Skip to Main content Skip to Navigation
Theses

Hydrothermal alterations, Cu-Ag mineralizations and structural geology of the volcanic rocks from Seival Mine, Camaquã Neoproterozoic Basin, Southern Brazil

Abstract : The volcanogenic rocks of the Seival Mine belong to Hilário Formation from Camaquã Basin, with ages Neoproterozoic. These rocks contain six inactive mines with various prospects of copper-silver. Mineralization are associated with intense structural control in brittle regime. Chemical transformation of hydrothermal alteration associated with paleostress is not very well understood in the region. We propose a characterization of mineral chemistry of the magmatic phases, tardi–magmatic and hydrothermal as well as understand the paleostress and geochemistry of late veins. For this, we realized analyses of mineral chemistry of magmatic and alteration phase. Mineral chemistry coupled with thermodynamic modeling allowed to characterize the alteration as tardi–magmatic. The albitization (650 to 350 °C) occurred in association with chloritization (312 to 120 °C), and with pyrite and chalcopyrite. The lowest temperatures (150 to 50 °C) were related to formation of smectite and interlayered chlorite/smectite, and with chalcocite–covellite, chalcocite–bornite or barite. We perform structural analyzes through kinematic measures and failure/fracture directions. The analysis on faults, fractures and mineralization showed three main stresses occurring in the Seival Mine and Lavras do Sul Mining District: NW–SE compression; NE–SW compression; ENE–SWS distension. The NW–SE paleostress is the main effort related to the dikes and mineralization in both areas.
Document type :
Theses
Complete list of metadatas

Cited literature [59 references]  Display  Hide  Download

https://tel.archives-ouvertes.fr/tel-02051414
Contributor : Abes Star :  Contact
Submitted on : Wednesday, February 27, 2019 - 5:13:07 PM
Last modification on : Wednesday, October 14, 2020 - 4:22:26 AM

File

2018AZUR4001.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-02051414, version 1

Collections

Citation

Rodrigo Winck Lopes. Hydrothermal alterations, Cu-Ag mineralizations and structural geology of the volcanic rocks from Seival Mine, Camaquã Neoproterozoic Basin, Southern Brazil. Earth Sciences. Université Côte d'Azur; Universidade Federal do Rio Grande do Sul (Porto Alegre, Brésil), 2018. Portuguese. ⟨NNT : 2018AZUR4001⟩. ⟨tel-02051414⟩

Share

Metrics

Record views

292

Files downloads

149