Data for: Late Quaternary changes in sediment composition in NE Greenland Fjords, Shelf, and Slope

• Main Author: Andrews, John
• Format: Dataset
• Language: English
• Published: NSF Arctic Data Center 2015
• Subjects: EARTH SCIENCE > CLIMATE INDICATORS > CRYOSPHERIC INDICATORS; SHIP; oceans; Greenland; Jan Mayen
• Online Access: https://dx.doi.org/10.18739/a20v89h84; https://arcticdata.io/catalog/view/doi:10.18739/A20V89H84

Methods and Data are provided on three sediment properties from a series of Polarstern cores (Hubberten and al., 1995) and on a Jan Mayen core (Husum, 2007). In addition, tables of some aspects of data analysis are also included such as the results of Principal Component Analysis of the mineral weight% data, and the clustering of the grain-size curves (Minasny and McBratney, 2002). Data are also included on the results of a sediment unmixing exercise using the .xls macro program SedUnMixMC. 1) Core location and water depth 2) New radiocarbon dates for cores PS2631, PS2640, and JM07-174GC. 3) Data for color reflectance (CIE*) are listed for cores PS2623, PS2631 and PS2640. 4) Grain-size data from the Malvern laser system are given for cores PS2623, PS2631, PS2640, and PS2641. 5) Mineral weight% data based on quantitative X-ray diffraction analysis (Eberl, 2003) of the < 2 mm sediment are listed for cores PS2623, PS2627, PS2729, PS2630, PS2631, PS2640, and PC2641, and JM07-174GC. 6) Principal component scores for all cores on XRD logratio mineralogy 7) Results of fuzzy clustering of the grain-size % data and the logratio data 8) Results of running SedUnMixMC on the source sediments---the red numbers indicate the fraction associated with that sediment source---ideally should be close to 1.0. 9) Results of the 4 source sediment unmixing analysis using SedUnMixMC (Andrews et al., 2015; Andrews and Eberl, 2012) Methods The color reflectance of dried sediment was measured with an X-Rite spectrophotometer, Model 500 Series, using the CIE* system, with L* a measure of black to white, a* (blue to red) and b* (yellow to green. The prepared dry samples were tapped into a 2.5 cm dia. aluminum XRD holder, overlain by a clear glass slide, and measured. A Pantone Color Chip (4705) was measured repeatedly to evaluate instrument drift. Grain-size analyses were undertaken on sediments from PS2623, PS2631, PS2640, and PS2641 using a Malvern model 2000 laser system for the range 2000 to 0.5 µm. Add 5mL of hydrogen peroxide again and repeat the process. Keep repeating the process until the organic is gone (there is no reaction occurring). When organic is removed and the beakers are cooled a little add 8-10mL of magnesium chloride to each beaker. We employ the quantitative X-ray diffraction method developed by Eberl (2003, 2004). The sediment < 2 mm are spiked by 10% by weight of zincite, milled, and the samples are scanned on a D5000 Siemens X-Ray Diffractometer between 5° and 65° 2-theta with a 0.02° step and a 2-sec count. The resulting 3000 data points are loaded into the Excel macro-program Rockjock v6 (Eberl, 2003) and the weight% of minerals in the sediment mixtures calculated against a suite of 124 "standard" mineral patterns (Eberl, 2003). Finally, the data are normalized to sum to 100%. In this paper we present the results on 8 cores. For PS2641 this included data on both the < 63µm fraction and the < 2mm fraction (0-300 cm).