Fechar
Metadados

@Article{Rossetti:2014:RoTeLa,
               author = "Rossetti, Dilce de F{\'a}tima",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)}",
                title = "The role of tectonics in the late Quaternary evolution of Brazil´s 
                         Amazonian landscape",
              journal = "Earth-Science Reviews",
                 year = "2014",
               volume = "139",
                pages = "362--389",
                month = "Dec.",
             keywords = "late pleistocene–holocene, amazonian lowland, morphostructural 
                         features, fault reactivation, strike-slip deformation, intraplate 
                         stresses, neotect{\^o}nica, Amaz{\^o}nia, an{\'a}lise 
                         morfoestrutural, pleistoceno tardio, holoceno.",
             abstract = "Tectonic reactivation has long been suggested to have occurred 
                         over several areas of the Amazonian lowland in the 
                         NeogeneHolocene. Numerous landscape changes documented in this 
                         region, particularly variations in fluvial dynamics and 
                         morphologies, have nevertheless been exclusively attributed to 
                         climatic fluctuations. Minimizing the effect of tectonics over the 
                         NeogeneHolocene evolution of the Amazon basin can result in a 
                         distorted interpretation of the sedimentary record and, as a 
                         consequence, equivocal paleoclimatic reconstructions. Climate has 
                         often prevailed as a hypothesis to explain changes in fluvial 
                         dynamics possibly due to the still scarce synthesizing 
                         publications focusing exclusively on the neotectonic influence 
                         over this region. The present work provides a review of existing 
                         data focusing on Quaternary tectonics over a large area of the 
                         Amazonian lowland. The existing information is complemented by 
                         original morphostructural data on Quaternary terrains from this 
                         region, which were acquired through remote sensing. The goals were 
                         to analyze the geographic extent of late Quaternary deposits, and 
                         to determine the impact of tectonics on their development and on 
                         the latest evolution of the Amazon drainage basin. The analysis 
                         shows that: 1. the Amazonian lowland experienced geographically 
                         widespread sedimentation in the Late PleistoceneHolocene; 2. 
                         sedimentation was promoted by the creation of new depositional 
                         sites mostly likely resulting from tectonic activity; and 3. 
                         tectonic reactivation impacted the latest evolution of this entire 
                         region, with particular influence on drainage basins, as revealed 
                         by river courses with an abundance of morphostructural lineaments 
                         evidencing fault control. Hence, the NW-, NE-, nearly N-S and, to 
                         a lesser extent, W-E morphostructural trends recorded in all areas 
                         investigated here are generally associated with strike-slip 
                         deformation. In addition, they are conformable with the main 
                         orientation of tectonic structures from adjacent crystalline rocks 
                         of the Precambrian basement. They also match tectonic trends 
                         documented in Neogene and younger sedimentary deposits from this 
                         and several other areas of northeastern Brazil. Furthermore, some 
                         are detected locally in the subsurface by geophysical data. 
                         Furthermore, a profusion of morphostructural anomalies is 
                         imprinted on the surface of NeogeneHolocene deposits of the 
                         Amazonian lowland, the main ones consisting of: 1. highly 
                         asymmetric modern drainage basin still undergoing organization, 
                         with anomalous patterns (i.e., trellis, sub-dendritic, 
                         sub-parallel and rectangular) that often vary from one another, 
                         frequent river captures and rivers flowing in contrary directions 
                         along the time, and straight channels that form triangular shapes 
                         or triple junctions or with local meandering and subtle 
                         enlargements; 2. an abundance of channels, floodplains, lakes and 
                         entire valleys with straight and orthogonal margins that locally 
                         form rhombic shapes or which may be laterally displaced; 3. 
                         fluvial rias (i.e., rivers that became enlarged as their mouth 
                         were barred) bounded by sharp and orthogonal lineaments which 
                         result in rectangular shapes; 4. termination of megafans into 
                         rhombic-shaped depressions bounded by straight lineaments or their 
                         lateral displacement several kilometers apart; and 5. rivers with 
                         asymmetric terraces laterally displaced by faults. These 
                         observations together are consistent with a landscape controlled 
                         by neotectonic activity. The modern seismogenic record, which 
                         reveals even high-magnitude earthquakes, indicates active 
                         deformation over the Amazonian lowland at the Present time. The 
                         neotectonic history of the Amazonian lowland is explained within 
                         the context of an overarching mechanism most likely related to 
                         intraplate stresses. This was probably caused by reactivation of 
                         pre-existing structures since the Neogene that was most likely 
                         promoted by activity along oceanic fracture zones and transform 
                         faults of the Brazilian Equatorial margin, as well as tectonism in 
                         the Andean region.",
                  doi = "10.1016/j.earscirev.2014.08.009",
                  url = "http://dx.doi.org/10.1016/j.earscirev.2014.08.009",
                 issn = "0012-8252",
                label = "lattes: 0307721738107549 1 Rossetti:2014:RoTeLa",
             language = "pt",
        urlaccessdate = "29 nov. 2020"
}


Fechar