X-ray diffraction results from IODP Hole 386-M0083B

Results of X-ray diffraction (XRD) analyses from the above given hole of International Ocean Discovery Program (IODP) Expedition 386 (Japan Trench Paleoseismology). The offshore phase of this expedition took place between 2021-04-13 and 2021-06-01 onboard Japanese R/V Kaimei from and to Yokosuka, Japan, followed by an onshore phase onboard D/V Chikyu between 2022-02-14 – 2022-03-15. During the onshore phase a set of solid-phase samples, with a volume of approx. 10 cubic centimeters each, were taken with the purpose to be later on split into aliquots for the following three analyses: X-ray diffraction, carbon and X-ray fluorescence. The bulk solid-phase samples were taken from the work halves of core sections at about one sample per meter on average. Unprocessed samples were then shipped to the MARUM - Center for Marine Environmental Sciences of the University of Bremen (Germany), where they were freeze-dried, ground and homogenized to a fine powder (<20 µm particle size) by ECORD Science Operator staff using a pestle and an agate mortar. The aliquots for XRD analysis were prepared with the Philips backloading system in the Crystallography and Geomaterials Research laboratories of the Geoscience Department at the University of Bremen (Germany). X-ray diffractograms were measured on a Bruker D8 Discover diffractometer. Mineral identification and semi-quantification were done using the Philips software X'Pert HighScore Version 1.2 (Degen et al., 2014, https://doi.org/10.1017/S0885715614000840) and follows concepts of Vogt (2009, https://doi.org/10.2204/iodp.proc.302.203.2009). Minimum relative errors are given based on Vogt et al., 2002 (https://doi.org/10.1346/000986002760833765). Clay Mineral groups are used as sums of multiple minerals. In many samples there is a bulb below 20-25° 2theta pointing to amorphous SiO2, which can be biogenic (e.g. diatoms etc.) or volcanic glass. The bulb size could implicate about 10-20 wt.% of amorphous SiO2. Exact quantification of this component would require more detailed XRD experiments. […]

本数据集为国际大洋发现计划（International Ocean Discovery Program, IODP）第386航次（日本海沟古地震学研究）指定钻孔的X射线衍射（X-ray diffraction, XRD）分析结果。该航次海上作业阶段于2021年4月13日至2021年6月1日期间开展，搭载日本“开阳号”（R/V Kaimei）研究船从日本横须贺出发并返回；后续陆上作业阶段于2022年2月14日至2022年3月15日期间在“地球号”（D/V Chikyu）钻探船上完成。陆上作业阶段中，采集了单个体积约10立方厘米的固相样品，后续将其拆分为若干分样，用于开展三项分析：X射线衍射、碳元素分析以及X射线荧光（X-ray fluorescence）分析。块状固相样品取自岩心剖面的工作半片，平均采样密度约为每1米1个样品。未处理的样品被运送至德国不来梅大学海洋环境科学中心（MARUM - Center for Marine Environmental Sciences of the University of Bremen），由ECORD科学运营商的工作人员使用研钵和玛瑙研钵进行冷冻干燥、研磨均质处理，最终制备得到粒径小于20微米的细粉。用于X射线衍射分析的分样在德国不来梅大学地球科学系晶体学与地球材料研究实验室中，采用飞利浦背载系统完成制样。X射线衍射图谱采用布鲁克D8 Discover衍射仪进行采集。矿物鉴定与半定量分析借助飞利浦X'Pert HighScore 1.2版软件完成（Degen等人，2014，https://doi.org/10.1017/S0885715614000840），分析方法遵循Vogt（2009）提出的相关理念（https://doi.org/10.2204/iodp.proc.302.203.2009）。最小相对误差的计算依据Vogt等人2002年的研究成果（https://doi.org/10.1346/000986002760833765）。黏土矿物组以多种矿物的总和形式进行统计。多数样品在2θ角20°至25°以下区域存在鼓包状衍射峰，指示存在非晶态二氧化硅，该物质可能为生物成因（如硅藻等）或火山玻璃。该鼓包的强度大致对应约10%至20%质量百分比的非晶态二氧化硅，若要对该组分进行精确定量，则需开展更为细致的X射线衍射实验。[…]