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@Article{RossettiMoliCrem:2016:GeLaAm,
               author = "Rossetti, Dilce de F{\'a}tima and Molina, Eder Cassola and 
                         Cremon, {\'E}dipo Henrique",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and 
                         {Universidade de S{\~a}o Paulo (USP)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)}",
                title = "Genesis of the largest Amazonian wetland in northern Brazil 
                         inferred by morphology and gravity anomalies",
              journal = "Journal of South American Earth Sciences",
                 year = "2016",
               volume = "69",
                pages = "1--10",
                month = "Aug.",
             keywords = "Gravity anomaly, Morphology, Northern Amazonia, 
                         Pleistocene-Holocene, Sedimentary basin.",
             abstract = "The Pantanal Setentrional (PS) is the second largest wetland in 
                         Brazil, occurring in a region of northern Amazonia previously 
                         regarded as part of the intracratonic Solim{\~o}es Basin. 
                         However, while Paleozoic to Neogene strata are recorded in this 
                         basin, the PS constitutes a broad region with an expressive record 
                         of only Late Pleistocene and Holocene deposits. The hypothesis 
                         investigated in the present work is if these younger deposits were 
                         formed within a sedimentary basin having a geological history 
                         separated from the Solim{\~o}es Basin. Due to the location in a 
                         remote region of low accessibility, the sedimentary fill of the PS 
                         wetland remains largely unknown in subsurface. In the present 
                         work, we combine geomorphological and gravity data acquired on a 
                         global basis by several satellite gravity missions to approach the 
                         geological context of this region. The results revealed a wetland 
                         characterized in surface by a low-lying terrain with wedge shape 
                         and concave-up geometry that is in sharp contact with highland 
                         areas of Precambrian rocks of the Guiana Shield. Such contact is 
                         defined by a series of mainly NE- or NW-trending straight 
                         lineaments that eventually extend into both the Guiana Shield and 
                         the PS wetland. Also of relevance is that a great part of the PS 
                         wetland sedimentary cover consists of dominantly sandy deposits 
                         preserved as residual paleo-landforms with triangular shapes 
                         previously related to megafan depositional systems. These are 
                         distributed radially at the northern margin of the PS, with axis 
                         toward basement rocks and fringes toward the wetland's center, the 
                         latter containing the largest megafan landform. The analysis of 
                         gravity anomaly data revealed a main NNE-trending chain ~500 km in 
                         length defined by high gravity values (i.e., up to 60 mGal); these 
                         are bounded by negative anomalies as low as -90 mGal. The chain 
                         with positive gravity anomaly marks the center of a subsiding area 
                         having a geological evolution that differs from the adjacent 
                         intracratonic Solim{\~o}es Basin. Deep rifting associated with 
                         the rise of high-density material from the mantle in replacement 
                         of low-density continental crust is hypothesized as the most 
                         likely load-driving mechanism responsible for the subsidence of 
                         the PS sedimentary basin. Alternatively, this might be a shallow 
                         basin formed during the Late Quaternary due to mild subsidence of 
                         a high-density basement. This process would have been caused by 
                         tectonic reactivations of NE-trending strike-slip faults along a 
                         zone of low elastic thickness of the lithosphere that 
                         characterizes this region of South American platform.",
                  doi = "10.1016/j.jsames.2016.03.006",
                  url = "http://dx.doi.org/10.1016/j.jsames.2016.03.006",
                 issn = "0895-9811",
             language = "en",
           targetfile = "Rossetti_genesis.pdf",
        urlaccessdate = "23 nov. 2020"
}


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