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Resetting of Shallow-Water Carbonate Boron Isotope Values During Marine Burial Diagenesis 海洋埋藏成因过程中浅水碳酸盐硼同位素值的重置
IF 2.9 3区 地球科学 Q3 GEOSCIENCES, MULTIDISCIPLINARY Pub Date : 2024-01-09 DOI: 10.2475/001c.91398
Mingyu Zhao, B. Beaty, L. Tarhan, Noah Planavsky
The boron isotopic composition (δ11B) of bulk carbonates may provide an archive to reconstruct changes in ocean pH. Reconstructions from ancient carbonates typically assume that no significant resetting of δ11B occurred during marine burial diagenesis. However, our understanding of B isotopic behavior associated with this process remains limited. Here we provide measurements of B/Ca and B isotopic composition (δ11B) from a modern peri-platform carbonate sequence near the Great Bahama Bank that has undergone marine burial diagenesis. Our results reveal significant decreases in both δ11B (~13 ‰) and B/Ca (~80 %) of bulk carbonates with depth. We attribute this pattern to the release of isotopically light B (δ11B ~20 ‰) to porewater during aragonite dissolution, with uptake of substantially isotopically lighter borate ions (δ11B ~-1 ‰) from porewater by newly forming low-Mg calcite. A quantitative model adds further support for this interpretation and provides an estimate of average neomorphism rate ( k0) in the range of 1×10-6 to 5×10-6 yr-1, which is comparable to previous rate estimates for neomorphism and/or recrystallization during meteoric diagenesis. Our results demonstrate the strong potential for resetting δ11B signatures in bulk carbonates during recrystallization, which must be considered in future attempts to reconstruct pH and pCO2 from these records and may require reinterpretation of existing records. Our results also suggest the potential of B isotopes as a proxy for carbonate recrystallization/neomorphism and original carbonate mineralogy.
块状碳酸盐的硼同位素组成(δ11B)可以为重建海洋 pH 值的变化提供档案。根据古碳酸盐进行重建时,通常假定在海洋埋藏成岩过程中,δ11B 没有发生明显的重置。然而,我们对与这一过程相关的 B 同位素行为的了解仍然有限。在此,我们提供了大巴哈马海岸附近一个经历过海洋埋藏成岩作用的现代近地台碳酸盐序列的 B/Ca 和 B 同位素组成(δ11B)的测量结果。我们的研究结果表明,随着深度的增加,块状碳酸盐的 δ11B(约 13 ‰)和 B/Ca(约 80 %)都明显下降。我们将这种模式归因于文石溶解过程中向孔隙水释放了同位素轻的硼(δ11B ~20 ‰),而新形成的低镁方解石从孔隙水中吸收了同位素实质上较轻的硼酸根离子(δ11B ~-1 ‰)。定量模型为这一解释提供了进一步的支持,并提供了平均新形速率(k0)的估计值,其范围在1×10-6至5×10-6 yr-1之间,与之前对陨石成因过程中新形和/或再结晶速率的估计值相当。我们的研究结果表明,在重结晶过程中,重置块状碳酸盐岩中的δ11B特征具有很大的潜力,在今后试图根据这些记录重建pH和pCO2时必须考虑到这一点,并且可能需要对现有记录进行重新解释。我们的研究结果还表明,B同位素有可能成为碳酸盐再结晶/形貌和原始碳酸盐矿物学的替代物。
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引用次数: 0
Eating behaviour, body image, and mental health: updated estimates of adolescent health, well-being, and positive functioning in Aotearoa New Zealand. 饮食行为、身体形象和心理健康:新西兰奥特亚罗瓦青少年健康、幸福和积极功能的最新估计。
IF 1.2 3区 地球科学 Q3 GEOSCIENCES, MULTIDISCIPLINARY Pub Date : 2023-12-01 DOI: 10.1071/HC23048
Katie M Babbott, Nathan S Consedine, Marion Roberts

Introduction Body image dissatisfaction and its associated challenges have been related to poorer health outcomes among adolescents worldwide, including disordered eating behaviour, depression, and anxiety. However, current prevalence estimates of these issues in Aotearoa New Zealand or, relatedly, the estimates of positive attitudes and behaviours, such as intuitive eating and body appreciation are dated. Aim The primary aim of this paper was to provide updated estimates for a variety of constructs related to eating behaviours and body image, sourced from a diverse range of early adolescent participants. Methods For this report, a brief online survey was advertised to adolescents throughout Aotearoa New Zealand (n  = 893) via school and community noticeboards. Results Approximately one-in-three male participants and one-in-two female participants reported body image dissatisfaction. One in four participants reported clinically significant symptoms of depression and anxiety. Discussion Given such issues, there is clearly still much progress to be made in advancing positive health among early adolescents. Identifying potentially protective constructs such as intuitive eating and body appreciation may offer guidance into the best targets for prevention and early intervention.

导言:身体形象不满意及其相关挑战与全球青少年较差的健康结果有关,包括饮食行为紊乱、抑郁和焦虑。然而,目前对这些问题在新西兰奥特亚罗瓦地区的流行率的估计,或与此相关的积极态度和行为的估计,如直觉饮食和身体欣赏,都是过时的。目的 本文的主要目的是提供与饮食行为和身体形象相关的各种构建的最新估计值,这些估计值来自不同的青少年早期参与者。方法 为撰写本报告,我们通过学校和社区布告栏向新西兰奥特亚罗瓦地区的青少年(n = 893)发布了一份简短的在线调查。结果 大约三分之一的男性参与者和二分之一的女性参与者表示对身体形象不满意。每四名参与者中就有一人报告了严重的抑郁和焦虑症状。讨论 鉴于这些问题,在促进青少年积极健康方面显然还有许多工作要做。识别直觉饮食和身体鉴赏等潜在的保护性建构,可为预防和早期干预的最佳目标提供指导。
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引用次数: 0
A Cenozoic Record of Deep Oceanic Zn Isotopic Composition in Ferromanganese Crusts 铁锰结壳中深海锌同位素组成的新生代记录
IF 2.9 3区 地球科学 Q3 GEOSCIENCES, MULTIDISCIPLINARY Pub Date : 2023-11-16 DOI: 10.2475/001c.89628
Mingyu Zhao, Noah Planavsky, Xiangli Wang, Yiyue Zhang, J. Hein
The zinc (Zn) isotopic composition (δ66Zn) of the deep ocean (>1000 m) can provide insights into the carbon cycle, the biological pump, and hydrothermal activity. However, we have an incomplete view of the temporal and spatial evolution of deep-ocean Zn isotopes. Here, we present new δ66Zn values of Fe-Mn crusts from the Pacific Ocean, which we used to reconstruct the evolution of deep-ocean δ66Zn for the Cenozoic. Our results suggest that the δ66Zn values remain stable in the deep Pacific Ocean at around ~ 0.5‰ through the Cenozoic. Our results limit the extent of change in organic zinc burial through the Cenozoic. However, given uncertainties in the global mass balance and analytical error, variations of roughly 20% in organic zinc burial are still possible.
深海(>1000 米)的锌(Zn)同位素组成(δ66Zn)可以让我们深入了解碳循环、生物泵和热液活动。然而,我们对深海锌同位素时空演变的了解并不全面。在此,我们展示了太平洋铁锰壳的δ66Zn新值,并以此重建了新生代深海δ66Zn的演变。我们的结果表明,在整个新生代,太平洋深海的δ66Zn值稳定在约0.5‰。我们的结果限制了新生代有机锌埋藏的变化范围。然而,考虑到全球质量平衡的不确定性和分析误差,有机锌埋藏量仍有可能出现约20%的变化。
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引用次数: 0
Insights Into the Terminal Ediacaran Marine Carbonate Record From Shale-Hosted Carbonate Carbon Isotopes 从页岩碳酸盐碳同位素研究埃迪卡拉纪晚期海相碳酸盐记录
3区 地球科学 Q3 GEOSCIENCES, MULTIDISCIPLINARY Pub Date : 2023-11-08 DOI: 10.2475/001c.88082
Fred Bowyer, Mariana Yilales, Rachel Wood, Simon W. Poulton
The marine carbon isotope record (δ 13 C) used for chemostratigraphy and reconstruction of carbon cycle dynamics is commonly assembled using carbonate rocks. There is, however, evidence that carbonate cements hosted within fine-grained clastics (shales and mudstones) in some settings may also express δ 13 C trends that covary with the record from carbonates. We present new carbon and oxygen isotopic data from shale-hosted carbonate cements (herein termed δ 13 C carb-sh and δ 18 O carb-sh, n = 107, <16 wt% CaCO 3 ) of the terminal Ediacaran Nama Group, Namibia (≥550.5 to <539.6 Million years ago; Ma). These data are compared with the published carbon and oxygen isotopic record from coeval carbonates (δ 13 C carb and δ 18 O carb , n = 1611) and total organic carbon (TOC) concentrations. We show that, in the Nama Group, δ 13 C carb-sh compositions in samples of intermediate to high CaCO 3 /TOC (>0.4) can approximate contemporaneous δ 13 C carb in open marine mixed carbonate-clastic settings. By contrast, δ 13 C carb-sh values in samples with low CaCO 3 /TOC (<0.4) that were deposited in clastic settings distant from the locus of carbonate deposition are more negative than contemporaneous δ 13 C carb . These data suggest that δ 13 C carb-sh may approach seawater composition in samples with low TOC when deposited in settings characterized by high CO 3 2- concentration, where carbonate can rapidly precipitate from seawater during early diagenesis. However, the use of δ 13 C carb-sh to infill gaps in the existing δ 13 C carb record remains uncertain, even when these criteria are fulfilled. Intervals of δ 13 C-δ 18 O co-variability in the Nama Group succession appear to correlate with units where seawater mixing with meteoric fluids was more likely during early diagenesis, such as clastic-dominated settings, which also show significant decreasing δ 18 O through time with gradual sub-basin infill. We further consider uncertainties in lithostratigraphic correlation of the upper Urusis Formation of the Nama Group that enable three new possible correlations to be proposed for δ 13 C carb-sh data within the terminal Ediacaran to lower Cambrian (<542.65 Ma to >532 Ma) regional and global δ 13 C carb records.
用于化学地层学和碳循环动力学重建的海相碳同位素记录(δ 13c)通常使用碳酸盐岩进行组合。然而,有证据表明,在某些环境下,在细粒碎屑(页岩和泥岩)中的碳酸盐胶结物也可能表达与碳酸盐记录共同变化的δ 13c趋势。本文介绍了来自纳米比亚埃迪卡拉末期Nama群(≥550.5 ~ 5.396亿年前)页岩型碳酸盐胶结物(这里称为δ 13c碳水化合物-sh和δ 18o碳水化合物-sh, n = 107, <16 wt% caco3)的新的碳氧同位素数据。马)。将这些数据与同期碳酸盐(δ 13c碳水化合物和δ 18o碳水化合物,n = 1611)的碳氧同位素记录和总有机碳(TOC)浓度进行了比较。研究表明,在Nama群中,中高caco3 /TOC (>0.4)样品的δ 13c碳水化合物组成与开阔海相混合碳酸盐岩-碎屑环境中同期δ 13c碳水化合物组成相近。相比之下,在远离碳酸盐岩沉积地点的碎屑环境中沉积的低caco3 /TOC (<0.4)样品的δ 13c碳水化合物-sh值比同时期的δ 13c碳水化合物更负。这些数据表明,当沉积在具有高co32 -浓度的环境中,碳酸盐在早期成岩作用中迅速从海水中析出时,δ 13c碳水化合物可能接近于低TOC样品的海水组成。然而,即使满足这些标准,利用δ 13c碳水化合物-sh来填补现有δ 13c碳水化合物记录的空白仍然不确定。Nama群演替中δ 13c -δ 18o共变区间与早期成岩作用中海水与大气流体混合的可能性较大的单元(如碎屑岩为主的环境)有关,δ 18o随时间的推移也随着次盆地的逐渐充填而显著降低。我们进一步考虑了Nama群上乌鲁西组岩石地层对比的不确定性,从而提出了埃迪卡拉末至下寒武统(<542.65 Ma至>532 Ma)区域和全球δ 13c碳水化合物记录的三种新的可能对比。
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引用次数: 0
Oxygen Isotopes of Iron Oxides as a Diagnostic Tool for Iron Formation-Hosted High-Grade Magnetite-Hematite Deposits 氧化铁氧同位素作为含铁高品位磁铁矿-赤铁矿床的诊断工具
3区 地球科学 Q3 GEOSCIENCES, MULTIDISCIPLINARY Pub Date : 2023-10-26 DOI: 10.2475/001c.88909
Flávia Cristina Silveira Braga, Carlos Alberto Rosière, Andreas Pack, Steffen G. Hagemann, João Orestes Schneider Santos
Coarse-grained granoblastic magnetite-hematite and sheared platy hematite iron orebodies comprise several small deposits (5 to 30 Mt each) on the eastern margin of the São Francisco Craton, bordering the Ediacaran–Cambrian Brasiliano Orogenic belt. Three main mineralization stages are associated with the Brasiliano Orogeny: (1) syn- to the late-collisional stage ( ca . 580–560 Ma) with development of lens-shaped schistose orebodies along thrust planes. (2) late- to the post-collisional stage ( ca . 560–530 Ma) with the formation of massive magnetite bodies by contact metamorphic-metasomatism with pegmatite. (3) Post-tectonic stage with crystallization of granular hematite associated with late pegmatite ( ca . 530–490 Ma). In order to better evaluate the fluid oxygen signature of each mineralization stage, new oxygen isotopes measurements were performed on ore bodies associated with the three stages. These stages are followed by changes in the oxygen isotope signature, with a progressive decrease of the δ18O from the iron formation (1.7 to 8.1‰) to high-grade ore (-1.6 to 2.6‰) that appears to be a common aspect of the mineralization of iron formations. In the present cases, magmatic fluids (δ 18 O from 4.6 to 13.1‰) have imprinted a relatively “heavier” signature than the most hypogene iron formation high-grade ores worldwide that was progressively modified by meteoric water percolated along extensional fractures. The iron oxides from the contact zones of pegmatitic yielded intermediate δ 18 O values (1.8 to 5.0‰), indicating a higher magmatic fluid/rock ratio.
粗粒粒状磁铁矿-赤铁矿和剪切板状赤铁矿铁矿体在弗朗西斯科克拉通东缘与埃迪卡拉-寒武纪巴西利亚造山带接壤,由几个小矿床组成(每个5 - 30 Mt)。与巴西利亚造山运动有关的成矿阶段主要有三个阶段:(1)同—晚碰撞阶段(约2 ~ 3年)。580 ~ 560 Ma),沿冲断面发育透镜状片岩矿体。(2)后期-碰撞后阶段(约60年)。560 ~ 530 Ma),与伟晶岩接触变质交代形成块状磁铁矿体。(3)构造后阶段,粒状赤铁矿结晶与晚期伟晶岩伴生(ca。530 - 490 Ma)。为了更好地评价每个成矿阶段的流体氧特征,对三个阶段相关的矿体进行了新的氧同位素测量。这些阶段之后是氧同位素特征的变化,δ18O从铁组(1.7 ~ 8.1‰)到高品位矿石(-1.6 ~ 2.6‰)逐渐降低,这似乎是铁组矿化的一个共同方面。在本研究中,岩浆流体(δ 18o为4.6 ~ 13.1‰)与世界上大多数受伸展裂缝渗透的大气水逐渐改造的下第三系铁成矿高品位矿石相比,具有相对“较重”的特征。辉长岩接触带氧化铁δ 18o值中等(1.8 ~ 5.0‰),岩浆液岩比较高。
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引用次数: 0
Chemical Alteration of Riverine Particles in Seawater and Marine Sediments: Effects on Seawater Composition and Atmospheric CO2 海水和海洋沉积物中河流颗粒的化学变化:对海水成分和大气CO2的影响
3区 地球科学 Q3 GEOSCIENCES, MULTIDISCIPLINARY Pub Date : 2023-09-19 DOI: 10.2475/001c.87455
Klaus Wallmann, Sonja Geilert, Florian Scholz
Numerous studies have shown that riverine particles react with seawater. Reactions include dissolution of reactive silicate minerals (e.g., feldspars) and formation of authigenic clays and carbonates. Previous studies have either focused on mineral dissolution (marine silicate weathering) or authigenic phase formation (reverse weathering). A comprehensive study that assesses all processes affecting the marine alteration of riverine particle has -to our knowledge- not yet been conducted. Our contribution aims to fill this gap. We first quantify cation exchange between seawater and riverine particles that occurs when particles enter the marine realm and show that significant global cation fluxes are induced by this process (-1.3 Tmol Na yr -1 , -0.2 Tmol K yr -1 , -0.4 Tmol Mg yr -1 , +1.2 Tmol Ca yr -1 ) where the positive sign indicates cation release into seawater while the negative sign denotes uptake on particles. We then use thermodynamic and kinetic modeling to investigate how much of the suspended particle load dissolves in contact with seawater and estimate corresponding global release rates for dissolved cations and silica assuming congruent dissolution (+0.06 Tmol Na yr -1 , +0.15 Tmol Ca yr -1 , +2.8 Tmol Si yr -1 ). Subsequently, we investigate rates of mineral dissolution and authigenic clay and carbonate formation in marine sediments applying reactive transport modeling, porewater data and mass balance calculations. Our best estimates for net fluxes across the sediment/water interface (dissolution–mineral formation) result as +1.5 Tmol Na yr -1 , -2.5 Tmol K yr -1 , -2.0 Tmol Mg yr -1 , +2.5 Tmol Ca yr -1 , and +1.9 Tmol Si yr -1 where most of the Na and Ca release is induced by plagioclase dissolution, K is taken up in authigenic clays and Mg is removed from solution by authigenic clay and carbonate formation. We conclude that the alkalinity of seawater is not significantly affected by marine silicate alteration since cation release fluxes (Na, Ca) are as high as cation uptake fluxes (K, Mg) on equivalent basis. Moreover, marine silicate weathering and reverse weathering are closely coupled since Al required for clay formation is mostly provided by feldspar dissolution while Al removal in authigenic clay promotes and maintains feldspar dissolution in marine sediments. Authigenic carbonate formation in anoxic subsurface sediments sequesters significant amounts of carbon (2.5 Tmol C yr -1 ) according to our estimates where most of the Ca and alkalinity required for carbonate formation are provided by the dissolution of Ca-bearing silicate minerals. This hidden sedimentary cycle provides a sink for dissolved inorganic carbon that may drive a slow draw-down of atmospheric CO 2 on geological timescales. Marine silicate alteration has an even stronger effect on the geochemical evolution of seawater by generating large fluxes of dissolved K, Mg, Ca and Si.
许多研究表明,河流颗粒与海水发生反应。反应包括活性硅酸盐矿物(如长石)的溶解和自生粘土和碳酸盐的形成。以往的研究要么集中在矿物溶解(海相硅酸盐风化),要么集中在自生相形成(逆风化)。据我们所知,尚未进行一项全面的研究,评估影响河流颗粒海洋变化的所有过程。我们的贡献旨在填补这一空白。我们首先量化了颗粒进入海洋领域时海水和河流颗粒之间发生的阳离子交换,并表明这一过程诱导了显著的全球阳离子通量(-1.3 Tmol Na yr -1, -0.2 Tmol K yr -1, -0.4 Tmol Mg yr -1, +1.2 Tmol Ca yr -1),其中正号表示阳离子释放到海水中,负号表示颗粒吸收。然后,我们使用热力学和动力学模型来研究悬浮颗粒负载在与海水接触时溶解了多少,并在假设完全溶解(+0.06 Tmol Na / yr -1, +0.15 Tmol Ca / yr -1, +2.8 Tmol Si / yr -1)的情况下估计溶解阳离子和二氧化硅的相应全球释放率。随后,我们利用反应输运模型、孔隙水数据和质量平衡计算,研究了海洋沉积物中矿物溶解和自生粘土和碳酸盐形成的速率。我们对沉积物/水界面(溶解-矿物形成)净通量的最佳估计结果为+1.5 Tmol Na / yr -1、-2.5 Tmol K / yr -1、-2.0 Tmol Mg / yr -1、+2.5 Tmol Ca / yr -1和+1.9 Tmol Si / yr -1,其中大部分Na和Ca释放是由斜长石溶解引起的,K被自生粘土吸收,Mg被自生粘土和碳酸盐形成从溶液中去除。我们得出结论,海水的碱度不受海洋硅酸盐蚀变的显著影响,因为阳离子释放通量(Na, Ca)与阳离子吸收通量(K, Mg)相当。此外,由于粘土形成所需的铝主要由长石溶蚀提供,而自生粘土中铝的去除促进并维持了海洋沉积物中长石的溶蚀,因此海相硅酸盐风化和逆风化是紧密耦合的。根据我们的估计,缺氧地下沉积物中自生碳酸盐的形成吸收了大量的碳(2.5 Tmol C / 1),其中碳酸盐形成所需的大部分钙和碱度是由含钙硅酸盐矿物的溶解提供的。这个隐藏的沉积旋回为溶解的无机碳提供了一个汇,它可能会在地质时间尺度上推动大气二氧化碳的缓慢减少。海相硅酸盐蚀变通过产生大量溶解的K、Mg、Ca和Si,对海水的地球化学演化具有更强的影响。
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引用次数: 0
The Influence of Warming on Phosphorus Burial in Continental Margin Sediments 气候变暖对陆缘沉积物磷埋藏的影响
IF 2.9 3区 地球科学 Q3 GEOSCIENCES, MULTIDISCIPLINARY Pub Date : 2023-08-29 DOI: 10.2475/001c.85110
Mingyu Zhao, L. Tarhan, N. Planavsky, T. Isson
The marine phosphorus cycle plays a critical role in regulating rates of primary productivity and thus the size of the marine biosphere. Yet, the cumulative effects of temperature change—and warming, in particular—on marine phosphorus burial remain poorly understood. Here, we explore a benthic biogeochemical model that accounts for the compounded effect of temperature on the kinetics of key diagenetic reaction pathways, diffusion coefficients, seawater pH, dissolved O2 concentration and bioturbation, in order to provide a new predictive framework for understanding the temperature response associated with P burial in continental margin settings. We find that temperature has a direct and positive impact on marine phosphorus burial, as it directly increases the formation rate of key mineral P-removal pathways—foremost carbonate fluorapatite (CFA). The increase in authigenic P burial during climate warming is likely to partially counter the effects of increased water-column P regeneration rate during climate warming events, and thus influence the extent of oceanic anoxia and organic matter burial, a factor that should be considered when assessing the response of the P cycle in the face of warming.
海洋磷循环在调节初级生产力以及海洋生物圈规模方面发挥着关键作用。然而,人们对温度变化——尤其是变暖——对海洋磷埋藏的累积影响仍知之甚少。在这里,我们探索了一个海底生物地球化学模型,该模型考虑了温度对关键成岩反应途径动力学、扩散系数、海水pH、溶解氧浓度和生物扰动的复合影响,以便为理解大陆边缘环境中与磷埋藏相关的温度响应提供一个新的预测框架。我们发现,温度对海洋磷的埋藏有着直接而积极的影响,因为它直接增加了关键矿物磷去除途径——最重要的碳酸盐氟磷灰石(CFA)的形成速率。气候变暖期间自生磷埋藏的增加可能部分抵消气候变暖事件期间水柱磷再生率增加的影响,从而影响海洋缺氧和有机质埋藏的程度,这是评估磷循环对变暖的反应时应考虑的一个因素。
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引用次数: 0
Isotope Ratio – Discharge Relationships of Solutes Derived From Weathering Reactions 风化反应中溶质的同位素比值-放电关系
IF 2.9 3区 地球科学 Q3 GEOSCIENCES, MULTIDISCIPLINARY Pub Date : 2023-08-15 DOI: 10.2475/001c.84469
J. Druhan, P. Benettin
To date, the vast majority of studies seeking to link discharge to solute concentrations have been based on representations of fluid age distributions in watersheds that are time-invariant. As increasingly detailed spatial and temporal datasets become available for weathering-derived riverine solute concentrations, the capacity to link this mass flux to transient routing of reactive fluids through Critical Zone environments is vital to quantitative interpretation. Relationships between fluid age distributions and the stable isotope ratios of these geogenic solutes are even less developed, yet these signatures are vital to parsing the suite of water-rock-life interactions that create concentration-discharge relationships. Here we offer the first merging of a hydrological model featuring time-variant fluid age distributions with a geochemical model for isotopically fractionating weathering reactions. Using SiO2(aq) and the corresponding silicon isotope ratio δ30Si as an example, we show that the stable isotope signatures of riverine solutes produced by weathering reactions reflect a component of the fluid age distribution that is unique to the corresponding solute concentrations. This distinct sensitivity is the result of a stronger link between isotope ratios and the age distribution parameters describing a given watershed. This novel modeling framework is used to provide a quantitative basis for the interpretation of SiO2(aq) and δ30Si in six low-order streams spread across a diversity of climates, geologies, and ecosystems. To our knowledge, this is the first forward and process-based model to describe the isotopic signatures of solutes derived from weathering reactions in watersheds subject to time-varying discharge.
到目前为止,绝大多数试图将流量与溶质浓度联系起来的研究都是基于流域中流体年龄分布的时间不变表示。随着越来越详细的空间和时间数据集可用于风化衍生的河流溶质浓度,将这种质量通量与反应流体通过临界区环境的瞬态路径联系起来的能力对于定量解释至关重要。流体年龄分布和这些地质溶质的稳定同位素比率之间的关系甚至还不太发达,但这些特征对于解析产生浓度-排放关系的水-岩-生命相互作用套件至关重要。在这里,我们首次将具有时变流体年龄分布的水文模型与同位素分馏风化反应的地球化学模型相结合。以SiO2(aq)和相应的硅同位素比率δ30Si为例,我们表明风化反应产生的河流溶质的稳定同位素特征反映了相应溶质浓度所特有的流体年龄分布成分。这种独特的敏感性是同位素比率与描述给定流域的年龄分布参数之间更强联系的结果。这种新的建模框架用于为解释分布在不同气候、地质和生态系统中的六个低阶流中的SiO2(aq)和δ30Si提供定量基础。据我们所知,这是第一个描述受时变放电影响的流域风化反应产生的溶质同位素特征的正演和基于过程的模型。
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引用次数: 0
[Prognostic value of periprocedural dynamics of left ventricular ejection fraction and subclinical pulmonary congestion in patients with myocardial infarction]. [心肌梗死患者左心室射血分数和亚临床肺充血的围手术期动态预后价值]。
IF 0.3 3区 地球科学 Q3 GEOSCIENCES, MULTIDISCIPLINARY Pub Date : 2023-05-31 DOI: 10.26442/00403660.2023.04.202159
T M Timofeeva, Z D Kobalava, A F Safarova, F Cabello Montoya

Aim: To assess the joint prognostic value of periprocedural dynamics of the left ventricular ejection fraction (PPD of LVEF) and subclinical pulmonary congestion during lung stress ultrasound in patients with first acute myocardial infarction (AMI) and percutaneous coronary intervention (PCI) in relation to the development of heart failure (HF) in the postinfarction period.

Materials and methods: Our prospective, single-centre, observational study included 105 patients with a first MI with no HF in the anamnesis and successful PCI. All patients underwent standard clinical and laboratory tests, NT-proBNP level assessment, echocardiography, lung stress ultrasound with a 6-minute walk test. All patients had no clinical signs of heart failure at admission and at discharge. Criteria for PPD of LV EF: improvement in LV EF≥50%; ∆LV EF more than 5%, but LV EF<50%. According to the results of lung stress ultrasound, pulmonary congestion was diagnosed: mild (2-4 B-lines), moderate (5-9 B-lines) and severe (≥10 B-lines). The end point was hospitalization for HF for 2.5 years.

Results: Upon admission, LV EF of 50% or more was registered in 45 patients (42.9%). Positive PPD was registered in 31 (29.5%) patients. After stress ultrasound of the lungs, 20 (19%) patients had mild subclinical pulmonary congestion, 38 (36%) moderate and 47 (45%) severe according to the criteria presented. During the observation period, patients with no PPD of LVEF were significantly more likely to be hospitalized for the development of HF (in 44.4% of cases) compared with patients with positive PPD (in 15.2% of cases) and with initial LV EF≥50% (in 13.4% of cases; p=0.005). When performing logistic regression analysis, the best predictive ability was found in the combination of the absence of PPD of LV EF and the sum of B-lines ≥10 on exercise (relative risk 7.45; 95% confidence interval 2.55-21.79; p<0.000).

Conclusion: Evaluation of the combination of PPD of LV EF and the results of stress lung ultrasound at discharge in patients with first AMI and successful PCI with no HF in anamnesis allows us to identify a high-risk group for the development of HF in the postinfarction period.

目的:评估首次急性心肌梗死(AMI)和经皮冠状动脉介入治疗(PCI)患者围术期左室射血分数动态变化(LVEF的PPD)和肺应激超声检查亚临床肺充血与梗死后心力衰竭(HF)发展的联合预后价值:我们的前瞻性、单中心、观察性研究纳入了 105 名首次心肌梗死且无心力衰竭病史并成功进行了 PCI 的患者。所有患者均接受了标准的临床和实验室检查、NT-proBNP 水平评估、超声心动图检查、肺部负荷超声检查和 6 分钟步行测试。所有患者在入院和出院时均无心力衰竭的临床症状。LV EF PPD的标准:LV EF改善≥50%;∆LV EF超过5%,但LV EFR结果:入院时,45 名患者(42.9%)的 LV EF 达到或超过 50%。31名患者(29.5%)PPD呈阳性。对肺部进行压力超声检查后,根据提出的标准,20 名患者(19%)有轻度亚临床肺充血,38 名患者(36%)有中度充血,47 名患者(45%)有重度充血。在观察期间,与 PPD 阳性(15.2%)和初始 LV EF≥50% 的患者(13.4%;P=0.005)相比,LVEF 无 PPD 的患者因发展为 HF 而住院的几率明显更高(44.4%)。在进行逻辑回归分析时,发现 LV EF 无 PPD 和运动时 B 线总和≥10 的组合具有最佳预测能力(相对风险为 7.45;95% 置信区间为 2.55-21.79;p):对首次发生急性心肌梗死并成功进行 PCI 且无心房颤动病史的患者出院时的左心室 EF PPD 和肺部应激超声结果进行综合评估,可帮助我们识别出心梗后时期发生心房颤动的高危人群。
{"title":"[Prognostic value of periprocedural dynamics of left ventricular ejection fraction and subclinical pulmonary congestion in patients with myocardial infarction].","authors":"T M Timofeeva, Z D Kobalava, A F Safarova, F Cabello Montoya","doi":"10.26442/00403660.2023.04.202159","DOIUrl":"10.26442/00403660.2023.04.202159","url":null,"abstract":"<p><strong>Aim: </strong>To assess the joint prognostic value of periprocedural dynamics of the left ventricular ejection fraction (PPD of LVEF) and subclinical pulmonary congestion during lung stress ultrasound in patients with first acute myocardial infarction (AMI) and percutaneous coronary intervention (PCI) in relation to the development of heart failure (HF) in the postinfarction period.</p><p><strong>Materials and methods: </strong>Our prospective, single-centre, observational study included 105 patients with a first MI with no HF in the anamnesis and successful PCI. All patients underwent standard clinical and laboratory tests, NT-proBNP level assessment, echocardiography, lung stress ultrasound with a 6-minute walk test. All patients had no clinical signs of heart failure at admission and at discharge. Criteria for PPD of LV EF: improvement in LV EF≥50%; ∆LV EF more than 5%, but LV EF<50%. According to the results of lung stress ultrasound, pulmonary congestion was diagnosed: mild (2-4 B-lines), moderate (5-9 B-lines) and severe (≥10 B-lines). The end point was hospitalization for HF for 2.5 years.</p><p><strong>Results: </strong>Upon admission, LV EF of 50% or more was registered in 45 patients (42.9%). Positive PPD was registered in 31 (29.5%) patients. After stress ultrasound of the lungs, 20 (19%) patients had mild subclinical pulmonary congestion, 38 (36%) moderate and 47 (45%) severe according to the criteria presented. During the observation period, patients with no PPD of LVEF were significantly more likely to be hospitalized for the development of HF (in 44.4% of cases) compared with patients with positive PPD (in 15.2% of cases) and with initial LV EF≥50% (in 13.4% of cases; <i>p</i>=0.005). When performing logistic regression analysis, the best predictive ability was found in the combination of the absence of PPD of LV EF and the sum of B-lines ≥10 on exercise (relative risk 7.45; 95% confidence interval 2.55-21.79; <i>p</i><0.000).</p><p><strong>Conclusion: </strong>Evaluation of the combination of PPD of LV EF and the results of stress lung ultrasound at discharge in patients with first AMI and successful PCI with no HF in anamnesis allows us to identify a high-risk group for the development of HF in the postinfarction period.</p>","PeriodicalId":7660,"journal":{"name":"American Journal of Science","volume":"27 1","pages":"296-301"},"PeriodicalIF":0.3,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90921804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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: 0
INTEGRATED LITHO-, CHEMO- AND SEQUENCE-STRATIGRAPHY OF THE EDIACARAN GAMETRAIL FORMATION ACROSS A SHELF-SLOPE TRANSECT IN THE WERNECKE MOUNTAINS, YUKON, CANADA 加拿大育空沃内克山陆架斜坡样带埃迪卡拉纪gametrail组岩石、化学和层序地层学综合研究
IF 2.9 3区 地球科学 Q3 GEOSCIENCES, MULTIDISCIPLINARY Pub Date : 2023-05-25 DOI: 10.1130/abs/2020am-356393
J. Busch, Thomas H. Boag, E. Sperling, J. Higgins, J. Strauss
The Ediacaran Gametrail Formation of northwestern Canada chronicles the evolution of a complex carbonate ramp system in response to fluctuations in relative sea level and regional tectonic subsidence alongside exceptional global change associated with the Shuram carbon isotope excursion (CIE). Here, we use extensive outcrop exposures of the Gametrail Formation in the Wernecke Mountains of Yukon, Canada, to construct a shelf-slope transect across the Shuram CIE. Twelve stratigraphic sections of the Gametrail Formation are combined with geological mapping and a suite of geochemical analyses to develop an integrated litho-, chemo-, and sequence stratigraphic model for these strata. In the more proximal Corn/Goz Creek region, the Gametrail Formation represents a storm-dominated inner to outer ramp depositional setting, while slope depositional environments in the Nadaleen River region are dominated by hemipelagic sedimentation, turbidites, and debris flows. The magnitude of the Shuram CIE is largest in slope limestones which underwent sediment-buffered diagenesis, while the CIE is notably smaller in the inner-outer ramp dolostones which experienced fluid-buffered diagenesis. Our regional mapping identified a distinct structural panel within the shelf-slope transect that was transported ~30 km via strike-slip motion during the Mesozoic–Cenozoic Cordilleran orogeny. One location in this transported structural block contains a stromatolite reef complex with extremely negative carbon isotope values down to ~ -30‰, while the other location contains an overthickened ooid shoal complex that does not preserve the characteristic negative CIE associated with the Shuram event. These deviations from the usual expression of the Shuram CIE along the shelf-slope transect in the Wernecke Mountains, and elsewhere globally, provide useful examples for how local tectonic, stratigraphic, and/or geochemical complexities can result in unusually large or completely absent expressions of a globally recognized CIE.
加拿大西北部埃迪卡拉纪Gametrail组记录了一个复杂的碳酸盐斜坡系统的演化,以响应相对海平面的波动和区域构造沉降,以及与Shuram碳同位素偏移(CIE)相关的异常全球变化。在这里,我们利用加拿大育空地区Wernecke山脉的Gametrail组的大量露头,构建了一个横跨Shuram CIE的大陆架斜坡样带。研究人员将Gametrail组的12个地层剖面与地质测绘和一套地球化学分析相结合,为这些地层建立了一个完整的岩性、化学和层序地层模型。在更近的Corn/Goz Creek地区,Gametrail组代表了以风暴为主的内到外斜坡沉积环境,而Nadaleen河地区的斜坡沉积环境则以半深海沉积、浊积岩和泥石流为主。舒拉姆斜坡灰岩的CIE值在经历沉积缓冲成岩作用的斜坡灰岩中最大,而在经历流体缓冲成岩作用的内外斜坡白云岩中CIE值明显较小。我们的区域制图在中新生代科迪勒拉造山运动中通过走滑运动在陆架斜坡样带内发现了一个明显的构造板块,移动了约30公里。该搬运构造块的一个位置包含一个碳同位素值极负的叠层石礁复合体,其碳同位素值低至~ -30‰,而另一个位置包含一个过厚的鲕滩复合体,其不保留与Shuram事件相关的特征负CIE。沿着Wernecke山脉和全球其他地方的大陆架斜坡样带,这些与Shuram CIE通常表达的偏差,为局部构造、地层和/或地球化学复杂性如何导致全球公认的CIE异常大或完全不存在的表达提供了有用的例子。
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