Geology setting and metallogenesis of the Alta Floresta Province, southern Amazon Craton (Brazil)

Veronica Trevisan, Roberto Xavier, Steffen Hagemann, Anthony Kemp, Robert Loucks, Jian-Feng Gao, Rafael Rodrigues de Assis, Antônio João Paes de Barros

Research output: Chapter in Book/Conference paperConference paper

Abstract

The Alta Floresta Province consists of Paleoproterozoic plutono-volcanic sequences (2.01-1.75 Ga) originated from a series of successive magmatic arcs that accreted to the southwestern margin of the Central Amazon Province. The geologic framework of the eastern sector of the province is organized into: 2.8-1.97 Ga deformed metamorphic and metamorphosed granitic basement; 1.97-1.78 Ga I-type plutono-volcanic and volcano-sedimentary sequences; 1.78-1.77 Ga post-orogenic and anorogenic plutono-volcanic units; and Mesoproterozoic (~1.3 Ga) to Quaternary sedimentary sequences. The deposits are clustered into four main groups: (i) disseminated Au±Cu(±Mo); (ii) structurally-controlled vein-type Au±Cu(±Mo); (iii) disseminated Cu+Mo; and (iv) structurally-controlled vein-type Au+Zn+Pb±Cu. Ore zones in groups (i) to (iii) are represented by pyrite±chalcopyrite±molybdenite, whereas group (iv) consists of pyrite+sphalerite+galena±chalcopyrite. In most deposits, mineralization is contained within muscovite-chorite-quartz-rich or silica-rich zones. The fluid regime of groups (i) and (ii) is mainly represented by CO2-rich fluids, whereas group (iv) by two-phase aqueous fluids with heterogeneous degree of filling. Pyrite and molybdenite Re-Os and pyrite Pb-Pb systematics constrain the mineralization age in the 1.84-1.77 Ga range, which overlaps with the ages of porphyritic granitoids, and in a regional scale, to the Colíder and Teles Pires suites ages. These deposits represent magmatic-hydrotermal systems and are considered to share broad similarities with porphyry-epithermal deposits.
Original languageEnglish
Title of host publicationSociety for Geology Applied to Mineral Deposits Conference Glasgow Proceedings
PublisherSociety for Geology Applied to Mineral Deposits
Pages1-5
Number of pages5
Publication statusPublished - Aug 2019
Event15th Biennial Meeting of the Society for Geology Applied to Mineral Deposits: Life with Ore Deposits on Earth - University of Glasgow, Glasgow, United Kingdom
Duration: 27 Aug 201930 Aug 2019

Conference

Conference15th Biennial Meeting of the Society for Geology Applied to Mineral Deposits
Abbreviated titleSGA 2019
CountryUnited Kingdom
CityGlasgow
Period27/08/1930/08/19

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