Geology and Fluid Characteristics of the Mina Velha and Mandiocal Orebodies and Implications for the Genesis of the Orogenic Chega Tudo Gold Deposit, Gurupi Belt, Brazil

摘要

The Chega Tudo gold deposit is located in the Gurupi belt of northern Brazil. Gold mineralization in the Mina Velha (upper level) and Mandiocal (intermediate and lower levels) orebodies is hosted in highly strained Paleoproterozoic (2148–2160 Ma) felsic to intermediate metavolcanic rocks and schists that record greenschist facies metamorphism. The orebodies are broadly concordant with the regional northwest-oriented foliation, and mineralization comprises thick quartz vein sets and small quartz-carbonate-sulfide veinlets and enclosing hydrothermally altered host rocks. The hydrothermal mineral assemblage is postpeak metamorphism, syn- to late tectonic, and includes quartz, calcite, chlorite, white mica, pyrite, subordinate chalcopyrite, and traces of sphalerite and galena.