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Article ; Online: Distribution of natural and anthropogenic radionuclides in sediments from the Vefsnfjord, Norway.

Heldal, H E / Helvik, L / Haanes, H / Volynkin, A / Jensen, H / Lepland, A

2021 Volume 172, Page(s) 112822

Abstract: Areas in central Norway were heavily contaminated with fallout from the Chernobyl accident in 1986. In this study, we ... ...

Abstract	Areas in central Norway were heavily contaminated with fallout from the Chernobyl accident in 1986. In this study, we assess
MeSH term(s)	Estuaries ; Geologic Sediments ; Norway ; Radiation Monitoring ; Radioactivity ; Water Pollutants, Radioactive/analysis
Chemical Substances	Water Pollutants, Radioactive
Language	English
Publishing date	2021-08-14
Publishing country	England
Document type	Journal Article
ZDB-ID	2001296-2
ISSN	1879-3363 ; 0025-326X
ISSN (online)	1879-3363
ISSN	0025-326X
DOI	10.1016/j.marpolbul.2021.112822
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Article ; Online: Hydrothermal Regeneration of Ammonium as a Basin-Scale Driver of Primary Productivity.

Stüeken, Eva E / Kirsimäe, Kalle / Lepland, Aivo / Prave, Anthony R

Astrobiology

2022 Volume 23, Issue 2, Page(s) 195–212

Abstract: Hydrothermal vents are important targets in the search for life on other planets due to their potential to generate key catalytic surfaces and organic compounds for biogenesis. Less well studied, however, is the role of hydrothermal circulation in ... ...

Abstract	Hydrothermal vents are important targets in the search for life on other planets due to their potential to generate key catalytic surfaces and organic compounds for biogenesis. Less well studied, however, is the role of hydrothermal circulation in maintaining a biosphere beyond its origin. In this study, we explored this question with analyses of organic carbon, nitrogen abundances, and isotopic ratios from the Paleoproterozoic Zaonega Formation (2.0 Ga), NW Russia, which is composed of interbedded sedimentary and mafic igneous rocks. Previous studies have documented mobilization of hydrocarbons, likely associated with magmatic intrusions into unconsolidated sediments. The igneous bodies are extensively hydrothermally altered. Our data reveal strong nitrogen enrichments of up to 0.6 wt % in these altered igneous rocks, suggesting that the hydrothermal fluids carried ammonium concentrations in the millimolar range, which is consistent with some modern hydrothermal vents. Furthermore, large isotopic offsets of ∼10‰ between organic-bound and silicate-bound nitrogen are most parsimoniously explained by partial biological uptake of ammonium from the vent fluid. Our results, therefore, show that hydrothermal activity in ancient marine basins could provide a locally high flux of recycled nitrogen. Hydrothermal nutrient recycling may thus be an important mechanism for maintaining a large biosphere on anoxic worlds.
MeSH term(s)	Ammonium Compounds ; Nitrogen/analysis ; Carbon ; Silicates ; Hydrothermal Vents
Chemical Substances	Ammonium Compounds ; Nitrogen (N762921K75) ; Carbon (7440-44-0) ; Silicates
Language	English
Publishing date	2022-12-26
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2047736-3
ISSN	1557-8070 ; 1531-1074
ISSN (online)	1557-8070
ISSN	1531-1074
DOI	10.1089/ast.2021.0203
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Article ; Online: Oxygen isotope compositions of conodonts – analytical challenges of in situ SIMS studies

Wudarska, A. / Wiedenbeck, M. / Hints, O. / Männik, P. / Lepland, A. / Joachimski, M. / Couffignal, F. / Scicchitano, M. / Wilke, F.

Estonian Journal of Earth Sciences

2023

Abstract: Reliable deep-time environmental and climate reconstructions are needed to understand the drivers of Earth's system evolution over geological time. Palaeozoic temperature estimates, including reconstructions of the climate change through the Ordovician, ... ...

Abstract	Reliable deep-time environmental and climate reconstructions are needed to understand the drivers of Earth's system evolution over geological time. Palaeozoic temperature estimates, including reconstructions of the climate change through the Ordovician, are based mainly on oxygen isotope (18O/16O; δ18OVSMOW) thermometry derived from carbonate rocks with fossils such as calcitic brachiopods and phosphatic conodonts that are often the best preserved repositories of environmental conditions. Palaeoenvironmental reconstructions are reliable only if the geochemical data is obtained using well-calibrated analytical tools. Most previous research devoted to oxygen isotope composition of conodonts has been conducted using the bulk method (gas source isotope ratio mass spectrometry (GS-IRMS)) that typically requires pooling several dozens of conodont elements for a single isotope ratio measurement. As such, studies of conodont-poor intervals and assessments of taxon-specific δ18O variability require extensive sample preparation and are challenging using the bulk method. Such challenges can be addressed by in situ secondary ion mass spectrometry (SIMS) analyses using only picogram sampling masses. However, several studies have reported inconsistencies between SIMS and GS-IRMS δ18O data for the same research material. We aim to solve this controversy by establishing a robust analytical protocol for conodont isotope analysis by SIMS. Here we present conodont data on Pterospathodus and Amorphognathus specimens extracted from Ordovician strata in Nurme and Mehikoorma-421 boreholes (Estonia). Oxygen isotope composition of conodonts was analysed by both SIMS and GS-IRMS, where we paid particular attention to four inorganic apatite reference materials in order to understand the offset between these two techniques that have been reported in the literature. While the results of GS-IRMS measurements conducted using high-temperature reduction of Ag3PO4 represent exclusively δ18O of phosphate-bound oxygen, SIMS analyses do not ...
Subject code	550
Publishing country	de
Document type	Article ; Online
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Article ; Online: Geochronology of sediment cores from the Vefsnfjord, Norway.

Heldal, H E / Helvik, L / Appleby, P / Haanes, H / Volynkin, A / Jensen, H / Lepland, A

Marine pollution bulletin

2021 Volume 170, Page(s) 112683

Abstract: The sedimentary environment is a repository and carrier for a variety of pollutants, and sediment transport from land to coastal areas is an important environmental process. In the present study, we ... ...

Abstract	The sedimentary environment is a repository and carrier for a variety of pollutants, and sediment transport from land to coastal areas is an important environmental process. In the present study, we use
MeSH term(s)	Cesium Radioisotopes/analysis ; Estuaries ; Geologic Sediments ; Norway ; Water Pollutants, Radioactive/analysis
Chemical Substances	Cesium Radioisotopes ; Water Pollutants, Radioactive
Language	English
Publishing date	2021-07-02
Publishing country	England
Document type	Journal Article
ZDB-ID	2001296-2
ISSN	1879-3363 ; 0025-326X
ISSN (online)	1879-3363
ISSN	0025-326X
DOI	10.1016/j.marpolbul.2021.112683
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Article ; Online: Putative fossils of chemotrophic microbes preserved in seep carbonates from Vestnesa Ridge, off northwest Svalbard, Norway

Himmler, T. / Crémière, A. / Birgel, D. / Wirth, R. / Orphan, V. / Kirsimäe, K. / Knies, J. / Peckmann, J. / Lepland, A.

Geology

2022

Abstract: The microbial key players at methane seeps are methanotrophic archaea and sulfate-reducing bacteria. They form spherical aggregates and jointly mediate the sulfate-dependent anaerobic oxidation of methane (SD–AOM: CH4 + SO42– → HCO3– + HS– + H2O), ... ...

Abstract	The microbial key players at methane seeps are methanotrophic archaea and sulfate-reducing bacteria. They form spherical aggregates and jointly mediate the sulfate-dependent anaerobic oxidation of methane (SD–AOM: CH4 + SO42– → HCO3– + HS– + H2O), thereby inducing the precipitation of authigenic seep carbonates. While seep carbonates constitute valuable archives for molecular fossils of SD–AOM-mediating microbes, no microfossils have been identified as AOM aggregates to date. We report clustered spherical microstructures engulfed in 13C-depleted aragonite cement (δ13C values as low as –33‰) of Pleistocene seep carbonates. The clusters comprise Mg-calcite spheres between ~5 μm (single spheres) and ~30 μm (clusters) in diameter. Scanning and transmission electron microscopy revealed a porous nanocrystalline fabric in the core area of the spheres surrounded by one or two concentric layers of Mg-calcite crystals. In situ measured sphere δ13C values as low as –42‰ indicate that methane-derived carbon is the dominant carbon source. The size and concentric layering of the spheres resembles mineralized aggregates of natural anaerobic methanotrophic archaea (ANME) of the ANME-2 group surrounded by one or two layers of sulfate-reducing bacteria. Abundant carbonate-bound 13C-depleted lipid biomarkers of archaea and bacteria indicative of the ANME-2-Desulfosarcina/Desulfococcus consortium agree with SD–AOM-mediating microbes as critical agents of carbonate precipitation. Given the morphological resemblance, in concert with negative in situ δ13C values and abundant SD–AOM-diagnostic biomarkers, the clustered spheres likely represent fossils of SD–AOM-mediating microbes.
Publishing country	de
Document type	Article ; Online
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Article: Distribution of natural and anthropogenic radionuclides in sediments from the Vefsnfjord, Norway

Heldal, H.E. / Helvik, L. / Haanes, H. / Volynkin, A. / Jensen, H. / Lepland, A.

Marine pollution bulletin. 2021 Nov., v. 172

2021

Abstract: Areas in central Norway were heavily contaminated with fallout from the Chernobyl accident in 1986. In this study, we assess ¹³⁷Cs in surface sediments and sediment cores collected in the Vefsnfjord in Nordland county. Concentrations of ¹³⁷Cs in surface ... ...

Abstract	Areas in central Norway were heavily contaminated with fallout from the Chernobyl accident in 1986. In this study, we assess ¹³⁷Cs in surface sediments and sediment cores collected in the Vefsnfjord in Nordland county. Concentrations of ¹³⁷Cs in surface sediments ranged from 159 to 191 Bq kg⁻¹ dry weight (d.w.). Sub-surface peaks of ¹³⁷Cs were observed in all cores, with a maximum concentration of 432 Bq kg⁻¹ d.w. Given that little is known about the distribution of naturally occurring radionuclides in Norwegian fjords and coastal areas, a better understanding of the total burden of radioactivity is important for the Norwegian fishing and aquaculture industries. Therefore, analyses of the natural radionuclides ⁴⁰K, ²²⁶Ra, ²²⁸Ra and ²¹⁰Pb were included in the study. Analyses of total sulphur (TS), total carbon (TC), total organic carbon (TOC) and grain size distribution have been performed to provide a sedimentologic context for interpreting the radionuclide results.
Keywords	accidents ; aquaculture ; cesium radioisotopes ; marine pollution ; particle size distribution ; radioactivity ; sediments ; sulfur ; total organic carbon ; Norway ; Ukraine
Language	English
Dates of publication	2021-11
Publishing place	Elsevier Ltd
Document type	Article
ZDB-ID	2001296-2
ISSN	1879-3363 ; 0025-326X
ISSN (online)	1879-3363
ISSN	0025-326X
DOI	10.1016/j.marpolbul.2021.112822
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Article: Geochronology of sediment cores from the Vefsnfjord, Norway

Heldal, H.E. / Helvik, L. / Appleby, P. / Haanes, H. / Volynkin, A. / Jensen, H. / Lepland, A.

Marine pollution bulletin. 2021 Sept., v. 170

2021

Abstract	The sedimentary environment is a repository and carrier for a variety of pollutants, and sediment transport from land to coastal areas is an important environmental process. In the present study, we use ²¹⁰Pb/²²⁶Ra and ¹³⁷Cs in sediment cores to assess sediment supply rates at four sites within the Vefsnfjord in Nordland county, Norway. This area was highly affected by fallout from the Chernobyl accident in 1986 and inventories of ¹³⁷Cs in the fjord are much higher than in many other Norwegian fjords. Sedimentation rates between 0.042 and 0.25 g cm⁻² y⁻¹ (0.060 and 0.38 cm y⁻¹) were determined using a combination of the Constant Rate of Supply (CRS) and Constant Flux:Constant Sedimentation rate (CF:CS) models. Well-defined ¹³⁷Cs concentration peaks were used as a supplementary tool to the ²¹⁰Pb dating methods.
Keywords	accidents ; cesium radioisotopes ; geochronology ; marine pollution ; sediment transport ; sedimentation rate ; sediments ; Norway ; Ukraine
Language	English
Dates of publication	2021-09
Publishing place	Elsevier Ltd
Document type	Article
ZDB-ID	2001296-2
ISSN	1879-3363 ; 0025-326X
ISSN (online)	1879-3363
ISSN	0025-326X
DOI	10.1016/j.marpolbul.2021.112683
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Article ; Online: Lithostratigraphic analysis of a new stromatolite-thrombolite reef from across the rise of atmospheric oxygen in the Paleoproterozoic Turee Creek Group, Western Australia.

Barlow, E / Van Kranendonk, M J / Yamaguchi, K E / Ikehara, M / Lepland, A

Geobiology

2016 Volume 14, Issue 4, Page(s) 317–343

Abstract: This study describes a previously undocumented dolomitic stromatolite-thrombolite reef complex deposited within the upper part (Kazput Formation) of the c. 2.4-2.3 Ga Turee Creek Group, Western Australia, across the rise of atmospheric oxygen. Confused ... ...

Abstract	This study describes a previously undocumented dolomitic stromatolite-thrombolite reef complex deposited within the upper part (Kazput Formation) of the c. 2.4-2.3 Ga Turee Creek Group, Western Australia, across the rise of atmospheric oxygen. Confused by some as representing a faulted slice of the younger c. 1.8 Ga Duck Creek Dolomite, this study describes the setting and lithostratigraphy of the 350-m-thick complex and shows how it differs from its near neighbour. The Kazput reef complex is preserved along 15 km of continuous exposure on the east limb of a faulted, north-west-plunging syncline and consists of 5 recognisable facies associations (A-E), which form two part regressions and one transgression. The oldest facies association (A) is characterised by thinly bedded dololutite-dolarenite, with local domical stromatolites. Association B consists of interbedded columnar and stratiform stromatolites deposited under relatively shallow-water conditions. Association C comprises tightly packed columnar and club-shaped stromatolites deposited under continuously deepening conditions. Clotted (thrombolite-like) microbialite, in units up to 40 m thick, dominates Association D, whereas Association E contains bedded dololutite and dolarenite, and some thinly bedded ironstone, shale and black chert units. Carbon and oxygen isotope stratigraphy reveals a narrow range in both δ(13) Ccarb values, from -0.22 to 0.97‰ (VPDB: average = 0.68‰), and δ(18) O values, from -14.8 to -10.3‰ (VPDB), within the range of elevated fluid temperatures, likely reflecting some isotopic exchange. The Kazput Formation stromatolite-thrombolite reef complex contains features of younger Paleoproterozoic carbonate reefs, yet is 300-500 Ma older than previously described Proterozoic examples worldwide. Significantly, the microbial fabrics are clearly distinct from Archean stromatolitic marine carbonate reefs by way of containing the first appearance of clotted microbialite and large columnar stromatolites with complex branching arrangements. Such structures denote a more complex morphological expression of growth than previously recorded in the geological record and may link to the rise of atmospheric oxygen.
MeSH term(s)	Calcium Carbonate/chemistry ; Fossils ; Geologic Sediments/chemistry ; Minerals/analysis ; Oxygen ; Western Australia
Chemical Substances	Minerals ; Calcium Carbonate (H0G9379FGK) ; Oxygen (S88TT14065)
Language	English
Publishing date	2016
Publishing country	England
Document type	Journal Article
ZDB-ID	2113509-5
ISSN	1472-4669 ; 1472-4677
ISSN (online)	1472-4669
ISSN	1472-4677
DOI	10.1111/gbi.12175
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Article ; Online: Fluid-deposited graphite and its geobiological implications in early Archean gneiss from Akilia, Greenland.

Lepland, A / van Zuilen, M A / Philippot, P

Geobiology

2011 Volume 9, Issue 1, Page(s) 2–9

Abstract: Graphite, interpreted as altered bioorganic matter in an early Archean, ca. 3.83-Ga-old quartz-amphibole-pyroxene gneiss on Akilia Island, Greenland, has previously been claimed to be the earliest trace of life on Earth. Our petrographic and Raman ... ...

Abstract	Graphite, interpreted as altered bioorganic matter in an early Archean, ca. 3.83-Ga-old quartz-amphibole-pyroxene gneiss on Akilia Island, Greenland, has previously been claimed to be the earliest trace of life on Earth. Our petrographic and Raman spectroscopy data from this gneiss reveal the occurrence of graphitic material with the structure of nano-crystalline to crystalline graphite in trails and clusters of CO₂, CH₄ and H₂O bearing fluid inclusions. Irregular particles of graphitic material without a fluid phase, representing decrepitated fluid inclusions are common in such trails too, but occur also as dispersed individual or clustered particles. The occurrence of graphitic material associated with carbonic fluid inclusions is consistent with an abiologic, fluid deposited origin during a poly-metamorphic history. The evidence for fluid-deposited graphitic material greatly complicates any claim about remnants of early life in the Akilia rock.
MeSH term(s)	Carbon Dioxide/chemistry ; Fossils ; Geologic Sediments/chemistry ; Geologic Sediments/microbiology ; Graphite/analysis ; Greenland ; Methane/chemistry ; Minerals/analysis ; Quartz/analysis ; Spectrum Analysis, Raman ; Water/chemistry
Chemical Substances	Minerals ; Water (059QF0KO0R) ; pyroxene (12174-37-7) ; Carbon Dioxide (142M471B3J) ; Quartz (14808-60-7) ; Graphite (7782-42-5) ; Methane (OP0UW79H66)
Language	English
Publishing date	2011-01
Publishing country	England
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2113509-5
ISSN	1472-4669 ; 1472-4677
ISSN (online)	1472-4669
ISSN	1472-4677
DOI	10.1111/j.1472-4669.2010.00261.x
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Article ; Online: Chlorine Isotope Composition of Apatite from the >3.7 Ga Isua Supracrustal Belt, SW Greenland

Wudarska, A. / Słaby, E. / Wiedenbeck, M. / Birski, Ł. / Wirth, R. / Götze, J. / Lepland, A. / Kusebauch, C. / Kocjan, I.

Minerals

2020

Abstract: The study of the oldest surviving rock suites is crucial for understanding the processes that shaped the early Earth and formed an environment suitable for life. The metasedimentary and metavolcanic rocks of the early Archean Isua supracrustal belt ... ...

Abstract	The study of the oldest surviving rock suites is crucial for understanding the processes that shaped the early Earth and formed an environment suitable for life. The metasedimentary and metavolcanic rocks of the early Archean Isua supracrustal belt contain abundant apatite, the geochemical signatures of which may help decipher ancient environmental conditions. However, previous research has shown that secondary processes, including amphibolite-facies metamorphism, have reset the original hydrogen isotope composition (δD) of apatite from the Isua belt; therefore, δD values are not indicative of primary conditions in the Archean. Here, we report the first in situ chlorine isotope (δ37Cl) analyses by Secondary Ion Mass Spectrometry (SIMS) from Isua apatite, which we combine with information from transmission electron microscopy, cathodoluminescence imaging, and spectroscopy, documenting the micron-scale internal features of apatite crystals. The determined δ37ClSMOC values (chlorine isotope ratios vs. standard mean ocean chloride) fall within a range from −0.8‰ to 1.6‰, with the most extreme values recorded by two banded iron formation samples. Our results show that δ37Cl values cannot uniquely document primary signatures of apatite crystals, but the results are nonetheless helpful for assessing the extent of secondary overprint
Subject code	550
Language	English
Publishing country	de
Document type	Article ; Online
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