Geomorphological, seismostratigraphic and faciological characterization of bioclastic environments in the Vitória-Trindade Chain

• Grant number: 21/11388-6
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Start date: November 01, 2021
• End date: April 30, 2025
• Field of knowledge: Physical Sciences and Mathematics - Oceanography - Geological Oceanography
• Principal Investigator: Luigi Jovane
• Grantee: Mateus Alexander Campeche Gama
• Host Institution: Instituto Oceanográfico (IO). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 16/24946-9 - Sea-level changes and Global Monsoon System: clues from marine cores in Brazil, AP.PFPMCG.TEM

Abstract

The Brazilian bioclastic deposits are constituted by rigid carbonate features like reefs and unconsolidated like rhodolite banks extending along the entire Brazilian coast, accumulated after the drowning of the platform that occurred in the last glacial maximum. Brazilian reefs are dated to about 7000 years old, when the sea level reached stability close to its current level. Considered a collection of marine biodiversity, reef environments have been increasingly threatened by anthropogenic influences at different spatial scales, synergistically affecting these environments. In order to investigate the carbonate banks of the Vitória-Trindade Chain and their geochronological characteristics, to determine the importance of seamounts in glacial conditions for Brazilian reef ecosystems and also how carbonate banks accumulated in the mountains near the largest reef complex in the South Atlantic and the largest rhodolito bank in the world, which is the Abrolhos bank. The Vitória-Trindade Chain extends for 1200 miles in the oceanic basin, having seamounts reaching between 10 and 110 meters in depth, with the upper surface of these mountains occupied by bioclasts. To perform high resolution imaging of the morphological features, bathymetric data with multibeam from the top of the mount will be collected.The multichannel seismic with Geo-Spark 2000X has an energy emission of 7kj providing high resolution and its processing will occur with the RadExPro program to obtain the seismic profiling. The bottom sample data will be collected with the Van-Veen dredger at different depth gradients and as absorbed will subsequently be reserved for microscopic and structural analysis to characterize the bioclastic environments and their facies. In addition to the petrographic analyses, carbon isotopic (14 C) dating will be carried out with the collected surfaces. The results will be the architecture of the carbonate deposits, rocky outcrops of the seamounts and the bottom structure in the region of the top of the mountains. Furthermore, compare the carbonate basement with sea level oscillations caused by melting pulses. Finally, correlate if the obtained results approximate the hypotheses elaborated in the project, about the geochronology of Brazilian carbonate environments during the last glacial maximum. (AU)