FN Archimer Export Format
PT J
TI Joint inversion of receiver functions and surface wave dispersion in the Reconcavo-Tucano basin of NE Brazil: implications for basin formation
BT 
AF DORING, M. F.
   JULIA, J.
   EVAIN, Mikael
AS 1:1;2:1,2;3:3;
FF 1:;2:;3:PDG-REM-GEOOCEAN-GIPS;
C1 Programa Posgrad Geodinam & Geofis - UFRN, Natal, RN CEP 59078-970, Brazil.
   Departamento de Geofisica - UFRN, Natal, RN CEP 59078-970, Brazil.
   IFREMER, Marine Geosciences, Centre de Brest, CS10070, 29280 Plouzane, France
C2 UNIV FED RIO GRANDE DO NORTE, BRAZIL
   UNIV FED RIO GRANDE DO NORTE, BRAZIL
   IFREMER, FRANCE
SI BREST
SE PDG-REM-GEOOCEAN-GIPS
UM GEO-OCEAN
IN WOS Ifremer UMR
   copubli-int-hors-europe
   copubli-sud
IF 2.8
TC 5
UR https://archimer.ifremer.fr/doc/00763/87522/93018.pdf
   https://archimer.ifremer.fr/doc/00763/87522/93019.pdf
LA English
DT Article
DE ;South America;Joint Inversion;Crustal imaging;Continental tectonics: extensional
AB The crustal structure of the Reconcavo-Tucano basin, an aborted rift system that developed in NE Brazil during extension related to the opening of the South Atlantic Ocean, has been investigated through local constraints from receiver functions developed at 18 seismic stations in the region. Gravity modelling has proved unable to unequivocally localize crustal thinning under the basin depocentre and, together with a general lack of sediments from a putative thermal sag phase, this has led to a range of basin formation models invoking either pure or simple shear or a combination of both. In particular, the 'flexural cantilever' model has assumed simple shear extension in the upper crust and pure shear extension in the lower crust and mantle, enabling local erosion of the rift flanks after footwall uplift and regional erosion of the thermal sag phase after magmatic underplate of the basin's crust. Our results reveal that the crust is over 40 km thick beneath the Tucano and Reconcavo basins and that it contains a thick (5-8 km) layer of high velocity (Vs > 4.0 km s(-1)) material below similar to 35 km depth. These observations contrast with structure immediately West (Sao Francisco Craton) and East (Borborema Province) of the basin, for which crustal thicknesses average 42 and 36 km, respectively, lower crustal velocities are below 4.0 km s(-1), and local instances of crust as thin as 33.5 km are observed. We propose, in agreement with the 'flexural cantilever' model, that the fast velocity layer making the basin's lowermost crust resulted from mafic underplating after stretching and thinning during the syn-rift phase, restoring crustal thickness to pre-rift values (or larger) and providing the necessary buoyancy to trigger regional uplift. Moreover, although not pervasive, instances of thin crust along the footwall could be related to rift flank erosion. We thus conclude that, regardless of the mode of extension in the upper crust, our results favour models of basin formation invoking extension of the lower crust by pure shear. 
PY 2022
PD MAR
SO Geophysical Journal International
SN 0956-540X
PU Oxford Univ Press
VL 230
IS 1
UT 000773023400017
BP 317
EP 333
DI 10.1093/gji/ggac080
ID 87522
ER

EF