Goldschmidt2021 abstracts最新文献

MICROBIAL REDUCTION OF SYNTHETIC BIOGENIC IRON OXIDES CONTAINING VARIOUS AMOUNTS OF ORGANIC CARBON AND SILICA. 微生物还原合成含不同数量有机碳和二氧化硅的生物氧化铁。

Goldschmidt2021 abstracts Pub Date : 2023-10-17 DOI: 10.7185/gold2021.6365

Daniela Quintero Morales, D. Fortin

{"title":"MICROBIAL REDUCTION OF SYNTHETIC BIOGENIC IRON OXIDES CONTAINING VARIOUS AMOUNTS OF ORGANIC CARBON AND SILICA.","authors":"Daniela Quintero Morales, D. Fortin","doi":"10.7185/gold2021.6365","DOIUrl":"https://doi.org/10.7185/gold2021.6365","url":null,"abstract":"Iron oxides formed in close association with bacteria are referred to as biogenic minerals (BIOS). Both the organic part of BIOS and the iron oxide particles affect the net surface charge of those iron-organic carbon aggregates and offer reactive sites that can immobilize many soluble contaminants (Warren and Haack 2001) making BIOS a contender in bioremediation technologies. However, before using BIOS in bioremediation, it is essential to understand the interactions of impurities such as organic matter and other minor components (including silica) (Dyer et al. 2010). This project involves the synthesis of Biogenic Iron Oxides (BIOS) using various silica contents and different soluble alginate concentrations (as an analogue for bacterial exopolysaccharides) close to natural environmental conditions. The mineralogical, chemical and physical composition of the synthesized samples was determined by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Field Emission Scanning Electron Microscopy (FESEM), Fourier-transform Infrared Spectroscopy (FTIR), and with a Malvern Zetasizer Nano instrument. The various samples (mainly ferrihydrite) were then reduced in the presence of Shewanella putrefaciens CN32, a well-known iron reducing bacterium. All microbial reduction experiments (see Table 1) with different types of BIOS were performed under anoxic conditions.\u0000 Results indicate that the ratio of organic matter and silica to Fe (III) in BIOS affects the reduction rate. It is proposed that alginate binds to iron oxide particles and protects them from reduction. However, samples in presence of high concentration of silica (i.e.,> 0.05) showed structural disorder which likely prevented nucleation of well ordered ferrihydrite, which in return increased their rate of reduction. In addition, higher reduction rates of ferrihydrite were reported at higher concentrations of silica in BIOS, even in the presence of alginate.","PeriodicalId":124249,"journal":{"name":"Goldschmidt2021 abstracts","volume":"136 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125238359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

An isotopically enriched mantle component in the source of Rodrigues, Réunion volcanic hotspot 罗德里格斯火山热点源区同位素富集地幔组分

Goldschmidt2021 abstracts Pub Date : 2023-08-01 DOI: 10.7185/gold2021.5175

Marc C. Halfar, B. Peters, J. Day, M. Schönbächler

{"title":"An isotopically enriched mantle component in the source of Rodrigues, Réunion volcanic hotspot","authors":"Marc C. Halfar, B. Peters, J. Day, M. Schönbächler","doi":"10.7185/gold2021.5175","DOIUrl":"https://doi.org/10.7185/gold2021.5175","url":null,"abstract":"The Mascarene Islands in the western Indian Ocean, encompassing La Réunion, Mauritius and Rodrigues, provide one of Earth’s most pristine records of its deep interior and primordial history. Ocean island basalts (OIB) from these islands, which sample the Réunion hotspot, exhibit a remarkably limited range in isotopic compositions that generally overlap the focal zone (FOZO) in the mantle array. Besides this signature, Mascarene lavas may preserve influences from sources with distinct compositions, including: (1) shallow continental crust preserved by Archaean-aged zircons in Mauritian trachytes; (2) deeper continental crust components preserved by slightly elevated 87 Sr/ 86 Sr and 208 Pb/ 206 Pb ratios in lavas from the Piton des Neiges volcano on La Réunion; and (3) an isotopically depleted component resulting from migration of Central Indian Ridge (CIR) material. We use major and trace element compositions, as well as new Sr and Pb isotope data of basaltic lavas from all three Mascarene Islands to investigate their mantle sources in terms of their relationship to well-characterized mantle endmember compositions. The trace element data reveals distinct patterns for each island. Rodrigues lavas are the most enriched in the highly incompatible trace elements, which likely reflects a lower degree of partial melting. Combined Pb-Sr isotopic compositions indicate that Mauritian Older Series lavas have a stronger Réunion-type component, while those from the Mauritian Younger and Intermediate Series, along with Rodrigues, display a contribution of a more depleted component. Lead isotopes further suggest the contribution of an enriched component in the Rodrigues basalts. Isotope mixing models reveal that the Pb isotopic signature of Rodrigues rocks is","PeriodicalId":124249,"journal":{"name":"Goldschmidt2021 abstracts","volume":"782 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123285615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

An experimental study of the effect of pressure on the formation of chromite deposits 压力对铬铁矿形成影响的实验研究

Goldschmidt2021 abstracts Pub Date : 2023-05-10 DOI: 10.7185/gold2021.6288

Natashia Drage, J. Brenan

{"title":"An experimental study of the effect of pressure on the formation of chromite deposits","authors":"Natashia Drage, J. Brenan","doi":"10.7185/gold2021.6288","DOIUrl":"https://doi.org/10.7185/gold2021.6288","url":null,"abstract":"\u0000 Despite extensive research on massive chromitites, the mechanism(s) that form such anomalous chromite segregations remains uncertain. Recent work that considered a theoretical parental melt to the Critical Zone of the Bushveld Complex applied the MELTS thermodynamic model to propose that reduction of pressure upon magma ascent shifts the silicate-in temperature to lower values, such that chromite is the sole liquidus phase, resulting in formation of chromitites. Herein the effect of pressure on Cr solubility at constant fO2 relative to the FMQ buffer is evaluated through laboratory phase equilibrium experiments done at 0.1 MPa, 0.5 GPa, and 1 GPa. Two bulk compositions were employed: (1) the theoretical melt used in the MELTS modelling study and (2) B1, which is a widely accepted parental composition to the Bushveld Critical Zone. Experiments were conducted at 0.1 MPa by equilibrating compositions on Fe-Ir alloy wire loops from 1170-1300°C in a vertical-tube, gas-mixing furnace for 12-48 hours. Experiments at 0.5 GPa and 1 GPa were conducted with a piston-cylinder apparatus at 1230°C and 1280°C for 4-12 hours using Fe-Ir alloy and graphite-lined Pt capsules. Experiments show that the B1 composition reproduces phase equilibria and mineral compositions observed in the Bushveld whereas mineral compositions produced by the theoretical melt composition used in the MELTS modelling study are too Al-rich, excluding it as viable parental liquid. Results show no significant change in Cr content of the melt at chromite saturation with pressure at constant relative fO2. However, reduction of pressure can promote chromite crystallization, as the modal abundance and DCr(px/liq) of orthopyroxene decrease with pressure in experiments, increasing the availability of Cr for chromite crystallization. While a low-pressure interval of chromite-alone crystallization is plausible, results indicate that significant volumes of unusually Cr-enriched B1 magma would be required to produce the chromitites observed in the Bushveld by the pressure reduction mechanism.","PeriodicalId":124249,"journal":{"name":"Goldschmidt2021 abstracts","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131742394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Natural attenuation of heavy metals via secondary hydrozincite precipitation in an abandoned Pb-Zn mine 废弃铅锌矿二次氢锌矿沉淀对重金属的自然衰减

Goldschmidt2021 abstracts Pub Date : 2023-05-01 DOI: 10.7185/gold2021.7243

M. Giannetta, J. Cama, J. Soler, I. Queralt, Robert Benaiges

引用次数: 1

Coherent Tracer Correlations in Deep-sea Corals and Implications for Biomineralization Mechanisms underlying Vital Effects 深海珊瑚的相干示踪剂相关性及其对生物矿化机制的影响

Goldschmidt2021 abstracts Pub Date : 2022-12-01 DOI: 10.7185/gold2021.6775

Sang Chen, E. Littley, J. Rae, Chris M. Charles, Y. Guan, Jessica M. Adkins

引用次数: 1

Investigating boron isotopes and FTIR as proxies for bushfire severity 研究硼同位素和FTIR作为森林火灾严重程度的替代指标

Goldschmidt2021 abstracts Pub Date : 2022-12-01 DOI: 10.7185/gold2021.5485

Shawn Lu, Anthony Dosseto, D. Lemarchand, P. Dlapa, R. Bradstock

引用次数: 1

Radium inputs into the Arctic Ocean from rivers: a basin-wide estimate 镭从河流进入北冰洋:一个全流域的估计

Goldschmidt2021 abstracts Pub Date : 2022-09-08 DOI: 10.7185/gold2021.7214

Emma Bullock, L. Kipp, Willard Moore, K. Brown, P. Mann, J. Vonk, N. Zimov, M. Charette

引用次数: 0

The zinc isotope composition of late Holocene open-ocean marine sediments 晚全新世公海海相沉积物锌同位素组成

Goldschmidt2021 abstracts Pub Date : 2022-06-01 DOI: 10.7185/gold2021.7744

Alex Dickson

引用次数: 2

Sedimentary Ce anomalies: secular change and implications for paleoenvironmental evolution 沉积Ce异常:长期变化及其古环境演化意义

Goldschmidt2021 abstracts Pub Date : 2022-03-01 DOI: 10.7185/gold2021.5546

kun zhang, G. Shields

{"title":"Sedimentary Ce anomalies: secular change and implications for paleoenvironmental evolution","authors":"kun zhang, G. Shields","doi":"10.7185/gold2021.5546","DOIUrl":"https://doi.org/10.7185/gold2021.5546","url":null,"abstract":"Due to its redox sensitivity, the Ce anomaly preserved in sedimentary rocks has been widely applied to reconstruct seawater redox states [1]. However, there is so far no relatively complete Ce anomaly compilation, hindering our understanding of oceanic redox evolution. Here, we report a novel compilation of >2000 screened Ce anomaly data from chemical sedimentary rocks of Archean-Phanerozoic age, including carbonate rocks, iron formations, phosphorites, and cherts, deposited in different environments. The temporal variations in Ce anomalies are mostly consistent with the present consensus around oceanic redox evolution. Nevertheless, pulsed oxygenation events in the mid-Proterozoic are evidenced by profound negative Ce anomalies. Statistical analyses suggest an overall gradual oxygenation in the late Tonian to the early Cambrian. While shallow marine environments were broadly well oxygenated during the Proterozoic-Phanerozoic transition interval, the deep ocean remained largely anoxic, consistent with the persistence of a dissolved organic carbon reservoir that acted as a redox buffer. Statistical analyses indicate that pervasive and sustained ocean oxygenation was probably not achieved until middle Devonian times, potentially related to the evolution of secondary woody tissues and forests. According to a thermodynamics-based Ce oxidation model [2], atmospheric p O 2 could have been as high as 3% PAL during the mid-Proterozoic and 9% PAL in the late Ediacaran-early Cambrian, which is broadly consistent with previous estimates. We concur that the marine sedimentary Ce anomaly responds sensitively to oceanic redox changes and is a reliable proxy to track Earth system evolution.","PeriodicalId":124249,"journal":{"name":"Goldschmidt2021 abstracts","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129157097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 22

Empirical and Experimental Constraints on Fe-Ti Oxide-Melt Titanium Isotope Fractionation Factors Fe-Ti氧化物-熔体钛同位素分馏因素的经验和实验约束

Goldschmidt2021 abstracts Pub Date : 2022-02-01 DOI: 10.7185/gold2021.7529

L. Hoare, M. Klaver, S. Klemme, D. Muir, J. Barling, J. Lissenberg, M. Millet, I. Parkinson

{"title":"Empirical and Experimental Constraints on Fe-Ti Oxide-Melt Titanium Isotope Fractionation Factors","authors":"L. Hoare, M. Klaver, S. Klemme, D. Muir, J. Barling, J. Lissenberg, M. Millet, I. Parkinson","doi":"10.7185/gold2021.7529","DOIUrl":"https://doi.org/10.7185/gold2021.7529","url":null,"abstract":": The Titanium (Ti) isotope compositions of felsic rocks are heavier than their mafic counterparts, and alkaline magmas develop heavier Ti isotope compositions compared to other magma series during magmatic differentiation. Both observations are interpreted to reflect the preferential sequestration of light Ti isotopes in Fe-Ti oxides, such as rutile, ilmenite and titanomagnetite. However, such interpretations .so far rely on whole rock studies of cogenetic magmatic samples and the detailed mechanics of oxide-melt equilibrium on the Ti isotope composition of magmas is poorly constrained. To address this, we have measured the Ti isotope composition of co-existing Fe-Ti oxides and groundmass or silicate melt in both natural lavas from contrasting tectonic settings (Heard Island and Santorini), and experimental run products (rutile-melt). All Fe-Ti oxide phases are consistently isotopically lighter than their respective host groundmass or silicate melt, with the magnitude of ∆49/47Tioxide-melt increasing from rutile to ilmenite, and titanomagnetite. The observed difference in Ti isotope fractionation between rutile-melt experiments and ilmenite-groundmass pairs is primarily reflective of small differences in their Ti-O bond length, with ilmenite being isotopically lighter (∆49/47Tiilmenite-melt extrapolated to 1000","PeriodicalId":124249,"journal":{"name":"Goldschmidt2021 abstracts","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126849214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 8