Brazilian Journal of Geology最新文献_第9页

The Barreiro suite in the central Ribeira Belt (SE-Brazil): a late Tonian tholeiitic intraplate magmatic event in the distal passive margin of the São Francisco Paleocontinent 里贝拉带中部(巴西东南部)的Barreiro套:<s:1>旧金山古大陆远端被动边缘的晚托尼世拉斑岩板内岩浆事件

IF 1.4 4区地球科学

Brazilian Journal of Geology Pub Date : 2019-08-01 DOI: 10.1590/2317-4889201920180129

M. Heilbron, Caroline D. Oliveira, Marcela Lobato, C. Valeriano, I. Dussin, E. Dantas, A. Simonetti, H. Bruno, Felipe Corrales, Eduardo Socoloff

{"title":"The Barreiro suite in the central Ribeira Belt (SE-Brazil): a late Tonian tholeiitic intraplate magmatic event in the distal passive margin of the São Francisco Paleocontinent","authors":"M. Heilbron, Caroline D. Oliveira, Marcela Lobato, C. Valeriano, I. Dussin, E. Dantas, A. Simonetti, H. Bruno, Felipe Corrales, Eduardo Socoloff","doi":"10.1590/2317-4889201920180129","DOIUrl":"https://doi.org/10.1590/2317-4889201920180129","url":null,"abstract":"New geochemical, U-Pb, Lu-Hf and Sr-Nd data from the Barreiro Suite metabasites in comparison with enclaves within the distal Andrelândia Group and the orthogranulites of the Juiz de Fora Complex are presented. Geochemical data suggest intraplate setting, with high and low- TiO 2 , TDM Nd ages between 1.80 and 1.41 Ga, negative ENd t and ( 87 Sr/ 86 Sr) i between 0.714 and 0.747. Results contrast with part of the Juiz de Fora Complex enclaves, with island arc tholeiites- calcalkaline basalts (IAT-CAB) geochemical signatures, TDM Nd ages between 2.58 and 2.16 Ga, positive ENd t values and ( 87 Sr/ 86 Sr) i between 0.700 and 0.712. U-Pb data for the Barreiro Suite yielded a crystallization age of 766 ± 13 Ma and a metamorphic overprint of 619 ± 6 Ma. The results indicate three episodes of mafic magmatism in the Occidental terrane of the Ribeira Belt. The two older episodes are related to Rhyacian arc evolution (ca. 2.2 to 2.1 Ga) and to the Statherian (ca. 1.7 Ga) tectonics, and occur only within the Juiz de Fora Complex, while the younger ca. 766 Ma episode constrains the timing of distal passive margin evolution. An important implication is that these late Tonian metabasic rocks could have been a source of detrital zircons for the sedimentation along the distal Andrelândia basin.","PeriodicalId":9221,"journal":{"name":"Brazilian Journal of Geology","volume":"57 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80319201","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 12

Interpretation software applied to the evaluation of shallow seismic data processing routines in fluvial deposits 应用解译软件评价河流沉积浅层地震资料处理程序

IF 1.4 4区地球科学

Brazilian Journal of Geology Pub Date : 2019-08-01 DOI: 10.1590/2317-4889201920180121

Ariel Henrique do Prado, R. P. Almeida, L. N. Tamura, C. Galeazzi, Marco Ianniruberto

{"title":"Interpretation software applied to the evaluation of shallow seismic data processing routines in fluvial deposits","authors":"Ariel Henrique do Prado, R. P. Almeida, L. N. Tamura, C. Galeazzi, Marco Ianniruberto","doi":"10.1590/2317-4889201920180121","DOIUrl":"https://doi.org/10.1590/2317-4889201920180121","url":null,"abstract":"High-resolution seismic surveys have been successfully applied in the study of active sedimentary environments in shallow submerged settings, particularly improving the interpretation of sedimentary facies and architectural elements that characterize fluvial rock records. Nevertheless, specific data processing workflows to emphasize sedimentary structures have not been proposed or tested, so that interpretation currently relies on the subjective opinion of individual interpreters, which might lead to biased conclusions. Aiming at the construction of a less biased data processing workflow, we developed a software that analyzes seismic data and performs standardized interpretation by linking individual seismic traces to generate interpreted reflector lines. A dataset acquired with boomer continuous seismic profiler in the sedimentary bed of the Amazonas river in Brazil was processed with a typical sequence of filter and gain (using Seismic UNIX software), as well as a routine of trace interpolation written in GNU Octave. The application of the Standardized Interpreter at different stages of processing enabled the comparison of the resulting interpretation scenarios in terms of the representation of geometries related to internal sedimentary structures, thus leading to the proposition of a workflow adapted to the specific needs of sedimentary structure interpretation from seismic data.","PeriodicalId":9221,"journal":{"name":"Brazilian Journal of Geology","volume":"28 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81969946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Vegetation and climate changes in the forest of Campinas, São Paulo State, Brazil, during the last 25,000 cal yr BP 巴西圣保罗州坎皮纳斯森林的植被和气候变化，在过去25000 calyr BP

IF 1.4 4区地球科学

Brazilian Journal of Geology Pub Date : 2019-01-01 DOI: 10.1590/2317-4889201920190040

Adriana Mercedes Camejo Aviles, F. Ricardi-Branco, M. Ledru, L. Bernacci

{"title":"Vegetation and climate changes in the forest of Campinas, São Paulo State, Brazil, during the last 25,000 cal yr BP","authors":"Adriana Mercedes Camejo Aviles, F. Ricardi-Branco, M. Ledru, L. Bernacci","doi":"10.1590/2317-4889201920190040","DOIUrl":"https://doi.org/10.1590/2317-4889201920190040","url":null,"abstract":"A paleoenvironmental reconstruction was performed in a Riparian Forest near Campinas to improve knowledge of paleoclimate and paleoenvironment in the State of São Paulo, Brazil. A sediment core of 182 cm depth was collected in a swamp located within a Cerrado/Seasonal Semi-deciduous ecotone forest. The chronological frame is given by eight radiocarbon dating methods. Pollen and stable isotope analyses (δ 13C and δ 15N) were performed all along the core. Modern pollen rain is based on five surface samples collected along the Riparian Forest. Results show a sequence of changes in vegetation and climate between 25 and 13 cal kyr before present (BP), and from 4 cal kyr BP to the present time, with a hiatus between 11 and 4 kyr cal BP. Drier climatic conditions characterized the late Pleistocene and early Holocene, although they had moisture peaks able to maintain an open forest. The Riparian Forest became fully installed from 4 cal kyr BP onward. Our results are in agreement with other regional studies and contribute to build a regional frame for past climatic conditions at the latitude of São Paulo.","PeriodicalId":9221,"journal":{"name":"Brazilian Journal of Geology","volume":"64 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80856541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Sequence stratigraphy of fluvial to shallow-marine deposits: The case of the early Permian Rio Bonito Formation, Paraná Basin, southernmost Brazil 河流-浅海沉积的层序地层学:以巴西最南部帕拉南<e:1>盆地早二叠世Rio Bonito组为例

IF 1.4 4区地球科学

Brazilian Journal of Geology Pub Date : 2019-01-01 DOI: 10.1590/2317-4889201920190059

Ricardo Maahs, J. Küchle, C. Scherer, R. Alvarenga

{"title":"Sequence stratigraphy of fluvial to shallow-marine deposits: The case of the early Permian Rio Bonito Formation, Paraná Basin, southernmost Brazil","authors":"Ricardo Maahs, J. Küchle, C. Scherer, R. Alvarenga","doi":"10.1590/2317-4889201920190059","DOIUrl":"https://doi.org/10.1590/2317-4889201920190059","url":null,"abstract":"This study presents new sedimentology data and attempts to understand coastal processes, sedimentary dynamics and stratigraphic patterns of the Rio Bonito Formation (early Permian) in Paraná Basin, southern Brazil. The study was performed based on the description of five cores, located in a small-scale area — São Gabriel City — in Rio Grande do Sul State, southern Brazil. Eighteen facies were described and grouped into nine facies associations. Later, these facies associations were then grouped into three depositional systems: fluvial, tide-dominated estuary and wave-dominated shallow-marine depositional systems. A paleoenvironmental evolution is proposed using three block diagrams showing the paleoenvironmental stage (S1, S2, and S3). S1 contains the oldest part of the sedimentary record with predominance of fluvial system deposits, S2 comprises dominantly estuarine system deposits, and S3 is mostly composed of shallow-marine deposits. Stratigraphic framework showed a general retrogradacional tendency, with thickness variations along the systems tracts that allowed for the construction of a curve of accommodation changes to the Rio Bonito Formation in the region of São Gabriel during the early Permian. This study contributes to a better understanding of the fluvial discharges, tidal and oscillatory (wave) currents and their interactions and dominances along stratigraphic records of coastal deposits.","PeriodicalId":9221,"journal":{"name":"Brazilian Journal of Geology","volume":"28 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85553052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 9

The sedimentary record of wet and dry eolian systems in the Cretaceous of Southeast Brazil: stratigraphic and paleogeographic significance 巴西东南部白垩纪干湿风成体系的沉积记录:地层学和古地理意义

IF 1.4 4区地球科学

Brazilian Journal of Geology Pub Date : 2019-01-01 DOI: 10.1590/2317-4889201920190057

P. Mescolotti, F. G. Varejão, L. Warren, F. Ladeira, P. C. Giannini, M. L. Assine

{"title":"The sedimentary record of wet and dry eolian systems in the Cretaceous of Southeast Brazil: stratigraphic and paleogeographic significance","authors":"P. Mescolotti, F. G. Varejão, L. Warren, F. Ladeira, P. C. Giannini, M. L. Assine","doi":"10.1590/2317-4889201920190057","DOIUrl":"https://doi.org/10.1590/2317-4889201920190057","url":null,"abstract":"Sedimentologic and stratigraphic studies of paleo-deserts from the Brazilian Cretaceous are of great potential to understand the paleoclimate and paleogeography of Gondwana during its final rifting stage. Herein, we describe and discuss two depositional units characterized by two distinct eolian systems that are bounded by a long-lived unconformity. The Lower Unit (Barremian/Aptian) encompasses a wet eolian system composed of dune, interdunes, and ephemeral alluvial deposits. A continuous paleosol horizon in the upper part of the Lower Unit records dune stabilization and end of eolian accumulation, in a period of climate amelioration possibly in the late Aptian. The stratigraphic gap proposed for the unconformity (Cenomanian to Coniacian) coincides with the Cretaceous Thermal Maximum. The Upper Unit (Santonian?/ Campanian) comprises dune fields of a dry eolian system capped by the Mata da Corda volcanic rocks. Cross stratification dip directions from both eolian systems shows transport towards SSW. Paleo-winds coming from the northeast quadrant reveal that the continental breakup and drifting had little influence on the surface winds in this Gondwana sector. The Upper Cretaceous paleo-winds are coherent with global paleo-circulation models, based on a high-pressure cell over the South Atlantic proto-ocean, favoring desertification in the inner portion of the southwestern Gondwana.","PeriodicalId":9221,"journal":{"name":"Brazilian Journal of Geology","volume":"45 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85317329","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 18

Geochemistry, Sm-Nd isotopes and SHRIMP U-Pb geochronology of the Morro do Coco Granite (RJ, Brazil): another piece of the post-collisional magmatism of the Ribeira Belt Morro do Coco花岗岩(RJ，巴西)地球化学、Sm-Nd同位素和SHRIMP U-Pb年代学:Ribeira带碰撞后岩浆活动的另一块

IF 1.4 4区地球科学

Brazilian Journal of Geology Pub Date : 2019-01-01 DOI: 10.1590/2317-4889201920190010

Fellippe R. A. Bione, E. Bongiolo, J. Mendes, Camila Leão Roland

{"title":"Geochemistry, Sm-Nd isotopes and SHRIMP U-Pb geochronology of the Morro do Coco Granite (RJ, Brazil): another piece of the post-collisional magmatism of the Ribeira Belt","authors":"Fellippe R. A. Bione, E. Bongiolo, J. Mendes, Camila Leão Roland","doi":"10.1590/2317-4889201920190010","DOIUrl":"https://doi.org/10.1590/2317-4889201920190010","url":null,"abstract":"The Morro do Coco granite (MC) is a post-collisional intrusive body that was emplaced at Ribeira Belt, in the Cambro-Ordovician, succeeding the final stages of the Gondwana supercontinent amalgamation. This unit requires more studies, contrasting with similar best investigated occurrences of the central Ribeira Belt. This work presents a detailed investigation of such unit using petrography, Inductively Coupled Plasma (ICP), X-Ray Fluorescence (XRF) whole-rock geochemistry, U-Pb (SHRIMP) geochronology and Sm-Nd isotopes. The rock is a nearly undeformed syenogranite, geochemically classified as a high-K calc-alkaline magnesian, with metaluminous to slightly peraluminous affinity. Strongly light rare earth elements (LREE)-enriched patterns with significant negative Eu anomalies, typical of post-collisional granites, are identified. Similarly to other post-collisional granites of the central Ribeira Belt, U-Pb zircon data provide crystallization age of 496 ± 3 Ma . Sm-Nd isotopic data suggest crustal magma source as indicated by εNd(496) of -9, 143Nd/144Nd ratios between 0.511747 and 0.511752 and Mesoproterozoic TDM ages of 1.3 Ga. Based on its geochemical characteristics, morphology and geochronology, this unit is considered here as a member of Nova Friburgo Suite. Geochronological data defined three pulses of magmatism in this part of the orogen during the Cambro-Ordovician (515, 490 and 460 Ma).","PeriodicalId":9221,"journal":{"name":"Brazilian Journal of Geology","volume":"14 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87968240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

Reconstruction of Precambrian terranes of Northeastern Brazil along Cambrian strike-slip faults: a new model of geodynamic evolution and gold metallogeny in the State of Bahia 巴西东北部沿寒武系走滑断裂前寒武纪地体重建:巴伊亚州地球动力学演化与金矿成矿新模式

IF 1.4 4区地球科学

Brazilian Journal of Geology Pub Date : 2019-01-01 DOI: 10.1590/2317-4889201920190009

J. Teixeira, A. Misi, Maria da Glória da Silva, R. S. C. Brito

引用次数: 10

The Cristalino IOCG deposit: an example of multi-stage events of hydrothermal alteration and copper mineralization 晶石岩储层矿床:多期热液蚀变与铜成矿的一个例子

IF 1.4 4区地球科学

Brazilian Journal of Geology Pub Date : 2019-01-01 DOI: 10.1590/2317-4889201920180015

Gustavo Souza Craveiro, R. Xavier, R. N. Villas

{"title":"The Cristalino IOCG deposit: an example of multi-stage events of hydrothermal alteration and copper mineralization","authors":"Gustavo Souza Craveiro, R. Xavier, R. N. Villas","doi":"10.1590/2317-4889201920180015","DOIUrl":"https://doi.org/10.1590/2317-4889201920180015","url":null,"abstract":"The Cristalino deposit is located 40 km east of Sossego mine, Carajás. The orebody lies along a NW-SE-striking shear zone and is mainly hosted by the Neoarchean bi-modal volcanics of the Grão Pará Group. Field work and petrographic data seconded by SEM-EDS analysis allowed recognizing an early sodic metasomatism that was followed by calcic-ferric, potassic and propylitic alterations, and finally by carbonatization. The volcanic rocks were altered under deformation regimes that changed from ductile-brittle to brittle. The deposit resulted from two mineralizing stages. The early stage took place at a greater depth and produced an ore association composed chiefly of chalcopyrite, pyrite, and magnetite as disseminations, breccia and veins particularly in Ca-Fe altered rocks. The later stage occurred at a shallower depth and formed a practically magnetite-free ore association, consisting essentially of chalcopyrite ± pyrite ± hematite in breccias and veins generated mostly during the potassic alteration. These ore associations indicate that the hydrothermal system evolved with temperature decrease and increase in fO2, Cu/Fe ratio and sulfur activity. Cristalino is conceived as a multi-stage IOCG deposit similar to others lying in the Carajás E-W corridor of IOCG systems.","PeriodicalId":9221,"journal":{"name":"Brazilian Journal of Geology","volume":"54 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80731838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 11

Writing papers with an emphasis on structural geology and tectonics: advices and warnings 撰写以构造地质学和构造学为重点的论文:建议和警告

IF 1.4 4区地球科学

Brazilian Journal of Geology Pub Date : 2019-01-01 DOI: 10.1590/2317-4889201920190109

H. Fossen

{"title":"Writing papers with an emphasis on structural geology and tectonics: advices and warnings","authors":"H. Fossen","doi":"10.1590/2317-4889201920190109","DOIUrl":"https://doi.org/10.1590/2317-4889201920190109","url":null,"abstract":"The objective of this short paper was to provide some advice on how to write a geoscience paper of international standard and to warn against some common pitfalls. It is focused on how to structure a paper and stresses the importance of building its contents around a well-defined problem. Furthermore, the importance of moving away from outdated and counterproductive ways of describing and interpreting deformation is emphasized. In particular, describing structures and tectonic evolution in a poorly founded scheme of multiple deformation phases and making stress interpretations from structurally complex and heterogeneous rocks where rotations and stress perturbations are difficult or impossible to account for are strongly discouraged. Instead, I encourage the use of modern structural geology and tectonics ideas that, among other things, allow for composite and overprinting structures to form progressively and diachronously with a wide variation in style and orientation during a single deformation history. Also, more emphasis should be put on strain and kinematics, toning down the use of stress. After all, stress is only observed through strain and kinematics; going from one to the other is not straightforward in general, and particularly difficult in ductilely deformed rocks.","PeriodicalId":9221,"journal":{"name":"Brazilian Journal of Geology","volume":"50 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77576855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 9

Integrating geological and airborne geophysical data to review the cartography of Rio Itanguá Batholith, Araçuaí Orogen, Brazil 整合地质与航空地球物理资料，检视巴西Araçuaí造山带Rio itanguth基岩的制图

IF 1.4 4区地球科学

Brazilian Journal of Geology Pub Date : 2019-01-01 DOI: 10.1590/2317-4889201920190019

J. Grochowski, Matheus Kuchenbecker, Danilo Barbuena, T. Novo

引用次数: 7