Banca de DEFESA: HELIÁSIO AUGUSTO SIMÕES

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : HELIÁSIO AUGUSTO SIMÕES
DATE: 06/10/2022
TIME: 09:00
LOCAL: videoconferência https://www.youtube.com/watch?v=x2750bmqPvQ
TITLE:

Mapping of mafic/ultramafic bodies in oceanic core complex in the Equatorial Mid-Atlantic Ridge: Saint Paul Fracture Zone to Bogdanov Fracture Zone

KEY WORDS:

Slow-spreading ocean ridge; multibeam echo-sounding; morphostructural mapping; mantle uplift, oceanic core complexes.

PAGES: 88
BIG AREA: Ciências Exatas e da Terra
AREA: Geociências
SUMMARY:

The exposure of rocks from the lower crust / upper mantle is a common accretion process
in slow and ultraslow spreading oceanic ridges, such as the Equatorial Mid-Atlantic Ridge. This region is still poorly studied. In this sense, the objective of this research project was to map the upper mantle rock exhumations, the Oceanic Core Complexes, and their associated structures and morphologies. For this purpose, we work here with a dataset comprising 40,000 km2 of high-resolution multibeam bathymetry (100 m/pixel) and gravimetric data collected on the ship during two scientific cruises between 2012 and 2013, carried out by the Geological Survey of Brazil. This dataset includes the seismological records of the last 100 years and free-air gravimetric anomalies derived from satellite altimetry. This is along with the axis ridge segments of the Equatorial Mid-Atlantic, going from the São Paulo Fracture Zone (0o 50’ north) to the Bogdanov Fracture Zone (7o 10’ north). Five oceanic fracture zones (Bogdanov, Sierra Leone, Strakhov, São Pedro, and São Paulo) and nine non-transform offsets of the ridge segments were mapped. Twelve occurrences of Oceanic Core Complexes were inferred, which are associated with corrugated massifs, non-corrugated massifs, and back-tilted ridges. These morphological features commonly show smoothed bathymetric patterns
parallel to the accretion direction, positive Bouguer anomalies, and low seismicity. The Oceanic Core Complexes occur consistently and branch out from non-transform offsets in the asymmetric accretion segments. These exhumations of rocks from the lower crust / upper mantle mark periods in the techno-magmatic evolution of the Equatorial Mid-Atlantic Ridge, where it was cold and magmatic depletion.

COMMITTEE MEMBERS:
Presidente - 2042405 - MOAB PRAXEDES GOMES
Externa à Instituição - NARELLE MAIA DE ALMEIDA - UFC
Externa à Instituição - TEREZA CRISTINA MEDEIROS DE ARAÚJO - UFPE