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Found 12 results.

Chemical, mineralogical and isotopic characterization of Ca-Mg-Fe carbonates for SIMS microanalysis

Carbonate minerals of the dolomite-ankerite and magnesite-siderite series are often found in sedimentary basins associated with economically viable ore deposits and as alteration product of Ca-Mg-Fe-silicates in igneous and metamorphic rocks. Analysis of oxygen and carbon isotopes in such carbonates gives important information, among others, on their evolution and spatial distribution during sediment burial and diagenesis, crystallization temperature during sedimentation, diagenesis and hydrothermal alteration, fluid and carbon sources, mechanisms of CO2 sequestration (e.g., (Śliwiński et al., 2016, 2018 and references therein). Because of their common chemical zoning at the microscale, in-situ techniques such as Secondary Ion Mass Spectrometry (SIMS) are fundamental to unravel intragrain and intergrain isotopic heterogeneities at scales < 50 µm. Due to instrumental artifacts, SIMS analyses need to be calibrated with matrix-matched reference materials to be accurate. This dataset describes a newly compiled set of Ca-Mg-Fe carbonates that were characterized for their mineralogical (XRD), major and minor element chemical composition (EPMA), oxygen and carbon isotopic composition by acid digestion gas-source isotope ratio mass spectrometry (GS-IRMS), and oxygen and carbon isotopic homogeneity at the microscale (SIMS). Three dolomites and one ankerite with Fe# (molar Fe/(Fe+Mg)) ranging from 0.0004 to 0.3429, one magnesite (Fe# = 0.0099) and one siderite (Fe# = 0.6152) are now available for the global SIMS community.

Compilation of Cenozoic temperature proxies for terrestrial and marine surface environments

We provide a globally distributed compilation of published surface temperature proxies for eight Cenozoic time periods that cover the range of paleoclimate states. The proxies have both a marine and terrestrial provenance and are compared to the annual temperature of the same location today. This data is then used to quantify long-term temperature changes on zonal and global levels. When coupled with recent estimates of atmospheric CO2 concentration, temperature data constrains the sensitivity of Earth's climate system to perturbation of the radiative balance, with possible implications for the future response to anthropogenic forcing. The dataset consists of an excel file with eight sheets for the eight selected timeslices, namely, • mid-Pliocene (3,0 - 3,3 Ma) • late Miocene (7,2 - 11,6 Ma) • mid-Miocene (14,7 - 17,0 Ma) • early Miocene (20,3 - 23,0 Ma) • early Oligocene (27,8 - 33,9 Ma) • late Eocene (33,9 - 37,8 Ma) • middle Eocene (42 - 46 Ma) • early Eocene (48 - 55 Ma)

Carbon and oxygen isotope in situ analysis of calcite using secondary ion mass spectrometry in the Permian Kupferschiefer system, Saale subbasin, Eastern Germany

The Kupferschiefer districts in Central Europe contain some of the world’s highest-grade sediment-hosted stratiform Cu (SSC) deposits (see Borg et al., 2012). The high-grade sulfide mineralization in the organic matter-rich marine mudstones of the Kupferschiefer (T1), and also in the underlying continental sandstones of the uppermost Rotliegend (S1) and overlying Zechstein Limestone (Ca1), in the Saale subbasin (Eastern Germany) are dominantly formed as a replacement of calcite cement (Mohammedyasin et al., 2023). We provide carbonate major element chemistry, carbon isotope composition of organic matter, and calcite carbon and oxygen isotope microanalysis datasets of drill core samples from the Saale subbasin in Eastern Germany. The samples include the uppermost Rotliegend sandstone (S1), Kupferschiefer (T1) mudstones and lowermost Zechstein Limestone (Ca1), referred as the Kupferschiefer system, from three drill cores (Sangerhausen, Allstedt and Wallendorf). For further details, see Mohammedyasin et al. (Chemical Geology, when available).

Measurements of net soil-atmosphere carbon dioxide exchange and its oxygen and carbon isotope composition in incubations of soil sampled from 44 sites in western Eurasia and northeastern Australia

Soils were sampled from 27 sites in western Eurasia during 2016 and 17 sites in northeastern Australia during 2017. Triplicate replicate microcosm incubations were created from homogenised soil from each site. The net soil-atmosphere exchange of carbon dioxide and its oxygen and carbon isotope composition between the soil and atmospheric was measured under two different headspace conditions using a custom built gas-exchange system. Subsequently the pH, microbial biomass and the availability of ammonium and nitrate were determined for incubated soils. An additional fertlisation experiment, consisting of a 0.7 mg addition of ammonium nitrate per gram of dry soil, was conducted on soils from 14 sites. The data from these incubations are reported along with the characteristics of the original sampling sites.

Information and meterological data of collection sites of land snails from Europe

The first table provide data on the meteorological conditions of the sites where land snails were collected, and the calculated stable oxygen isotope compositions of local rainwater.

Stable carbon, oxygen and clumped isotope data of land snails from natural populations across Europe

These data include carbon, oxygen and clumped isotope compositions of shells of natural populations of three land snail species (Clausilia pumila, Succinella oblonga and Trochulus hispidus) across Europe. δ¹³C, δ¹⁸O and Δ₄₇ values of snail shells from field-collections were determined in two laboratories (Institute for Nuclear Research, Debrecen, and Geological Institute, ETH Zürich) using IRMS. Detailed analysis and interpretations of the results obtained can be read in the original publication.

LPEE reconstructions of oxygen and hydrogen isotope compositions of precipitation based on the analysis of pedogenic siderites and published records of plant wax n-alkanes

Meterological and stable carbon, oxygen and clumped isotope data of land snails from Europe

These data include site information and collection dates of land snails (Clausilia pumila, Succinella oblonga, Trochulus hispidus), meteorological data of collection sites using the ClimateEU software, as well as carbon, oxygen and clumped isotope compositions of snail shells of the mentioned three species from culturing experiments and natural populations across Europe. During the laboratory experiments at the University of Lodz (Poland) individuals of the three species were kept at 12, 18 and 24 °C temperatures in climate chambers, fed exclusively by fresh lettuce and humidity was controlled using tap water (δ¹⁸O: -9.29 ±0.52 ‰, V-SMOW). δ¹³C, δ¹⁸O and Δ₄₇ values of snail shells from lab experiments and field-collections were determined in two laboratories (Institute for Nuclear Research, Debrecen, and Geological Institute, ETH Zürich) using IRMS. Detailed analysis and interpretations of the results obtained can be read in the original publication.

Reconstruction of continental temperatures and oxygen isotope compositions of precipitation based on clumped and oxygen isotope analysis of pedogenic siderites

Earth's climate sensitivity – defined as the temperature increase for a doubling of pCO2 – and the mechanisms responsible for amplification of high latitude warming remain controversial. The latest Paleocene/earliest Eocene (LPEE; 57-55 million years ago) is a time when pCO2 peaked between 1400 and 4000 ppm, which allows us to evaluate the climatic response to high pCO2. Here, we present a reconstruction of continental temperatures and oxygen isotope compositions of precipitation – reflective of specific humidity – based on clumped and oxygen isotope analysis of pedogenic siderites. We show that continental mean annual temperature reached 41 °C in the equatorial tropics, and summer temperatures reached 23 °C in the Arctic. The oxygen isotope compositions of precipitation reveal that compared to the present-day the hot LPEE climate was characterized by an increase in specific humidity and the average residence time of atmospheric moisture and by a decrease in the subtropical-to-polar specific humidity gradient. The global increase in specific humidity reflects the fact that atmospheric vapor content is more sensitive to changes in pCO2 than evaporation and precipitation, resulting in an increase in the residence time of moisture in the atmosphere. Pedogenic siderite data from other super-greenhouse periods support the evidence that the spatial patterns of specific humidity and warmth are related providing new means to evaluate Earth's climate sensitivity.

Redox-sensitive metal concentrations and isotopic composition of dissolved sulfate in a sandy subterranean estuary of the southern North Sea (Spiekeroog Island, May 2014)

The redox-sensitive metals Mn, Fe, U, Re, Mo, and V and sulfur cycling were studied within the subterranean estuary of a sand beach on Spiekeroog Island, Northern Germany. Pore water samples were obtained along a cross-shore transect down to 5 m below the sediment surface. Redox conditions range from oxic, close to the base of the dune, to sub- to anoxic towards the low water line. We could show that biogeochemical processes alter not only the pore water concentrations of the trace metals, but are also reflected by the O isotope- and to a minor degree the S isotope composition of dissolved sulfate. Seawater circulation through sediments of the upper beach (duneward part of the intertidal zone) removes U and V from solution, but serves as a source for Mn, Fe, Re, and Mo to the ocean. Pore water discharging from a berm close to the low water line exhibits lower U, V, and Re concentrations than adjacent seawater. This part of the beach thus serves as a sink for U, V, and Re, but as a source for Mn, Fe, and Mo. No significant Mo depletion is found in the pore water, due to the lack of dissolved sulfide.

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