Navegando por Assunto "Sedimentologia"

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Acesso aberto (Open Access)
Afinidades geoquímicas entre sedimentos (solos) e vegetação (gramíneas e cultivares), além de cabelo de ribeirinhos, ao longo das praias de rios da bacia do Juruá, no estado do Acre e sua importância ambiental
(Universidade Federal do Pará, 2005-06-10) RÊGO, José de Arimatéia Rodrigues do; COSTA, Marcondes Lima da; http://lattes.cnpq.br/1639498384851302
The State of the Acre is located in the southwestern extremity of the Brazilian Amazonia, in an area of 153.149 km2, with a low population density (3,66 inhabitants/km2). The studied area comprehends the basin of the Juruá river between the Feijó and Cruzeiro do Sul cities, including Tarauacá and Rodrigues Alves. In the basin the main rivers are: Juruá, Tarauacá, Envira, Muru and Moa. The same carry in sediments great amounts by traction and suspension from siltic- argillaceous rocks of the Solimões Formation and deposite in beaches formed along the rivers. In drought periods the beaches (point bars) are displayed in its meanders and benefit the riparian that use them to leisure and to short cycle agriculture. The beaches sometimes are used to cultivs of maize (Zea-Mays) and beans (Vigna unguiculata (1) Walp). These beaches also present a vegetation succession of canarana grass (Costus spicatus) and orvalho grass (Brachiaria decumbes). This study evaluates the high fertility of the beaches sediments (soils) and the geochemistry affinity between their sediments and the crops besides riparian hair and the environmental importance of this cycle. So the main rivers that constitute the Juruá basin, enclosing Feijó, Tarauacá, Cruzeiro do Sul and Rodrigues Alves cities were related. Nine stations were established along the rivers and samples of beach sediments, canarana grass leaves, orvalho grass leaves and seeds and beans leaves had been leaves were collected. Besides this, measurement of phisical-chemical parameters of the rivers waters were caried out. Human hair samples were collected in the cities. The sediments samples were analyzed by X-ray difraction (XRD) for mineral determination, are by chemical ICP-MS for characterization (major and trace elements). In attempt to verify the content of Major and Trace Elements, like Ca, Fe, K, Na, Ba, Zn, Mo, Co, Cr, Cu, Pb, Hg, As and Se and their sediment — (solil) — crops transference were camet the chemical compositions analyses were carried out with regal water plus MS-ICP and neutron activation. The studied beaches sediments in the cultivated areas excet the beach of Moa river are essentially fine-grained, ranging from fine sand to silt. And are formed by in decressent order quartz, feldspars clay minerals (smectite, illte and kaolinite) and feldspars. Chemical are constitute binaimes by SiO, (68,0 98,9 % in weight), following by significaty lower values, of Fe>03 (0,13 to 4,37 %), MgO (0,02 to 1,03 %), KO (0,16 to 1,94 %), CaO (0,02 to 1,05 %) and Na,0 (0,02 to 1,03 %) and AlOs, are more concentrated in the sediments of Envira, Tarauacá and Juruá rivers. These values compened chemical with that one of the PAAS and, the Upper Crust, are slightly impoverished in Al, Fe, Mg, K, Ti as well as slightly in Ca and Na, diluted certainly for the high contents of SiO2. In general, the rivers waters of the Juruá basin are dark-colored, as white waters type, due to inorganic material in suspension (suspensates) in high concentration. The criterion of suspensates and phisical-chemical parameters (pH, DO, TDS, temperature, resistivity, electric conductivity and salinity) delimit three geographic zones (sub-basins): a) Envira-Tarauacá, b) Juruá and c) Moa rivers. The first one presents the highest values of all the analyze phisical-chemical parameters, except resistivity, and the area coincides with the more fertile land area State of the Acre. Among the studied vegetables the canarana grass leaves revealed are richerest in K, S, Ca, Mg, P than orvalho grass leaves. Canarana and orvalho grass present chemical similarity in relation to K, P, S, Mg and Ca elements. Only canarana grass, collected in the sediments of the Juruá river tends to become richer in Ca and S. The chemical elements transference sediment (soil)-vegetable presents an absorption for vegetal of the K>P>Ca>P. This order presents the major values for vegetables collected in the sediments of Envira river, emphisizing the importance of Envira river with greater transference potential of macronutrients and being a probable pointer of its superior fertility in relation to the other rivers of Juruá basin. In the sediment-crop-human chain the cycle of Hg shows that in the beach sediments of the Juruá, Envira and Tarauacá rivers the average concentration of Hg (27 ppb) in the sediments below the background range (50 ppb) and in the plants is in according to normal considered range (< 500 ppb) for plants that grow in soils with low contents of Hg; the average contents of Hg in hair in Tarauacá, Cruzeiro do Sul, Rodrigues Alves and Feijó rivers is about 3992 ppb. The lower concentration (average 1680 ppb) was found in Feijó and the higher (6240 ppb) in Cruzeiro do Sul, being normal values and slightly impact indicators, not observed in the region. The slightly anomalous values of Hg in hair is not related to the crops, as well as to the sediments. For hunam other sources of Hg disponibilization must be evaluated as fish or domestic or wild animals meats. The beaches and abrupt declivities (banks) of the white water rivers of the central and western regions of Acre (Juruá basin) are really fertile, adequated to short cycle agriculture and its nutrients and other elements are completely assimilated by vegetables and crops. For the present study the chemistry of the sediments and crops, as well as of human hair, shows that the region does not present geochemistry anomaly of any considerable antropogenic impact.
Acesso aberto (Open Access)
Análise da dinâmica morfo-sedimentar da praia da Marieta – Ilha do Marco-Maracanã (NE do Pará)
(Universidade Federal do Pará, 2010-04-19) GUERREIRO, Juliana de Sá; EL-ROBRINI, Maâmar; http://lattes.cnpq.br/5707365981163429
This study aims the investigation of the morphological and sedimentological variations occurred in Marieta’s Beach- Marco Island (NE of Pará) during the rainy season (March) and rainyless season (November) of 2007, seeking to identify the main factors responsible by these variations. The Marieta’s beach has 3 km long, with NW-SE direction, and is supported by the sediments of the Barreiras Group, Post-Barreiras and the recent sediments that provide much of the sediment at the mouth of the estuary Urindeua. Topographic profiles were conducted in June in the following subdivisions Beach Marieta: Sector sandy spit - profiles I and II (tgβ = 0.0015); central section - profiles III, IV (tgβ = 0.0017) and NW sector - and V profiles VI (tgβ = 0.005). We applied the following morphological beach models: Inmam & Guza (1975), Sandy Spur -        in the rainy season         in the rainyless period, Sector Central -      12 in the rainy season        during rainyless. These results show a strong reflection with some dissipation, characterized as Intermediate Bar and Longitudinal with the NW sector, which indicated a Dissipative behavior during the two periods studied, According to Wright & Short (1984) had a whole beach Dissipative behavior during the two periods studied -       in the rainy season         in the less rainy period; And following Masselink & Short (1993) showed the profiles to be modified by tides, with dissipative bars RTR = 4 in the rainy season and RTR= 3.6 in the rainyless period. The beaches are predominantly covered by very fine sand, very well selected and moderately selected, with mesocurtic and platicurtic kurtosis and negative asymmetry at the supratidal zones during the rainy season and in areas of infratidal in the rainyless season in other areas of the beach Marieta were approximately symmetrical and positive asymmetries. The Marieta’s beach has been profiled morpho-sedimentary influenced by the displacement of the Convergence Zone Inter-Tropical (ITCZ) in the rainy season (1736.6 mm) and at rainless (2.4 mm). The speed of the wind was weaker during the rainy season with an average of 6.7 nodes while in the less rainy period the average speed was 11.3 knots with preferential direction NE, and therefore, buckled with higher energy (Hb = 1 , 5 m in the rainy season in March). Coupled with an amplitude of 5.5 m tide reaching the innermost areas of the beach. In the less rainy period, the waves were smaller, compared to the rainy season, which reached 1.2 m combined with an amplitude of 4.8 m tide. Through these parameters showed that the major changes in the beach profile were associated mainly to the interaction of the effects of winds, waves and tides, showing the strong relationship between the shape and orientation of the beach and the incidence of these agents.
Acesso aberto (Open Access)
Análise integrada da morfologia e sedimentologia do baixo curso do rio Xingu
(Universidade Federal do Pará, 2019-01-28) SILVA, Ariane Maria Marques da; ASP NETO, Nils Edvin; http://lattes.cnpq.br/7113886150130994
The Xingu River is an important tributary of the Amazon River, contributing with 5% of its total water discharge. Nevertheless, it does not contribute substantially with sediment load. The lower reaches of the Xingu River correspond to a Ria, as a result of the Holocene sea-level rise. It is also classified as a tidal river, where tides reach over 1 m at its confluence with the Amazon River. This study evaluated the morphology and sedimentology of the area, correlating it with hydrodynamics, aiming to understand the still ongoing infilling process of the Xingu Ria. The study area encompasses a stretch of about 180 km, from the Xingu-Amazon river confluence upward to the narrowing of the channel, near the city of Vitória do Xingu. During the maximum sediment discharge of the Amazon River (i.e., feb/2016) 109 bottom sediment samples were collected, whereas 11 of the sampling sites were re-sampled during the minimum water discharge period of both rivers (i.e., nov/2016). During the maximum water discharge period of the Amazon River (i.e., jun/2018), additional water level measurements were undertaken simultaneously in several locations along the Xingu River, as it was also performed during the other campaigns. The morphology was evaluated on the basis of the bathymetric surveys of the Brazilian Navy (CLSAOR/DHN), including about 20,000 points. The results showed that the infilling process of the ria lake has taken place from both ‘ends’ of the area- from the Xingu River itself, forming a prominent bay-head delta, as well as from the Xingu-Amazon River confluence, where tides have transported Amazon River sediments upstream into the Xingu Ria. Furthermore, there is a central portion of the ria lake with large cross-sectional areas, reached only by relatively small amounts of sediments, being a quiescent environment within muddy sedimentation. In a transversal perspective, sands seem to prevail along the margins, where local wave action seem to result in bluff erosion. Longitudinally, sands are substantially more frequent at the bay-head delta area, and at the confluence area, where cross-sections are clearly narrower. Results also suggest that the sediment input from the Amazon River into the Xingu ria has reduced over time, whereas the combination of cross-section area variation and the Xingu River water discharge itself reduce the sediment flux from the Amazon River into the Xingu River.
Acesso aberto (Open Access)
A aplicação da cromatografia gasosa acoplada (GC-FID), isótopos estáveis, palinologia e razão C:N na reconstituição paleoambiental de manguezais do Estado da Bahia e Espírito Santo.
(Universidade Federal do Pará, 2024-07-30) SILVA, Fernando Augusto Borges da; ALBERGARIA-BARBOSA, Ana Cecília Rizzatti de; http://lattes.cnpq.br/2666263256585897; FRANÇA, Marlon Carlos; http://lattes.cnpq.br/8225311897488790; https://orcid.org/0000-0002-3784-7702
Mangroves depend on ideal geomorphological, geochemical, and climatic factors to develop. Brazil, with its highly indented coastline under tropical and sub-tropical climate regimes, presents suitable conditions for the establishment of these ecosystems and distribution. The dynamics of these mangroves can be influenced by factors related to climatic variations and changes in hydrodynamic flow, resulting in modifications in sediment input and the origin of organic matter. These changes can be observed throughout the Holocene in different regions in of the country. On the northeast and southeast coast, the evolution of these ecosystems is associated with fluctuations in relative sea level (RSL) and sedimentary dynamics, while in the southern region, the change in the distribution of mangroves is a reflection of fluctuations in the RSL and climate changes caused by warming global. Recent studies seek to describe the evolution of these environments based on the elemental and isotopic characterization of organic matter. These constitute important tools in paleoenvironmental reconstruction. However, it is necessary to remember that the comparative analysis of the largest possible number of independent parameters is relevant as it adds value to the research and increases the reliability of the data to be analyzed, generating more precise information. Therefore, aiming to unravel the dynamics of organic matter in mangrove environments, as well as understanding movements of expansion and/or contraction of these ecosystems, analyzes of nalkanes were carried out using chromatography (GC-FID), associated with the sedimentary study, pollen data, isotopic and elemental analyses, synchronized with 14C and 210Pb dating, which allowed obtaining information about past biogeochemical processes and environmental changes during the Holocene and Anthropocene in the coastal plain at the mouth of the Itapicuru river (BA) and at the mouth of the Barra Seca and Jucu rivers (ES). Thus, the results of this research are presented in five scientific articles. The first, see chapter III, deals with the expansion of mangroves at the mouth of the Itapecuru river (BA) during the Anthropocene. The second scientific article (chapter IV) deals with the dynamics of mangroves at the mouth of the Barra Seca River, on the northern littoral of the State of Espírito Santo. The third article (chapter V) discusses the palynology tool used to understand the dynamics of coastal vegetation.The fourth article (chapter VI) presents the environmental changes that occurred at the mouth of the Jucu River, on the central coast of the State of Espírito Santo. Finally, the fifth article presents the results of n-alkanes analyses, compared with isotopic, elemental, palynological data, and 14C dating on the coastal plain of the Barra Seca River.
Acesso aberto (Open Access)
Aspectos diagenéticos dos Arenitos Bom Gosto - área leste da Bacia de Barreirinhas - (MA)
(Universidade Federal do Pará, 1986-10-17) CORRÊA, José Augusto Martins; TRUCKENBRODT, Werner Hermann Walter; http://lattes.cnpq.br/5463384509941553
Acesso aberto (Open Access)
Caracterização faciológica de sedimentos glaciais da formação cabeças na borda sudoeste da Bacia do Parnaíba
(Universidade Federal do Pará, 1997-02-19) OLIVEIRA, Marcelo José de; CAPUTO, Mário Vicente; http://lattes.cnpq.br/1028384858323270
Acesso aberto (Open Access)
Caracterização geomorfológica estratigráfica e geoquímica da Planície Costeira do município de Itarema-CE.
(Universidade Federal do Pará, 2011-09-01) PEREIRA, Lamarka Lopes; FREIRE, Geoerge Satander Sá; http://lattes.cnpq.br/6803944360256138; 6803944360256138; EL-ROBRINI, Maâmar; http://lattes.cnpq.br/5707365981163429; 5707365981163429
The Itarema coastal plain, situated at the western coast of Ceará, in the area dominated by the Cenozoic sedimentary cover. This thesis shows the geomorphological, sedimentological and geochemical features of this coastal plain. The Itarema coastal plain is subdivided in two major morpho-structural units: pre-coastal ¨plateaus¨ and coastal plain, that is subdivided into lithostratigraphic units, lagoon plain, tidal plain with and without mangroves, marine and fluvial plain, mobile and fixed dunes, beach ridges, tidal channels, sand bars and beaches. The supply and sediment transport in the area are closely linked to the climatic, meteorological and oceanographic conditions. The sedimentary, stratigraphy, geomorphological and geochemical data have been defined: (1) five lithological units: Lagoon Deposits, dune deposits, eolianits deposits, beach deposits and alluvial deposits and (2) seven lithofacies: mud sandy, mud, Sand mud, fine sand, medium sand, thick sand, conglomeratic sand-clay with different characteristics which have been drawn through the lateral and vertical correlations, thus allowing the interpretation of depositional paleoenvironments related to the evolution of the Itarema Coastal Plain. The analysis of the lithological units allowed the reconstruction of the processes indicative of a transgressive sucession prograded during which the lagoon-barrier system was installed on the system of alluvial fans, the bus of small streams, forming the lagoon plain, it was also noted that the lagoon has undergone changes in their size both by progradation of the barrier and subsequently by the deposition of sediments within the same wind. The Itarema coastal plain presents physiographic features of an coastal promontory or embaiments of central nuclei as a spiral, that would have provided the evolution to the current environment and the current model of coastline with beaches of the barrier beach-type and suggests that is occurring repetition in the construction of comparative morphology morphogenetic active in the region's past.
Acesso aberto (Open Access)
Caracterização morfossedimentar durante o ano de 2007 das praias estuarinas da ilha de Cotijuba (Baía do Marajó) no estado do Pará.
(Universidade Federal do Pará, 2008-08-22) OLIVEIRA, Gheisa Karla Martins de; EL-ROBRINI, Maâmar; http://lattes.cnpq.br/5707365981163429
The Cotijuba Island located at 90 km from the mouth of the Pará river is embedded in a tidal zone of the river, where the salinity is zero, and conductivity average is 65.70 μ S. The island belonging to the municipality of Belém is located 33 km of this, with 15 km2 of size and elongated shape in NE-SW direction. The island is supported by: (1) Barreiras sediments, outcroping in the form of exposed cliffs and platforms of abrasion, on the west side, (2) Pós Barreiras sediments, which are above and separated by a erosional surface (SÁ, 1969 apud SANTOS, 1996) and (3) Recent sediments (mangroves, marine terraces, bars and beaches). The study of sedimentmorph characterization of the morpho-sedimentary estuarine beaches of Saudade and Vai-quem-quer during the year 2007 (January, March and August), showed clear seasonal changes of these beaches. They were executed topographical profiles: nine on the beach of Saudade and twelve on the beach of Vai-quem-quer using a Total Station, in addition to the sediments collection. The beach of Saudade is 800 m length and is located on the southern island, with high topographic gradient ranging from tg d = 0,030 to tg d = 0,286. In the northern part of the island is the beach Vai-quem-quer with 1 km in length, which has a gradient topographic trivial compared to the beach of Saudade, ranging from tg d = 0069 to tg d = 0143. Have been applied on these beaches the morphological models of Guza & Inmam (1975), Wright & Short (1984) and Masselink & Short (1993) prepared for ocean beaches. Through the parameters used the beach showed state reflective of Saudade (b = 0.10 to 2.38) and longshore bar and runnel (b = 2.70 to 12.90), during the rainy season and only reflective (b = 0.05 to 1.84), during the dry season of Guza & Inmam (op. cit.). By the measure of Wright & Short (op. cit.) behaved the beach itself as refletiva (g = 1.08 and 0.86 in January and March, respectively, and in August g = 0.43) in the two periods. The beach of Vai-quem-quer presented by the measure of Guza & Inmam (op. cit.) states dissipativo (b = 20.05 to 31.28) and longshore bar and runnel (b = 9.21 to 18.23), in the rainy season. In the dry season, showed the states reflective (b = 1.61 to 2.46) and longshore bar and runnel (b = 2.63 to 3.44). For the parameter of Wright & Short (op. cit.) was classified as dissipative (g = 4.12) in January; longshore bar and runnel (g = 2.64) in March, and terrace of low tide (g = 2.38) in August. The parameter of RTR Masselink & Short (1993) stated that in January the beach of Saudade was influenced by waves and tides (RTR = 5.2) and in March by tides (RTR = 14.5). Already the beach of Vai-quem-quer either in January was influenced by waves (RTR = 2.15) and in March by waves and tides (RTR = 4.80). In the dry period, the two beaches were influenced by waves and tides (RTR = 10.5 and 3.16 for the beach of Saudade and Vai-quem-quer, respectively). The beaches are mostly covered by sand average (65%), moderately selected (59%), with kurtosis mesocúrtica (53%) and asymmetry negative (54%) on the beach of Saudade and approximately symmetrical (43%) on the beach of Vai-quem-quer. There was evidence of seasonality through profiles of acression and erosion, respectively, in dry and wet periods. On the beach of Saudade erosion occurred during the rainy season and acression, during the dry period. This beach has been divided into two sectors: North and South Sector. The South did not present major changes, however in the North Sector was developing a system of ridge and runnel and this has been intense variations with the changes of measures zones of intertidal and supratidal. On the beach of Vai-quem-quer either there was no notable changes during the rainy season. However, in the dry period was noticed acression in zones of upper intertidal and supratidal due to wind influence on the sediments that are at dried in this period. The characterization of the morphosedimentary estuarine beaches of Saudade and Vai-quem-quer is influenced by the Intertropical Convergence Zone (ITCZ), in the rainy season. It intensifies the winds in this period, which reached maximum speed of 7.5 m/s and preferential NE direction, and consequently, formed waves with higher energy (Hb = 1.3 m in January on the beach of Vai-quem-quer) and contributed to the beach erosional process. In addition to the high tides (Hm = 2.9 m in March) who achieved the most internal of these beaches.
Acesso aberto (Open Access)
Caracterização paleoambiental dos sedimentos Códo-Grajaú, Bacia de São Luis (MA)
(Universidade Federal do Pará, 1992-06-25) BATISTA, Ana Maria Nunes; TRUCKENBRODT, Werner Hermann Walter; http://lattes.cnpq.br/5463384509941553
Acesso aberto (Open Access)
Depósitos sedimentares neoproterozoicos do Grupo Tucuruí - Cinturão Araguaia, Nordeste do Pará
(2014-03) DUTRA, Alessandra de Cássia dos Santos; GORAYEB, Paulo Sérgio de Sousa; NOGUEIRA, Afonso César Rodrigues
The Tucuruí Group of Neoproterozoic age outcrops in Tucuruí region, northeastern of Pará state, along with the transition between the Amazonian Craton and Araguaia Belt. The group is defined by a volcano-sedimentary sequence containing basaltic flows and diabase sill intrusions interbedded with siliciclastics deposits. The Tucuruí thrust fault override these sets rocky westward resulting in shearing, fracturing and fluid percolation in these rocks. The siliciclastic deposits consist of amalgamated subarkoses and siltstones, whose layers are oriented NNE-SSW direction with low dip to SE. In addition presenting coarsening and thickening upward. In this investigation were recognized two sedimentary facies associations: Deposits of Shoreface and Coastal Tempestites Face. This association suggests easy transport processes and sedimentation linked to a shallow marine environment, following the foreshore zone to zone shoreface under influence of wave storm. The petrographic analysis revealed the compositional and textural immaturity of arkosean sandstone and siltstone indicating nearby source area of provenance of mafic to intermediate igneous rocks. The sequence was subject to the mesodiagenetic sedimentary conditions. Thus, the siliciclastic deposits of Tucuruí Group represent the portion of a preserved segment influenced by coastal storm waves in a rift basin or foreland with nearby source area, composed of igneous rocks with strong relief, and marked predominantly by physical weathering. Basaltic volcanic flows occurred during the evolution of this basin.
Acesso aberto (Open Access)
A dinâmica dos manguezais subtropicais no litoral norte de Santa Catarina durante o Holoceno tardio.
(Universidade Federal do Pará, 2019-06-28) PINHEIRO, Vanessa da Conceição; FRANÇA, Marlon Carlos; http://lattes.cnpq.br/8225311897488790
The goal of this work is identifying the establishment and expansion of mangroves on the northern coast of Santa Catarina during the Late Holocene. For this work, pollen data, 14C dating, organic geochemical (δ13C, C:N, TN and TOC) and results of sedimentary analyzes were integrated. These data were obtained from the analyses carried out from two sedimentary cores (SF7 and SF8) collected using a Russian sampler in the Babitonga Bay, northern coast of Santa Catarina. The data reveals a typical tidal channel and tidal plain deposits throughout the records. The tidal channel deposit was accumulated between > 1692 cal yr BP to ~ 667 cal yr BP, close to the bottom of the cores. This deposit is formed by fine-to-medium sand with parallel laminated sand (Sp facies), cross lamination (facies Sc), low angle planar lamination (Sb facies) and massive sand (Sm facies). The sedimentary deposit is characterized as a tidal plain around ~ 1223 cal yr BP, constituted by facies flaser heterolithic bedding (Hf), wavy heterolithic bedding (Hw), lenticular heterolithic bedding (H1) and parallel mud (Mp). The pollen content preserved along the tidal channel deposits reveals predominance of trees, shrubs, herbs and palms surroundings of the channel and on topographically higher regions. Only SF8 core was found mangroves pollen while the isotopic data revealed δ13C (-24.4 to -21.47 ‰), C/N ratio (4.77 to 20.81) with a strong contribution of marine organic matter and C3 terrestrial plants. The tidal channel was clogged and allowed the beginning of the deposition of the tidal plain. The deposit of the tidal plain has a large amount of plants fragments and pollen content characterized by predominance of herbs, trees, shrubs, palms and mangroves. The results of δ13C (-22.48 to -21.18 ‰) and C:N ratio (11.49 to 19.89) indicated the contribution of C3 terrestrial plants as well as contribution of marine organic matter. In addition, the mangroves beginning from approximately ~1692 cal yr BP with the genus Laguncularia and Avicennia, still at the edge of the tidal channel. Around ~586 cal yr BP was observed the mangrove development with a Rhizophora genus. The Laguncularia and Avicennia were initially established in sandy substrates and then also occupied in silty sandy soil. In the tidal plain environment, the genus Rhizophora was established in mud substrate. The mangroves of this region settled in the topographically higher regions and later expanded to the lower and closest regions of the Babitonga bay, possibly due to the decrease of the relative sea level recorded during the late Holocene as well as the migration and filling of the tidal channels. The occurrence of Rhizophora pollen close to the surface probably was a result of the temperature rise during the Late Holocene.
Acesso aberto (Open Access)
Os efeitos das oscilações climáticas e variações do nível do mar sobre o manguezal de Laguna (SC) - limite sul americano
(Universidade Federal do Pará, 2018-04-19) RODRIGUES, Patrícia Silva; MARLON, Carlos França; http://lattes.cnpq.br/8225311897488790; https://orcid.org/0000-0002-3784-7702
A mangrove ecosystem located in the Santo Antônio Lagoon, Laguna (SC), Southern Brazil is considered to be the southern limit of mangroves occurrence in South America has been chosen as the study site for this work. Our major goal was to study the dynamic of this mangrove regarding climatic changes during the mid- to late-Holocene. The study has been carried out based on one sediment core, RP-01 (4.75 m depth) sampled using a Peat Sampler set. A multiproxy analysis that links geochemistry (ie. Total C, Total N, C/N, C/S, δ13C and δ15N), sedimentology and palynology have been used in order to achieve the main goal. These data were temporally synchronized with six radiocarbon ages. Five facies were described considering their geometry, sediment composition, texture, grain size and geochemistry. They were grouped into two facies associations: i) lagoon and ii) distributary mouth bar. A transition from marine to terrestrial influence on the organic matter source during the mid-late Holocene has been proposed for the area. The increase in the terrestrial organic matter, especially occurred from the late Holocene on, just as the bigger contribution of the Sambaqui and Tubarão Rivers towards the lagoon has favored the development of the distributary mouth. The vegetation has also changed during this time. Pollen data indicated that over the mid-Holocene herbaceous plants dominated the area suggesting a less humid climate than the present one. The enhancement in the pollen grains of trees, shrubs, palms and the appearance of the mangrove towards the late Holocene it is interpreted as a sign of more humid and warm climate conditions than the later one in this region. This is probably related to the shifting of the ITCZ southwards and the intensification of the SAMS causing higher precipitation rates. The development of the studied mangrove site has occurred mainly during the past centuries, highlighting changes on the climate in the Laguna (SC) region and showing a sett up of a warmer and more humid climate than that observed during the mid-Holocene.
Acesso aberto (Open Access)
Estudo morfoestratigráfico e sedimentológico dos depósitos holocênicos da planície costeira de Maracanã – NE do Pará
(Universidade Federal do Pará, 2007-03-15) CARVALHO, Charles de Almeida; EL-ROBRINI, Maâmar; http://lattes.cnpq.br/5707365981163429
The Maracanã Coastal Plain is located in the northeastern part of the Para State where there are some coastal rias. This place is over tertiary sediments of the Barreiras and Pirabas Formations as well as is over quaternary sediments of the Pos-Barreiras. The Maracana Coastal Plain is influenced by an macrotidal regime (amplitude > 4 m). The Maracana Coastal Plain is characterized by three different geomorphologic domains: (1) Coastal Upland that presents active and inactive cliffs, and platforms of abrasion build in the laterites of Barreiras Formation as well as outcrop of the limestone from Pirabas Formation; (2) Coastal Plain that presents coastal dune fields and palaedunes, beach, mud-tide flat (mangrove), sandy plain, edd-tide delta, beach ridge plain and lakes; (3) Estuarine Plain which presents estuarine funnel, tidal channel and floodflat. In the Maracana Coastal Plain were identified nine morfostratigraphic units: (1) mud-tidal flat, (2) point bar, (3) Sandy plain, (4) dune, (5) paleodune, (6) beach, (7) ebbtide delta, (8) beach ridge plain, and (9) lake. These morfostratigraphic units are associated to three stratigraphic facies: (1) sand facies and point bar mud facies (sandy and muddy) that show alternate layers of greenish gray mud and light gray sand; (2) sea sand facies located over infratide mangrove that it has light olive gray and yellowish gray sands; (3) estuarine mud-sand facies that mean a variable thicking alternate layers with dark gray mud or greenish gray mud. In the Maracana Coastal Plain were characterized three depositional sequences: (1) Basal Transgressive Marine Succession S1, (2) Regressive Marine Succession S2 and (3) Transgressive Marine Succession S3. S1 show mid-large sand in its base (tidal channel) so that following by dark mud with high concentrations of organic matter (sand-silty clay). In these base, the sand is in moderate selection, but to top the sand is fine to middle size and it’s negative asymmetry. Distribution of the mineral clay was homogeneous (kaolinite = 45 %, ilite = 37 % and smectite = 18 %). Heavy minerals show larger concentration in the sandy facies, but the relative amount these minerals increased upward which owing zircon (35 %), staurolite (28 %), epidote (9 %) and cianita (11 %) presences. This sequence of sediments marks an estuarine mud, sea sand and seamud depositions during marine transgressive period. S2 is constituted by thin-very thin, well selected, near asymmetric sand that could be classified as clay-sand sediment. The mineral clay is represented by slight increase of the smectite as well as a decrease of the kaolinite in top sequence. The main heavy mineral located in the point bar are staurolite (44 %), zircon (39 %) and tourmaline (9 %) while there are zircon (39 %) and staurolite (27 %) contents at bottom sequence. This sequence was build during a marine regressive period from coastal upland so that consist the progradational deposits over sequence S1. The sequence S3 corresponds to unit of dunes, barrier-arrow beach, sandy and muddy bars. Coastal dune deposits show some crossing stratification to slow slope and thin layer of mud. Beach deposits show crossing stratus in low angle. Sandy bars presents a full structure with some bioturbation. The contents of sand are well selected and it has quartz as main mineral. The amount of heavy mineral was lower at top layer. Composition and texture of heavy mineral provide a rounding shape of the sediments because it has been transported, reworked and it was suffering a strong abrasion. In the Maracana Coastal Plain, grain size and mineral distribution are homogeneous being not possible to determine a clear edge between stratigraphic sequences either continental contribution or sea sediment source. There are so many morphologic features (cheniers, paleochannel, paleodelta) and some stratigraphic characteristics that suggest an occurrence of sea level oscillations as well as a migration in the shoreline position. The presence of transition environment deposits (tide flat) show some stratigraphic evidence in the study area. The Maracana Coastal Plain and the northeastern coastal area of the Para State (Bragança, Salinopolis and Marapanim) are over actual transgression event (large sandy plain and beach presences).
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Estudo sedimentológico da formação Pedra de Fogo-Permiano: Bacia do Maranhão
(Universidade Federal do Pará, 1979-10-17) FARIA JUNIOR, Luis Ercílio do Carmo; TRUCKENBRODT, Werner Hermann Walter; http://lattes.cnpq.br/5463384509941553
The Pedra de Fogo Formation of the Early-Middle-Permian in the Maranhão Basin is characterized by a ciclic sedimentation with fine sandstone intercalated with siltstones, shales and carbonatic banks which have abundant sílex beds and concretions. On surface this unit is divided into three members named Basal' Silex, Middle and Upper, Trisidela. Silicified oolites, pellets, coquinas with ' fish remains, stromatolitic beds and wood remains are found in the Pedra de Fogo. Formation sediments. The lithologies indicate a shallow, restricted, marine environment ' with two transgressions phases separated by a regression phase. The lateral facies changes reflect the sedimentary dynamism and suggest that the marine environment progressed from a transitional, deltaic to shallow neritic one. The main source areas of the clastic sediments and some of the sílica are, located in the northestern to the southern parts of the Basin and derived ' from the Borborema and São Francisco Provinces rockes. The Tocantins and. Tapajós Provinces to the west and southest have supplied material also. The climate during the Pedra de Fogo sedimentation has varied from moderate to arid as a consequence of the northward South American continent slow migration. The Maranhão had tectonic stability during the Permian. The marine in cursions took place from west, through the Amazonas Basin. Besed on the cyclothemes thickness, it seems that the Pedra de Fogo sedimentation occured from the water level oscilations in the Basin, which had also motivated the transgressions and regressions phases and whose origin should be related to the climatic changes during the Permian time.
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Estudo sedimentológico da Formação Pimenteira (Devoniano) na borda sudoeste da bacia do Parnaíba (TO)
(Universidade Federal do Pará, 1998-04-15) SILVA, Valter Fernandes; CAPUTO, Mário Vicente; http://lattes.cnpq.br/1028384858323270
The part of the Pimenteira Formation studied occurs in the southwest portion of the Parnaíba Basin, in the region between the cities of Paraíso, Miranorte, Miracema, Tocantinea, Pedro Afonso and Itacajás in the State of Tocantins. This formation is considered to be deposited in a transgressive sea system tract of Middle and Late Devonian age (Givetian to Famenian). In the area on stage, the studies of the facies made it possible to individualize three associations of facies named here as A, B and C that were deposited on a shallow marine platform during transgressive sea level, regressive sea level and high sea level, respectively. These facies associations were interpreted as a product of the following depositional environments: 1) LAMMA MARINE PLATFORM (association of facies A) represented by F1 (laminated shale facies), Alp (sandstone with plane-parallel lamination and Aab (sandstone intercalated to claystones with sand pockets) where the deposition took place mainly from fine suspended sediments (pelites) intercalated with fine to very fine sandstones (psamites) deposited under the influence of oscillatory and tractive flow originated by waves; 2) PROXIMAL GLACIOMARINHO with SUBGLATIAL CHANNEL, associated (association of facies B), represented by facies Dmm (massive diamictite), Acf (sandstone with fluidized clast), F1 (laminated shale), Pgm (massive coarse paraconglomerate), Pfm (massive fine paraconglomerate) and Agm ( massive coarse sandstone), were deposited from glaciers, with associated subglacial channels, ice rafts and/or icebergs that displaced from the continent, floated in the sea, released generating melt water bringing a large amount of fine and coarse sediments, forming a plume loaded with suspended sediments in front of the gallery. With the decrease in energy, extensive layers of mud are deposited, with pebbles and gravels, dispersed, being released from ice rafts and/or icebergs, as they melt. The facies F1, Pgm, Pfm and Agm represent a bar deposit remaining from a subglacial channel. Subglacial channels discharge coarse sediments in front of the glacier that can be transported further by turbidity currents forming lenticular or layered deposits interspersed with diamictites; 3) SHALLOW MARINE PLATFORM UNDER THE ACTION OF STORMWAVES (association of facies C) represented by facies F-A1 (shale-laminated sandstone), F1-S (laminated shale interleaved with siltstones), Aco (sandstone with wavy cross bedding truncated by wave), Ap (sandstone with plane-parallel bedding), Apt (sandstone with plane-parallel and tabular cross bedding), Acot (sandstone with wavy truncated wave and tangential cross bedding), Ach (sandstone with hamocky cross bedding), Aptb (sandstone with plane-parallel and cross-tabular bioturbated bedding), Apmo (sandstone with plane-parallel bedding and wavy marks), Amg (massive sandstone with dispersed granules and pebbles) and Pm (massive paraconglomerate). The deposits are characteristic of platform bars with dominant hummocky structures, attesting to the action of storm waves, covered by extensive layers of marine shales deposited during the good weather phase. This facies association predominates in the upper portion of the Pimenteira Formation gradually passing to the deformed sandstones and diamictites of the Cabeças Formation east of the town of Pedro Afonso.
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Estudo sedimentológico dos paleocanais da região do rio Paracauari, Ilha de Marajó - estado do Pará
(Universidade Federal do Pará, 1981-11-19) BEMERGUY, Ruth Léa; TRUCKENBRODT, Werner Hermann Walter; http://lattes.cnpq.br/5463384509941553
This investigations deals with the paleochannels of the Paracauari river In the northeastern region of Marajó island, based on the photogeological interpretation of maps (scale: 1:20.000) and Sedimentological studies of 13 holes with maximun depth of 50 meters. Morphologically the paleochannels are caracterized by meandering forms and are easily recognized by the vegetation and topographic features. The paleochannels are constituted of texturally mature and well sorted sands. The study of the heavy minerals fractions shows that following species are more importante: tourmaline, staurolite, zircon, andalusite and kianite. These minerals constitute a mature suite whi.ch are not only from the Amazon river system but also from the Tocantins river system. The clay fraction are represented by kaolinite, montmorilionite, illite and chlorite. These mineralogical composition reveals the influente of the more them one climatic change. The possible sources areas for these minerals are: the Andes Mountains; the upper Amazon and the Tocantins basin from this work we conclude that the methods of sedimentological research presented here with the studies of the morphological patterns in the northern and northeastern regions of Marajó Island can be applied to groundwater prospecting.
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Estudo sedimentológico dos sedimentos Barreiras, Ipixuna e Itapecuru no nordeste do Pará e noroeste do Maranhão
(Universidade Federal do Pará, 1981-06-24) GÓES, Ana Maria; TRUCKENBRODT, Werner Hermann Walter; http://lattes.cnpq.br/5463384509941553
Barreiras, Itapecuru and Ipixuna are exposed in large regions of Pará and Maranhão State. The Barreiras sedimente are divided in conglomeratic, sandy clay and sandy lithofacies. Textural imaturity and abundant mud-s.upported clastics in particular, suggest depositions mainly by debris flows under semiarid conditions. The three lithofacies were probably derived from Precambrian schists of Santa Luzia Formation and preexisting sedimente. The Itapecuru sedimenta consist of crossbedded sandstones, locally with minor conglomerates and mudstones, deposited in fluvial environment, probably tending to a semiarid conditions. The Ipixuna facies consiste of crossbedded kaolinitic sandstones, minor mudstones (lithology A) and laminated mudstonefine sandstone units including thick kaoline layers (lithology B). The fine sandstones are texturally and mineralogically mature. Lacustrine-fluvial origin is proposed for Ipixuna facies. The impoverished heavy-mineral assemblage and thick kaoline-layers suggest humid hot climate that probably prevailed before (during?) the Ipixuna sedimentation. Textural and structural characteristics of the sedimente studied show that there is a olear difference between Barreiras Group and Ipixuna facies and that the latter is correlated with the Itapecuru Formation. Bauxitization of lower Tertiary age affected only the Ipixuna and Itapecuru sedimentary rocks.
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Estudo sedimentológico e estratigráfico dos sedimentos holocênicos da costa do Amapá - setor entre a ilha de Maracá e o cabo Orange
(Universidade Federal do Pará, 1994-02-21) MENDES, Amilcar Carvalho; FARIA JUNIOR, Luis Ercílio do Carmo; http://lattes.cnpq.br/2860327600518536
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Fáceis litorâneas glaciais da formação Nhamundá (Siluriano inferior), na região de Presidente Figueiredo, AM, Bacia do Amazonas
(Universidade Federal do Pará, 1998-11-29) SOARES, Emílio Alberto Amaral; TRUCKENBRODT, Werner Hermann Walter; http://lattes.cnpq.br/5463384509941553
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Fáceis sedimentares e evolução diagenética dos arenitos da Formação Faro (Eo-Carbonífero) da Bacia do Amazonas
(Universidade Federal do Pará, 1993-01-11) AMADOU, Ba Ibrahim; TRUCKENBRODT, Werner Hermann Walter; http://lattes.cnpq.br/5463384509941553