Mechanical and microstructural data from deformation experiments on marine and meteoric ice from the Amery Ice Shelf

These data were collected from compressional ice deformation experiments on samples of standard (laboratory-made) ice, and marine and meteoric ice from the Amery Ice Shelf, cores AM01, AM04 and G1. Experiments were performed in the IMAS Ice Mechanics Laboratory between 2018 and 2022, following the methods described in:

Craw, L., Treverrow, A., Fan, S., Peternell, M., Cook, S., McCormack, F., and Roberts, J.: The temperature change shortcut: effects of mid-experiment temp
erature changes on the deformation of polycrystalline ice, The Cryosphere, 15, 2235–2250, https://doi.org/10.5194/tc-15-2235-2021, 2021.

all_experiments.csv contains a list of all experiments performed, and the following fields:
temperature = target temperature of the experiment, in degrees (actual temperature is recorded in the data files for each experiment)
ice_type = string denoting standard, marine or meteoric ice
starting_point = the index of the data point in the raw data file where the experiment begins (i.e. load was applied to the sample)
end_point = the index of the data point in the raw data file where the experiment ends
secondary_rate = secondary minimum strain rate, picked manually from the curve
secondary_strain = the total strain at the secondary minimum
tertiary_rate_1 = first tertiary strain rate, picked manually from the curve
tertiary_strain_1 = the total strain at the first tertiary creep stage
tertiary_rate_2 = second tertiary strain rate, picked manually from the curve (this value only exists in experiments with more than one temperature point)
tertiary_strain_2 = the total strain at the second tertiary creep stage
max_axial_strain = the maximum (final) axial strain reached
max_octahedral_strain = the maximum (final) octahedral strain reached
total_time_hours = total experiment run-time in hours
total_time_days = total experiment run-time in days
undeformed_median_grain_size = median grain size measured in a thin section before the experiment (this was not always recorded)
undeformed_number_of_grains = the number of grains in the section used to calculate the median grain size (for quality control purposes)
deformed_median_grain_size = median grain size measured in a thin section after the experiment (this was not always recorded)
deformed_number_of_grains = the number of grains in the section used to calculate the median grain size (for quality control purposes)
undeformed_jindex = J-index describing the density of c-axis alignment measured in a thin section taken before the experiment (1 denotes random distribution, an infinite value denotes a single orientation)
deformed_jindex = J-index describing the density of c-axis alignment measured in a thin section taken after the experiment (1 denotes random distribution, an infinite value denotes a single orientation)

For each experiment listed in all_experiments.csv, a raw mechanical data file and a processed mechanical data file are supplied, alongside .mat files containing fabric analyser and EBSD data (where collected) from thin sections.

[experiment_number]_raw_data.csv contains the data as logged during the experiment:
time = time in hours
v_dis = vertical diplacement of the top platen (at the top of the sample) relative to its original position
h_dis = not recorded in these experiments
temp = temperature in degrees celsius

[experiment_number]_smoothed.csv contains the processed data used to plot strain rate vs. strain curves:
smoothed_mean_time = the mean time in hours corresponding to the strain rate data
smoothed_axial_strain = the total axial strain calculated over intervals of 250 data points
smoothed_axial_strain_rate = the axial strain rate calculated over intervals of 250 data points
smoothed_octahedral_strain = the total octahedral strain calculated over intervals of 250 data points
smoothed_octahedral_strain_rate = the octahedral strain rate calculated over intervals of 250 data points

[experiment_number]_FA_smoothed.mat contains fabric analyser data (spatially indexed Euler orientations) formatted to be read by the MTEX toolbox (https://mtex-toolbox.github.io/). These were converted from the original .cis data format using methods outlined in Craw et al., 2021 (reference above).

[experiment_number]_ebsd_smoothed.mat contains EBSD data (spatially indexed Euler orientations) formatted to be read by the MTEX toolbox (https://mtex-toolbox.github.io/). These data have been smoothed using a half quadratic filter.

Please direct any questions to [e-mail].

本数据集采集自三类冰样品的压缩冰变形实验：标准实验室制备冰，以及采自埃默里冰架AM01、AM04与G1岩芯的海冰与大气冰。实验于2018年至2022年间在海洋与南极研究所（IMAS）冰力学实验室开展，遵循Craw等人2021年发表的实验方法进行：

Craw, L.、Treverrow, A.、Fan, S.、Peternell, M.、Cook, S.、McCormack, F. 与 Roberts, J.：《实验中途温度变化对多晶冰变形的影响：温度变化捷径》，《冰冻圈》，15，2235–2250，https://doi.org/10.5194/tc-15-2235-2021，2021。

all_experiments.csv 包含本次所有开展实验的列表，各字段说明如下：
- temperature：实验目标温度，单位为摄氏度（各实验的实际温度记录于对应原始数据文件中）
- ice_type：字符串类型，用于标识冰样类型，可选值为标准冰、海冰或大气冰
- starting_point：实验起始时刻在原始数据文件中的数据点索引，即对样品施加载荷的时刻
- end_point：实验结束时刻在原始数据文件中的数据点索引
- secondary_rate：手动从应变曲线中选取的第二阶段最小应变速率
- secondary_strain：对应第二阶段最小应变速率的总应变
- tertiary_rate_1：手动从应变曲线中选取的第一阶段第三期应变速率
- tertiary_strain_1：对应第一阶段第三期蠕变阶段的总应变
- tertiary_rate_2：手动从应变曲线中选取的第二阶段第三期应变速率，仅存在于包含多个温度节点的实验中
- tertiary_strain_2：对应第二阶段第三期蠕变阶段的总应变
- max_axial_strain：实验达到的最大（最终）轴向应变
- max_octahedral_strain：实验达到的最大（最终）八面体应变
- total_time_hours：实验总运行时长，单位为小时
- total_time_days：实验总运行时长，单位为天
- undeformed_median_grain_size：实验前通过薄片分析测得的中位晶粒尺寸，并非所有实验均记录该参数
- undeformed_number_of_grains：用于计算中位晶粒尺寸的薄片内晶粒总数，用于质量控制
- deformed_median_grain_size：实验后通过薄片分析测得的中位晶粒尺寸，并非所有实验均记录该参数
- deformed_number_of_grains：用于计算中位晶粒尺寸的薄片内晶粒总数，用于质量控制
- undeformed_jindex：实验前取自薄片的样品c轴取向密度表征参数J指数，1代表随机取向分布，无穷大代表单一取向
- deformed_jindex：实验后取自薄片的样品c轴取向密度表征参数J指数，1代表随机取向分布，无穷大代表单一取向

针对all_experiments.csv中列出的每一项实验，均配套提供了原始力学数据文件、处理后的力学数据文件，以及包含织构分析仪数据与电子背散射衍射（EBSD）数据的.mat文件（若已采集对应数据）。

[experiment_number]_raw_data.csv 包含实验过程中记录的原始力学数据：
- time：时间，单位为小时
- v_dis：样品顶部压头相对于初始位置的垂直位移
- h_dis：本次实验未记录该参数
- temp：温度，单位为摄氏度

[experiment_number]_smoothed.csv 包含用于绘制应变速率-应变曲线的处理后数据：
- smoothed_mean_time：与应变速率数据对应的平均时间，单位为小时
- smoothed_axial_strain：以250个数据点为间隔计算得到的总轴向应变
- smoothed_axial_strain_rate：以250个数据点为间隔计算得到的轴向应变速率
- smoothed_octahedral_strain：以250个数据点为间隔计算得到的总八面体应变
- smoothed_octahedral_strain_rate：以250个数据点为间隔计算得到的八面体应变速率

[experiment_number]_FA_smoothed.mat 包含织构分析仪数据（空间索引欧拉取向），格式适配MTEX工具箱（https://mtex-toolbox.github.io/）读取。该数据通过Craw等人2021年（前文引用文献）所述方法从原始.cis数据格式转换而来。

[experiment_number]_ebsd_smoothed.mat 包含电子背散射衍射（EBSD）数据（空间索引欧拉取向），格式适配MTEX工具箱读取。该数据已通过半二次滤波器进行平滑处理。

如有任何疑问，请联系 [e-mail]。