Artigos - Geologia Aplicada - IGCE

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Early Aptian marine incursions in the interior of northeastern Brazil following the Gondwana breakup
(2023-12-01) Fauth, Gerson ; Kern, Henrique Parisi ; Villegas-Martín, Jorge ; De Lira Mota, Marcelo Augusto ; dos Santos Filho, Marcos Antonio Batista ; Santa Catharina, Amanda ; Leandro, Lilian Maia ; Luft-Souza, Fernanda ; Strohschoen, Oscar ; Nauter-Alves, Andressa ; Tungo, Edna de Jesus Francisco ; Bruno, Mauro Daniel Rodrigues ; Ceolin, Daiane ; Baecker-Fauth, Simone ; Bom, Marlone Heliara Hünnig ; Lima, Francisco Henrique de Oliveira ; Santos, Alessandra ; Assine, Mario Luis ; Unisinos University ; Universidade Estadual Paulista (UNESP) ; Research Center (CENPES)
This study reports a set of primeval marine incursions identified in two drill cores, 1PS-06-CE, and 1PS-10-CE, which recovered the Barbalha Formation, Araripe Basin, Brazil. Based on a multi-proxy approach involving stratigraphy, microbiofacies, ichnofossils, and microfossils, three short-lived marine incursions were identified, designated Araripe Marine Incursions (AMI) 1–3. AMI-1 and AMI-2, which occur within the shales of the Batateira Beds (lower part of the Barbalha Formation), were identified by the occurrence of benthonic foraminifera, calcareous nannofossils, dinocysts, and a mass mortality event of non-marine ostracods. AMI-3 was recognized in the upper part of the Barbalha Formation, based on the occurrence of ichnofossils and planktonic foraminifera. The observation of the planktonic foraminifera genus Leupoldina for the first time in the basin indicates early Aptian/early late Aptian age for these deposits, and the first opportunity of correlation with global foraminifera biozonation. Our findings have implications for the breakup of the Gondwana Supercontinent, as these incursions represent the earliest marine-derived flooding events in the inland basins of northeastern Brazil.
A New Genus and Species of †Cladocyclidae (Teleostei: †Ichthyodectiformes) from the Lower Cretaceous “Batateira Beds”, Barbalha Formation, Araripe Basin: The First Vertebrate Record in a Still Poorly Explored Fossil Site
(2023-03-01) de Mayrinck, Diogo ; Ribeiro, Alexandre Cunha ; Assine, Mario Luis ; Spigolon, André Luis Durante ; Universidade do Estado do Rio de Janeiro (UERJ) ; Universidade Federal de Mato Grosso ; Universidade Estadual Paulista (UNESP) ; Desenvolvimento e Inovação Leopoldo Américo Miguez de Mello–CENPES/PETROBRÁS
The Mesozoic Teleostei †Ichthyodectiformes presents a widespread distribution in marine brackish and freshwater deposits worldwide. The Brazilian fossil record of this group is represented by five nominal genera distributed exclusively in the sedimentary basins of Northeast Brazil (cf. Parnaíba, Sergipe-Alagoas, Recôncavo, Tucano, and Araripe). In the Araripe basin, the unique representative of the order is †Cladocyclus gardneri, restricted to the Crato and Romualdo Formations. Recent collecting efforts carried out in the Araripe Basin led to the discovery of two specimens of †Cladocyclidae. Based on the comparison with the known Brazilian taxa, we conclude that this new record represents a new genus and species of this clade. †Cladocynodon araripensis represents the first vertebrate described from the dark shales of the “Batateira Beds” of the Barbalha Formation and differs from the other †Cladocyclidae by the presence of hypertrophied bony fangs at the anterior region of the dentary, with other relatively small true teeth abruptly reduced posteriorly, and by presenting premaxillary and maxillary teeth significantly reduced in size. †Cladocynodon araripensis increases the anatomic diversity and temporal range of †Cladocyclidae in Gondwana.
Heat flow modelling of the Punta del Este Basin (offshore Uruguay) and its correlation with structural crustal domains
(2023-05-05) Novo, Rodrigo ; de Jesus Perinotto, José Alexandre ; Castillo, Maria Gabriela ; Conti, Bruno ; ANCAP ; Universidade Estadual Paulista (UNESP) ; Independent Consultant
The Punta del Este Basin is located at the offshore of Uruguay, and it is considered an underexplored basin with a high potential for holding hydrocarbon plays. Geologically, it constitutes an aborted rift related to the Gondwana fragmentation process, and subsequent opening of the Atlantic Ocean (Upper Jurassic - Lower Cretaceous). The stratigraphic and tectonic evolution comprises four phases from the Paleozoic pre-rift stage to present-day post-rift stage (Neogene/Quaternary). Due to the estimated hydrocarbon potential of this basin, exploratory activities have been intensified in the last decades, based on the acquisition of a significant amount of geophysical data which allowed a better comprehension of the basin's geology. Previous studies related to this basin were mainly oriented to the stratigraphy, structural framework, and petroleum systems comprehension. This research is focused on the thermal evolution of the Punta del Este Basin and its correlation with the crustal geological structure. For this purpose, a heat flow model was developed in order to understand thermal evolution through geological time. A 2D heat flow modelling based on pseudo wells was carried out to research and reconstruct the paleo heat flow. Bottom-hole temperatures (BHTs), seabed heat flow measurements, and Moho discontinuity depth interpretations have been employed in the reconstruction of heat flow evolution through time. A structural analysis based on seismic interpretation allowed to identify the Moho discontinuity and define four crustal domains in the study area: proximal (unattenuated crust), necking, hyperextended (stretched and thinned transition crust), and oceanic crust. The thermal model shows a strong correlation between heat flow and crustal thickness. In this way, the proximal domain develops low heat flow values while the distal sector shows higher values, due to the strong influence of the rifting event in crust thinning.
Hazard assessment of debris-flow-prone watersheds in Cubatão, São Paulo State, Brazil
(2023-04-01) Veloso, Vinicius Queiroz ; Reis, Fabio Augusto Vieira Gomes ; Cabral, Victor ; Zaine, José Eduardo ; dos Santos Corrêa, Claudia Vanessa ; Gramani, Marcelo Fischer ; Kuhn, Caiubi Emmanuel ; Universidade Estadual Paulista (UNESP) ; Institute for Technological Research – IPT
In Brazil, research related to the occurrence and prevention of debris flows is incipient when compared to the extent of the impacts caused by the phenomena. There is a need for further studies that consider susceptibility and hazard, especially in areas that are environmentally and socioeconomically vulnerable. This study aimed at assessing debris-flow hazard in the Rio das Pedras watershed, in Cubatão (State of São Paulo, Brazil), based on a set of different physiographic parameters (geomorphological, morphometric, geological) and in the application of empirical models. The hazard assessment was based on: (1) the evaluation of the history of events in the region; (2) the identification of the geomorphic controlling factors; (3) the estimation of the magnitude of a potential event; and (4) the identification of the elements at hazard. The results show that a debris-flow event in Rio das Pedras would more severely impact the Anchieta Highway (SP-150), the gas pipeline GASAN, the oil pipeline OSSP and the districts Pinhal do Miranda and Cota 95. These results highlight the relevance of geomorphological and geological parameters when estimating the extent of debris runoff, which is essential when defining the hazard in a debris-flow-prone watershed.
Transtensional tectonics during the Gondwana breakup in northeastern Brazil: Early Cretaceous paleostress inversion in the Araripe Basin
(2023-01-05) Rosa, Milena Cristina ; Morales, Norberto ; Assine, Mario Luis ; Universidade Estadual Paulista (UNESP)
Intraplate deformation during the Mesozoic breakup of West Gondwana predominantly occurred along major ancient lithospheric discontinuities. The Precambrian Patos Shear Zone (PASZ) is an inherited lithospheric discontinuity in the interior of northeastern Brazil which is closely linked to the evolution of the Araripe Basin. In this study, unlike previous interpretations of purely extensional tectonics, we conducted stratigraphic and structural field mapping as well as paleostress reconstruction to demonstrate the role of intraplate transtensional tectonics during the Araripe Basin evolution. Limited to the north by the PASZ and associated with sinistral reactivation, a set of normal to oblique NE–SW faults constituting a transtensional horsetail structure generated the initial basin geometry. Stratigraphic records of this rift phase comprise the Jurassic to Early Cretaceous Brejo Santo, Missão Velha, and Abaiara formations. Paleostress reconstruction showed a NE–SW/subhorizontal σ1 axis, a vertical σ2 axis, and a NW–SE/subhorizontal σ3 axis, resulting in a sinistral transtensional tectonic regime, which was mainly governed by intraplate processes that reflected the opening of the Brazilian East Margin. The subsequent Aptian post-rift early phase was characterized by NE–SW reverse faults and a succession of normal to oblique normal faults striking NW–SE to WNW–ESE. This fault arrangement generated a new NW–SE transtensional basin, which controlled the Barbalha Formation and modified and partially preserved the previous NE-SW transtensional basin. Paleostress reconstruction showed a NW–SE/subhorizontal σ1 axis and NE–SW/subhorizontal σ3 axis for strike-slip faults but NE–SW extension for normal faults. This is related to a second dextral reactivation of the PASZ following propagation of intraplate stress during the opening of the Brazilian Equatorial Margin. In summary, tectonic evolution of the Araripe Basin was strongly influenced by stress propagation from the Gondwana breakup into intraplate settings, with two distinct reactivations of the PASZ pre-existing basement structures which results in a paleostress inversion during basin evolution.
The largest Quaternary inland eolian system in Brazil: Eolian landforms and activation/stabilization phases of the Xique-Xique dune field
(2023-01-01) Mescolotti, Patricia Colombo ; Giannini, Paulo César Fonseca ; Pupim, Fabiano do Nascimento ; Sawakuchi, André Oliveira ; Ladeira, Francisco Sérgio Bernardes ; Assine, Mario Luis ; Universidade Federal de Mato Grosso do Sul (UFMS) ; Universidade de São Paulo (USP) ; Universidade Federal de São Paulo (UNIFESP) ; Universidade Estadual de Campinas (UNICAMP) ; Universidade Estadual Paulista (UNESP)
Eolian systems are sensitive to vegetation and climate changes, but also to the sediment supplied by neighbor depositional systems. This sensitivity is manifested in the alternation between periods of sand dune mobility and stability. In the Xique-Xique eolian system, the largest Quaternary interior dune field in Brazil (∼8000 km2), the neighboring depositional system responsible for the sand supply is the São Francisco River. We interpreted periods of dune activity and stabilization by mapping eolian landforms of this system, describing depositional facies under them and dating by optically stimulated luminescence (OSL-SAR). The stabilized parabolic landforms characterized and mapped (all formed by SE to E winds) were simple megadunes (25.5 ± 4.4 to 5.8 ± 2.0 ka), compound dunes (15.8 ± 1.2 to 5.2 ± 1.4 ka) and perched dunes (14.0 ± 1.0 and 1.2 ± 0.1 ka). We also recognized eolian plains (14.0 ± 2.1 to 6.5 ± 0.7 ka) and active parabolic dunes. Eolian deposits of undifferentiated landforms have also been described and dated (253.8 ± 19.0 to 8.2 ± 1.3 ka). The ages obtained allowed identification of two main phases of dune activity (∼60 to 18 ka and ∼16 to 5 ka) separated by a short period of stabilization marked by a paleosol (∼18 ka). The main periods of eolian activity are associated with phases of fluvial aggradation and high sediment supply, whereas dune stabilization since 5 ka is correlated with low sediment supply during the Late Holocene fluvial incision phase. The periods of eolian activity and stabilization respond not only to climate changes in the area occupied by the eolian system but mainly to local fluvial sediment supply by the river, which in turn can respond to more regional climatic controls. The Xique-Xique eolian system results from the coupling of abundant sediment supply from the fluvial system, high eastern wind speeds, and a significant wind deceleration caused by mountains on the western border of the dune field.
Pre-Quaternary Glaciations
(2020-01-01) Assine, Mario Luis ; Warren, Lucas Verissimo ; Universidade Estadual Paulista (UNESP)
Pre-Quaternary glaciations were recognized worldwide and have deeply influenced and conditioned the bioevolutive events and geochemical cycles of the Earth. Geological history has revealed that glaciations during icehouse intervals are typically periods of global sea level falls, while greenhouse intervals are marked by rising sea levels and reduced, or even absent, polar ice sheets. Defining the causes of glaciations is a complex task because the triggers, related to terrestrial and orbital forcing factors, are diverse and sometimes controversial. Glaciations were not common events in most of the Precambrian time, which covers about nine tenths of Earth's history. The glacial rocks of the Meso-Archean Pongola Supergroup and those related to the Huronian glaciation are evidences of ice ages before the Proterozoic “Boring Billion” period. Glaciations in Earth's history became frequent since the beginning of the Cryogenian, suggesting a global cooling of the planet's climate, influenced by a progressively complex biosphere and important changes in geochemical cycles. Ice sheets covered large areas of the planet land surface during three Cryogenian-Ediacaran glaciations, when the Earth was possibly completely covered by ice (“Snowball Earth” hypothesis). Following the long Neoproterozoic icehouse interval, the Earth experienced greenhouse conditions from Cambrian to Middle Devonian, only interrupted by the short-lived widespread late Ordovician glaciation (Hirnantian). The Late Paleozoic Ice Age (LPIA) encompasses glaciations occurred from late Devonian to Permian in many parts of Gondwana. During the Paleozoic, landmasses were concentrated in high southern latitudes forming this supercontinent, and glacial centers migrated following the drift of this huge landmass across the South Pole. The Late Cenozoic Ice Age is the icehouse interval that started at the Eocene-Oligocene boundary and is still ongoing, encompassing all known Quaternary glaciations.
Earth, wind and fire: Interactions between Quaternary environmental dynamics and human occupation on the southern coast of Brazil
(2023-02-01) Alessandretti, Luciano ; Giannini, Paulo César Fonseca ; Warren, Lucas ; Brückmann, Matheus Philipe ; Martini, Amós ; Universidade Federal de Uberlândia (UFU) ; Universidade de São Paulo (USP) ; Universidade Estadual Paulista (UNESP) ; Universidade Federal do Rio Grande do Sul-UFRGS ; Universidade Federal de Viçosa (UFV)
The southern coast of Brazil has been settled in different episodes between ca. 7.5 and 0.5 ka before the present by hunter-fisher-gatherers, shell mound builders of the pre-colonial Sambaqui cultural tradition. The factors that influenced human migrations in these episodes are diverse. They include cultural changes due to the coming of other groups, chronic food shortages, sea level changes, and lagoon silting. This paper combines geological, geomorphological, meteorological, and archaeological data to show how interactions between environmental dynamics and human settlement played a central role in modeling coastal sedimentary and rocky landscapes on the southern coast of Brazil during the middle Pleistocene to late Holocene. On Costão do Ilhote, a north-south oriented granitic promontory in Laguna County, Santa Catarina State, erosional features such as facets, keels, grooves, flutes, pits, and polished surfaces that developed on granitic boulders and pavements were recognized as ventifacts. In the same context, hundreds of fixed sharpeners/polishers from the production of polished objects by the sambaqui culture have been found crosscutting the ventifacts. Based on crosscut relationships between pre-colonial aged fixed sharpeners/polishers and ventifacts, relative sea-level changes during the Holocene, the age of distinct generation of sand dunes, and the age of shellmounds (sambaquis), four potential intervals of ventifaction are proposed: last 650 ka, last 350 ka, between ca. 115 and 5 ka BP, and between ca. 2.0 and ∼0.5 ka BP, with separated estimated abrasion rates of approximately 3.5 × 10−5 mm/yr, 7.0 × 10−5 mm/yr, 1.7 × 10−4 mm/yr, and 1.3 × 10−2 mm/yr, respectively. The ca. ∼1.5 ka of the last ventifaction interval was synchronous with a period of sambaqui culture retreat in the southern coastal plain of Santa Catarina, and also coincided with a period of abundant sand availability. This period is characterized by a drastic decline in sambaquis construction along the sand barrier and paleolagoon and a migration towards lagoonal and coastal rocky promontories, including Costão do llhote. Based on these pieces of evidence, we propose to add new components to the close interactions between environmental evolution and prehistoric human occupation on the southern coast of Santa Catarina during the Holocene: the strong winds combined with sand availability.
Metais e Não-Metais em Sedimentos de um Manguezal Não-Poluído, Ilha do Cardoso, Cananéia (SP)
(2007-01-01) Semensatto, Décio Luis ; Araújo, Geórgia Christina Labuto ; Funo, Rogério Hideki Ferreira ; Santa-Cruz, Joana ; Dias-Brito, Dimas ; Universidade Estadual Paulista (UNESP) ; Universidade de São Paulo (USP) ; Gerência Executiva I ; Fundação de Apoio à Pesquisa Científica e Tecnológica de Santa Catarina
This work aims to assess the spatial distribution and the seasonal behavior of metals, no-metals, physical and chemical variables and provide a pre-impact geochemical scenario from non-polluted mangrove sediments of a transect at the Cardoso Island (Cananéia, São Paulo State, Brazil) extending 340 m long landward. Triplicate samples from eight stations were collected in December 2001 and June 2002. Conductivity, pH, temperature, salinity and dissolved oxygen from the sediment interstitial water were checked in field using a Horiba U-10 probe. Metals and no-metals concentrations were obtained employing an inductively coupled plasma optical emission spectrometer (ICP OES) Vista-RL-Varian, radial vision. The sediments reflected two distinct intertidal segments: a “lower plain” (LP) and an “upper plain” (UP). The LP, which comprises the first 100 m landward from the bay, is a muddy environment with higher metal concentration and seasonally more stable than the UP. This latter, extending until the upper boundary of the intertidal zone, is a more oxygenated sandy flat with lower metal concentration. The distinct behavior of the geochemistry pattern observed along the transect in December and June is interpreted as associated with seasonal pluviometric fluctuations. The low metal concentrations denote low anthropogenic interference in the area, one of the most well preserved Brazilian coastal regions. It can be used as reference area to comparative studies involving similar ecosystems and, in the future, to check the environmental state of this mangrove flat.
Taphonomy of fish, invertebrates and plant remains in the first Tethyan-South Atlantic marine ingression along Cretaceous rift systems in NE-Brazil
(2023-07-01) Voltani, Cibele Gasparelo ; Osés, Gabriel Ladeira ; Freitas, Bernardo Tavares ; Prado, Gustavo Marcondes Evangelista Martins ; Rohn, Rosemarie ; Pacheco, Mírian Liza Alves Forancelli ; Anelli, Luiz Eduardo ; de Almeida, Renato Paes ; Simões, Marcello Guimarães ; Caldeira do Prado, Ludmila Alves ; Araripe, Rilda Verônica Cardoso de ; Galante, Douglas ; Rangel, Elidiane Cipriano ; Universidade de São Paulo (USP) ; Universidade Federal de São Carlos (UFSCar) ; Universidade Estadual de Campinas (UNICAMP) ; Universidade Estadual Paulista (UNESP) ; Universidade Regional Do Cariri ; Universidade Federal de Pernambuco (UFPE) ; Centro Nacional de Pesquisa Em Energia e Materiais
The Aptian–Albian Amargosa Bed, Tucano Basin, which was recently considered as a Konservat-Lagerstätten, is a relatively thin, siliciclastic-dominated succession of yellowish and grayish papyraceous shales. We analyzed the taphonomy of fishes, gastric ejecta, freshwater shrimps and conchostracans, euryaline ostracods, and plants. Fish biostratinomic signatures indicate point to changes in water alkalinity/salinity as their causa mortis, occasionally subject to weak currents. The preferential preservation of flexed shrimps and isolated pleons corroborates this interpretation. Conchostracans, recorded in distinct levels, indicate episodes of mass mortality, variable transport and temporal mixing, and at least one faunal change. During the fossilization, primary P and Ca from shrimps and fishes probably generated phosphates, which finally altered to Fe oxy-/hydroxides, yielding a mixed elemental composition, not expressed in other mineralogies than Fe oxy-/hydroxides. The original calcite of ostracod valves likely has been dissolved/replaced by a K-rich aluminosilicate, or by a precursor phase. Plants were preserved by Fe oxy-/hydroxides or by kerogenisation. Previous studies show that marine ingression of Tethyan waters into the central segment of the proto-South Atlantic gulf flooded the continental scale axial river system captured by the Tucano rift basin, affecting base level up to the Araripe Basin. Here it is interpreted that tributary river systems with relatively steeper stream gradients were less affected by marine transgression than the axial system, resulting in local freshwater riverine influx across the elongated epeiric sea developed over the interior rift basins of NE-Brazil, resulting in a mixed biota of distinct water salinities that alternate in the Amargosa Bed type-section.
The consequences of debris flows in Brazil: a historical analysis based on recorded events in the last 100 years
(2023-03-01) Cabral, Victor ; Reis, Fábio ; Veloso, Vinicius ; Correa, Claudia ; Kuhn, Caiubi ; Zarfl, Christiane ; Universidade Estadual Paulista (UNESP) ; University of Tübingen
This study aims at providing an overview of the socioeconomic consequences that debris-flow events have caused in Brazil, positioning the country in the international scenario and identifying areas where targeted actions are necessary. The analysis is conducted by calculating the debris-flow mortality rate (MR) and by using the so-called F-N plots (frequency of events that have caused N or more fatalities vs. the number of fatalities), based on a compilation of debris-flow-related disasters from 1920 to 2021. In total, 45 debris-flow events were documented in the considered period, responsible for 5771 fatalities and more than 5.5 billion USD in economic losses. The Serra do Mar Mountain Range is the main site of reported debris-flow occurrences (64.5%), followed by Serra da Mantiqueira (13.3%), and Serra Geral (13.3%). Southeast Brazil (SEB) is the region most affected by debris-flow events, due to the highest population density and the development of several cities in hilly areas, such as Petrópolis (Rio de Janeiro state) and Cubatão (São Paulo state). The debris-flow MR of SEB is higher than any other region in Brazil, pushing the national debris-flow MR upwards, and the F-N curve of SEB consolidates the region as the one with the highest risk to the phenomenon, indicating a higher probability of fatal events. The F-N plots further show that debris-flow events in Brazil represent a higher societal risk than in countries such as China, Japan and Italy. While there are differences in country size and the scale effect should be considered, these results highlight the urgent need for investments in disaster prevention and preparedness programs.
Stratigraphy, isotope geochemistry, seismic stratigraphy and paleogeography of the Lagoa do Jacaré Formation, Bambuí Foreland Basin (Ediacaran-Cambrian), Southeast Brazil
(2023-01-01) Santana Dantas, Márcio Vinicius ; Uhlein, Alexandre ; Uhlein, Gabriel Jubé ; Okubo, Juliana ; Moura, Samuel Amaral ; Universidade Federal de Minas Gerais (UFMG) ; Universidade Estadual Paulista (UNESP) ; Torre Oeste - Av. República do Chile
The Bambuí Group is a lithostratigraphic unit that comprises a mixed carbonate-siliciclastic platform deposited in a foreland basin. It is a 1st order sequence that filled the São Francisco Basin during the Ediacaran-Cambrian in southeast Brazil. The Lagoa do Jacaré Formation is the second carbonate unit of the Bambuí Group and is related to a 2nd-order regressive hemicycle composed of dark gray shallow water carbonates with high positive ẟ1³C values (>+10‰) related to the upper part of the Middle Bambuí Excursion (MIBE). We described four outcrops in the center-north of Minas Gerais state (Paraopeba, Curvelo, Montes Claros and Ubaí areas) coupled with ẟ13C and ẟ18O, and SEM-EDS analysis in order to support detailed facies analyses. One seismic line and three well logs in the south part of the Januária High were also used to define the stratigraphic framework of the Lagoa do Jacaré Formation in the Bambuí Foreland Basin system. Eight facies were interpreted from the outcrop data and grouped into five facies associations, that represent peritidal zone (FA1), ooidal sand shoals (FA5), tempestites of mid ramp (FA3), fine-grained carbonate of outer ramp (FA4), and fine-grained siliciclastic from offshore (FA2). The strong presence of terrigenous material (quartz, feldspars, muscovite, biotite, apatite) with some authigenic/diagenetic minerals (pyrite, titanite, rutile) in all facies are the main petrographic aspect of the studied carbonate rocks, related to high sedimentary input and some events during early diagenesis. FA1 with lower mean values of ẟ1³C (+9‰) predominates in the north, meanwhile FA3 is the main association in the south with higher ẟ1³C mean values (+12‰). This difference is probably related to the stratigraphic differences between the basal section (at south) and upper section (at north) of the Lagoa do Jacaré Formation. The Januária High was the main controlling element for the deposition of the carbonate ramp in the north sector of the basin, close to the Ubaí and Montes Claros cities. Probably, this structural high also played an important role as source area in the forebulge sector, uplifted by flexure due to the orogeny of the Brasília and Araçuaí (still in development) Belts (∼540-520 Ma). To the east, a N–S carbonate ramp system was developed in the back-bulge sector according to the main paleocurrents measurements. This ramp is related to a 300 m thickness section of the Lagoa do Jacaré Formation that was firstly identified and correlated to the successions on the surface using well logs, possibly registering at the top the decreasing in the ẟ1³C values, after the main stages of the MIBE probably in close association with Ediacaran-Cambrian boundary, related to the assembling of the Gondwana Supercontinent recorded in this region of southeast Brazil.
Assessment of Groundwater Resources in Brazil: Current Status of Knowledge
(Crc Press-taylor & Francis Group, 2016-01-01) Feitosa, Fernando A. C. ; Diniz, Joao Alberto O. ; Kirchheim, Roberto Eduardo ; Kiang, Chang Hung ; Feitosa, Edilton Carneiro ; Thangarajan, M. ; Singh, V. P. ; CPRM Geol Survey Brazil ; LEBAC Basin Studies Lab ; Universidade Estadual Paulista (UNESP) ; LABHID Hydrogeol Lab ; Universidade Federal de Pernambuco (UFPE)
Combining ultrafiltration and diffusive gradients in thin films techniques for speciation/fractionation of Cu and Zn in cytosol of liver of Nile tilapia (Oreochromis niloticus)
(Oxford Univ Press, 2023-04-03) Gemeiner, Hendryk ; Menegario, Amauri Antonio ; Eismann, Carlos Eduardo ; Elias, Lucas Pellegrini ; Pedrobom, Jorge Henrique ; Dourado, Thiago de Araujo ; Chang, Hung Kiang ; Conceicao, Fabiano Tomazini da ; Moruzzi, Rodrigo Braga ; Universidade Estadual Paulista (UNESP)
This work aims to evaluate the size and lability of Cu and Zn bound to proteins in the cytosol of fish liver of Oreochromis niloticus by employing solid-phase extraction (SPE), diffusive gradients in thin films (DGT), and ultrafiltration (UF). SPE was carried out using Chelex-100. DGT containing Chelex-100 as binding agent was employed. Analyte concentrations were determined by ICP-MS. Total Cu and Zn concentrations in cytosol (1 g of fish liver in 5 ml of Tris-HCl) ranged from 39.6 to 44.3 ng ml(-1) and 1498 to 2106 ng ml(-1), respectively. Data from UF (10-30 kDa) suggested that Cu and Zn in cytosol were associated with similar to 70% and 95%, respectively, with high-molecular-weight proteins. Cu-metallothionein was not selectively detected (although 28% of Cu was associated with low-molecular-weight proteins). However, information about the specific proteins in the cytosol will require coupling UF with organic mass spectrometry. Data from SPE showed the presence of labile Cu species of similar to 17%, while the fraction of labile Zn species was >55%. However, data from DGT suggested a fraction of labile Cu species only of 7% and a labile Zn fraction of 5%. This data, as compared with previous data from literature, suggests that the DGT technique gave a more plausible estimation of the labile pool of Zn and Cu in cytosol. The combination of results from UF and DGT is capable of contributing to the knowledge about the labile and low-molecular pool of Cu and Zn.
UPLIFTING MOUNTAINS AND SHAKING DESERTS: VOLCANO-TECTONIC EARTHQUAKES REVEALED BY SOFT-SEDIMENT-DEFORMATION STRUCTURES IN UPPER CRETACEOUS AEOLIAN DEPOSITS
(Sepm-soc Sedimentary Geology, 2023-01-01) Alessandretti, Luciano ; Warren, Lucas V. ; Varejaeo, Filipe G. ; Rassi, Raul ; Dos Santos, Mauricio G. M. ; Silva, Mariana N. M. ; Honorato, Fernando R. ; Estrada, Michele J. T. ; Cunha, Joao V. O. ; Universidade Federal de Uberlândia (UFU) ; Universidade Estadual Paulista (UNESP) ; Univ Fed Ouro Preto ; Universidade Federal do ABC (UFABC)
During the last stages of Gondwana fragmentation, large regions of the newly formed South American continent were covered by extensive deserts. Some parts of this continental landmass were synchronously affected by pronounced tectonism and magmatism, which were responsible for reshaping the regional topography. In this context, the southwestern part of the Sanfranciscana Basin in central Brazil is a key area for understanding this particular basin occur in direct association with volcanic rocks of the Upper Cretaceous Mata da Corda Group. Here, we report evidence of synsedimentary magmatism in direct association with soft-sediment-deformation structures, including flame structures, load casts and pseudonodules, water-escape structures, convolute lamination, faults, breccias, and clastic dikes, developed exclusively in aeolian sandstone and siltstone facies. The deformation features are interpreted as indicative of liquefaction, fluidization, and brittle behavior of the loose to partially lithified, wet sandy-silty sediments. The Late Cretaceous aeolian sedimentation is contemporaneous with the uplift of the Paranaiba High and activities are considered to have triggered ductile to brittle deformation in the reported aeolian deposits.
Isotope stratigraphy of Precambrian sedimentary rocks from Brazil: Keys to unlock Earth's hydrosphere, biosphere, tectonic, and climate evolution
(Elsevier B.V., 2019-01-01) Caxito, Fabricio de A. ; Uhlein, Gabriel J. ; Uhlein, Alexandre ; Pedrosa-Soares, Antonio Carlos ; Kuchenbecker, Matheus ; Reis, Humberto ; Sial, Alcides N. ; Ferreira, Valderez P. ; Souza Alvarenga, Carlos Jose ; Santos, Roberto Ventura ; Vieira, Lucieth Cruz ; Dantas, Elton ; Babinski, Marly ; Trindade, Ricardo ; Boggiani, Paulo Cesar ; Warren, Lucas ; Hippertt, Joao Pedro ; Sotero, Marcus Paulo ; Paula, Janaina Rodrigues de ; Montenari, M. ; Universidade Federal de Minas Gerais (UFMG) ; Universidade Federal de Viçosa (UFV) ; Univ Fed Ouro Preto UFOP ; Universidade Federal de Pernambuco (UFPE) ; Universidade de Brasília (UnB) ; Universidade de São Paulo (USP) ; Universidade Estadual Paulista (UNESP) ; SUREG BH ; VALE SA
Brazil is a natural laboratory for the application of isotope stratigraphy tools on the study of Precambrian sedimentary successions, with excellent registers of Archean, Paleo, Meso, and Neoproterozoic age. Those successions witnessed the most extreme and unidirectional events in Earth's history, such as the Paleoproterozoic and Neoproterozoic oxygenation events (GOE and NOE), the main stages of iron formation deposition, the global Cryogenian glaciations and the explosive diversification of metazoans near the Precambrian/Cambrian border. Chemical sedimentary rocks such as carbonates, iron formations and evaporites that can act as natural recorders of seawater composition are present in all of those successions and furnish important pieces of evidence in order to reconstruct the chemostratigraphic record. The field of isotope stratigraphy keeps expanding in Brazil and novel information from developing isotopic systems will surely add to the growing database and provide important information on Earth's ancient biogeochemical cycles in the years to come.
Functional fluvial landforms of the Pantanal: Hydrologic trends and responses to climate changes
(2022-11-01) Bergier, Ivan ; Assine, Mario Luis ; Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) ; Universidade Estadual Paulista (UNESP)
Large-scale fluvial landforms emerge from iterative processes that sculpt Earth's surface. Tectonics, climate variability and erosion are major recurrent processes reshaping fluvial landforms ending up in self-affine patterns. In the case of the Pantanal, the largest wetland in South America, its depositional tract can be subdivided as fluvial megafans, interfans and the main trunk system. Here we provide an outlook of their origins by means of self-affine landforms and on the feedback of climate changes over landform functionalities. Climate variability modulates the magnitude of interannual fluvial discharge and sediment load from highlands to plains, affects groundwater recharge, as well as the subsidence and generation of accommodation in the depositional tract through river avulsion. Scenarios are envisaged by analyzing long-term summer rainfall intensity and the number of dry days in autumn/winter over the Upper Paraguay River Basin, and annual flood peaks measured at fluvial gauge stations in the Paraguay River at Ladário (Brazil) and Asunción (Paraguay). The frequency distributions of the annual flood peaks are found unimodal for Asunción and bimodal for Ladário, which suggests an unknown water supply at Asunción, likely from Pilcomayo River and Pantanal's groundwater. The latter might play a delayed role on Pantanal's hydrologic functioning at 20–40 years timescales. Besides the Paraguay River flood peaks, summer rainfall intensity and the number of dry days in autumn/winter are quasi-periodic at interannual and decadal scales. Cross-correlations analyses indicate a long-range memory between river floods and rainfall intensity, and 15–20 years lag between river floods and the number of dry days in drought seasons. Trends analysis suggests that summer rainfall intensity and the number of dry days in autumn/winter have been consistently increasing by about 0.6 mm/day/decade and 1 day/decade, respectively. Therefore, magnifications of fluvial discharge and sediment load at wet seasons and water deficits at drought seasons are anticipated. Such a scenario indicates extreme dry cycles over all self-affine functional landforms, particularly on abandoned lobes relying exclusively on rainwater, whereas extremes of rainfall intensity at rivers headwaters may amplify the risks of large-scale avulsions at active lobes of the fluvial megafans. In contrast, active lobes of megafans, interfans and the main trunk river system emerge as hotpots for wildlife refuge and ecosystem services.
Assessment of Groundwater Resources in Brazil: Current Status of Knowledge
(2016-01-01) Feitosa, Fernando A. C. ; Diniz, João Alberto O. ; Kirchheim, Roberto Eduardo ; Kiang, Chang Hung ; Feitosa, Edilton Carneiro ; CPRM-Geological Survey of Brazil ; LEBAC-Basin of Studies Laboratory ; Universidade Estadual Paulista (UNESP) ; LABHID-Hydrogeology Laboratory ; Universidade Federal de Pernambuco (UFPE)
The Brazilian orogenic cycle activities lasted up to the Upper Ordovician/Lower Silurian whereby the actual tectonic framework of the Brazilian territory has been built. The geologic framework described before and the assessment of the water well logs and oil soundings suggest that the Alter do Chao formation is the main regional aquifer functioning under an unconfined regime. The issue regarding the high heterogeneity and anisotropy of the fractured media depends directly on the assessment scale. The hydrogeological map of Brazil, launched by the Brazilian Geological Survey-CPRM/SGB at the end of 2014, represents a synthesis of the hydrogeological information data sets available in the country. The concept of “hydrographic regions” defined by the Water Resources National Council-CNRH has been adopted. The geological database was obtained from the geographical information systems Bazil from the CPRM and based on a simplification of unit attributes and conversion into hydrogeology characteristics, such as groundwater transmissivity and storage.
Cryptospores of Iapó formation: The first evidence of early land plants from Late Ordovician in Paraná Basin, Brazil.
(2022-10-01) Rodrigues, Lívia C. ; do Carmo, Dermeval ; Assine, Mario ; Steemans, Philippe ; UnB ; Universidade Estadual Paulista (UNESP) ; Liège University
Assemblages of cryptospores were reported and detailed for the first time from the Upper Ordovician from Brazil. These assemblages were recovered from diamictites and shales with dropstones of the Iapó Formation, Rio Ivaí Group, Paraná Basin. The analyzed sequence represents the Hirnantian glacial deposits containing well-preserved palynomorphs with low thermal maturity and low total organic carbon. The cryptospore assemblages comprise monads, dyads, permanent tetrads, and polyads, naked or enclosed in an envelope, totalizing 17 species. The associated marine palynomorphs consist of 12 species of acritarchs and prasinophycean algae which are not discussed in detail herein. It is noticied the occurrence of Tortotubus protuberans and abundant black fragments at the lowermost portion of diamictites. The Late Ordovician cosmopolitan assemblages of cryptospores corroborate the early radiation of the land plants in western Gondwana. These results contribute to a better knowledge of Late Ordovician in Brazil and more generally in South America.
U-isotopes and weathering rates in watersheds of Araxa city, Minas Gerais State, Brazil
(Elsevier B.V., 2022-05-01) Bonotto, Daniel Marcos ; IGCE ; Universidade Estadual Paulista (UNESP)
This work was conducted at Araxa city, Minas Gerais State, Brazil. The aim was to characterize by different approaches weathering rates at six watersheds occurring there. The study area is well-known in the country due to economic and touristic reasons. Beginning in the 1960's and 1970's, nowadays huge mining activities for niobium and phosphate fertilizer exploitation by different companies are taking place there along with the use of natural mineral waters for health treatment, following a tradition that started in the 19th century for tuberculosis treatment. The dataset utilized in this investigation comprised results obtained in the analysis of distinct geochemical compartments, i.e. rocks, soils, bottom sediments, rainwater and surface waters from small hy-drographic basins. The waters of three catchments are extensively used by water-supply systems of Araxa city in order to meet the demand of this resource as a possible supply of drinking water for the local community. Hydrochemical (major and trace constituents) and radionuclides (U-238, U-234, and Po-210) analyses of rainwater and water bodies samples allowed estimates of the fluxes in each drainage. These fluxes were subtracted from rainfall deposition, yielding positive net values only for bicarbonate and U-isotopes as natural tracers in all watersheds, which allowed to calculate chemical weathering rates of 2.6-38.9 ton/km2yr (bicarbonate) and 0.09-19.8 ton/km(2)yr (U-isotopes). Physical weathering rates were obtained from Pb-210 data in bottom sediments and exceeded 200 to 1.3 x 105 times the chemical weathering rates evaluated by the U-isotopes approach, a finding compatible with others reported in literature but adopting a diverse conceptual framework. Thus, the development of all analytical protocols along this investigation permitted an integrated appraisal of distinct approaches applied to the same selected site, as well as a comparison of weathering rates with other values reported in the literature, improving the knowledge about this subject in Araxa city watersheds. The novel dataset reported in this paper constitutes an aid to the already existing number of weathering rates elsewhere, helping modellers engaged on predicting future landscape changes.

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