További információ: csaba.szabo@ttk.elte.hu; aradi.laszloelod@ttk.elte.hu

Geochemical vectoring for Cu-Au±Ag-Pb-Zn mineralization in magmatic-hydrothermal systems: case studies from the Western Tethyan Belt
István MÁRTON
Stockwork Geoconsulting Ltd, Odorheiu Secuiesc/ Székelyudvarhely, Romania
University of Babeș–Bolyai, Faculty of Biology and Geology, Department of Geology, Cluj-Napoca/ Kolozsvár, Romania

Recent developments in exploration geochemistry and better instrumentation of industrial geochemical laboratories provide large and high-precision partial digestion multi-element datasets for mineral exploration projects. Additionally, the expansion of portable and desktop XRF, SWIR and XRD devices deliver fast and reliable characterization of mineralogy and geochemistry of drill core, soil and rock samples. Although these exploration geochemical datasets are often regarded with large skepticism by the academic world, systematic and rigorous use of this data provide critical information about ore genetic and mineralization controlling aspects, about alteration footprint and optimal drill-spacing, about vectors to fertile host rocks and economic ore bodies and on perspectives of geometallurgical domaining at any mineral exploration project.
The presentation will provide insights on the use of these exploration geochemical tools and interpretations. Case studies will include the world-class Late-Cretaceous Chelopech Cu-Au deposit from the Panagyurishte district of Bulgaria and the Tertiary Au-Cu Artsiv prospect from Armenia. The studied high-sulfidation style magmatic-hydrothermal deposits and prospects are represented by sulphide- and sulphosalt-rich replacement zones associated with a well-zoned advanced argillic alteration (AAA) footprint. The inner core of AAA is represented by vuggy silica and APS minerals (alunite, svanbergite, woodhousite, plumbogummite, etc) surrounded by a competent dickite-silica-APS alteration assemblage. The outer zones are represented by lower crystallinity kaolinite and illite alteration. The deep part of the AAA is characterized by muscovite, pyrophyllite and diaspore alteration, which usually marks the lower limit of economic copper grades. An extensive SWIR dataset and the Sr-K-Na-Ca-Rb-Li multielement whole-rock interpolants provide primary vectors to mineralization within this alteration footprint. The ore zones show vertical and lateral zonation also in chalcophile components: The innermost economic zone is represented by Cu-Au-As-Ag-Te assemblages whereas the outer part is marked by relative enrichment of Pb-Zn-Mn-Tl-Ag-Au. The deep core of the ore bodies is marked by relative enrichment of Au-Sb-Bi-Te-W-Mo.