Genesis and evolution of the peatlands in geomorphic surfaces of Serra do Espinhaço Meridional – MG

`The Serra do Espinhaco -SdEM has predominantly quartzite lithologies and is characterized by diff er altitudes and dissected areas intermingled the planning surfaces, where, in the depressions occur peatlands. These planation surfaces are the result of a succession of denudation and depositional events compartmentalized relief along the geodynamic evolution of the ridge. The aim of this study was to map the peatlands of the northern part of the ridge and discuss the genesis and evolution of pedoenvironments the geomorphic surfaces of the SdEM. The determination of the area and mapping of peatland was conducted through field work, images and aerial photographs analysis. Sampling was carried out in eight peatlands in the northern portion of SdEM. Samples for dating and characterization of the photosynthetic cycle were collected with the help of vibracoring at diff erent depths, depending on local attributes, for determining the carbon isotope (delta 13C and 14C). The northern portion of SdEM occupies an area of 1,180,109.00 ha, which were mapped 14,287.55 ha of peatlands, which represents 1.2% of the total area. In peatlands dominated the stages of advanced decomposition (sapric), followed by intermediate (hemic). Four levels of geomorphical surfaces were identifi ed throughout the length of SdEM: Surface I (S1), Surface II (S2), Surface III (S3) and Surface IV (S4). Considering the altimetry as the main factor, the S1 was cronocorrelated with Post-Gondwana Surface and S2 cronocorrelated with the South American Surface. The Surface III (S3) had correspondence with the South American Surface I and Surface IV (S4), in turn, with the South American Surface II. Most peatlands developed in Quaternary between the Pleistocene and Holocene, formed on Post-Gondwana Surface (S1) and in the South American Surface (S2) in altimetric levels ranging between 1,100-1,400 meters. The predominance of plants with photosynthetic cycles CAM and C3 showed colonization of SdEM by species such as bromeliads, cacti and some euphorbiaceae typical of rupestrian fi elds and trees and shrubs along the PleistoceneHolocene transition, refl ections of local and regional environmental changes occurred in the Quaternary, possibly associated with paleoclimates.A Serra do Espinhaço Meridional – SdEM possui litologias predominantemente quartzíticas e é caracterizada por apresentar áreas dissecadas entremeadas a superfícies de aplainamento em diferentes altitudes, onde, nas depressões, ocorrem as turfeiras. Essas1816579FAPEMIG - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE MINAS GERAISsem informação`The Serra do Espinhaco -SdEM has predominantly quartzite lithologies and is characterized by diff er altitudes and dissected areas intermingled the planning surfaces, where, in the depressions occur peatlands. These planation surfaces are the result of aOs autores agradecem à FAPEMIG, à UFVJM, à ESALQ-USP e ao IFSULDEMINAS pelo apoio, fundamental na consolidação dessa pesquis

Equipamento inderbitzen modificado para simulação da erosão hídrica em amostras de solo indeformado

Several devices have been developed to assess soil losses by water erosion. However, they rarely assess the combined effects of raindrop impact and surface runoff together with vegetation cover on varying slopes. This study aimed to design and validate an equipment, on laboratory scale, to evaluate the effect of water erosion on undisturbed soil samples with and without plant cover, as well as to assess the kinetic energy of simulated rain and the resultant shear stress at varying runoff intensities. The equipment is composed of a rainfall simulator, an adjustable stand for different slopes and falling heights, and a runoff ramp for testing undisturbed soil samples measuring 15 x 20 x 40 cm (height, width, and length). In this study, the equipment simulated and evaluated the effect of precipitation and runoff on soil losses, allowing to obtain different values of the kinetic energy of precipitation and runoff. For a f low rate of 12 L min-1 and slope of 35%, the shear stress could reach up to 8 Pa. Furthermore, the equipment showed the effect of vegetation cover and slope on soil losses in different granulometric fractions (< 0.106 mm, 0.106 to 0.25 mm, 0.25 to 0.5 mm, 0.5 to 1.0 mm, 1.0 to 2.0 mm, and > 2.0 mm), revealing the potential of its use in several erosion studies on a laboratory scale.Diversos equipamentos foram desenvolvidos para a avaliação das perdas de solo por erosão hídrica. No entanto, raramente eles avaliam o efeito do impacto das gotas de chuva e do escoamento superficial em conjunto com a cobertura vegetal em diferentes declividades. Este estudo objetivou projetar e validar um equipamento, em escala de laboratório, para avaliar o efeito da erosão hídrica em amostras indeformadas de solo, bem como avaliar a velocidade de queda e tamanho das gotas de chuva simulada na superfície do solo e a intensidade do escoamento superficial em amostras com e sem cobertura vegetal. O equipamento é composto de um simulador de chuva, um suporte ajustável para diferentes declividades e alturas de queda e uma rampa de escoamento para testar amostras de solo indeformadas, com 15 x 20 x 40 cm (altura, largura e comprimento). Neste estudo, o equipamento simulou e avaliou o efeito da precipitação e do escoamento superficial nas perdas de solo, possibilitando a obtenção de diferentes valores de energia cinética de precipitação e escoamento. Para uma vazão de 12 L min-1 e inclinação de 35%, a tensão de cisalhamento pode chegar a 8 Pa. Além disso, o equipamento evidenciou o efeito da cobertura vegetal e da declividade nas perdas de solo em diferentes frações granulométricas (< 0,106 mm, 0,106 a 0,25 mm, 0,25 a 0,5 mm, 0,5 a 1,0 mm, 1,0 a 2,0 mm, e > 2,0 mm), demonstrando o potencial do seu uso em diversos estudos de erosão em escala de laboratório

Solos em topossequência de veredas das chapadas do Alto Vale do Jequitinhonha, MG: I - caracterização e classificação

In the upper Jequitinhonha valley, state of Minas Gerais, Brazi, there are large plane areas known as chapadas, which are separated by areas dissected by tributaries of the Jequitinhonha and Araçuaí rivers. These dissected areas have a surface drainage system with tree, shrub, and grass vegetation, more commonly known as veredas, i.e., palm swamps. The main purpose of this study was to characterize soil physical, chemical and morphological properties of a representative toposequence in the watershed of the Vereda Lagoa do Leandro, a swamp near Minas Novas, MG, on chapadas, the highlands of the Alto Jequitinhonha region Different soil types are observed in the landscape: at the top - Typic Haplustox (LVA), in the middle slope - Xanthic Haplustox (LA), at the footslope - Xanthic Haplustox, gray color, here called Gray Haplustox (LAC) and, at the bottom of the palm swamp - Typic Albaquult (GXbd). These soils were first morphologically described; samples of disturbed and undisturbed soils were collected from all horizons and subhorizons, to evaluate their essential physical and chemical properties, by means of standard determination of Fe, Al, Mn, Ti and Si oxides after sulfuric extraction. The contents of Fe, Al and Mn, extracted with dithionite-citrate-bicarbonate and oxalate treatments, were also determined. In the well-drained soils of the slope positions, the typical morphological, physical and chemical properties of Oxisols were found. The GXbd sample, from the bottom of the palm swamp, is grayish and has high texture gradient (B/A) and massive structure. The reduction of the proportion of crystalline iron compounds and the low crystallinity along the slope confirmed the loss of iron during pedogenesis, which is reflected in the current soil color. The Si and Al contents were lowest in the LAC soil. There was a decrease of the Fe2O3/TiO2 ratio downhill, indicating progressive drainage restriction along the toposequence. The genesis and all physical and chemical properties of the soils at the footslope and the bottom of the palm swamp of the chapadas of the Alto Jequitinhonha region are strongly influenced by the occurrence of ground water on the surface or near the surface all year long, at present and/or in the past. Total concentrations of iron oxides, Fe d and Fe o in soils of the toposequence studied are related to the past and/or present soil colors and drainage conditions.No Alto Vale do Jequitinhonha - MG ocorrem extensas áreas de relevo aplainado denominadas de chapadas, que estão separadas por áreas dissecadas pelos rios Jequitinhonha e Araçuaí e seus afluentes. Nessas áreas dissecadas é encontrado um sistema de drenagem superficial com vegetação arbóreo-arbustiva e gramíneas, comumente denominado de vereda. O objetivo deste estudo foi caracterizar física, química e morfologicamente os solos de uma topossequência da microbacia da Vereda Lagoa do Leandro, representativa das veredas das chapadas do Alto Jequitinhonha, localizada no município de Minas Novas - MG. Os solos estudados ocupam as seguintes posições na vertente: topo - Latossolo Vermelho Amarelo (LVA); terço médio da vertente - Latossolo Amarelo (LA); sopé - Latossolo Amarelo, de cor cinzenta, aqui denominado Latossolo Acinzentado (LAC); e base da vereda - Gleissolo Háplico (GXbd). Esses solos foram descritos morfologicamente e foram coletadas amostras deformadas e indeformadas em todos os horizontes e sub-horizontes para realização das análises físicas e químicas de rotina, determinação de óxidos de Fe, Al, Mn, Ti e Si após extração por ataque sulfúrico e determinação dos teores de Fe, Al e Mn extraídos por ditionito-citrato-bicarbonato e oxalato. Os solos das posições bem drenadas da vertente apresentaram atributos morfológicos, físicos e químicos típicos da ordem dos Latossolos. Na base da vereda encontra-se o GXbd, que apresenta cores acinzentadas, elevado gradiente textural B/A e estrutura maciça. A diminuição do teor de Fe cristalino e de baixa cristalinidade ao longo da vertente confirmou a perda de Fe durante o processo de pedogênese e refletiu na cor dos solos. Os teores de Si e Al foram mais baixos no LAC. Verificou-se diminuição da relação Fe2O3/TiO2 vertente abaixo, indicando impedimentos à drenagem ao longo da topossequência. A gênese e os atributos dos solos do sopé e da base das veredas das chapadas do Alto Vale do Jequitinhonha - MG são fortemente influenciados pela presença do nível freático na superfície ou próximo à superfície o ano todo, no presente e, ou, no passado. Os teores totais de óxidos de Fe, Fe o e Fe d dos solos da topossequência estudada estão relacionados com as cores dos solos e com condições de drenagem presentes e,ou, pretéritas

Chapadas do Alto Vale do Jequitinhonha, MG: II - mineralogia, micromorfologia e evolução da paisagem

Palm swanp formations, the so-called veredas, typically occur in the Brazilian biome known as Cerrado (savanna-like vegetation), especially on flattened areas or tablelands (chapadas). The aim of this study was to characterize the mineralogy and micromorphology of soil materials from a representative toposequence of the watershed of the vereda Lagoa do Leandro, located in Minas Novas, state of Minas Gerais, Brazil, on plains in the region of the upper Jequitinhonha valley, emphasizing essential aspects of their genesis and landscape evolution. The toposequence is underlain by rocks of the Macaúbas group and covered with detrital and metamorphic rocks (schists of Proterozoic diamictites). The soil profiles were first pedologically described; samples of the disturbed and undisturbed soils were collected from all horizons for further micromorphological and mineralogical analyses. The mineralogical analysis was mainly based on powder X ray diffractometry (XRD) and micromorphological descriptions of thin sections under a petrographic microscope. The soils from the bottom to the top of this toposequence were classified as: Typic Albaquult (GXbd), Xanthic Haplustox, gray color, here called Gray Haplustox (LAC), Xanthic Haplustox (LA) and Typic Haplustox (LVA). The clay mineralogy of all soils was found to be dominated by kaolinite. In soil of LA and LVA, the occurrence of goethite, gibbsite, and anatase was evidenced; LAC also contained anatase and the GXbd, illite, anatase, and traces of vermiculite. The micromorphological analyses of the LVA, LA and LAC soils showed the prevalence of a microaggregate-like or granular microstructure, and aggregate porosity has a stacked/packed structure, which is typical of Oxisols. A massive structure was observed in GXbd material, with the presence of illuviation cutans of clay minerals and iron compounds. Paleogleissolos, which are strongly weathered, due to the action of the excavating fauna , and resulted in the present LAC. The GXbd at the base of the vereda preserved the physical, mineralogical and micromorphological properties that are typical of a pedogenesis with a strong influence of long dry periods.As veredas são formações típicas que ocorrem no Cerrado brasileiro, principalmente nas áreas aplainadas denominadas chapadas. O objetivo deste trabalho foi caracterizar mineralógica e micromorfologicamente os solos de uma topossequência representativa da microbacia da Vereda Lagoa do Leandro, localizada no município de Minas Novas - MG, situada nas chapadas do Alto Vale do Jequitinhonha, enfatizando aspectos de suas gêneses e da evolução da paisagem. A topossequência está embasada em rochas do Grupo Macaúbas, com cobertura detrítica e rochas metamórficas (xistos diamictitos do Proterozoico). Os solos foram descritos em trincheiras, e amostras deformadas e indeformadas foram coletadas em todos os horizontes, para análises mineralógicas e micromorfológicas. As análises mineralógicas da fração argila foram determinadas pela técnica de difração de raios X (DRX), e as micromorfológicas, por descrições de lâminas delgadas em microscópio petrográfico. Os solos caracterizados da base da vereda para o topo foram Gleissolo Háplico (GXbd), Latossolo Amarelo, de cor cinzenta, aqui denominado Latossolo Acinzentado (LAC), Latossolo Amarelo (LA) e Latossolo Vermelho-Amarelo (LVA). A mineralogia da fração argila em todos os solos é dominada pela caulinita. Nos LVA e LA foram identificadas goethita, gibbsita e anatásio; no LAC, anatásio; e no GXbd, ilita, anatásio e traços de vermiculita. A micromorfologia do LVA, LA e LAC é dominada pela microestrutura do tipo granular ou microagregados e porosidade do tipo empilhamento/empacotamento, típicos de Latossolos. No GXbd predomina a estrutura maciça, com a presença de cutãs de iluviação e ferri-argilãs. Paleogleissolos foram latolizados pela ação da fauna escavadora e deram origem aos atuais LAC. Os GXbd da base da vereda preservaram atributos físicos, mineralógicos e micromorfológicos que tiveram suas gêneses em períodos secos

Flexural strength of high-performance soil-cement: a new, alternative, sustainable construction material

Soil-cement is a building material that is considered low-cost and has a low environmental impact. Despite its benefits, performance optimisation studies are scarce compared to other materials such as concrete. The possibility of obtaining soil-cement with improved characteristics, such as flexural strength, would enable the increased use of this product in new applications in construction. The aim of this study is to produce high-performance soil-cement (HPSC) specimens and to evaluate and compare this new material with high-performance concrete (HPC) in terms of flexural strength. A total of 12 specimens were produced with a mixture of 23.5% (by mass) of cement with the application of 10 MPa of pressure for its compaction. The results show that, at 28 days, the specimens reached an average strength of 6.73 MPa and, at 240 days, 12.34 MPa. This means that the HPSC reached a flexural strength resistance equivalent to HPC without the need for mined materials, such as sand and gravel, or the additives adopted in some doses of HPC, such as superplasticisers. Therefore, when using local soil, HPSC can be considered an environmentally preferable alternative to HPC for many construction applications where flexural strength is a requirement.Peer ReviewedPostprint (published version

Late Quaternary vegetation and climate dynamics in central-eastern Brazil : insights from a ~35k cal a BP peat record in the Cerrado biome

Acknowledgements This work was supported by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)/Brazil (grant to I.H.T. – regular doctoral scholarship FAPESP 2010/51637‐0 and research internships abroad BEPE/FAPESP 2012/00676‐1), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)/Brazil (Universal 14/2011−482815/2001‐6), Ministério de Economia y Competitividad (CGL2010‐20662) and Xunta de Galícia (10PXIB200182PR, ED431D2917/08 and ED431B2018/20). We are grateful to Noemí Silva Sánchez and Luis Rodriguez Lado (Univesidad de Santiago de Compostela), and Fabrício da Silva Terra (Universidade Federal dos Vales do Jequitinhonha e Mucuri) for their collaboration and assistance during different stages of the research.Peer reviewedPostprin

Contributions of mean and shape of blood pressure distribution to worldwide trends and variations in raised blood pressure: A pooled analysis of 1018 population-based measurement studies with 88.6 million participants

© The Author(s) 2018. Background: Change in the prevalence of raised blood pressure could be due to both shifts in the entire distribution of blood pressure (representing the combined effects of public health interventions and secular trends) and changes in its high-blood-pressure tail (representing successful clinical interventions to control blood pressure in the hypertensive population). Our aim was to quantify the contributions of these two phenomena to the worldwide trends in the prevalence of raised blood pressure. Methods: We pooled 1018 population-based studies with blood pressure measurements on 88.6 million participants from 1985 to 2016. We first calculated mean systolic blood pressure (SBP), mean diastolic blood pressure (DBP) and prevalence of raised blood pressure by sex and 10-year age group from 20-29 years to 70-79 years in each study, taking into account complex survey design and survey sample weights, where relevant. We used a linear mixed effect model to quantify the association between (probittransformed) prevalence of raised blood pressure and age-group- and sex-specific mean blood pressure. We calculated the contributions of change in mean SBP and DBP, and of change in the prevalence-mean association, to the change in prevalence of raised blood pressure. Results: In 2005-16, at the same level of population mean SBP and DBP, men and women in South Asia and in Central Asia, the Middle East and North Africa would have the highest prevalence of raised blood pressure, and men and women in the highincome Asia Pacific and high-income Western regions would have the lowest. In most region-sex-age groups where the prevalence of raised blood pressure declined, one half or more of the decline was due to the decline in mean blood pressure. Where prevalence of raised blood pressure has increased, the change was entirely driven by increasing mean blood pressure, offset partly by the change in the prevalence-mean association. Conclusions: Change in mean blood pressure is the main driver of the worldwide change in the prevalence of raised blood pressure, but change in the high-blood-pressure tail of the distribution has also contributed to the change in prevalence, especially in older age groups