@Article{PintoPáUsViPaBr:2010:GeInCr,
               author = "Pinto, Luis Gustavo Rodrigues and P{\'a}dua, Marcelo Banik de and 
                         Ussami, Naomi and Vitorello, Icaro and Padilha, Antonio Lopes and 
                         Braitenberg, Carla",
          affiliation = "Departamento de Geofisica, Instituto de Astronomia, 
                         Geof{\'{\i}}sica e Ci{\^e}ncias Atmosf{\'e}ricas, Universidade 
                         de S{\~a}o Paulo, Rua do Mat{\~a}o 1226, 05508-090, S{\~a}o 
                         Paulo, Brazil and {Instituto Nacional de Pesquisas Espaciais 
                         (INPE)} and Departamento de Geofisica, Instituto de Astronomia, 
                         Geof{\'{\i}}sica e Ci{\^e}ncias Atmosf{\'e}ricas, Universidade 
                         de S{\~a}o Paulo, Rua do Mat{\~a}o 1226, 05508-090, S{\~a}o 
                         Paulo, Brazil and {Instituto Nacional de Pesquisas Espaciais 
                         (INPE)} and {Instituto Nacional de Pesquisas Espaciais (INPE)} and 
                         Department of Earth Sciences, University of Trieste, Via Weiss 1, 
                         34100 Trieste, Italy",
                title = "Magnetotelluric deep soundings, gravity and geoid in the south 
                         S{\~a}o Francisco craton: Geophysical indicators of cratonic 
                         lithosphere rejuvenation and crustal underplating",
              journal = "Earth and Planetary Science Letters",
                 year = "2010",
               volume = "297",
                pages = "423--434",
                 note = "{Setores de Atividade: Outras atividades de servi{\c{c}}os.}",
             keywords = "Metodo Magnetotelurico, M{\'e}todos Potenciais, Interpretacao 
                         Integrada.",
             abstract = "In the south S{\~a}o Francisco craton a circular and 8-m 
                         amplitude geoid anomaly coincides with the outcropping terrain of 
                         an ArcheanPaleoproterozoic basement. Broadband magnetotelluric 
                         (MT) data inversions of two radial profiles within the positive 
                         geoid and Bouguer gravity anomaly yield geo-electrical crustal 
                         sections, whereby the lower crust is locally more conductive (10 
                         to 100 \Ωm) in spatial coincidence with a denser lower crust 
                         modeled by the gravity data. This anomalous lower crust may have 
                         resulted from magmatic underplating, associated with Mesoarchean 
                         and Proterozoic episodes of tholeiitic dike intrusion. Long-period 
                         MT soundings reveal a low electrical resistivity mantle (20 to 200 
                         \Ωm) from depths beyond 120 km. Forward geoid modeling, 
                         using the scope of the low electrical resistivity region within 
                         the mantle as a constraint, entails a density increase (40 to 50 
                         kg/m3) possibly due to Fe enrichment of mantle minerals. However, 
                         this factor alone does not explain the observed resistivity. A 
                         supplemented presence of small amounts of percolated carbonatite 
                         melting (~0.005 vol.%), dissolved water and enhanced oxygen 
                         fugacity within the peridotitic mantle are viable agents that 
                         could explain the less resistive upper mantle. We propose that 
                         metasomatic processes confined in the sub-continental lithospheric 
                         mantle foster the conditions for a low degree melting with 
                         variable CO2, H2O and Fe content. Even though the precise age of 
                         this metasomatism is unknown it might be older than the Early 
                         Cretaceous based on the evidence that a highdegree of melting in a 
                         lithospheric mantle impregnated with carbonatites originated the 
                         tholeiitic dike intrusions dispersed from the southeastern border 
                         of the S{\~a}o Francisco craton, during the onset of the 
                         lithosphere extension and break-up of the western Gondwana. The 
                         proxies are the NE Paran{\'a} and Espinha{\c{c}}o (130 Ma, Ar/Ar 
                         ages) tholeiitic dikes, which contain (~3%) carbonatites in their 
                         composition. The occurrence of a positive geoid anomaly (+10 m) 
                         and pre-tholeiites (ageN138 Ma), carbonatites and kimberlites 
                         along the west African continental margin (Angola and Namibia) 
                         reinforces the presumed age of the S{\~a}o FranciscoCongo craton 
                         rejuvenation to be prior to its fragmentation in the Lower 
                         Cretaceous.",
                  doi = "10.1016/j.epsl.2010.06.044",
                  url = "http://dx.doi.org/10.1016/j.epsl.2010.06.044",
                 issn = "0012-821X",
                label = "lattes: 0842543237562135 5 PintoP{\'a}UsViPaBr:2010:GeInCr",
             language = "en",
           targetfile = "1-s2.0-S0012821X1000419X-main.pdf",
        urlaccessdate = "21 maio 2024"
}