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Yu, C., Boily, J.-F., Shchukarev, A., Drake, H., Song, Z., Hogmalm, K. J. & Åström, M. E. (2018). A cryogenic XPS study of Ce fixation on nanosized manganite and vernadite: Interfacial reactions and effects of fulvic acid complexation. Chemical Geology, 483, 304-311
Open this publication in new window or tab >>A cryogenic XPS study of Ce fixation on nanosized manganite and vernadite: Interfacial reactions and effects of fulvic acid complexation
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2018 (English)In: Chemical Geology, ISSN 0009-2541, E-ISSN 1872-6836, Vol. 483, p. 304-311Article in journal (Refereed) Published
Abstract [en]

This study investigated interfacial reactions between aqueous Ce(III) and two synthetic nanosized Mn (hydr-) oxides (manganite: γ-MnOOH, and vernadite: δ-MnO2) in the absence and presence of Nordic Lake fulvic acid (NLFA) at circumneutral pH by batch experiments and cryogenic X-ray photoelectron spectroscopy (XPS). The surfaces of manganite and vernadite were negatively charged (XPS-derived loadings of (Na+K)/Cl > 1) and loaded with 0.42–4.33 Ce ions nm−2. Manganite stabilized Ce-oxidation states almost identical to those for vernadite (approximately 75% Ce(IV) and 25% Ce(III)), providing the first experimental evidence that also a Mn (III) phase (manganite) can act as an important scavenger for Ce(IV) and thus, contribute to the decoupling of Ce from its neighboring rare earth elements and the development of Ce anomaly. In contrast, when exposed to Ce (III)-NLFA complexes, the oxidation of Ce by these two Mn (hydr-)oxides was strongly suppressed, suggesting that the formation of Ce(III) complexes with fulvic acid can stabilize Ce(III) even in the presence of oxidative Mn oxide surfaces. The experiments also showed that Ce(III) complexed with excess NLFA was nearly completely removed, pointing to a strong preferential sorption of Ce(III)-complexed NLFA over free NLFA. This finding suggests that the Ce(III)-NLFA complexes were most likely sorbed by their cation side, i.e. Ce(III) bridging between oxide groups on the Mn (hydr-)oxides and negatively-charged functional groups in NLFA. Hence, Ce(III) was in direct contact with the oxidative manganite and vernadite but despite that not oxidized. An implication is that in organic-rich environments there may be an absence of Ce(IV) and Ce anomaly despite otherwise favorable conditions for Ce(III) oxidation.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Cryogenic XPS, Manganite, Vernadite, Oxidative scavenging, Ce anomaly
National Category
Earth and Related Environmental Sciences
Research subject
Natural Science
Identifiers
urn:nbn:se:lnu:diva-72684 (URN)10.1016/j.chemgeo.2018.02.033 (DOI)000429492300027 ()
Available from: 2018-04-13 Created: 2018-04-13 Last updated: 2018-07-10Bibliographically approved
Drake, H., Ivarsson, M., Tillberg, M., Whitehouse, M. & Kooijman, E. (2018). Ancient Microbial Activity in Deep Hydraulically Conductive Fracture Zones within the Forsmark Target Area for Geological Nuclear Waste Disposal, Sweden. Geosciences, 8(6), Article ID 211.
Open this publication in new window or tab >>Ancient Microbial Activity in Deep Hydraulically Conductive Fracture Zones within the Forsmark Target Area for Geological Nuclear Waste Disposal, Sweden
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2018 (English)In: Geosciences, E-ISSN 2076-3263, Vol. 8, no 6, article id 211Article in journal (Refereed) Published
Abstract [en]

Recent studies reveal that organisms from all three domains of life—Archaea, Bacteria, and even Eukarya—can thrive under energy-poor, dark, and anoxic conditions at large depths in the fractured crystalline continental crust. There is a need for an increased understanding of the processes and lifeforms in this vast realm, for example, regarding the spatiotemporal extent and variability of the different processes in the crust. Here, we present a study that set out to detect signs of ancient microbial life in the Forsmark area—the target area for deep geological nuclear waste disposal in Sweden. Stable isotope compositions were determined with high spatial resolution analyses within mineral coatings, and mineralized remains of putative microorganisms were studied in several deep water-conducting fracture zones (down to 663 m depth), from which hydrochemical and gas data exist. Large isotopic variabilities of δ13Ccalcite (−36.2 to +20.2‰ V-PDB) and δ34Spyrite (−11.7 to +37.8‰ V-CDT) disclose discrete periods of methanogenesis, and potentially, anaerobic oxidation of methane and related microbial sulfate reduction at several depth intervals. Dominant calcite–water disequilibrium of δ18O and 87Sr/86Sr precludes abundant recent precipitation. Instead, the mineral coatings largely reflect an ancient archive of episodic microbial processes in the fracture system, which, according to our microscale Rb–Sr dating of co-genetic adularia and calcite, date back to the mid-Paleozoic. Potential Quaternary precipitation exists mainly at ~400 m depth in one of the boreholes, where mineral–water compositions corresponded

Place, publisher, year, edition, pages
MDPI, 2018
National Category
Environmental Sciences Geosciences, Multidisciplinary Geochemistry Geology
Research subject
Natural Science, Environmental Science
Identifiers
urn:nbn:se:lnu:diva-77641 (URN)10.3390/geosciences8060211 (DOI)
Funder
Swedish Research Council Formas, 2017-00766Swedish Research Council, 2017-0518
Available from: 2018-09-10 Created: 2018-09-10 Last updated: 2018-09-20Bibliographically approved
Ivarsson, M., Bengtson, S., Drake, H. & Francis, W. (2018). Fungi in Deep Subsurface Environments. Advances in Applied Microbiology, 102, 83-116
Open this publication in new window or tab >>Fungi in Deep Subsurface Environments
2018 (English)In: Advances in Applied Microbiology, ISSN 0065-2164, Vol. 102, p. 83-116Article, review/survey (Refereed) Published
Abstract [en]

The igneous crust of the oceans and the continents represents the major part of Earth's lithosphere and has recently been recognized as a substantial, yet underexplored, microbial habitat. While prokaryotes have been the focus of most investigations, microeukaryotes have been surprisingly neglected. However, recent work acknowledges eukaryotes, and in particular fungi, as common inhabitants of the deep biosphere, including the deep igneous provinces. The fossil record of the subseafloor igneous crust, and to some extent the continental bedrock, establishes fungi or fungus-like organisms as inhabitants of deep rock since at least the Paleoproterozoic, which challenges the present notion of early fungal evolution. Additionally, deep fungi have been shown to play an important ecological role engaging in symbiosis-like relationships with prokaryotes, decomposing organic matter, and being responsible for mineral weathering and formation, thus mediating mobilization of biogeochemically important elements. In this review, we aim at covering the abundance and diversity of fungi in the various igneous rock provinces on Earth as well as describing the ecological impact of deep fungi. We further discuss what consequences recent findings might have for the understanding of the fungal distribution in extensive anoxic environments and for early fungal evolution.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Fungi, Deep biosphere, Igneous crust
National Category
Biological Sciences
Research subject
Natural Science, Ecology
Identifiers
urn:nbn:se:lnu:diva-70484 (URN)10.1016/bs.aambs.2017.11.001 (DOI)000436595200003 ()29680127 (PubMedID)
Available from: 2018-02-05 Created: 2018-02-05 Last updated: 2018-07-19Bibliographically approved
Drake, H., Mathurin, F. A., Zack, T., Schäfer, T., Roberts, N., Whitehouse, M., . . . Åström, M. E. (2018). Incorporation of Metals into Calcite in a Deep Anoxic Granite Aquifer. Environmental Science and Technology, 52(2), 493-502
Open this publication in new window or tab >>Incorporation of Metals into Calcite in a Deep Anoxic Granite Aquifer
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2018 (English)In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 52, no 2, p. 493-502Article in journal (Refereed) Published
Abstract [en]

Understanding metal scavenging by calcite in deep aquifers in granite is of importance for deciphering and modeling hydrochemical fluctuations and water–rock interaction in the upper crust and for retention mechanisms associated with underground repositories for toxic wastes. Metal scavenging into calcite has generally been established in the laboratory or in natural environments that cannot be unreservedly applied to conditions in deep crystalline rocks, an environment of broad interest for nuclear waste repositories. Here, we report a microanalytical study of calcite precipitated over a period of 17 years from anoxic, low-temperature (14 °C), neutral (pH: 7.4–7.7), and brackish (Cl: 1700–7100 mg/L) groundwater flowing in fractures at >400 m depth in granite rock. This enabled assessment of the trace metal uptake by calcite under these deep-seated conditions. Aquatic speciation modeling was carried out to assess influence of metal complexation on the partitioning into calcite. The resulting environment-specific partition coefficients were for several divalent ions in line with values obtained in controlled laboratory experiments, whereas for several other ions they differed substantially. High absolute uptake of rare earth elements and U(IV) suggests that coprecipitation into calcite can be an important sink for these metals and analogousactinides in the vicinity of geological repositories.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
National Category
Earth and Related Environmental Sciences
Research subject
Natural Science
Identifiers
urn:nbn:se:lnu:diva-70485 (URN)10.1021/acs.est.7b05258 (DOI)000423012200013 ()29251499 (PubMedID)
Available from: 2018-02-05 Created: 2018-02-05 Last updated: 2018-02-08Bibliographically approved
Drake, H. & Ivarsson, M. (2018). The role of anaerobic fungi in fundamental biogeochemical cycles in the deep biosphere. Fungal Biology Reviews, 32(1), 20-25
Open this publication in new window or tab >>The role of anaerobic fungi in fundamental biogeochemical cycles in the deep biosphere
2018 (English)In: Fungal Biology Reviews, ISSN 1749-4613, E-ISSN 1878-0253, Vol. 32, no 1, p. 20-25Article in journal (Refereed) Published
Abstract [en]

A major part of the biologic activity on Earth is hidden underneath our feet in an environment coined the deep biosphere which stretches several kilometers down into the bedrock. The knowledge about life in this vast energy-poor deep system is, however, extremely scarce, particularly for micro-eukaryotes such as fungi, as most studies have focused on prokaryotes. Recent findings suggest that anaerobic fungi indeed thrive at great depth in fractures and cavities of igneous rocks in both the oceanic and the continental crust. Here we discuss the potential importance of fungi in the deep biosphere, in particular their involvement in fundamental biogeochemical processes such as symbiotic relationships with prokaryotes that may have significant importance for the overall energy cycling within this vast subsurface realm. Due to severe oligotrophy, the prokaryotic metabolism at great depth in the crust is very slow and dominantly autotrophic and thus dependent on e.g. hydrogen gas, but the abiotic production of this gas is thought to be insufficient to fuel the deep autotrophic biosphere. Anaerobic fungi are heterotrophs that produce hydrogen gas in their metabolism and have therefore been put forward as a hypothetical provider of this substrate to the prokaryotes. Recent in situ findings of fungi and isotopic signatures within co-genetic sulfide minerals formed from bacterial sulfate reduction in the deep continental biosphere indeed seem to confirm the fungi-prokaryote hypothesis. This suggests that fungi play a fundamental biogeochemical role in the deep biosphere.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Anaerobic fungi Continental crust Deep biosphere Geomycology Oceanic crust
National Category
Biological Sciences
Research subject
Ecology, Microbiology
Identifiers
urn:nbn:se:lnu:diva-70483 (URN)10.1016/j.fbr.2017.10.001 (DOI)000425575100003 ()
Available from: 2018-02-05 Created: 2018-02-05 Last updated: 2018-03-09Bibliographically approved
Drake, H., Whitehouse, M. J., Heim, C., Reiners, P. W., Tillberg, M., Hogmalm, K. J., . . . Åström, M. E. (2018). Unprecedented 34S-enrichment of pyrite formed following microbial sulfate reduction in fractured crystalline rocks. Geobiology, 16(5), 556-574
Open this publication in new window or tab >>Unprecedented 34S-enrichment of pyrite formed following microbial sulfate reduction in fractured crystalline rocks
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2018 (English)In: Geobiology, ISSN 1472-4677, E-ISSN 1472-4669, Vol. 16, no 5, p. 556-574Article in journal (Refereed) Published
Abstract [en]

In the deep biosphere, microbial sulfate reduction (MSR) is exploited for energy. Here, we show that, in fractured continental crystalline bedrock in three areas in Sweden, this process produced sulfide that reacted with iron to form pyrite extremely enriched in S-34 relative to S-32. As documented by secondary ion mass spectrometry (SIMS) microanalyses, the S-34(pyrite) values are up to +132 parts per thousand V-CDT and with a total range of 186 parts per thousand. The lightest S-34(pyrite) values (-54 parts per thousand) suggest very large fractionation during MSR from an initial sulfate with S-34 values (S-34(sulfate,0)) of +14 to +28 parts per thousand. Fractionation of this magnitude requires a slow MSR rate, a feature we attribute to nutrient and electron donor shortage as well as initial sulfate abundance. The superheavy S-34(pyrite) values were produced by Rayleigh fractionation effects in a diminishing sulfate pool. Large volumes of pyrite with superheavy values (+120 +/- 15 parts per thousand) within single fracture intercepts in the boreholes, associated heavy average values up to +75 parts per thousand and heavy minimum S-34(pyrite) values, suggest isolation of significant amounts of isotopically light sulfide in other parts of the fracture system. Large fracture-specific S-34(pyrite) variability and overall average S-34(pyrite) values (+11 to +16 parts per thousand) lower than the anticipated S-34(sulfate,0) support this hypothesis. The superheavy pyrite found locally in the borehole intercepts thus represents a late stage in a much larger fracture system undergoing Rayleigh fractionation. Microscale Rb-Sr dating and U/Th-He dating of cogenetic minerals reveal that most pyrite formed in the early Paleozoic era, but crystal overgrowths may be significantly younger. The C-13 values in cogenetic calcite suggest that the superheavy S-34(pyrite) values are related to organotrophic MSR, in contrast to findings from marine sediments where superheavy pyrite has been proposed to be linked to anaerobic oxidation of methane. The findings provide new insights into MSR-related S-isotope systematics, particularly regarding formation of large fractions of S-34-rich pyrite.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2018
Keywords
continental crust, deep biosphere, microbial sulfate reduction, pyrite, sulfur isotopes
National Category
Environmental Sciences
Research subject
Natural Science, Environmental Science
Identifiers
urn:nbn:se:lnu:diva-77727 (URN)10.1111/gbi.12297 (DOI)000441436700007 ()29947123 (PubMedID)
Projects
Characteristics and extent of microbial anaerobic methane oxidation and sulfate reduction in the deep terrestrial subsurface over geological time scalesProduction and consumption of the greenhouse gas methane in the crystalline bedroc
Funder
Swedish Research Council, 2017-05186Swedish Research Council Formas, 2017-00766
Available from: 2018-09-13 Created: 2018-09-13 Last updated: 2018-09-13Bibliographically approved
Drake, H., Ivarsson, M., Bengtson, S., Heim, C., Siljeström, S., Whitehouse, M. J., . . . Åström, M. E. (2017). Anaerobic consortia of fungi and sulfate reducing bacteria in deep granite fractures. Nature Communications, 8, 1-9, Article ID 55.
Open this publication in new window or tab >>Anaerobic consortia of fungi and sulfate reducing bacteria in deep granite fractures
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2017 (English)In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 8, p. 1-9, article id 55Article in journal (Refereed) Published
Abstract [en]

The deep biosphere is one of the least understood ecosystems on Earth. Although most microbiological studies in this system have focused on prokaryotes and neglected microeukaryotes, recent discoveries have revealed existence of fossil and active fungi in marine sediments and sub-seafloor basalts, with proposed importance for the subsurface energy cycle. However, studies of fungi in deep continental crystalline rocks are surprisingly few. Consequently, the characteristics and processes of fungi and fungus-prokaryote interactions in this vast environment remain enigmatic. Here we report the first findings of partly organically preserved and partly mineralized fungi at great depth in fractured crystalline rock (−740 m). Based on environmental parameters and mineralogy the fungi are interpreted as anaerobic. Synchrotron-based techniques and stable isotope microanalysis confirm a coupling between the fungi and sulfate reducing bacteria. The cryptoendolithic fungi have significantly weathered neighboring zeolite crystals and thus have implications for storage of toxic wastes using zeolite barriers.

Place, publisher, year, edition, pages
Nature Publishing Group, 2017
National Category
Biological Sciences
Research subject
Ecology, Microbiology
Identifiers
urn:nbn:se:lnu:diva-70482 (URN)10.1038/s41467-017-00094-6 (DOI)
Available from: 2018-02-05 Created: 2018-02-05 Last updated: 2018-02-26Bibliographically approved
Yu, C., Drake, H., Mathurin, F. A. & Åström, M. E. (2017). Cerium sequestration and accumulation in fractured crystalline bedrock: The role of Mn-Fe (hydr-)oxides and clay minerals. Geochimica et Cosmochimica Acta, 199, 370-389
Open this publication in new window or tab >>Cerium sequestration and accumulation in fractured crystalline bedrock: The role of Mn-Fe (hydr-)oxides and clay minerals
2017 (English)In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 199, p. 370-389Article in journal (Refereed) Published
Abstract [en]

This study focuses on the mechanisms of Ce sequestration and accumulation in the fracture network of the upper kilometer of the granitoid bedrock of the Baltic Shield in southeast Sweden (Laxemar area, Sweden). The material includes 81 specimens of bulk secondary mineral precipitates ("fracture coatings") collected on fracture walls identified in 17 drill cores, and 66 groundwater samples collected from 21 deep boreholes with equipment designed for retrieval of representative groundwater at controlled depths. The concentrations of Ce in the fracture coatings, although varying considerably (10-90th percentiles: 67-438 mg kg(-1)), were frequently higher than those of the wall rock (10-90th percentiles: 70-118 mg kg(-1)). Linear combination fitting analysis of Ce L-III-edge X-ray absorption near-edge structure (XANES) spectra, obtained for 19 fracture coatings with relatively high Ce concentrations (>= 145 mg kg(-1)) and a wide range of Ce-anomaly values, revealed that Ce(IV) occurs frequently in the upper 10 m of the fracture network (Ce(IV)/Ce-total = 0.06-1.00 in 8 out of 11 specimens) and is mainly associated with Mn oxides (modeled as Ce oxidatively scavenged by birnessite). These features are in line with the strong oxidative and sorptive capacities of Mn oxide as demonstrated by previous studies, and abundant todorokite and birnessite-like Mn oxides identified in 3 out of 4 specimens analyzed by Mn K-edge X-ray absorption spectroscopy (XAS) in the upper parts of the fracture network (down to 5 m). For a specimen with very high Ce concentration (1430 mg kg(-1)) and NASC-normalized Ce anomaly (3.63), the analysis of Ce XANES and Mn XAS data revealed (i) a predominance of Ce oxide in addition to Ce scavenged by Mn oxide; and (ii) a large fraction of poorly-crystalline hexagonal birnessite and aqueous Mn2+, suggesting a recent or on-going oxidation of Mn2+ in this fracture. In addition, the Ce oxide precipitates on this fracture observed by in situ SEM-EDS contained considerable amounts of Mn. These spectroscopic and microscopic features led us to suggest that the remarkable accumulation of Ce(IV) in this fracture is a result of repeated formation and dissolution of Mn oxides, that is, formation of Mn oxide followed by oxidative scavenging of Ce as Ce oxide nanoparticles, which largely remained during the subsequent reductive dissolution of the Mn oxides. In addition, the XANES data indicate that goethite has the capability to oxidize Ce at near-neutral pH under our experimental conditions (goethite reacted with 0.001M Ce for 48 h in a glove box with O-2 < 1 ppm). This previously unrecognized Ce oxidation pathway also seems to contribute to a minor extent to the oxidative scavenging of Ce in the fracture network. Trivalent Ce in the fracture coatings, in particular below 2.5 m, is mainly sorbed as inner-sphere complexes on clay minerals. Taking into account the facts that Ce in the present groundwater is scarce and modeled to be largely complexed with humic substance, it is argued that the inner-sphere complexes were mainly formed from past (Paleozoic) hydrothermal fluids. (C) 2016 Elsevier Ltd. All rights reserved.

Keywords
Ce anomaly, Ce oxidation states, Oxidative scavenging, X-ray absorption near-edge structure
National Category
Geochemistry
Research subject
Natural Science
Identifiers
urn:nbn:se:lnu:diva-61146 (URN)10.1016/j.gca.2016.11.044 (DOI)000393125500023 ()
Available from: 2017-03-08 Created: 2017-03-08 Last updated: 2017-11-29Bibliographically approved
Drake, H., Heim, C., Whitehouse, M., Broman, C. & Åström, M. E. (2017). Episodic microbial methanogenesis, methane oxidation and sulfate reduction in deep granite fractures at Forsmark, Sweden. In: Marques, JM Chambel, A (Ed.), 15TH WATER-ROCK INTERACTION INTERNATIONAL SYMPOSIUM, WRI-15: . Paper presented at 15th Water-Rock Interaction International Symposium (WRI), OCT 16-21, 2016, Evora, PORTUGAL (pp. 702-705).
Open this publication in new window or tab >>Episodic microbial methanogenesis, methane oxidation and sulfate reduction in deep granite fractures at Forsmark, Sweden
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2017 (English)In: 15TH WATER-ROCK INTERACTION INTERNATIONAL SYMPOSIUM, WRI-15 / [ed] Marques, JM Chambel, A, 2017, p. 702-705Conference paper, Published paper (Refereed)
Abstract [en]

An extensive microanalytical isotope study of calcite and pyrite has been carried out in bedrock fractures at Forsmark, Sweden. The very large delta C-13(calcite)-variation of 103.4% V-PDB in total (-69.2 to +34.2%) evidences significant spatial and temporal variability in processes and carbon sources in the deep fracture system during the period when these minerals were formed (Phanerozoic). The substantial delta C-13(calcite)-span is mainly methane-related, with heavy and very light delta C-13 originating from ubiquitous in situ microbial methanogenesis and anaerobic oxidation of methane (AOM), respectively. Co-genetic cubic and framboidal pyrite showed substantial sulfate reducing bacteria (SRB)-related delta S-34 variation of 95% V-CDT overall (-29 to +66%), indicating closed system isotope distillation and point to similar genetic SRB methane-oxidizer relationships as in marine sediments. The depth distribution of the methanogenesis-, SRB- and AOM-signatures are from just below the ground surface down to about 800 m, which marks the deepest occurrence of AOM-related carbonate yet reported from the continental crystalline crust. Biomarkers and fluid inclusions suggest that the microbial activity in the bedrock fractures was closely related to descending surficial fluids and basinal brines rich in organic matter, in at least two pulses (70-80 degrees C and <50-62 degrees C). (C) 2017 Published by Elsevier B.V.

Series
Procedia Earth and Planetary Science, ISSN 1878-5220 ; 17
National Category
Biological Sciences
Research subject
Natural Science, Ecology
Identifiers
urn:nbn:se:lnu:diva-64309 (URN)10.1016/j.proeps.2016.12.158 (DOI)000398020400177 ()
Conference
15th Water-Rock Interaction International Symposium (WRI), OCT 16-21, 2016, Evora, PORTUGAL
Available from: 2017-05-23 Created: 2017-05-23 Last updated: 2017-05-23Bibliographically approved
Tillberg, M., Drake, H., Zack, T., Hogmalm, J. & Åström, M. E. (2017). In situ Rb-Sr dating of fine-grained vein mineralizations using LAICP-MS. In: Marques, JM Chambel, A (Ed.), 15TH WATER-ROCK INTERACTION INTERNATIONAL SYMPOSIUM, WRI-15: . Paper presented at 15th Water-Rock Interaction International Symposium (WRI), OCT 16-21, 2016, Evora, PORTUGAL (pp. 464-467).
Open this publication in new window or tab >>In situ Rb-Sr dating of fine-grained vein mineralizations using LAICP-MS
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2017 (English)In: 15TH WATER-ROCK INTERACTION INTERNATIONAL SYMPOSIUM, WRI-15 / [ed] Marques, JM Chambel, A, 2017, p. 464-467Conference paper, Published paper (Refereed)
Abstract [en]

Direct mineral dating is critical for thorough understanding of the genesis of hydrothermal mineralizations, ore forming processes and events of fracturing and related fluid-rock interaction. Since minerals of suitable type and sample volume for conventional techniques can be rare, development of high-precision in situ Rb-Sr dating of common rock-forming minerals such as micas, feldspars and calcite offers possibilities to gain temporal constraints of a wide variety of geological features with detailed spatial and depth resolution. This technique separates Sr-87 from Rb-87 by introducing a reaction gas between two quadropoles in a LAICP- MS system. In this study, in situ Rb-Sr geochronology distinguishes the timing of several different fracture-controlled hydrothermal events: 1 and 2) greisen mineralizations and associated far-field hydrothermal veins adjacent to a granite intrusion, 3) reactivation events within a mylonite shear zone and 4) low-temperature precipitation from saline organic-rich brines in thin veinlets. We demonstrate that in situ Rb-Sr dating is feasible for a broad range of mineral assemblages, textures, temperatures and ages, emphasizing the impending use of this new method in ore deposit exploration and many other research fields. (C) 2017 The Authors. Published by Elsevier B.V.

Series
Procedia Earth and Planetary Science, ISSN 1878-5220 ; 17
National Category
Earth and Related Environmental Sciences
Research subject
Natural Science
Identifiers
urn:nbn:se:lnu:diva-64308 (URN)10.1016/j.proeps.2016.12.117 (DOI)000398020400117 ()
Conference
15th Water-Rock Interaction International Symposium (WRI), OCT 16-21, 2016, Evora, PORTUGAL
Available from: 2017-05-24 Created: 2017-05-24 Last updated: 2017-05-24Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-7230-6509

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