Resumo: Esta pesquisa enfoca duas áreas distintas pertencentes ao Domínio Tectônico Cachoeirinha que corresponde ao setor oriental dos terrenos pré-cambrianos do sudoeste do Cráton Amazônico em Mato Grosso, constituído pelas seguintes unidades litoestratigráficas: Complexos Metavulcano- sedimentares Cabaçal e Quatro Meninas, Suíte Intrusiva Máfica- ultramáfica, Unidades Ortognáissicas, Tonalito Cabaçal, pelas suítes intrusivas Santa Cruz, Alvorada, Batólito Rio Branco, Grupo Aguapeí e Suíte Intrusiva Salto do Céu. A Área 1, representada pelas rochas granitóides da Suíte Intrusiva Santa Cruz, um batólito com direção NNW, foliado, com três fácies petrográficas principais compostas por biotita monzo a sienogranito e pela Suíte Intrusiva Alvorada, unidade intrusiva individualizada, fracamente anisotrópica composta por vários corpos de pequeno porte plugs, stocks e plutons, subcirculares a subelípiticos e composição monzo a granodiorítica. Os resultados geoquímicos para as suítes Santa Cruz e Alvorada relacionam estas, a Série Monzogranítica, cálcio- alcalina de alto a médio potássio, peraluminosas a metaluminosas sugerindo quanto ao ambiente tectônico, características sin a tardi- colisionais gerados em arco magmático. O padrão de distribuição REE, sugere a intensificação do processo de fracionamento do magma a partir da fase inicial e, possível geração de magmas contemporâneos e cogenéticos de mesmas fontes diferenciadas. A idade U-Pb para a S.I. Santa Cruz apresenta valor de 1561 ± 260 Ma. e a idade TDM sugere um sofreu fracionamento mantélico por volta de 2,0 Ga., enquanto o valor negativo de εNd(t) -0,89 a -2,75 assinalam a participação de material crustal, mais diferenciadas na formação do magma. / Abstract: This research deals with two distinct areas both within the Tectonic Domain of Cachoeirinha that correspond to the eastern portion of the Pre Cambrian terrains in the southwestern region of the Amazonian Craton in the State of Mato Gosso, Brazil. The lithostratigraphic units are: the metavolcanosedimentary Complex of Cabaçal and Quatro Meninas; intrusive mafic-ultramafic suits; orthogneisses Units; Cabaçal Tonalite; intrusive suits of Santa Cruz and Alvorada; Rio Branco Batholith, Aguapeí Group and intrusive Suit of Salto do Céu. The area 1 is represented by the granitic botholith of the Santa Cruz Suit, foliated with NNW direction, showing three petrographic facies dominated by biotite monzo to sienogranite and the Alvorada Intrusive Suit, weakly anisotropic and made up by many small bodies as plugs, stocks and plutons with circular to elliptic shapes and monzo to granitic compositions. Geochemical data for Santa Cruz and Alvorada Suits indicate that they belong to a Monzogranitic series of high to medium K calc alkaline, peraluminous to metaluminous suit suggesting a tardi-collisional magmatic arc environment. The REE distribution suggests an intense process of fractionation of the magma and possible generation of magmas of the same age and co genetic, derived of the same source. U/Pb age determinations shows values of 1551 ± 260 Ma. for the Santa Cruz Intrusive Suit with TDM ages suggesting the fractionate from the mantle at 2.0 Ga. The positive value of +3.50 for εND(t) indicates the presence of magmatic material with mantle signature, while an εND(t) negative of -0,89 to -1,20 characterize the participation of crustal material derived from more differentiated magma source. / Orientador: Antonio Misson Godoy / Coorientador: Maria Zélia Aguiar de Souza / Banca: Antenor Zanardo. / Banca: Marcos Aurélio Faria de Oliveira / Banca: Mauro César Geraldes / Banca: Ticiano José Saraiva dos Santos / Anexo 2 mapas / Doutor

In the Sergipe-Alagoas Basin, along the northeast coast of Brazil, the lacustrine, middle rift sequence is composed of the Lower Cretaceous Morro do Chaves and Coqueiro Seco Formations. Subsurface analysis permitted recognition and mapping of four principal types of depositional systems that infilled the basin with more than 3,000 meters of clastic-carbonate sediments: Morro do Chaves carbonate platform, Coqueiro Seco fluvial-deltaic, Coqueiro Seco fan delta, and Coqueiro Seco slope systems. The generally poor quality of seismic profiles in this rift sequence precludes conventional seismic stratigraphic approaches. Morro do Chaves lacustrine carbonate platform sediments were deposited on shallow positive areas flanking the principal point sources (rivers), and are composed of massively bedded, high energy limestones. Contemporaneous with shallow-water sedimentation, deepwater euxinic and bituminous lacustrine shales were deposited under starved basin conditions. Sublacustrine canyon excavation attested to the presence of a destructional slope episode. Coqueiro Seco fluvial-deltaic, fan delta, and slope sediments are principally terrigenous. Fluvialdeltaic and fan delta facies display high sand/shale ratios and blocky to massive E-log patterns; slope facies display serrate to digitate E-log patterns and are less sandy. Delta plain channel-fill facies and coarse-grained meanderbelt fluvial facies are dominant in fluvial-deltaic systems, and proximal to medial conglomerates and coarse conglomeratic sandstones are dominant facies in fan delta systems. Slope facies are composed of sublacustrine fans composed of fine-to medium-grained sandstones enveloped by thick, subbituminous shales, and thin, marly, lacustrine limestones. Coqueiro Seco clastic systems prograded across the basin and buried Morro do Chaves carbonate platforms in response to tectonic pulses related to rift development. Cyclic sedimentation occurred in the highly unstable Alagoas Sub-basin where fluvial-deltaic and slope systems are dominant, but fan delta and slope systems in the less complex Rio São Francisco Sub-basin do not exhibit cyclicity. Coqueiro Seco fluvial-deltaic, fan delta and slope sedimentation terminated because of continued basin subsidence and diminishing sediment supply as source areas were leveled. Consequently, the basin became the site of lacustrine shale deposition represented by the Ponta Verde Formation in the Alagoas Sub-basin. The rift sequence is truncated by a pre-Aptian unconformity in the Rio São Francisco Sub-basin. Evaluation of petroleum occurrences in relationship to defined depositional systems permitted recognition of several types of plays characterized by unique structural and stratigraphic relationships exhibited by reservoirs, source beds and structure. The Coqueiro Seco slope play, formed by updip pinchout of turbidite fans, is judged the most promising in the sequence. / text

The Lower Cretaceous tectonosequence constitutes a major chronostratigraphic interval in the Recôncavo Basin, Northeast Brazil. It encompasses a time span of ca. of 24 Ma and forms a continental sedimentary package that exceeds 5 km in thickness within its depocenters. The tectonosequence is bounded by two basinwide unconformities, the rift onset unconformity at its base and the breakup unconformity at its top. The basal deposits of the tectonosequence characterize transitional rift conditions. The bulk of the succession constitutes the record of the rift phase in the basin. Biostratigraphy in the Recôncavo Basin is based on nonmarine ostracods. The tectonosequence encompasses ostracod zones NRT 002 through NRT 009. Tectonic, sedimentologic, and paleoecologic characteristics permit the recognition of six tectono-depositional intervals within the tectonosequence. Tectono-depositional intervals cover a time span between 2 Ma and 7.5 Ma, and their boundaries are distinct marker beds. Lithologic, paleontologic, and geochemical characteristics of the marker beds suggest low sediment input at the time of their deposition. Tectonic and/or paleoclimatic changes may account for phases of marker bed creation. Within tectono-depositional inteivals II, IV, and V sedimentary cyclicity occurs. Sedimentary cycles spanning tens to hundreds of thousands years are termed tectono-depositional episodes. Such an episode is comparable in scale with a parasequence, and is also bounded by marker beds reflecting flooding events. Depositional systems within the tectonosequence show a change from lacustrine-dominated sedimentation at the base to fluvial-dominated deposition at the top. Reservoir potential increases toward the top of the tectonosequence, source rock and sealing conditions, however, follow the opposite path. The bulk of known hydrocarbon accumulations in the Recôncavo Basin occurs at the prerift/rift interface. Accumulation rate estimates show increasing values toward the top of the tectonosequence. This may be related to a better integration of the drainage system that fed into the basin and removal of possible structural barriers located along the basin's margins. Analysis of the sedimentary record of the tectonosequence suggests, besides tectonism, paleoclimate was an important mechanism controlling facies distribution and evolution. / text

Made available in DSpace on 2014-06-11T19:32:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-04-04Bitstream added on 2014-06-13T19:42:55Z : No. of bitstreams: 1 araujo_lmb_dr_rcla.pdf: 5931582 bytes, checksum: 06361dc85c9ed92cb3664deb385c584b (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Esta pesquisa enfoca duas áreas distintas pertencentes ao Domínio Tectônico Cachoeirinha que corresponde ao setor oriental dos terrenos pré-cambrianos do sudoeste do Cráton Amazônico em Mato Grosso, constituído pelas seguintes unidades litoestratigráficas: Complexos Metavulcano- sedimentares Cabaçal e Quatro Meninas, Suíte Intrusiva Máfica- ultramáfica, Unidades Ortognáissicas, Tonalito Cabaçal, pelas suítes intrusivas Santa Cruz, Alvorada, Batólito Rio Branco, Grupo Aguapeí e Suíte Intrusiva Salto do Céu. A Área 1, representada pelas rochas granitóides da Suíte Intrusiva Santa Cruz, um batólito com direção NNW, foliado, com três fácies petrográficas principais compostas por biotita monzo a sienogranito e pela Suíte Intrusiva Alvorada, unidade intrusiva individualizada, fracamente anisotrópica composta por vários corpos de pequeno porte plugs, stocks e plutons, subcirculares a subelípiticos e composição monzo a granodiorítica. Os resultados geoquímicos para as suítes Santa Cruz e Alvorada relacionam estas, a Série Monzogranítica, cálcio- alcalina de alto a médio potássio, peraluminosas a metaluminosas sugerindo quanto ao ambiente tectônico, características sin a tardi- colisionais gerados em arco magmático. O padrão de distribuição REE, sugere a intensificação do processo de fracionamento do magma a partir da fase inicial e, possível geração de magmas contemporâneos e cogenéticos de mesmas fontes diferenciadas. A idade U-Pb para a S.I. Santa Cruz apresenta valor de 1561 ± 260 Ma. e a idade TDM sugere um sofreu fracionamento mantélico por volta de 2,0 Ga., enquanto o valor negativo de εNd(t) -0,89 a -2,75 assinalam a participação de material crustal, mais diferenciadas na formação do magma. / This research deals with two distinct areas both within the Tectonic Domain of Cachoeirinha that correspond to the eastern portion of the Pre Cambrian terrains in the southwestern region of the Amazonian Craton in the State of Mato Gosso, Brazil. The lithostratigraphic units are: the metavolcanosedimentary Complex of Cabaçal and Quatro Meninas; intrusive mafic-ultramafic suits; orthogneisses Units; Cabaçal Tonalite; intrusive suits of Santa Cruz and Alvorada; Rio Branco Batholith, Aguapeí Group and intrusive Suit of Salto do Céu. The area 1 is represented by the granitic botholith of the Santa Cruz Suit, foliated with NNW direction, showing three petrographic facies dominated by biotite monzo to sienogranite and the Alvorada Intrusive Suit, weakly anisotropic and made up by many small bodies as plugs, stocks and plutons with circular to elliptic shapes and monzo to granitic compositions. Geochemical data for Santa Cruz and Alvorada Suits indicate that they belong to a Monzogranitic series of high to medium K calc alkaline, peraluminous to metaluminous suit suggesting a tardi-collisional magmatic arc environment. The REE distribution suggests an intense process of fractionation of the magma and possible generation of magmas of the same age and co genetic, derived of the same source. U/Pb age determinations shows values of 1551 ± 260 Ma. for the Santa Cruz Intrusive Suit with TDM ages suggesting the fractionate from the mantle at 2.0 Ga. The positive value of +3.50 for εND(t) indicates the presence of magmatic material with mantle signature, while an εND(t) negative of -0,89 to -1,20 characterize the participation of crustal material derived from more differentiated magma source.

Orientadores: Alvaro Penteado Crosta, Alfonso Schrank / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociencias / Made available in DSpace on 2018-08-13T07:15:05Z (GMT). No. of bitstreams: 1 Vieira_CesarKazzuo_M.pdf: 40895435 bytes, checksum: 81127eb9905b1b18af114978ccbf891d (MD5) Previous issue date: 2009 / Resumo: O Domo de Vargeão (SC), com 12,4km de diâmetro, é uma estrutura de impacto do tipo complexa parcialmente erodida, formada sobre os derrames vulcânicos da Formação Serra Geral, na bacia do Paraná. Em seu interior afloram, de forma anômala, arenitos atribuídos ás formações Botucatu e Pirambóia, normalmente situados a cerca de 1km abaixo da superfície atual. O objetivo principal deste estudo foi a caracterização geológica e geofísica do Domo de Vargeão, em superfície e em subsuperfície, por meio da integração de dados de sensoriamento remoto e geofísicos com informações geológicas em escala regional (1:250.000) e local (1:50.000) A análise dos dados aeromagnetométricos e sísmicos permitiram: (i) classificar o Domo de Vargeão como uma estrutura de expressão crustal rasa, com indicação da existência de uma zona de intensa deformação situada abaixo da mesma; (ii) associar o alto magnético associado com o núcleo da estrutura à ocorrência de brechas de impacto do tipo pseudotaquilíticas; e (iii) associar a zona anelar de baixo magnético, localizada próxima às bordas da estrutura, à ocorrência de blocos da unidade Ácidas Chapecó. A integração dos dados aeromagnetométricos com os de sensoriamento remoto (SRTM, Landsat/ETM+, Terra/ASTER, Radarsat-1) e geológicos revelaram a existência de um complexo sistema de falhas normais associado à borda da estrutura de Vargeão, que causou o basculamento de grandes blocos da unidade Ácidas Chapecó para o interior da estrutura. A análise dos dados geológicos permitiu: (i) a delimitação espacial das ocorrências de zonas de brechas no interior da estrutura e sua caracterização como brechas com material fundido (melt-fragment breccia); (ii) a identificação de feições típicas de metamorfismo de impacto que incluem a ocorrência de shatter cones em arenitos e basaltos e feições planares de deformação (PDFs) em grãos de quartzo; e (iii) a mensuração da direção cristalográfica preferencial dos PDFs segundo os planos (0001), {11¯11} e {11¯12}. Em conclusão, o Domo de Vargeão representa um notável e raro exemplo de estrutura de impacto complexa formada em rochas básicas e ácidas. O grau de exposicão e fácil acesso aos afloramentos rochosos em seu interior tornam esta estrutura um sítio potencial para a realização de estudos de análogos em processos de evolução das superfícies planetárias, que podem contribuir para o entendimento da evolução de corpos planetários sólidos como a Lua, Marte e Vênus, entre outros. / Abstract: Domo de Vargeão (SC), with a diameter of 12.4km, is a partially eroded complex impact structure formed on the lava flows of the Serra Geral Formation in the Paraná Basin. The anomalous occurrence of sandstones in its interior is related to the presence of the Botucatu and Pirambóia formations, uplifted from their regular stratigraphic level, sitting at approximately 1 km below the present surface. The objective of this study comprises the geologic and geophysical characterization of the Domo de Vargeão using remote sensing, geophysical and geological data integration, on a regional (1:250.000) and local (1:50.000) scale. Magnetic and seismic data analysis allowed: (i) to interpret it as shallow structure, with a strongly deformed zone underneath; (ii) to associate the magnetic high at the center of the structure to the occurrence of melt-fragment breccia; (iii) to associate the annular magnetic low located near the rim of the structure to the occurrence of large blocks of the Ácidas Chapecó unit. The integration of magnetic and remote sensing data (SRTM, Landsat/ETM+, Terra/ASTER, Radarsat-1) with geologic information unveiled a complex system of normal faults associated with the rim of Domo de Vargeão, responsible for the collapse of the blocks of Ácidas Chapecó towards the interior of the structure. The geologic data allowed: (i) to map the area of occurrence breccias and to characterize them as pseudotachylitic breccias; (ii) to identify and characterize impact features such as shatter cones in basalt and sandstone, and planar deformation features (PDFs) in quartz grains; and (iii) to measure the crystallographic direction of the PDFs along planes (0001), {11¯11} and {11¯12}. In conclusion, Domo de Vargeão constitutes a rare example on Earth of a complex impact structure formed in basic and acidic volcanic rocks. Its good exposure and easy access makes this impact structure potentially important for conducting analogous studies of planetary surfaces, thus helping to understand the evolutionary processes of solid bodies such as the Moon, Mars, Venus, among others. / Mestrado / Geologia e Recursos Naturais / Mestre em Geociências

Fifty-three basins with area less than 9.40 km² were mapped from 1:25,000-scale aerial photographs to provide data on basin morphometry. A significantly larger number of first-order streams exist than are expected according to the regression of stream number on order for each basin. This is attributed to the incorporation of recently formed gullies into the stream network as first-order streams. Most drainage density (Dd) values are in the coarse texture category (Dd<5.0 km/km²). Higher values of Dd correspond to areas of shallow soils. Total stream frequency (F[subscribe t]) and first-order stream frequency (F₁) are closely correlated with Dd (r=+0.86 and r=+0.89, respectively), but third-order stream frequency (F₃) is not (r=+0.70). F[subscribe t] is related to Dd as follows: F[subscribe t]=0.704 (Dd)²̇⁰⁸. Values of ruggedness number (HDd) and basin magnitude indicate that all basins are high-flood potential basins. This imposes serious limitations on the development of the watershed as a whole. Weighted mean percent silt-clay (M) and channel width-depth ratio (F) for 21 cross sections of stream channels were used to define cross section stability. Catchment area above each cross section is related to its stability. As area increases cross sections change from degrading to aggrading to stable conditions. There is a more gradual increase in F with decreasing M than in streams in the mid-western United States. This is attributed to the vigorous vegetation which stabilizes channel banks in the Mandaguari watershed. Recent climatic changes in the region rendered colluvial deposits susceptible to increased erosion under the present subtropical (Cwa) climate. When saturated, the latosols and podzols there are easily eroded owing to their low cohesion (PI=0-15). Recent deforestation and seasonal burning of pastures probably exacerbate this condition, contributing to the erosion of hillsides and the formation of gullies. Large, aggressive gullies (voçorocas) 10-15 m deep and 30-40 m wide occur in association with urban centers. Management of the Riberão do Mandaguari watershed should be based on considerations of (1) threshold conditions for instability of stream channel cross sections and soils and (2) complex responses of the watershed. Recommended actions are reforestation of slopes at and above the point of maximum profile steepness, induced incision of channel filling deposits, and control of runoff from urban centers. / text