Brazilian Journal of Geology最新文献_第9页

Age and petrogenesis of the beryl-bearing granitic magmatism of the Velasco Pegmatite District, Pampeana Province, NW Argentina 阿根廷西北部潘皮亚纳省Velasco伟晶岩区含绿柱石花岗质岩浆活动的年龄和岩石成因

IF 1.4 4区地球科学

Brazilian Journal of Geology Pub Date : 2021-01-01 DOI: 10.1590/2317-4889202120210030

F. Sardi, Silvana Marangone, J. M. Fuenlabrada

引用次数: 0

Provenance study of Phanerozoic rocks from the Cordillera Real of Bolivia 玻利维亚科迪勒拉雷亚尔显生宙岩石物源研究

IF 1.4 4区地球科学

Brazilian Journal of Geology Pub Date : 2021-01-01 DOI: 10.1590/2317-4889202120210036

A. R. Iriarte, U. Cordani, M. Basei

引用次数: 1

High-precision laser ablation inductively coupled plasma mass spectrometry determination of trace elements in geological glasses by internal standardization 高精度激光烧蚀电感耦合等离子体质谱法测定地质玻璃中的微量元素

IF 1.4 4区地球科学

Brazilian Journal of Geology Pub Date : 2021-01-01 DOI: 10.1590/2317-4889202120210018

A. Wegner, F. Leitzke, C. Porcher, R. Conceição, M.E.B. Gomes, D. G. Cedeño, M. R. O. Souza

引用次数: 0

Practical mineralogical quantification of bentonites supported for a PXRD calibrated hkl model PXRD校准hkl模型支持膨润土的实际矿物学定量

IF 1.4 4区地球科学

Brazilian Journal of Geology Pub Date : 2021-01-01 DOI: 10.1590/2317-4889202120200088

David Enrique Vega Porras, R. Angélica, S. Paz

{"title":"Practical mineralogical quantification of bentonites supported for a PXRD calibrated hkl model","authors":"David Enrique Vega Porras, R. Angélica, S. Paz","doi":"10.1590/2317-4889202120200088","DOIUrl":"https://doi.org/10.1590/2317-4889202120200088","url":null,"abstract":"In the bentonite industry — exploration and beneficiation — ore quality control has been traditionally carried out using the swelling parameter, denominating those that swell as naturally sodium bentonites and those that do not as naturally non-sodium bentonites. However, the properties of the bentonites can vary due to the quantity and cationic type of montmorillonite. The variation in those properties cannot always be predicted, because there is still no consolidated and convenient method for clays mineralogical quantification. A quantification via PXRD using the Rietveld method is only reliable when all the crystalline structures of the mineral phases are known. This is not the case for bentonites, since the montmorillonite shows turbostratic disorder that leads to extremely wide and asymmetric non-basal reflections that are not considered in the available structural models. Thus, in this work, is generate a calibrated hkl model for a Brazilian montmorillonite applying the combined Rietveld-Le Bail-Internal Standard method developed by Paz et al . (2018). The study concluded that the combined method is a good choice for the mineralogical quantification of the bentonites, handling turbostratic disorder of montmorillonite, since the develop hkl phase model showed good results in mixtures with >50% montmorillonite content (greater precision and reproducibility).","PeriodicalId":9221,"journal":{"name":"Brazilian Journal of Geology","volume":"19 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72872816","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: 3

Influence of preexisting structures on the variation of neotectonic paleostress orientation in an area of the Southeastern Brazilian Margin 巴西东南边缘地区先存构造对新构造古应力方向变化的影响

IF 1.4 4区地球科学

Brazilian Journal of Geology Pub Date : 2021-01-01 DOI: 10.1590/2317-4889202120190132

T. C. Brêda, C. L. Mello, A. Moraes

{"title":"Influence of preexisting structures on the variation of neotectonic paleostress orientation in an area of the Southeastern Brazilian Margin","authors":"T. C. Brêda, C. L. Mello, A. Moraes","doi":"10.1590/2317-4889202120190132","DOIUrl":"https://doi.org/10.1590/2317-4889202120190132","url":null,"abstract":"The Southeastern Brazilian Margin presents a NE-SW-striking structural framework, which is characteristic of the Neoproterozoic Ribeira Belt. Other important structural trends along the area are associated with E-W and NW-SE-striking structures, being most related to the Mesozoic-Cenozoic tectonic evolution. A succession of Cenozoic tectonic events has been described by many authors in the Southeastern Brazilian. Among those Cenozoic tectonic events, a Neogene to Quaternary E-W dextral strike-slip regime (EW-DT) shows a wide distribution, presenting some variations in the stress field orientation. This research investigates the influence of the preexisting structural framework on the variation of the paleostress field orientation associated with the EW-DT tectonic event in a selected area in the onshore continental margin of the Southeastern Brazil. The study was carried out in three main stages: lineament analysis, paleostress field analysis, and numerical mechanical modeling. The paleostress field related to the EW-DT tectonic event in the studied area presents: NNW-SSE-striking maximum horizontal stress, and counterclockwise rotation influenced by the structural framework. Regarding this, the regional variation of the paleostress field is influenced by a preferential reactivation of NE-SW-striking structures while sets of approximately E-W-striking structures are the main local control of counterclockwise rotation of the stress field.","PeriodicalId":9221,"journal":{"name":"Brazilian Journal of Geology","volume":"9 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73091852","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

Mineralogy, geochemistry and parent rock of Décio bauxite-bearing lateritic profile (Rondon do Pará, Eastern Amazon) 东亚马逊Rondon do par<e:1>含铝土矿红土剖面的矿物学、地球化学和母岩特征

IF 1.4 4区地球科学

Brazilian Journal of Geology Pub Date : 2021-01-01 DOI: 10.1590/2317-4889202120210037

Pabllo Henrique Costa dos Santos, M. Costa

引用次数: 3

Continental freshwater carbonate coated grains: oncoids in Quaternary deposits of the Serra da Bodoquena region, Central-West Brazil 大陆淡水碳酸盐包覆颗粒:巴西中西部Serra da Bodoquena地区第四纪沉积物中的蛇尾类

IF 1.4 4区地球科学

Brazilian Journal of Geology Pub Date : 2021-01-01 DOI: 10.1590/2317-4889202220210042

Adelita Carolina Rodrigues, Larissa da Rocha Santos, L. Cury, A. B. Rumbelsperger

引用次数: 0

Support method for interpretation of regional groundwater monitoring in urban areas 城市区域地下水监测解译的支持方法

IF 1.4 4区地球科学

Brazilian Journal of Geology Pub Date : 2021-01-01 DOI: 10.1590/2317-4889202120200053

Fabio Pileggi, R. Hirata, Nataly Aranda, Bruno Conicelli

引用次数: 2

New high-precision 40Ar/39Ar ages for the Serra do Mar alkaline magmatism in the São Sebastião Island, SE Brazil, and implications 巴西东南部<s:1> o sebasti<e:1>岛Serra do Mar碱性岩浆活动高精度40Ar/39Ar年龄及其意义

IF 1.4 4区地球科学

Brazilian Journal of Geology Pub Date : 2021-01-01 DOI: 10.1590/2317-4889202120210046

Maria Isabel Giraldo-Arroyave, S. Vlach, P. Vasconcelos

引用次数: 2

How Ground Penetrating Radar helps to understand the Nhecolândia lakes landscape in the Brazilian Pantanal wetland 探地雷达如何帮助了解巴西潘塔纳尔湿地的nhecolnindia湖泊景观

IF 1.4 4区地球科学

Brazilian Journal of Geology Pub Date : 2021-01-01 DOI: 10.1590/2317-4889202120200021

Fabio Taioli, M. G. Santos, M. L. Assine, D. Mendes

{"title":"How Ground Penetrating Radar helps to understand the Nhecolândia lakes landscape in the Brazilian Pantanal wetland","authors":"Fabio Taioli, M. G. Santos, M. L. Assine, D. Mendes","doi":"10.1590/2317-4889202120200021","DOIUrl":"https://doi.org/10.1590/2317-4889202120200021","url":null,"abstract":"The Pantanal wetland is an active sedimentary basin representing a relevant depositional setting for alluvial sedimentation studies. However, sedimentation homogeneity and the lack of outcrops makes sedimentary analysis more difficult. The Lower Nhecolândia is located at the Southern edge of the Taquari river megafan, whose genetic origin has been disputed as fluvial or eolian deposition. GPR analysis was used to characterize the subsurface stratigraphy and understand the region’s geomorphic evolution. The 100 MHz GPR provided continuous good quality sections up to a depth of 8 m. Two continuous reflections are disconformities that bound three depositional sequences characterized by distinct radar facies. The lower facies presents an upper erosional truncation followed by reflections presenting ~1.5 m deep channelized forms and concave-up low amplitude reflections. The intermediate facies (~4 m thick) presents a base with erosional truncation followed by concave-upward forms, ~10 m wide, 1–3 m deep, separated by 1–2 m, and offlapping geometry. The upper facies has a flat base and thickness of 2–4 m, with parallel reflections; it shows a strong correlation between the radar facies and the forms preserved in the landscape, suggesting that channelized fluvial streams did not form them. The results obtained indicate that GPR use in the Pantanal is an important method to elucidate its geologic evolution.","PeriodicalId":9221,"journal":{"name":"Brazilian Journal of Geology","volume":"1 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77025673","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