold and associated metals occur as disseminated, stockwork and veins. The granitoids range from quartz-alkali granitoids sensu stricto to diorite with various types of wallrock alterations including K-feldspar alteration, sericitization, silicification, and sulfidation/ferruginization. Most gold-bearing samples are extensively brecciated. Gold mineralization is accompanied with sericitization, silicification, and sulfidation/ferruginization alterations. Gold concentrations reach a high of 103.7 ppm. The granitic rocks are sub-alkaline. They show enrichment in the LREE, a negative Eu anomaly and a depletion in the HREE reflecting the breakdown and mobility of the initial plagioclase feldspar bearing HREE during fluid-rock interaction. On multielement variation diagrams, spikes at K, Ba, Pb, and Th are depicted resulting from selective enrichment during alteration. Mass gains/losses during alteration calculated using the immobile element method indicate, amongst others, gains in SiO2 (silicification), K2O (K-feldspar alteration), SO3 and Fe2O3 (sulfidation/ferruginization) with losses in Na2O linked to sericitization. The samples show Pd and Pt as high as 2 ppm. Gold mineralization is associated with wallrock alteration zones with elevated contents of As-Ba-Cu-Pb-Rb-Sr-Zn and Zr due to the neominerals developed during hydrothermal alteration. Au-Ag-Zn defines a potential pathfinder element cluster in the Batouri district
Keywords
No matching items found.
Documents
No matching items found.
