Elemental and mineral composition of bottom sediments and subsea permafrost from the Buor-Khaya Bay (Laptev Sea)
Description
The dataset provides elemental and mineral composition of bottom sediments and subsea permafrost from three sediment cores obtained during polar expeditions in the Buor-Khaya Bay in 2014-2015. Collection sites are located southeast of the Lena Delta near the Bykovsky Peninsula at the Buor-Khaya Bay. Mass concentration of 22 major elements and their oxides, as well as percentage of 41 accessory minerals are presented.
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Concentration of SiO2, Al2O3, Fe2O3, TiO2, MgO, Na2O, K2O, CaO, MnO, P2O5, Cl, Cr, S, Ni, Cu, Zn, Rb, Sr, Ba, Y, Zr in the samples were measured by energy dispersive X-ray fluorescence method on EDX-800-HS analyzer (Shimadzu, Japan). Before the procedure freeze-dried samples were finely pulverized with a Pulverisette 7 planetary mill (Fritsch, Germany) at 670 rpm for 10 min, then sieved and quartered. Samples for measurements were converted into the tablets with a diameter of 20 mm using a manual press. Pressure – 30 MPa, sample weight – 2 g, binding agent – H3BO3 (1 g of sample to 0.5 g of H3BO3). The source of excitation is an X–ray tube with a Rh anode. The exposure time of the sample was 100 s in each energy channel. The samples SRM 2702 (Inorganics in Marine Sediment) and SRM 2703 (Sediment for Solid Sampling (Small Sample) Analytical Techniques) were used as a reference. The analytical reproducibility of the measurements was estimated at ±5% for elements with a concentration > 1% and ±10% for elements with a concentration < 1% in the sample. Concentration of total organic carbon (TOC) was taken from [2]. Lithological description, moisture content and measured concentration of above mentioned elements and oxides for each sample are given in Supplementary Table 1. For mineral analysis dried samples of bottom sediments (50-100 g) were sieved. The sand fraction was divided into classes < 0.1, 0.1–0.25, 0.25–0.5, 0.5–1, 1-2.5, and 2.5–5 mm using a set of sieves with sizes 0.1, 0.25, 0.5, 1, 2.5 and 5 mm. Material of classes 0.5–1, 1-2.5, 2.5–5 and > 5 mm was weighed with an accuracy of 0.1 g on the AND HL-400 balance and investigated using the Altami SM0745 stereomicroscope. For quantitatification of accessory minerals classes < 0.5 mm was taken as the most presentative and analyzed according to the following scheme: 1. Weighing of the sample. 2. Separation the sample in a bromoform (p = 2.89 g/cm3) in separation funnels. 3. Separation of ferrimagnetic, paramagnetic and diamagnetic minerals using a universal permanent hand magnet S-5 (Sochnev magnet). 4. Weighing of the fractions. 5. Visual identification of minerals in the separated fractions using the Altami SM0745 stereomicroscope. A portable UV lamp was used to identify luminescent minerals. 6. Recalculation of the mass percentage of minerals in each class and the entire sample by the weight of class 0.1–0.25 mm as the most abundant. Mass percentage of the identified accessory minerals and heavy mineral fraction for each sample are given in Supplementary Table 2. Collection sites are shown in Figure 1. Table 1 provides GPS coordinates of sampling and brief drilling core data. Table 2 provides a list of identified accessory minerals in the samples. Tables 3 and 4 contain intervals and mean values of the concentration of elements and accessory minerals in the samples respectively.
Institutions
- Institut himii DVO RAN
- Institut okeanologii imeni P P Sirsova RAN