Olympic Domain SkyTEM312 AEM Survey, South Australia, 2017

The 2017 Olympic Domain Airborne Electro-Magnetic (AEM) Survey was conducted by Geoscience Australia as part of a collaborative project between the Commonwealth of Australia (Geoscience Australia) and its partner the State of South Australia (Department of State Development: Geological Survey of South Australia). Geoscience Australia contracted SkyTEM Australia Pty Ltd to acquire heliborne AEM data over the Olympic Domain in South Australia using their proprietary 312M SkyTEM Interleaved Low Moment and High Moment system trading as "SkyTEMfast". The raw data were processed using SkyTEM Aps Denmark, SkyTEM Australia Pty Ltd’s proprietary software. The survey area consists of 3073.4 line km of time-domain AEM geophysical data acquired in a single survey block located on the 1:250000 map sheets, SH53-12 (Andamooka) and SH53-16 (Torrens) approximately 420 kilometres north-north west of the city of Adelaide, SA. The traverse lines were flown in an East-West orientation with line spacing of 1500 and 3000m. Recent AusLAMP (Australian Lithospheric Architecture Magnetotelluric Project) results and modelling across the Gawler Craton have revealed zones of enhanced crustal conductivity at depths of 15-40km in the mid to lower crust along the eastern margin of the craton. These zones coincide with the highly prospective Olympic Domain IOCG belt and may indicate the presence of a mantle plumbing system that contributed to the formation of the mineral systems and deposits in this belt. A key example of this enhanced crustal conductivity exists in the Prominent Hill-Carrapateena-Punt Hill area within the central Olympic domain. The AEM flight line locations were designed to cover these AusLAMP identified deep crustal conductive zone and investigate possible upward continuation of the deep crustal anomaly through the cover sequence.The data have been inverted with the AarhusInv Program using the Aarhus Workbench LCI algorithm. The data release package includes: 1) Point-located Low Moment & High Moment dB/dt electromagnetic data with associated position, altimeter, orientation, and derived ground elevation data. These data are in ASCII column format with associated ASEG-GDF2 header files. 2) Point-located conductivity data derived from the inversion of the observed data with the AarhusInv Program using the Aarhus Workbench LCI algorithm. 3) Gridded data (600m cell size) in ER Mapper® binary raster grid format with associated header files for the conductivity depth slices derived from the Aarhus Workbench LCI data, with and without depth of investigation (DOI) masking. 4) Gridded magnetics and elevation data in ER Mapper® binary raster grid format with associated header files. 5) Graphical multiplots, in PNG format, for each flight line showing Aarhus Workbench LCI model sections (with DOI mask line) with profiles of the Low & High moment Z component dB/dt data and the model fit residual. 6) Contractor supplied Operations Report. 7) ESRI shapefiles of the flight lines. 8) Metadata and License files.

2017年奥林匹克域航空电磁（Airborne Electro-Magnetic, AEM）调查由澳大利亚地质调查局（Geoscience Australia）牵头开展，系澳大利亚联邦（澳大利亚地质调查局，Geoscience Australia）与其合作伙伴南澳大利亚州（州发展部：南澳大利亚州地质调查局）合作项目的组成部分。澳大利亚地质调查局委托SkyTEM澳大利亚私人有限公司（SkyTEM Australia Pty Ltd），在南澳大利亚州奥林匹克域范围内使用其专有的312M SkyTEM交错式低磁矩与高磁矩系统（对外品牌为"SkyTEMfast"）采集航空电磁数据。原始数据采用SkyTEM澳大利亚私人有限公司的专有软件（由丹麦SkyTEM Aps开发）进行处理。
本次调查覆盖南澳大利亚州阿德莱德市北偏西北约420公里处的单个调查区块，涉及1:250000比例尺图幅SH53-12（阿马库卡）与SH53-16（托伦斯）范围内的3073.4测线公里时域航空电磁地球物理数据。测线采用东西走向布设，线距分别为1500米与3000米。
近期针对高勒克拉通（Gawler Craton）开展的澳大利亚岩石圈构造大地电磁计划（Australian Lithospheric Architecture Magnetotelluric Project, AusLAMP）研究成果与模拟结果显示，在该克拉通东缘的中地壳至下地壳深度15-40公里处，存在地壳导电性增强的区域。这些区域与极具勘探潜力的奥林匹克域铁氧化物铜金型（Iron Oxide Copper Gold, IOCG）矿带重合，或表明存在一个地幔通道系统，该系统促成了该矿带内的矿化系统与矿床形成。奥林匹克域中部的普罗米尼特希尔-卡拉帕蒂纳-庞特希尔区域，便是这类地壳导电性增强现象的典型实例。
本次航空电磁测线的布设位置，旨在覆盖澳大利亚岩石圈构造大地电磁计划（AusLAMP）所识别的深部地壳导电区域，并探究深部地壳异常是否可通过覆盖层序列向上延伸。数据采用AarhusInv程序结合Aarhus Workbench LCI算法进行反演处理。
本次数据发布包包含以下内容：
1) 带点位信息的低磁矩与高磁矩dB/dt电磁数据，配套包含位置、高度计、方位角及推算的地面高程数据。该数据采用ASCII列格式存储，附带ASEG-GDF2格式头文件。
2) 通过AarhusInv程序结合Aarhus Workbench LCI算法对实测数据反演得到的点位式电导率数据。
3) 采用ER Mapper®二进制栅格格式存储的网格化数据（单元格大小为600米），附带头文件，对应由Aarhus Workbench LCI数据生成的电导率深度切片，分别包含与不包含探测深度（Depth of Investigation, DOI）掩膜。
4) 采用ER Mapper®二进制栅格格式存储的网格化磁测数据与高程数据，附带头文件。
5) 每条测线对应的PNG格式多幅组合图，展示Aarhus Workbench LCI模型剖面（带有DOI掩膜线），同时附带低磁矩与高磁矩Z分量dB/dt数据剖面及模型拟合残差。
6) 承包商提交的作业报告。
7) 测线的ESRI形状文件（ESRI shapefiles）。
8) 元数据与许可文件。