Elemental composition of sediment core Sardarya from southeast Iran


The proxy data reported here are measured from a sediment core collected from Lake Sardarya (28° 38' 03" N, 61° 00' 44" E, 2675 m a.s.l.) situated on the western slope of Taftan volcano, southeastern Iran. The core is 550 cm long and was collected in May 2017. The element composition of the core was measured using the AVAATECH XRF core scanner at MARUM, University of Bremen in 1 cm intervals using two different voltages of 30 and 10 kV for 20 and 15 s, respectively. For XRD mineralogy, samples were dried at 50 °C for 48 hours. The dried samples were ground and mixed thoroughly using mortar and pestle. XRD analyses were carried out using a Philips X'Pert Pro multipurpose diffractometer equipped with a Cu-tube (kα 1.541 Angström (Ǻ), 45 kV, 40 mA), a fixed divergence slit of ¼°, a 16 sample changer, a secondary Ni-Filter, and the X'Celerator detector system at the Crystallography and Geomaterials group, Dept. of Geosciences, University of Bremen. For carbon-nitrogen-sulfur measurement, Two sets of 28 samples from the Sardarya sediment core were collected, dried in a drying cabinet at 50 °C for 48 hours and ground and homogenized using mortar and pestle. One set of samples was weighed into tin capsules and analysed without further pretreatments. The other set of samples was pretreated with 3% and 20% HCl overnight at a temperature of 80 °C to remove carbonates and weighed into silver capsules. Finally, these samples were also analyzed with a Euro-EA Elemental Analyzer at the GEOPOLAR lab (Institute of Geography, University of Bremen) providing weight percentages of total organic carbon (TOC). Carbon to nitrogen ratio (C/N) was calculated by dividing TOC with total nitrogen (TN). To determine total organic (TOC) and inorganic carbon (TIC) contents, we used Fourier-transform infrared spectroscopy (FTIRS) analyses of the samples in a diffuse reflectance mode with a VERTEX 70 FTIRS spectrometer (BrukerOptik GmbH, Germany) equipped with a diffuse reflectance accessory (Praying Mantis Harrick Inc., USA). Sample pretreatment, IR spectroscopy measurement conditions and processing procedures applied to the raw spectra are described by Vogel et al. (2016). The pretreatment for all samples consisted of drying and grinding 50 mg smaller than 63 mm. Additionally, the Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) analysis was used to estimate biogenic silica (BSi) content. For DRIFTS analyses, 11 (±0.1) mg of the sample was mixed with 500 (±0.5) mg of KBr. Finally, the BSi content was determined using the calibration model by Meyer-Jacob et al. (2014), which is based on synthetic sediment mixtures with defined BSi concentrations. Leaf-wax n-alkanes were extracted using a DIONEX Accelerated Solvent Extractor (Dionex ASE-200). Neutral compounds such as hydrocarbons, ketones and alcohols were extracted after saponification. Non-polar hydrocarbons were separated from the natural fractions and analyzed using a Gas Chromatography/Flame Ionization Detector (GC/FID) at MARUM, University of Bremen. Individual n-alkanes were identified by comparison of retention times with an external standard. Stable carbon isotope (δ13C) analyses of n-alkanes were conducted on a Finnigan MAT 252 Isotope Ratio Mass Spectrometer coupled via a GC/C interface with a combustion reactor operated at 1000°C to a Thermo Fisher Scientific TRACE GC equipped with a HP-5ms column (30 m, 0.25 mm, 1 µm). Each sample was measured at least in duplicate.

XRF-core scanning: Analysed at MARUM-University of Bremen (10.07.2017)

DOI https://doi.pangaea.de/10.1594/PANGAEA.965843
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.965843
Creator Safaierad, Reza ORCID logo; Schefuß, Enno (ORCID: 0000-0002-5960-930X); Zolitschka, Bernd ORCID logo; Vogt, Christoph ORCID logo; Hahn, Annette (ORCID: 0000-0002-3647-473X); Yokoyama, Yusuke ORCID logo; Mohtadi, Mahyar ORCID logo
Publisher PANGAEA
Publication Year 2024
Rights Creative Commons Attribution 4.0 International; Data access is restricted (moratorium, sensitive data, license constraints); https://creativecommons.org/licenses/by/4.0/
OpenAccess false
Resource Type Dataset
Format text/tab-separated-values
Size 6084 data points
Discipline Earth System Research
Spatial Coverage (61.012 LON, 28.634 LAT); Taftan volcano, southeast Iran