%0 Conference Proceedings
%4 sid.inpe.br/marte2/2017/10.27.16.19.08
%2 sid.inpe.br/marte2/2017/10.27.16.19.09
%@isbn 978-85-17-00088-1
%F 60049
%T Estudo de assinaturas de reflectância de amostras de rocha do depósito de Au de Pedra Branca, região da Serra das Pipocas, CE
%D 2017
%A Naleto, João Luís Carneiro,
%A Perrotta, Monica Mazzini,
%A Souza Filho, Carlos Roberto,
%@electronicmailaddress joao.naleto@cprm.gov.br
%E Gherardi, Douglas Francisco Marcolino,
%E Aragão, Luiz Eduardo Oliveira e Cruz de,
%B Simpósio Brasileiro de Sensoriamento Remoto, 18 (SBSR)
%C Santos
%8 28-31 maio 2017
%I Instituto Nacional de Pesquisas Espaciais (INPE)
%J São José dos Campos
%P 7316-7322
%S Anais
%1 Instituto Nacional de Pesquisas Espaciais (INPE)
%X The Geological Survey of Brazil (CPRM) has been investigating the mineral resources potential of the Troia Massif, which is an Archean/Paleoproterozoic nucleus located at the central region of Ceará State. In this area, gold mineralization hosted by metavolcano-sedimentary sequences has been recently discovered by private exploration projects (Pedra Branca deposit). The gold is associated to quartz veins and hydrothermal alteration, hosted by amphibolites, metandesites, metatonalites and metasedimentary rocks, placed along a main NE-SW regional structure. In this context, a set of rock samples from the area were collected in order to study their compositional and physicochemical variations related to the hydrothermal alteration, through the extraction and analysis of their reflectance spectral signatures. The spectra of altered and fresh rocks samples were measured with an ASD FieldSpec-3 High-Resolution spectroradiometer and the mineralogical interpretations were performed visually, based on the GMEX and USGS reference spectral libraries. The results show a hydrothermal zonation consistent with orogenic gold deposits hosted by greenstone belts, defined by four main mineral assemblages: (i) amphiboles + biotite + epidote + Mg-chlorite (unaltered), (ii) FeMg-chlorite + calcite + paragonite (distal, chlorite zone), (iii) ankerite/siderite + muscovite + calcite + FeMg-chlorite (intermediate, carbonate zone), (iv) phengite + ankerite/siderite (proximal, muscovite zone). The mineralogical model proposed is coherent with the geological and metallogenetic patterns defined by previous studies, which indicates its feasibility in prospecting new Au deposits in the region.
%9 Geologia
%@language pt
%3 60049.pdf