Programa de Pós-Graduação em Geologia e Geoquímica - PPGG/IG
URI Permanente desta comunidadehttps://repositorio.ufpa.br/handle/2011/2603
O Programa de Pós-Graduação em Geologia e Geoquímica (PPGG) do Instituto de Geociências (IG) da Universidade Federal do Pará (UFPA) surgiu em 1976 como uma necessidade de desmembramento do então já em pleno desenvolvimento Curso de Pós-Graduação em Ciências Geofísicas e Geológicas (CPGG), instalado ainda em 1973 nesta mesma Universidade. Foi o primeiro programa stricto sensu de Pós-Graduação (mestrado e doutorado) em Geociências em toda Amazônia Legal. Ao longo de sua existência, o PPGG tem pautado sua atuação na formação na qualificação de profissionais nos níveis de Mestrado e Doutorado, a base para formação de pesquisadores e profissionais de alto nível. Neste seu curto período de existência promoveu a formação de 499 mestres e 124 doutores, no total de 623 dissertações e teses.
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Item Acesso aberto (Open Access) Aspectos lito-estruturais das minas de ferro N4E e manganês do azul, Serra dos Carajás-Pará(Universidade Federal do Pará, 1991-08-06) MARÇAL, Mônica dos Santos; COSTA, João Batista Sena; http://lattes.cnpq.br/0141806217745286The areas of iron (N4E) and manganese (Azul) mines in the Serra dos Carajás region were investigated with emphasis on structural geology, aiming to define the geometric arrangement of the various ore bodies and the kinematic framework, as well as their relationships with the regional structuring. The iron mine (N4E) is subdivided into two segments called Aba Leste and Aba Sul. The lithotypes occurring in this area are represented by friable itabitite (soft hematite HM, hard hematite HD), metajaspilite, metavolcanic rocks and canga. . Most of the rock units are distributed in the form of lenses and discontinuous and wedged bands, with a general orientation N-S on the East Rim and E-W on the South Rim, drawing a “J” with concavity facing northwest. The analysis of the structural elements present in the rocks of the N4E mine, in line with the information available for the Serra Norte region, allowed the characterization of three sets of main structures: the oldest set comprises the mylonitic foliation, the shear zones with oblique riding character, stretch lineation and associated folds; the second set refers to the NW-SE, E-W and N-S ductile transcurrent shear zones that cut and limit the body of N4; the last set corresponds to the folds and crenulations present throughout the entire ore body. These sets of structures are interpreted in the context of a single deformational event. The lithotypes that make up the manganese mine (Blue) are classified into three types: Protomines, Surface Deposits and Subsurface Deposits. Mining is currently being carried out in the central part of the deposit, between the LT00 and LT800E lines, where the ores related to surface and subsurface deposits were identified. The first includes pisolites (PIS), blocks (BL), platelets (PLT) and manganese breccias (BLM), and the second encompasses manganeseiferous mudstones (PM), granulated manganese material (MMG) and massive manganese material (MMM). The various types of manganese ore are wavy, defining synformal and antiformal structures oriented in the E-W direction and associated with strongly inclined thrusts to the north. The N4E and Azul mines are located on the northern edge and in the central-north region of the divergent macrostructure of Serra dos Carajás, respectively. Such a regional geometric arrangement is interpreted as a positive flower structure associated with an E-W sinistral binary. In this sense, the lithostructural units of the two studied areas must be understood as fractions of an inverted transcurrent volcano-sedimentary basin.Item Acesso aberto (Open Access) Aspectos litoestruturais e mineralizações Salobo 3A (Serra dos Carajás-PA)(Universidade Federal do Pará, 1996-10-29) SIQUEIRA, José Batista; COSTA, João Batista Sena; http://lattes.cnpq.br/0141806217745286The Salobo district is located at the Carajás Province in the Cinzento strike-slip system, and is formed of supracrustal rocks of the Salobo Group and gneisses of Xingu Complex, which were assembled by several generations of shear zones. The Salobo Group includes magnetite-fayalite schist, biotite-almandine-magnetite-fayalite-grϋnerite schist, biotite schist, anfibol schist, chlorite schist, banded iron formation and quartzite. The Xingu Complex includes banded tonalitic gneisses, trondhjemitc and granodiritic gneisses, partialy migmatized. The older shear zones correspond to ductile thrusts to which the generalized imbrication of the lithological units and the tectonic layering, defined by strips and lenses of supracrustais rocks alternated with gneisse is due. Their movements is synchronous to that of the Itacaiúnas belt; minerals transformations under thermal conditions of amphibolite facies, as well as important modifications in the stratigraphic relationships of several lithological units, are related to therm. The second generation of shear zones formed the transtensive Salobo-Mirim duplex. They are sinistral strike-slip shear zones, linked by normal shear zones along which minerals transformations of greenschist facies occurred. The development of the duplex was controled by the former tectonic layering, and its assymetric shape was influenced mainly by the presence of a basement gneiss megalense. The third generation of shear zones is of transcurrent type, with NW-SE and NNW-SSE trends, which modified the Salobo-Mirim duplex geometry, and are interpreted as X features linked to the sinistral moviments. The shear zones of the west corner of the area represent the propagation of a horse tail structure at the west end of the Carajás fault; in these case, they could be oblique thrust. The Salobo 3A deposit is situated in the central part of a normal oblique shear zone, which belongs to a release bend along the main strike-slip shear zone of the Salobo-Mirim duplex. The copper and gold mineralizations are hosted in extension structures, as single and composite pull-apart structures, transtensive sigmoide stringers, tension gashes, pressure shadows and star strucutures in the cross-cutting zones of descontinuities. The Salobo 3 A deposit is an example of concentracion/reconcentracion of cooper and gold mineralizations in s transtensive shear zone due to deformational, hydrothermal and metamorphic processes.Item Acesso aberto (Open Access) A associação anortosito-mangerito-granito rapakivi (AMG) do Cinturão Guiana Central, Roraima, e suas encaixantes paleoproterozóicas: evolução estrutural, geocronologia e petrologia(Universidade Federal do Pará, 2002-12-19) FRAGA, Lêda Maria; COSTA, João Batista Sena; http://lattes.cnpq.br/0141806217745286The geological mapping on a scale of 1:250,000, of an area of approximately 22,500 km2 in the central region of the state of Roraima, combined with the petrographic and microtectonic study and new geochronological, lithochemical and isotopic data, allowed the characterization of an anorthosite-mangerite association -rapakivi granite (AMG), Mesoproterozoic and its Paleoproterozoic host. Orthogneisses, foliated granitoids and charnockite rock bodies from the Serra da Prata Intrusive Suite show Pb-Pb (zircon evaporation) ages around 1.94 Ga, also inferred for the associated norites and gabbronorites. The Paleoproterozoic igneous suites were placed syn-kinematically, during Deformational Event D1, with the evolution of petroweaves indicative of high temperatures, from 600º-650ºC. These features include recrystallized feldspars by subgrain rotation, recrystallized perthitic alkali feldspars and quartz with checkerboard subgrains and have been observed in syn-plutonic dykes that cut the early-kinematic D1 fabric in the host country. The NE-NW arrangement of the Paleoproterozoic bodies was controlled by the previous structure of this sector of the Central Guiana Belt (CGC). The orthogneisses and foliated granitoids comprise two distinct suites, with lithochemical characteristics of type A granitoids, probably related to different oxidation conditions at the source. The charnockite rocks show chemical characteristics approaching those described for C-type magmatism. Sm-Nd TDM model ages between 2.19 Ga and 2.05 Ga, with ƐNd(T) values ranging from +0.68 to +2 ,47 suggested sources of limited crustal residence. The age of the orogenic events in Roraima has not yet been properly clarified, however, despite the limited data, a post-collisional positioning is proposed for the Paleoproterozoic suites studied after the accretion of transamazonian magmatic arcs. The Paleoproterozoic units constitute the basement of the Mesoproterozoic igneous suites, which comprise the anorthosites of the Repartimento unit and associated gabbronorites, the rapakivi granitoids of the Mucajaí Intrusive Suite (SIM), and the fine, porphyritic charnockites, of punctual occurrence and uncertain geochronological positioning. In SIM, three granite facies were identified (fayalite-pyroxene-quartz-mangerites to syenites; hornblende-biotite-granites; and biotite-porphyritic granites) geochemically and petrographically very similar to rapakivi granites from classical areas of Finland. The presence of fayalite in the most primitive rocks of the SIM indicates conditions of low oxygen fugacity, observed in several rapakivi granite complexes. Fine charnockites show no cpm to SIM chemical correlation. The Mesoproterozoic suites are part of an AMG (Anortosito-Mangerito-Granito rapakivi) association placed in an anorogenic environment between 1.54 and 1.53Ga. Model ages Sm-Nd, from 2.07 Ga to 2.01 Ga with ƐNd(T) values ranging from -2.37 to -1.27 suggest, for the granitoids in the association, crustal sources separate from the mantle in the Paleoproterozoic , probably during the Transamazônico. Mylonitic features related to the D2 Deformational Event, registering conditions of moderate to low temperatures (400º-450ºC), in a brittle-ductile environment, locally obliterate the igneous textures of the Mesoproterozoic units, as well as the high temperature D1 petrowebs in the Paleoproterozoic basement. These features are especially well developed in some shear zones that show dextral transpressive kinematics. The D2 event aged around 1.26 Ga relates to the K'Mudku Deformational Episode. The main D2 mylonitic zones were reactivated in the Mesozoic at shallow crustal levels and brittle conditions, during the evolution of Graben Tacutu.Item Acesso aberto (Open Access) Caracterização morfoestrutural e morfotectônica de áreas transpressivas: Serra dos Carajás e Serra do Tiracambú(Universidade Federal do Pará, 1999-12-11) ESPÍRITO SANTO, Cláudia Vilhena do; COSTA, João Batista Sena; http://lattes.cnpq.br/0141806217745286Item Acesso aberto (Open Access) O Cinturão Araguaia na região de Xambioá (TO) - São Geraldo do Araguaia: geometria, cinemática e aspectos litológicos(Universidade Federal do Pará, 1993-09-22) SANTOS, Raimundo Oliver Brasil dos; COSTA, João Batista Sena; http://lattes.cnpq.br/0141806217745286The northern segment of the Araguaia belt, near the cities of Xambioá and São Geraldo do Araguaia, consists mainly of supracrustal rocks from the Estrondo Group, in addition to gneisses from the Colméia Complex, exposed in the cores of the Lontra and Xambioá structures, exposed in the cores of the structures from Lontra and Xambioá, and from rocks from the Pequizeiro Group, which make up a narrow strip at the western end of the area. Considering the geometry and nature of the larger structures as well as the complexity of the structural framework, the area was divided into 5 (five) sectors. According to this picture, it was deduced that the macro geometric arrangement corresponds to an imbricated system of ductile thrusts, with rare "nappe"-type features standing out. thrusts; holomorphic folds related to late thrusts, or the transpression between transcurrent systems; and transcurrent shear zones, interpreted as lateral ramps. At the mesoscopic level, the structures are represented by the mylonitic foliation, the stretch lineation, folds of different styles and the On the other hand, thin lamina analysis revealed microstructures such as: porphyroclasts and asymmetric porphyroblasts with pressure shadows; quartz ribbons; S-C arrangements, tectonic twins in feldspar crystals; pisciform features; quartz-feldspathic aggregates in the form of lenses, microbanding, and recovery features. chthonic, four main movements were characterized in the progression of shear deformation: the first is related to the intense imbrication of rocky bodies resulting from the propagation of ductile thrusts, which must have been accompanied by the individualization of the lateral slopes; the second is associated with the uplift of splinters from the basement, imposing kilometric folds in the initial arrangements, due to a second generation of thrusts that did not affect the uppermost packages. At this point, it is assumed that there was significant movement along the side ramps; the third refers to the rotation of the megafolds, preferably in the central part of the area, due to the intensification of movements on the side ramps; and the fourth corresponds to the imbrication that was superimposed on the geometric arrangement created by these lateral ramps. Tectonic evolution, as understood here, developed according to the oblique collision process of continental masses, with preferential transport of rock units from SE to NW. Finally, a brittle regime is recorded through fault and fracture systems that are associated with Paleozoic and Mesozoic extensional events and, in part, with the neotectonic framework.Item Acesso aberto (Open Access) Considerações lito-estruturais sobre o duplex transpessivo Serra Pelada(Universidade Federal do Pará, 1992-07-18) OULD LAB, Khalifa; COSTA, João Batista Sena; http://lattes.cnpq.br/0141806217745286Item Acesso aberto (Open Access) Evolução estrutural da Bacia do Amazonas e sua relação com o embasamento(Universidade Federal do Pará, 1991-02-19) WANDERLEY FILHO, Joaquim Ribeiro; COSTA, João Batista Sena; http://lattes.cnpq.br/0141806217745286This dissertation presents some aspects concer- ning the structural evolution of the Amazon basin and discusses the role of the Pre-Cambrian structures in the development of its architeture. The Pre-Cambrian record comprises strutures re- lated to two main thermal-tectonic events. The oldest one, Archean age, is responsible for the installation of granitic- greenstone terrains, and also the formation of shear belts composed of high grade metamorphic rocks. This event controlled the formation of the basic structural lineaments, trending Nw- SE, NE-SW and E-W. The second event, in the eastern Amazon re- gion, caused the development of NW-SE and WNW-ESE normal faults and NE-SW transfer faults related to an extensional NE-SW proterozoic axis giving rise to the formation of several basins of which, Cachimbo Graben is the most remarkable one. The structural evolution of the Amazon basin throug Phanerozoic time is strongly related to the geometry of the Pre-Cambrian structures. The installation of the Amazon basin is related to cyclic opening and closing of the Iapetus ocean during Paleozoic time. During this cycle, ancient weakness zones tren- ding NE-SW and NW-SE were reactivated as normal and transfer faults respectively. The movements associated to the transfer faults compartmentalized the basin into four distinct structural blocks, of which the compartmental zone of Purus (Purus Ar- ch) isa special example. The Purus arch separates the Amazon basin to the East from Western Solimões basin. Its origin is related to reactivation of normal faults of the Cachimbo Graben. The fragmentation of the Gondwana megacontinent, during mesozoic time, is witnessed in the Amazon basin by the following features: a) NE-SW and NNE-SSW normal faults; b) Nw- SE transfer faults; c) ENE-WSW wrench faults and d) igneous and sedimentary infill. During Cenozoic time, the Amazon basin and adjacent zones suffered effects of stress that generated essencially dextral whrench faults.Item Acesso aberto (Open Access) Evolução paleogeográfica, durante o cenozóico, da região de Bragança, NE do estado do Pará(Universidade Federal do Pará, 2002-02-28) ALMEIDA, João Revelino Caldas de; BORGES, Mauricio da Silva; http://lattes.cnpq.br/1580207189205228; COSTA, João Batista Sena; http://lattes.cnpq.br/0141806217745286The main morphologic features of northeastemn Para State are strongiy related to middle Cenozoic extensional tectonics which is responsible by the Gondwana break up resulting in the formation of the Equatorial Atlantic Ocean and of the passive margin. The area is included in the Bragança-Viseu Basin, which evolved from the extensional tectonics incidence on the northeastem of the Para State since the Upper Jurassic. During the Miocene this area underwent transtensional tectonics that generated NW-SE normal faults and E-W and NE-SW dextral strike-slip faults. This tectonic event formed large subsided areas and corridors that facilitated transgression towards the continent since 150 km from the present coastline. This transgression originated the carbonatic sequence included in the Pirabas Formation, deposited in areas with drainage systems typical of subsided regions. Some areas remained emerged during the transgression. In the Bragança-Viseu Basin the sediments of Pirabas Formation are scarce, which suggest presence of a structural high blocking the transgression of the “Pirabas Sea”. The occurrence of limestone towards the south of Bragança suggest a cost line characterized by bay heads and promontories facing northwest. On the basis of geophysics interpretation, it was demonstrated in the Bragantina region the absence limestone towards the main depocenter of the Bragança-Viseu Basin. Therefore in this area, there are only occurrence of Precambrian rocks overlaid by Quaternary sediments (debris flows) included in the Post-Barreiras sequence.. The landscape has not change since Miocene - Pliocene, as can be demonstrated by the colinas relief. The geologic data suggest that the landscape evolution is controlled by structures related to the transtensional event.Item Acesso aberto (Open Access) Evolução tectono-estrutural da região de Dianópolis-Almas, SE do estado de Tocantins(Universidade Federal do Pará, 1993-12-17) BORGES, Maurício da Silva; COSTA, João Batista Sena; http://lattes.cnpq.br/0141806217745286Several geological sequences of rocks with distinct ages of evolution were mapped in the Dianopólis-Almas region (southwestern part of the State of Tocantins) in the Brasília block: an extensive segment of an Archean-Lower Proterozoic granite-greenstone terrain, Proterozoic metasediments of the Bambuí Group, Cretaceous continental deposits of the Urucuia Formation, colluvial and alluvial (partially lateritized) and Holocenic fluvial-lacustrine deposits. The granite-greenstone terrains include several strands of supracrustal rocks (Riachão do Ouro Group) and granitoid bodies (Serra do Boqueirão Suite), both developed over migmatized tonalitic gneisses, granulites and amphibolites of the Alto Paranã Complex. The Riachão do Ouro Group is composed of phyllite, schist, meta-rhyolite, meta-dacite, iron formation, quartzite, metaconglomerate and breccia; phyllite, schist and metavolcanic rocks are the dominant lithologies. The Serra do Boqueirão Suite includes granitoids of tonalitic, trondhjemitic, granodioritic and granitic compositions, which were strongly deformed in the border zones and cut by pegmatite and aplite veins. All there lithological units underwent ductile deformation which formed an anastomosed pattern of N10-20E, N45E, and N55W transcurrent shear zones. Along the shear zones there are asymmetric or symmetric transpressive duplexes alternating with straigth segments. These structures can be seen extensively developed at supracrustal rock-granitoid boundaries and are characterized by mylonitic foliation parallel to the tectonic layering; other structures are represented by internal duplexes, shear bands, pods of less deformed rocks, extensional cleavage of C' type (crenulation cleavage) and brittle-ductile shear zones expressed by dilatation structures (tension gashes). The stretching lineation is defined by rods of quartz, axes of agregates of elliptical minerais and elongated micas. Dextral sense of shearing is determined from kinematic criteria. Microfabric investigation suggest that the deformation was accommodated mainly by crystal plasticity and the crystallographic shape fabrics confirm the dextral sense of shearing. Only the N55W shear zones underwent sinistral movement. The observed sets of structures is interpreted as linked to a N20E dextral strike-slip system and, in this case, the N10-20E, N45E, N25W and N55W zones correspond respectively to Y, R, P and R' zones. The Archean-Lower Proterozoic evolution is understood in terms of an oblique collision of continental segments which uplifted the granulitic rocks and was followed by transtension regime which originated several basins in where the supracrustal rocks of the Riachão do Ouro Group were deposited, and the granitoids of the Serra do Boqueirão Suite were emplaced. The progressive deformation involved transpression characterized by ductile shear zones. The Middle to Upper Proterozoic is represented by the Bambuí Group which includes slates, metasiltites, phyllites and carbonate rocks. The tectonic structures linked to the São Francisco Basin inversion in the Upper Proterozoic, are represented by N-S oblique thrusts and NE-SW lateral ramps. During the Mesozoic (Upper Cretaceous) the Alto Sanfranciscana Basin was filled by continental sediments of the Urucuia Formation. The lithostratigraphic sequence is composed of the following lithofacies: 1) conglomeratic facies which represents residual paviments of.deflation and in part interdune deposits and wadifans related to an intermittent drainage system; 2) sandstone facies formed by ortoquartzite, arkose and subarkose which constitute wind deposits; 3) and stratified chert facies which represent chemical lacustrine deposits. The basin architecture includes also NNW-SSE listric normal faults and NE-SW transfer faults related to a N5OE extensional axis. During the Tertiary coluvial and aluvial deposits, which underwent lateritization as an immature profile, were formed. The Quaternary is represented by a lacustrine-fluvial sedimentary system. The drainage system is related to the basin of the Manoel Alves and Araguaia rivers, strongly controlled by NE-SW lineaments and associated to pull-apart structures linked to a dextral system.Item Acesso aberto (Open Access) A fragmentação do Gondwana na região meio-norte do Brasil durante o mesozóico(Universidade Federal do Pará, 2007-08-09) SOARES JÚNIOR, Adilson Viana; COSTA, João Batista Sena; http://lattes.cnpq.br/0141806217745286; 0141806217745286South America, Africa, India, Antarctic and Australia continents formed a great and complex supercontinent called Gondwana at the end of the Precambrian. From the Mesozoic this mega-continent underwent extension and regional uplift with volcanism associated, resulting in triple junctions which evolved to rift systems. These events are related to the Wealdenian Reactivation or South-Atlantic event witch took place in the interior and the boundary of the South America plate, been followed by intense basic magmatism and extensional systems formation, with listric and planar faults. Some basin architecture are controlled by ancient shear zones reactivations. From Triassic the extension gave rise to uplifts associates to the magmatism in the weakness areas of the basement, including the Paleozoic basins in the northern Brazil. This event responds to the Pangaea break-up, the formation of the Central Atlantic Ocean and the individualization of the Laurasia and Gondwana supercontinents. The arm of the Central Atlantic in the South America evolved to rift system in the Foz do Amazonas basin and volcanism in the Parnaíba Basin during the Triassic and Jurassic. This rifting event died out towards the south and propagated to the Caribbean region, resulting in North America plate formation. From the early Cretaceous (end of Barremian and beginning of the Aptian), new phase of rifting is registred in the region, without linkage to the Central Atlantic. This had been increased the Foz do Amazonas basin and Marajó basin formation and a new phase of uplifting followed by volcanism and rifting concentrated at the Ferrer-Urbano Santos Arc, Parnaíba Basin, and the formation of the Gurupi Graben System (Bragança-Viseu, São Luís and Ilha Nova basins) and Grajaú Basin. This event includes two distinct phases: early rifting resulting in the formation of the Bragança-Viseu and Ilha Nova basins; and thermal subsidence with the formation of the São Luís and Grajaú basins, separate by short time span. These basins underwent rapid evolution, with sedimentary environment records since fluvial and lacustrine until transgressions. In the Lower Cretaceous continued the evolution of the Foz do Amazonas Basin witch the fragmentation propagating towards the SE, resulting in the formation of the Pará-Maranhão Basin and Barreirinhas Basin at the beginning of the Albian. This event is resposible for the Equatorial Atlantic Ocean individualization, with associated transgression in the Pará-Maranhão and Barreirinhas basins, as well in the São Luís, Ilha Nova and Grajaú Basins, controled by NE-SW fractures and faults in the São Marcos Bay and by partial collapse of the Ferrer-Urbano Santos Arc. During the Late Cretaceous it had reducted the extension at the Marajó Basin, stopped the fragmentation in the Gurupi Graben System and the South America and African continents were completely pulled apart, with formation of oceanic crust and passive margins in the Foz do Amazonas, Pará-Maranhão and Barreirinhas Basins. From the Upper Cretaceous, the east margin of the South America and the west margin of Africa had assumed its current configuration, withchanges related to drifting and to the Neotectonic.Item Acesso aberto (Open Access) Geologia estrutural da Bacia do Marajó(Universidade Federal do Pará, 1994-12-01) CAHUANA VILLEGAS, Javier Marcelo; COSTA, João Batista Sena; http://lattes.cnpq.br/0141806217745286Item Acesso aberto (Open Access) Geologia estrutural do Cinturão Araguaia e ao longo da seção compreendida entre as cidades de Marabá e Apinagés(Universidade Federal do Pará, 1994-08-05) LIMA, Jairo Bezerra de; COSTA, João Batista Sena; http://lattes.cnpq.br/0141806217745286Item Acesso aberto (Open Access) Investigações tectônicas no embasamento da sub-bacia do Jandiatuba (bacia do Solimões)(Universidade Federal do Pará, 1995-08-10) VEGA SACASA, Roberto de Jesus; COSTA, João Batista Sena; http://lattes.cnpq.br/0141806217745286Through this work, we sought to understand the structural framework of the continental crust of the western portion of the Solimões Basin called Jandiatuba Sub-basin. With this approach, the nature of the basement and intrabasement structural systems of the basin was characterized based on the geometry and depth of the reflectors. The analysis of conventional seismic sections, used in oil prospecting, and of three versions of a deep seismic profile, with records from 15 to 19 seconds (double time), provided the definition of the following structural elements. (a) inverse faults in the Jandiatuba sub-basin sedimentary package; (b) fault zones that dip following a pattern in the form of ramps, which may be related to shear zones or back-thrusts, especially in the upper crust; (c) detachments that permeate the crust and project into the crust-mantle interface; (d) imbrications in the middle and lower intervals of the ductile crust expressed through a strongly anastomotic signature; (e) seismic “transparency” of the brittle upper crust evidenced by the absence of reflectors, in addition to “transparent” lenses in the deeper crustal levels; (f) the discontinuity of the Moho characterized by several anastomotic beams of reflectors, the differentiation of reflectivity and the decrease in amplitude and frequency in the range of 38 to 45 km. The analysis of the collection of results of the different programs existing on the various continents on deep reflection seismic (COCORP, BIRPS, DEKORP and ECORS), helped in the interpretation of the set of reflectors and was fundamental for the comparison and correlation between the different seismic signatures. The complexity of the seismic signatures of this crustal segment of Amazonia was mainly related to the geometry of structural systems of thrust belts and transcurrents, as well as extensional basins. In other words, seismic arrangements resulting from the action of compressive, directional and extensional regimes were identified. The defined structural framework was discussed through three models that consider compression and imbrication in the Precambrian, stretching in the early Paleozoic and transpression in the Jurassic. Therefore, the Jandiatuba sub-basin region corresponds to a crustal segment that experienced at least three main tectonic movements during its geotectonic evolution.Item Acesso aberto (Open Access) Metodologia de interpretação radargeológica: exemplo da sinéclise do Parnaíba e de seu embasamento(Universidade Federal do Pará, 1995-09-29) LIMA, Mário Ivan Cardoso de; COSTA, João Batista Sena; http://lattes.cnpq.br/0141806217745286This thesis develops the Radargraphic Elements Sistematic method, unknown throughout the world, in the geologic interpretation with Side-Looking Radar (Radargeology), a technique of major relevante in the field of natural resources, considering that the 1990s are the Radar's decade. The Radargraphic Elements Sistematic (SER) method reveals in a sistematic form the methodological route adopted , be it trough the text, trough schematic figures, or in Side-Looking Radar (SLR), with the radargraphic elements (features), ordered in five different stages: Reading, Recognizing, Identifying, Analisys and Interpretation (stricto senso). The stage Reading seeks to understand the meaning of the image elements in the terrain, with the goal of understand their meaning ; the Recognizing stages seek to group them according to the texture and tone radargraphic, so as to obtain homogeneous radargraphic zones; Identification seeks to study the relief forms in such zones, with regard to top and pending, as well as the studying of the drainage patterns, dissection degree and erosion resistance ;and the Analysis establishes the spacial and temporal relation of the relief forms researched through linear, planar and tabular features. With such information in hand , the Interpretation stage itself is reach, in which is possible to define lithologies, rounded structures, unconformities, discontinuities, folds and their interrelations,with a view to executing the Radargeological Map.In effect, a model area was selected to serve a paradigm for the the different methodological stages. To apply the Radargraphic Elements Sistematic method, the region encompassed by Parnaíba Sineclyse and its embasement was selected, with an area of around 925 000 km2, involving mostly Maranhão e Piauí states, located in northeastern region of Brazil. Such an example seeks to emphasys the applicability of the remote sensing in sedimentar terrains and their metamorphic embasement, due to academic and economic importance involved.. To carry out this stage, 52 SLR images mosaics were utilized, scale, I: 250 000, GEMS, X band, resulting in the definition of 39 basic radargeologicals unities, with a temporal stratigraphy, and 19 regional strucutures and 30 local ones, of which more than half were unpublished. These results are expressed in an explanatory text with ilustrations, including a Radargological Map on the milionth scale , and a structural sketch on the scale of 1:2 000 000. The study reaches a favorable conclusion regarding the potentialities of SLR images in geological whose difficulties in defining the radargraphic elements (features) due mainly to extensive shadows, foreshortening , layover and paralaxe effects, will be overcome with the use of more sophisticated Radar Systems (digital mode, stereoscopy, multifrequency, differents angles of incidence,etc) , as is the case with SIR-C and RADARSAT. Finally, the study attests of the excelence of Radargraphic Elements Sistematic method considering the results achieve with the study of the Parnaíba Sineclyse and its embasement, such as : definition of radargeological units, which mantain a strict relation with the lithostratigraphic units already described in the literature; structural setting with the identification of almost 50 morphostructures of regional and local character , and a perfect correlation with aeromagnetic maps.Item Acesso aberto (Open Access) Morfotectônica e evolução paleogeográfica da região da Calha do rio Amazonas(Universidade Federal do Pará, 1997-09-15) BEMERGUY, Ruth Léa; COSTA, João Batista Sena; http://lattes.cnpq.br/0141806217745286This work constitutes an example of intraplate application of the modern concept of Structural Geomorphology, which characterizes landforms and drainage patterns within the framework of the neotectonics of the Amazon region. The neotectonics conception adopted here comprises the various structural systems, the sedimentary 'sequences, the land systems and the pattern and anomalies of drainage which were developed during the Upper Terciary and Quatemary. Controversy is particularly intensive over the channel of the Amazon river, between the cities of Manaus and Belém, where plains are found in uplifted areas and also a large diversity of drainage patterns and anomalies. The main goal of the work is to establish a correlation between the complex geomorphological patterns and the structures derived from the transcurrent movements of the Miocene-Pliocene and Upper Pleistocene-Holocene. This implies in a revision of the concepts based on morphoclimatic conditions or domain of vertical movements. The scale of the geomorphological problems dictated the methodology, on a regional basis, which led to the characterization of six morphotectonic compartments as follows: Manaus-Nhamundá, Tupinambarana, Baixo Tapajós, Comandai, Gurupá e Marajoara. 1. The Manaus-Nhamundá compartment shows system landforms with hills where remnants of an erosion surface are present; it is found in the sediments of the Alter do Chão Formation and is controlled by compressive structures of the Upper Terciary. The trellis-type drainage pattern dips southeastward and the more important rivers follow NW-SE normal faults of Quatemary age. 2. The Tupinambarana compartment has a NE-SW rectangular shape. It comprises low relief gradients associated to a strong structural control of the drainage seen on the linear channels of rivers, linear borders of lakes and anomalies of the arch- and elbow of capture types which are derived from the NE-SW lineaments connected to less developed E-W lineaments. The NE-SW lineaments are interpreted as dextral strike-slip faults while the E-W lineaments represent normal faults, both as Quatemary age. 3. The Baixo-Tapajós compartment is characterized by relief of various types - cuesta, dome, volcanic and uplifted blocks which are morphostructures in advanced stages of erosion. Relief and drainage show control by two neotectonic systems: NE-SW and ENE-WSW folds of Upper Terciary age which gave rise to a strong relief gradient shown in landform systems with a widespread regional distribution including cuestas and the Monte Alegre dome. The Quaternary structures are defined by triple junctions of normal and strike-slip faults. 4. The Comandai compartment is observed on the northern margin of the Amazon river with cuestas systems, a morphology defined by the channels of the Jaraú river and its tributaries which cut those structures giving a trellis-type pattern.. The other important feature of this compartment is the residual hills system with flat tops at about 300 m and intrenched streams which channels are modelled by structures giving anomalies of the arch- and elbow of capture types. The landform hills forro a planation surface at 100 m with rectilinear slopes giving a dendritic-rectangular pattern of drainage. Structural control of the relief and drainage as well as the anomalies in the channel of the Amazon river are found to be related to the transcurrent branch of the Baixo-Tapajós triple junction. The other interpretation of those structures relates to the origin of the hills to remnants of the Gurupá Arch therefore associated to normal faults of Mesozoic age. 5. The Gurupá compartment shows, as an important feature in the Amazon plain, the archipelago in the mouth of the Amazon river with an anastomotic pattern. Islands here show NE-SW orientation and are rectangular in shape. In the continent, relief is the flat interfluvial surface type in the sandstones of the Alter do Chão Formation and in the sediments of the Barreiras Group. Drainage shows a subdendritic pattern. Tectonic activity is registered since the Mesozoic with NE-SW dextral strike-slip faults along which pull-apart basins were formed. These tectonics were active until the Upper Terciary. The landscape is modelled by dextral strike-slip systems with orientation NE-SW and ENE-WSW normal faults. 6. The Marajoara compartment comprises the Marajó Island and the northeastern region of the State of Pará with estuarine morphology and was subjected to subsidence tectonics since the Mesozoic. NW-SE normal faults were developed during the Upper Terciary and these and dextral strike-slip faults controlled the deposition of the Pirabas-Barreiras sequences. These movements were active still in the Quatemary and explain the coastal landforms. The development of these compartments is not directly related to the evolution of the northern and westem borders of the South-American plate.Item Acesso aberto (Open Access) Neotectônica e morfogênese da região de Carolina (Ma, To), bacia do Paranaíba(Universidade Federal do Pará, 1996-10-05) BEZERRA, Pedro Edson Leal; COSTA, João Batista Sena; http://lattes.cnpq.br/0141806217745286Item Acesso aberto (Open Access) Neotectônica na bacia de São Luís(Universidade Federal do Pará, 1996-02-12) FERREIRA JÚNIOR, Carlos Roberto Paranhos; COSTA, João Batista Sena; http://lattes.cnpq.br/0141806217745286Item Acesso aberto (Open Access) Organização lito-estrutural do duplex Salobo-Mirim Serra dos Carajás(Universidade Federal do Pará, 1990-06-06) SIQUEIRA, José Batista; COSTA, João Batista Sena; http://lattes.cnpq.br/0141806217745286The Salobo Group embodies a sequence of volcanosedimentary rocks, which overlain a sialic basement, and is linked to the evolution of the Cinzento Transcurrent System, situated immediately to the north of the transcurrent system which provided the estabelishment of the Grão-Pará Group. The macrostructure is formed by two major shear zones which join at the west and east end parts of the studied area, defining a WNW-ESE eliptcal structure. This structure, which is interpreted as an extensional duplex, comprises, internally, minor shear zones that converge to the main zones. NW-SE, NNE-SSW and NE-SW strike-slipe zones modify the major geometric pattern. The duplex lithologies underwent metamorphism of the amphibolite facies during regional transpression, followed by expressive hidrotermalism and greenschist facies transformation trought the progress of the deformation. Significant mineralizations of bornite, chalcocite and in some cases chalcopirite, with molibdenite, gold and silver, are mainly hosted by lenses of iron formations, besides magnetite. These sulphides are distrubuted as inclusions in the grains of silicate gangue minerals and oxides or between them, as well as along the ductile and ductile-ruptile features, such as milonitic S-C foliations and R, R', p and y=D fractures, showing the manifold origin of such mineralizing fluids. Two kinematics models can be visualized to explain the main litho-structural units: sinistral stike-slip system involving transtension, followed by transpression and then transtension; and crotonic reworking related to transtension regime.Item Acesso aberto (Open Access) Paleografia e evolução da paisagem do nordeste do estado do Pará e noroeste do Maranhão: cretáceo ao holoceno(Universidade Federal do Pará, 2002-02-28) SOARES JUNIOR, Adilson Viana; COSTA, João Batista Sena; http://lattes.cnpq.br/0141806217745286This research presents some aspects of the tectonics and paeleogeographic evolution of northeastem region of Pará State and northwestem region of Maranhão State in the northem Brazil, based on the integration of structural, tectonic, stratigraphic, sedimentological and paeleontological data. The Marajó basin is elongated in a NW-SE direction and includes a sedimentary sequence deposited ffom Upper Cretaceous to Upper Tertiary. The geometry of the Marajó Basin is characterised by NW-SE normal faults in the northwest-southeast direction and NE-SW and ENE-WSW strike-slip faults, which define the boundaries ofthe Mexiana, Limoeiro, Cametá and Mocajuba sub-basins. The Gurupi Graben System encompasses the Bragança-Viseu, São Luís and Ilha Nova basins, with Cretaceous and Tertiary sedimentary filling. The Bragança-Viseu Basin is formed by two assymmetric grabens - the Caeté depocenter (close to the northem border) and the Piriá depocenter, close to the southem limit - in a NW-SE direction, separated by a transcurrent fault. The São Luís Basin comprises three sub-basins: Maracaçumé, in the northwest, Bacuri, in the northeast, and Bequimão, toward the southeast. The Ilha Nova basin is divided into two halfgrabens separated by a transcurrent fault. The westem half-graben presents antithetic faults in the southem and northem borders, while these faults ocurr only in its northem extreme ofthe eastem halfgraben. The Grajaú Basin is an extensional feature of the Cretaceous, generated by normal fault propagation towards the continent interior, during the opening ofthe Equatorial Atlantic, and by partial reactivation of the Paleozoic structures of the Pamaíba basin. The stratigraphy is composed ofthe Grajaú, Codó and Itapecurú formations, controled by N-S planar normal faults, diping to the west, and linked through NE-SW transcurrent faults. The Gurupá Are strikes NW-SE, correspond to the boundary ofthe Amazon Basin, and defines the shoulder ofthe Marajó basin, closely associated with listric faults. Northem Marajó encompasses the region between the northeastem shoulder of the Marajó Basin and the Pará/Ilha de Santana Platform, and is characterised by neotectonic structures represented by NE-SW transcurrent faults, as those that control the mouth of the Tocantins river towards the northeast. 4 The Tocantins Are is a positive feature that bounds the Marajó and Grajaú basins, and corresponds to a transpressive region. The Gurupi Are is a positive feature that limits the Bragança-Viseu and São Luís basins, running in a NNE-SSW direction, and worked as an area wich accomodated high strain during the Cretaceous. The Ferrer-Urbano Santos Are is an E-W positive feature that limits the São Luís and Grajaú basins formed during the Cretaceous, with an axis of uplifting that migrated southwards through the time. The partial collapse ofthis are evolved to the São Luís Basin. The Tiracambú Hills derived from Grajaú Basin inversion, since the Paleocene, wich resulted in the propagation ofE-W transcurrent dextral systems and was followed by the tectonic calm that originated the mature lateritic profile. The Estrondo Hills is related to N-W normal faults, and is interpreted as derived by reactivation of older struetures during the Cretaceous-Upper Tertiary extensional event, controlling the courses ofthe Araguaia and Tocantins riversItem Acesso aberto (Open Access) Tectônica cenozóica e movimentação salífera na Bacia do Amazonas e suas relações com a geodinâmica nas placas da América do Sul, Caribe, Cocos e Nazca(Universidade Federal do Pará, 2002-09-13) COSTA, Antônio Roberto Almeida; COSTA, João Batista Sena; http://lattes.cnpq.br/0141806217745286This research, based on seismic section interpretations, deals with the tectonic events and salt movement (halotectonic) that took place in the Amazonas Basin during the Cenozoic. The main structures have been compared with the tectonic signatures of the Solimões, Acre and Tacutu basins in order to understand the kinematic events that affected the sedimentary filling of those basins. The Amazonas, Solimões, Acre and Tacutu basins and some parts of the South American Plate underwent intraplate deformational events during the Cenozoic. From tectonic data of the Northern Andes and Caribbean area, including the northern South American Plate, and available kinematic models, it could be reached the integration of the stress field that originated the major tectonic elements that affected the sedimentary basins of the Amazon region, especially the western part of the Amazonas Basin. From Upper Miocene to Holocene the Northern Andes reached its current configuration. The Upper Miocene corresponds to the beginning of the uplift of the northeastern Andes and represents the most dynamic tectonic phase of the Miocene. The main landforms of the Andean chain developed during the Miocene and few changes have occurred since then. The complex structural pattern of the northern South America is related to the oblique compressive stress in the plate margin that imposed deformation on the convergent systems of the Cretaceous and Paleocene, when South America has been pushed against the Caribbean and Nazca plates. The intraplate stress field data of the northern South America are still few to support the best characterization of the regional pattern of this long and vast area, which is marked by a high diversity and complex tectonic setting. The intraplate stress field seems to be the result of the action of local and regional forces in the lithosphere. Local stress pattern could be due to the structural heterogeneities, the increase and reduction of crustal load and the thermal anomalies from astenosphere. The regional forces are more uniform and directly related to the plates driving forces, such as: the force due to the spreading of the ocean floor (ridge-push); negative fluctuation of the subducted plate and forces of viscous shearing in the lithosphere-astenosphere boundary. The Juruá tectonic event was the most important mesozoic deformation that affected the Paleozoic Solimões and Amazonas Basins. The transpressive structures generated during this event are those revealed as petroleum traps, mainly in the Solimões Basin. From seismic interpretation of the Amazonas basin, it was demonstrated important structural style variation from region to region. Some areas show weak deformation while others are characterized by complex structures. On base of this criteria, the basin was divided into three structural domains, identified as North, South and Central domains and comprising 8 (eight) structural sectors. The North Domain includes the following sectors: Negro-Trombetas River and Curuá River; the South Domain comprises Canumã River, Mamuru River and Cupari River sectors; and the Central Domain includes Madeira River, Abacaxis-Tapajós River and Jurupari River sectors. Two tectonic events were characterized from seismic interpretations of the Amazonas Basin. The first was characterized only in the Manaus Platform area. The second is probably of Pliocene in age and it is characterized by folds and faulted blocks related to the transpressive system that affects post-Paleozoic sequences. The largest diversity and structural complexity were identified along the Abacaxis-Tapajós River sector, between the Central Domain and the boundaries of the North and South Domains. It is also in this area that occur the most important halotectonic features, as the salt pillows. The development of these features is mainly controlled by Cenozoic strike-slip tectonic events that caused the reactivation of ancient ductile zones and originated faults that cut the Amazonas Basin in the NE-SW and NW-SE directions; the largest thickness of the halite layers that occur in this region; the gravitational instability due to the differential load caused by diabase sills; and the steep dips of the layers. The halotectonic could have controlled the development of some relief features and part of the drainage systems of the Amazonas basin. The irregular and complex folds seen in the evaporitic sequence of the Nova Olinda Formation resulted from the high plastic behavior and tectonic mobility of the salt layers. Frequently the seismic layers under the sequence that contains halite are undeformed. But once deformed, they show different structural styles from those of the interval that contains halite. The structural styles in the platform areas (Manaus e Abacaxis-Mamuru) show geometric characteristics (transpressives and transtensives) which are very simple when compared with the more complex structures that occur in the area of the Central Domain that had been originated under a more plastic deformational regime due to the largest halite volume. The strike-slip faults usually originate complex structural effects in the geologic section of some basins which result in difficulty for the interpretation of seismic data. The complexities are related to the nature of the mechanism of the strike-slip faulting. The flow of salt along the strike-slip zones follows offsets upwards resulting in irregular folds when the salt thickness increases. Therefore, when the sequence that contains the salt layers is submitted to strike slip faulting, the geometry of the structures becomes normally complex. This could be explained due to the plastic behavior of the salt that acts as a layer where the strike-slip stresses are attenuated, hindering the faulting propagation in the upper sequences. In the Amazonas Basin is clear this relationship between the halotectonic features and Cenozoic strike-slip faulting. The seismic interpretations in this research are not enough to identify the structures related to the Quaternary events, but the geologic data and the information from focal solution mechanism of earthquakes and breakouts indicate that the Amazon Basin have remained active in the Quaternary time. Therefore, it is possible that halotecnonics have occurred during the Quaternary.