Geochemical data of S1 tephra from the ICDP Dead Sea Deep Drilling (DSDDP) 5017-1A record

This dataset presents the geochemical data from cryptotephra layers identified in the lacustrine record of the International Continental Drilling Program (ICDP) Dead Sea Deep Drilling Program (DSDDP) core 5017-1A (Levant) that has been correlated to the S1 tephra from Mt. Erciyes, Central Anatolian Volcanic Province (CAVP). Specific depths in the 5017-1A were targeted for cryptotephra investigation due to the known age of the S1 tephra (~8.9 ka BP) and the age-depth model created for the record, with specific focus on the laminated alternating aragonite detritus (aad) varves. Where peaks in shard concentrations were discovered, individual volcanic glass shards were analysed for their geochemical composition. For major elements, an Electron Probe Micro Analyser (EPMA) was used and for trace elements, a Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). The dataset is supplementary material to “Kearney et al. (submitted)” where additional details on the record and core sampling strategy are given. The data is provided as a single .xlsx file with tabs for each table.

Major and minor element composition using Electron Probe Micro Analyser (EPMA)
Glass shards from the identified concentration peaks of the core DSDDP 5017-1A were analysed using a JOEL JXA-8500F electron microprobe (EPM) at GFZ, Potsdam. The instrument setting was 15 kV voltage, 5nA beam current with a beam size of 5-10um. A count time of 20s for the elements Fe, Cl, Mn, Ti, Mg and P and 10s for F, Si, Al, K, Ca and Na were used. The secondary glass standards of ATHO-G, StHs6/80-6 and GOR128-G from the MPI-DING glasses were used along with Lipari obsidian to monitor precision and accuracy. Shards with analytical totals below 92% were excluded. The data is presented in Table 1 as unnormalized with analytical totals from the EPM. The normalised data is presented throughout Kearney et al. (submitted).
Trace element compositions using Laser Ablation Intercouple Mass Spectrometry (LA-ICP-MS
Trace element compositions were measured on individual glasses shards using Laser Ablation Intercouple Mass Spectrometry (LA-ICP-MS) at GFZ, Potsdam. The machine was a Teledyne Analyte Excite 193 nm excimer laser coupled to an iCAP RQ quadrupole ICP-MS. The procedure followed Tomlinson et al (2010) using a 20m spot. Only shards that were big enough for this size spot were chosen. The laser was operated at 5 Hz repetition rate using a fluence of 3.1 J/cm2 and a spot size of 20 µm. Prior to each ablation, an interval 40 seconds of gas blank data had been collected while the laser was warming up. The laser actively ablated for 40 seconds followed by 15 seconds of wash out. All samples were pre-ablated for 5 seconds. The analytical run included several analyses of unknown glasses and bracketed by MPI-DING (ATHO-G, StHs6/80-6 and GOR128-G), Lipari obsidian with NIST612 and NIST610 (GeoREM 11/2006) for calibration. 29Si has been used for internal normalisation.
Data processing and reduction were conducted using the program Iolite version 4.10.5, using 29Si data from the EPM for the individual shards. NIST612 was used as the calibration standard . There were problems with Ni element being below detection. As a result, ATHO-G was used for calibration of Ni, due this standard being of similar 29Si values measured in the samples. For certain samples, the average 29Si value from the whole sample of the EPMA was used. This was due to the fact that all shards analysed in the samples were correlated to the S1 in major elements. To ensure appropriate values for the individual samples, the duration was shortened to an appropriate length to ensure a clear signal of the cryptotephra. As these cryptotephra shards are very thin, it is easy to ablate through the shard quickly, resulting in a short useable signal. To reduce this problem and ensure appropriate results, the duration was shortened in processing. Those shards with durations shorter than 15 seconds are highlighted in the data file. Though not ideal to include, they have been used in included here and in the paper due to the little number of appropriate shard sizes and results that were above LOD.
The data presented in Table 2 are mean ppm for a total of 30 trace elements. The ± 2 standard deviation and LOD for each element and sample are also given.