Migration of fluids and hydrocarbons in fault zones from the Southern Ribeira Belt: a fluid inclusion study

• Grant number: 15/10894-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: July 01, 2015
• End date: December 31, 2015
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: Frederico Meira Faleiros
• Grantee: Joana Isabel Santiago Ferreira
• Host Institution: Instituto de Geociências (IGC). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The Capiru Formation (Cryogenian to Ediacaran) comprises a major unit presents in the southern Ribeira Belt, eastern Paraná State. The unit is composed of greenschist facies metasedimentary rocks, and several geological features raise the possibility of it hosting, or have hosted in the past, hydrocarbon accumulations: (1) metric-thick layers of metashale rich in organic matter would be likely source rocks for generating hydrocarbons; (2) thick layers of metasandstone could serve as reservoir rocks; (3) layers of metamudstone would serve as sealants for petroleum systems; (4) regional antiforms could represent structural traps for possible hydrocarbon accumulations; (5) Available petrologic data suggest that the metamorphic peak of the unit reached temperatures lower than 350-400°C, and are thus within the window generation of methane and other light hydrocarbons. This work aims the elaboration of a model of fluid circulation along fault zones that cut the Capiru Formation and could have served as conduits for possible migration of hydrocarbons. The work will involve petrographic and microthermometric analyzes of fluid inclusion assemblages present in veins of zones which have been subject to high fluid flow. It is intended to determine the compositions and physicochemical characteristics of fluids, the pressure and temperature trapping conditions, and the possible occurrence of hydrocarbons. Vein samples collected from known structural context will permit to assess the relationships between the fluid characteristics and the processes of faulting and fluid migration.