Arquitetura de fáceis e evolução estratigráfica de um sistema costeiro mistocarebonático-silicilástico dominado por ondas - Fm Caboclo, Chapada Diamantina - BA

Localizada no município de Morro do Chapéu no estado da Bahia, a gruta dos Cristais é entendida como a base da Formação Caboclo do Grupo Chapada Diamantina, Supergrupo Espinhaço. É constituída por sedimentos híbridos de composição carbonático-siliciclásticos depositados em um ambiente costeiro dominado por ondas de tempestade de idade Mesoproterozoica. Este trabalho tem como objetivo caracterizar em escala de alta resolução os processos sedimentares e propor um modelo deposicional e evolução estratigráfica para os depósitos costeiros dominados por onda da gruta dos Cristais. Para isso, foi realizado a análise de fácies, associações de fácies e técnicas complementares como petrografia e gamaespectrometria. A análise de fácies realizou-se com a descrição e interpretação de um perfil colunar do afloramento, de 46 m de espessura, em escala 1:20. Foram identificadas dez litofácies, que compõem três associações de fácies dispostas em um sistema de rampa mista carbonática-siliciclástica dominada por ondas de tempestade. As porções distais da rampa são dominadas por estromatólitos horizontais e subordinadamente sedimentos proximais são remobilizados por tempestade. A porção intermediária do sistema compõe bioermas e heterolitos, onde ocorrem com mais frequência arenitos e conglomerados depositados por eventos de tempestade. A porção proximal, caracterizada como rampa interna é dominada por arenitos híbridos e por conglomerados intraformacionais com estruturas de fluxo oscilatório ou combinado. A composição mista dos sedimentos ocorre por indução biogênica nas porções mais distais do sistema, em profundidade superior ao nível de base de ondas de tempo bom, e pela mistura de sedimentos aloquímicos e terrígenos nas porções proximais do sistema, causado por eventos de tempestade. Ciclos R de alta frequência, de caráter dominantemente progradacionais são identificados ao longo do perfil indicando uma tendência regressiva da linha de costa. Na sucessão estratigráfica geral do afloramento estudado é identificado um grande ciclo T-R.Located in Morro do Chapéu County, Bahia State, the Gruta dos Cristais cave is understood as the base of Caboclo Formation in Espinhaço Supergroup at Chapada Diamantina. It is constituted of carbonatic-siliciclastic hybrid sediments deposited in a Mesoproterozoic wave-dominated coastal environment. This work aims to characterize in a high-resolution approach the sedimentary process, propose the depositional model and the stratigraphic evolution of the coastal wave-dominated system of the Gruta dos Cristais cave. For this it was accomplished facies analysis, facies association and complementary techniques as petrography and gamma spectrometry. The facies analysis was made with the description and interpretation of a columnar profile in the Cristais outcrop, of 46 m thick, in a 1:20 scale. Ten lithofacies were identified, wich constitute three facies association in a mixed carbonatic-siliciclastic storm-dominated ramp system. Distal portions are dominated by horizontal stromatolites and subordinate by proximal sediments remobilized by storm events. The intermediate portion of the system is compound by bioherms and heterolites, where occurs sandstones and conglomerate more frequently by storm surges. The proximal part, characterized as intern ramp, is dominated by hybrid sandstones and intraformational conglomerates with oscillatory or combined flow structures. The mixed composition of the sediments occurs by microbial bioinduction in the distal portions of the system, below fair weather wave base, and by terrigenous and allochems sediments mixture in the proximal portions of the system. The physical process of mixture is induced by storm process. Predominantly progradational high frequency R-cycles identified in the profile indicating a short term regressive trend of the shoreline. While on an outcrop scale, it is identified a longest T-R cycle

Mixed carbonate-siliciclastic sedimentation in a mesoproterozoic storm-dominated ramp : depositional processes and stromatolite development

Records of shallow-marine ramps with the mixing of carbonate and siliciclastic sediments are common throughout the geological time. All these records have pure carbonate and pure siliciclastic deposits as end members, occurring contemporaneously in distinct depositional regions along the ramp, and transitional hybrid facies between them. The two end member can mix in different scales and can alternate in time due to climatic changes and regressions and transgressions. This work presents a detailed reconstruction of a Mesoproterozoic storm-dominated mixed carbonate-siliciclastic ramp composed of hybrid sediments and whithout the presence of pure siliciclastic or carbonate deposits, a rare example in the geological record. Based on a high resolution logged section (in 1:20 scale) and qualitative thin sections, eleven lithofacies were identified and grouped into three lithofacies associations (offshore, offshore transition and shoreface), which are stacked vertically forming a transgressive–regressive cycle. This faciological distribution indicates a low relief ramp with wide microbial colonization from shallow to relatively deep waters (below storm-wave base level). In offshore low-energy distal areas, microbial mats spread laterally over large distances with little or no interference from currents, while in the offshore transition the morphology of the bioherms is shaped by currents induced by waves. In turn, the high wave energy in the shoreface inhibits the formation of stromatolites, restricting their occurrence to thin layers of microbial carpets or intraclastic lags. The mixing occurs in compositional scale and is relatively homogeneous along the whole logged interval, independent of the shifts in lithofacies or lithofacies associations. This compositional homogeneity is linked to the wide distribution and regularity in the input of siliciclastic sediments during the sedimentary accumulation. Strong currents induced by storms allow the transport and mixing of siliciclastic sediments with carbonate grains generated in the basin during fair-weather periods

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Arquitetura de fáceis e evolução estratigráfica de um sistema costeiro mistocarebonático-silicilástico dominado por ondas - Fm Caboclo, Chapada Diamantina - BA

Localizada no município de Morro do Chapéu no estado da Bahia, a gruta dos Cristais é entendida como a base da Formação Caboclo do Grupo Chapada Diamantina, Supergrupo Espinhaço. É constituída por sedimentos híbridos de composição carbonático-siliciclásticos depositados em um ambiente costeiro dominado por ondas de tempestade de idade Mesoproterozoica. Este trabalho tem como objetivo caracterizar em escala de alta resolução os processos sedimentares e propor um modelo deposicional e evolução estratigráfica para os depósitos costeiros dominados por onda da gruta dos Cristais. Para isso, foi realizado a análise de fácies, associações de fácies e técnicas complementares como petrografia e gamaespectrometria. A análise de fácies realizou-se com a descrição e interpretação de um perfil colunar do afloramento, de 46 m de espessura, em escala 1:20. Foram identificadas dez litofácies, que compõem três associações de fácies dispostas em um sistema de rampa mista carbonática-siliciclástica dominada por ondas de tempestade. As porções distais da rampa são dominadas por estromatólitos horizontais e subordinadamente sedimentos proximais são remobilizados por tempestade. A porção intermediária do sistema compõe bioermas e heterolitos, onde ocorrem com mais frequência arenitos e conglomerados depositados por eventos de tempestade. A porção proximal, caracterizada como rampa interna é dominada por arenitos híbridos e por conglomerados intraformacionais com estruturas de fluxo oscilatório ou combinado. A composição mista dos sedimentos ocorre por indução biogênica nas porções mais distais do sistema, em profundidade superior ao nível de base de ondas de tempo bom, e pela mistura de sedimentos aloquímicos e terrígenos nas porções proximais do sistema, causado por eventos de tempestade. Ciclos R de alta frequência, de caráter dominantemente progradacionais são identificados ao longo do perfil indicando uma tendência regressiva da linha de costa. Na sucessão estratigráfica geral do afloramento estudado é identificado um grande ciclo T-R.Located in Morro do Chapéu County, Bahia State, the Gruta dos Cristais cave is understood as the base of Caboclo Formation in Espinhaço Supergroup at Chapada Diamantina. It is constituted of carbonatic-siliciclastic hybrid sediments deposited in a Mesoproterozoic wave-dominated coastal environment. This work aims to characterize in a high-resolution approach the sedimentary process, propose the depositional model and the stratigraphic evolution of the coastal wave-dominated system of the Gruta dos Cristais cave. For this it was accomplished facies analysis, facies association and complementary techniques as petrography and gamma spectrometry. The facies analysis was made with the description and interpretation of a columnar profile in the Cristais outcrop, of 46 m thick, in a 1:20 scale. Ten lithofacies were identified, wich constitute three facies association in a mixed carbonatic-siliciclastic storm-dominated ramp system. Distal portions are dominated by horizontal stromatolites and subordinate by proximal sediments remobilized by storm events. The intermediate portion of the system is compound by bioherms and heterolites, where occurs sandstones and conglomerate more frequently by storm surges. The proximal part, characterized as intern ramp, is dominated by hybrid sandstones and intraformational conglomerates with oscillatory or combined flow structures. The mixed composition of the sediments occurs by microbial bioinduction in the distal portions of the system, below fair weather wave base, and by terrigenous and allochems sediments mixture in the proximal portions of the system. The physical process of mixture is induced by storm process. Predominantly progradational high frequency R-cycles identified in the profile indicating a short term regressive trend of the shoreline. While on an outcrop scale, it is identified a longest T-R cycle