Banca de DEFESA: PATRICIA REIS ALENCAR OLIVEIRA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : PATRICIA REIS ALENCAR OLIVEIRA
DATE: 08/01/2025
TIME: 14:00
LOCAL: Videoconferência / Canal Youtube PPGG
TITLE:

The magmatic and tectonic role on spreading styles at ridge-transform intersection between Marathon and Vema Transform faults

KEY WORDS:

Mid-Atlantic Ridge; transform faults; non-transform discontinuities; detachment faults; morphotectonics

PAGES: 34
BIG AREA: Ciências Exatas e da Terra
AREA: Geociências
SUMMARY:

The Mid-Atlantic Ridge is a geotectonic region of high complexity, essential for understanding the evolution of oceanic crusts and the processes associated with divergent plate tectonics. This study analyzed approximately 400 km of the ridge's axial segment, between the Marathon Fracture Zone and 8°48'N, with depths ranging from 1,600 m to 6,000 m, using bathymetric, gravimetric, and seismicity data. The aim was to investigate the interaction between magmatism and tectonism in the formation of oceanic relief, with a focus on ridge-transform intersections (RTIs) and non-transform discontinuities (NTDs). The northern portion of the study area, located above the Vema Fracture Zone, was divided into two supersegments, 12°N and 11°N, the latter subdivided into segments 11°55'N and 11°20'N. The southern portion included the 9°N and 10°N supersegments, segmented by second-order discontinuities. The results indicate that these segmentations exhibit unique morphological and geophysical characteristics while sharing similar processes of formation and evolution. This highlights how the interaction between magmatism and tectonism directly influences the morphotectonic configuration of the Mid-Atlantic Ridge.Structures such as detachment faults in elevated inside corners play a crucial role in generating asymmetries, reflecting the impact of lithospheric decoupling in slow-spreading regions, with evidence of reduced magmatic flux. Additionally, NTDs promote the reduction and/or absence of magmatism, exposing massifs and rocks with altered rheology, distinct from those observed in the abyssal hills of the supersegments. These features, in particular, are favorable for fluid percolation and the formation of hydrothermal systems, standing out as priority areas for further investigation, especially at the intersection of the 11°20'N segment with the Vema transform fault.

COMMITTEE MEMBERS:
Externo à Instituição - DAVID LINO VASCONCELOS
Externa à Instituição - MARY LUCIA DA SILVA NOGUEIRA
Presidente - 2042405 - MOAB PRAXEDES GOMES
Externa à Instituição - NARELLE MAIA DE ALMEIDA
Externa à Instituição - TEREZA CRISTINA MEDEIROS DE ARAÚJO