Deep Ice Drilling on Law Dome

This dataset includes records from ANARE Research Notes 76; The scientific plan for the deep ice drilling on Law Dome. Per the abstract of the ANARE 76 report:Information on the past climatic and environmental conditions which existed on the surface of the earth and in its oceans, atmosphere and cryosphere can be gained by analysis of the solids, gases, water and dissolved matter contained in the Antarctic ice sheet. The Australian Antarctic Division will undertake a deep drilling program in the summer seasons 1989-90, 1990-91 and 1991-92 near the summit of Law Dome, Antarctica, to extract a 1240m ice core using an electromechanical drill in a fluid-filled borehole. The drill site has been selected to give optimum conditions for a detailed study of climatic and other changes. The snow accumulation rate at the site is 530 kg m^-2 a^-1, the surface temperature is -22 degrees C; and there is no evidence of the occurrence of surface melting in the summer months. It will be possible to determine an accurate age-depth scale for the core by counting annual layers, which are expected to be detectable to a depth of about 800m, equivalent to an age of 10,000 years. The age of the basal ice is expected to be of the order of 50,000 years.The report outlines the types of records it is intended to obtain from analysis of the core and surveys of the borehole, their potential applications and scientific justification. The recommended ice core analysis plan suggests the type and frequency of sampling required for the different parameters and describes the types of measurements and observations that will be made; e.g. visible features, oxygen and hydrogen isotope ratios, solid DC-conductivity, density, total gas content, gas composition, trace chemical and particulate content, radio-isotopes, crystal structure, etc. The high accumulation rate and low surface temperature at the site give excellent conditions for gas composition studies with an age resolution to as good as 20 years for the contained gases. It should also be possible to study the changes that have occurred in many parameters since the last ice age, at any temporal resolution from long term trends down to seasonal variations. Surveys of the borehole will be made to determine the vertical temperature profile and deformation rates inside the ice cap.The interrelation and interdependence of the various measurements is discussed. Experience gained from previous drilling and core analysis programs has been drawn upon to design a core processing and analysis plan. The schedule of activities has been arranged to optimise core conservation and the efficiency of the scheme. Available analysis facilities are reviewed and opportunities for collaboration with institutes in Australia and from other nations are highlighted.An outline of the logistic support required for the efficient running of the field program is included. A full environmental impact evaluation has been carried out elsewhere. A summary of the points addressed in the evaluation is included for information. They are specified in accordance with the Australian Antarctic Division guidelines.The fields in this dataset are:Year drilledLocationDrilling methodDepth of drillingAge at hole bottomTotal thicknessMean annual surface temperatureAnnual accumulation This project was rolled into ASAC project 757 (ASAC_757).The dataset was updated on 2023-06-30 to include scanned copies of log books of data that were collected as part of this project. Basic metadata concerning these log books was provided by Tas van Ommen, and is also included in the data download.The scanned logbooks are:1987 Glaciology Crystal Size 2.pdf1987 Glaciology Crystal Size 3.pdf1987 Glaciology Density In Traverse.pdf1987 Glaciology Law Dome Crystal Size 6.pdf1987 Glaciology Stratigraphy 1 DE08 Core.pdf1987 Glaciology Temperature Readings.pdf1988 Glaciology Crystal Size 5.pdfCasey 1987 Glaciology Crystal Size 4.pdfGW05 GW56 GW60 GW61 FW70 GW54 Stratigraphy Density.pdfLaw Dome 1988 Glaciology Crystal Size 7.pdfSGP SGC SGQ Stratigraphy Observation.pdfSGR LJ24 SGCN BHD Stratigraphy.pdf

本数据集收录自《澳大利亚国家南极研究探险队（ANARE）研究笔记第76号：劳穹隆（Law Dome）深部冰钻探科学计划》。

据ANARE第76号报告摘要所述：通过对南极冰盖所含固体、气体、水体及溶解物质开展分析，可获取地球地表、海洋、大气与冰冻圈既往的气候与环境状况相关信息。澳大利亚南极局（Australian Antarctic Division）计划于1989-1990、1990-1991及1991-1992年夏季，在南极洲劳穹隆主峰附近开展深部钻探项目，采用充液钻孔式电动机械钻机钻取总长1240米的冰芯。

该钻探点位经优选，可为气候及其他变化的精细化研究提供最优条件。该点位的年积雪累积率为530千克/(平方米·年)，地表温度为-22℃，且夏季无表面融雪迹象。通过计数年层，可建立冰芯精确的年龄-深度标尺，预计年层可在约800米深度内被识别，对应年龄可达10000年。冰芯底部冰层的年龄预计约为50000年。

本报告概述了拟通过冰芯分析与钻孔勘测获取的记录类型、相关潜在应用及科学依据。推荐的冰芯分析方案明确了不同参数所需的采样类型与频次，并详述了拟开展的各类测量与观测内容，例如：目视特征、氧与氢同位素比值、固态直流电导率、密度、总气体含量、气体组分、痕量化学组分与颗粒物含量、放射性同位素、晶体结构等。该点位较高的积雪累积率与较低的地表温度，为气体组分研究提供了极佳条件，可实现封存气体高达20年的年龄分辨率。同时，也可针对自末次冰期以来的诸多参数变化开展研究，时间分辨率可覆盖从长期趋势到季节波动的全范围。

将开展钻孔勘测，以获取冰盖内部的垂直温度剖面与变形速率。本报告讨论了各项测量之间的相互关联与依存关系。项目团队借鉴既往钻探与冰芯分析项目的经验，设计了冰芯处理与分析方案。活动日程经过优化，以最大化冰芯保护效果与项目实施效率。报告梳理了可用的分析设施，并重点提及了与澳大利亚及其他国家科研机构开展合作的契机。

本报告还概述了野外项目高效运行所需的后勤保障方案。完整的环境影响评估已在其他文件中完成，本数据集附该评估的要点摘要以供参考，摘要内容符合澳大利亚南极局的相关指南要求。

本数据集包含以下字段：钻探年份、钻探点位、钻探方法、钻探深度、孔底年龄、总厚度、年平均地表温度、年积雪累积量。

本项目已归入ASAC第757号项目（ASAC_757）。

本数据集于2023年6月30日更新，新增了本项目所收集数据的原始日志扫描副本。相关日志的基础元数据由Tas van Ommen提供，同样包含在数据下载包中。本次新增的扫描日志文件如下：
1987 Glaciology Crystal Size 2.pdf
1987 Glaciology Crystal Size 3.pdf
1987 Glaciology Density In Traverse.pdf
1987 Glaciology Law Dome Crystal Size 6.pdf
1987 Glaciology Stratigraphy 1 DE08 Core.pdf
1987 Glaciology Temperature Readings.pdf
1988 Glaciology Crystal Size 5.pdf
Casey 1987 Glaciology Crystal Size 4.pdf
GW05 GW56 GW60 GW61 FW70 GW54 Stratigraphy Density.pdf
Law Dome 1988 Glaciology Crystal Size 7.pdf
SGP SGC SGQ Stratigraphy Observation.pdf
SGR LJ24 SGCN BHD Stratigraphy.pdf