Banca de DEFESA: THABITA SOFIA GOMES BARBOSA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : THABITA SOFIA GOMES BARBOSA
DATE: 30/03/2022
TIME: 14:00
LOCAL: videoconferência https://www.youtube.com/channel/UCCBwJxTIfyeGmQSqDLK6duw
TITLE:

Lithospheric S-velocity structure of the on-shore Potiguar Basin, NE Brazil: High
heat- flow in an aborted rift

KEY WORDS:

Potiguar Basin; magmatic intrusions; lithosphere-asthenosphere boundary (LAB); sublithospheric flow

PAGES: 98
BIG AREA: Ciências Exatas e da Terra
AREA: Geociências
SUMMARY:

The lithospheric structure of the on-shore Potiguar Basin has been investigated through velocity-depth profiles developed from the joint inversion of receiver functions and surface-wave dispersion at 16 seismic stations in and around the basin. The Potiguar Basin is an aborted rift basin that formed during the opening of the South Atlantic Ocean in the Lower Cretaceous, and is characterized by an unusual surface heat-flow with values as high as 101 mW/m2. Our results reveal: (i) A relatively thin crust of ~30 km below the on-shore Potiguar Basin and a thicker crust of ~32 km around the basin; (ii) the existence of an anomalous layer of ~4.3 km/s at 30-40 km depth under most seismic stations; and (iii) the presence of a negative gradient starting at ~125 km depth, which probably represents a shallow Lithosphere Asthenosphere Boundary (LAB). We argue that the anomalous S-velocity layer is associated with magmatic intrusions just below the Moho, deeper than previously
postulated from independent heat-flow studies, and that those intrusions result from heating by an active, hot sublithospheric mantle under the basin that keeps the lithosphere thin. We further argue that heating from the magmatic intrusions, along with direct heating from the sublithospheric mantle, may explain the unusually elevated heat flow observed at the surface.

BANKING MEMBERS:
Presidente - 1451214 - ADERSON FARIAS DO NASCIMENTO
Externo à Instituição - CARLOS ALBERTO MORENO CHAVES - USP
Interno - 1315614 - DAVID LOPES DE CASTRO