The Heavy Mineral Map of Australia Project -- Data Release 1: The Darling-Curnamona-Delamerian Region

The National Geochemical Survey of Australia (NGSA) is Australia’s only internally consistent, continental-scale geochemical atlas and dataset. The present dataset contains additional mineralogical data obtained on NGSA samples selected from the Darling-Curnamona-Delamerian (DCD) region of southeastern Australia for the first partial data release of the Heavy Mineral Map of Australia (HMMA) project. The HMMA, a collaborative project between Geoscience Australia and Curtin University underpinned by a pilot project establishing its feasibility, is part of the Australian Government-funded Exploring for the Future (EFTF) program. The selected 223 NGSA sediment samples fall within the DCD polygon plus an approximately one-degree buffer. The samples were taken on average from 60 to 80 cm depth in floodplain landforms, dried and sieved to a 75-430 µm grainsize fraction, and the contained heavy minerals (HMs; i.e., those with a specific gravity >2.9 g/cm³) were separated by dense fluids and mounted on cylindrical epoxy mounts. After polishing and carbon-coating, the mounts were subjected to automated mineralogical analysis on a TESCAN® Integrated Mineral Analyzer (TIMA). Using scanning electron microscopy and backscatter electron imaging integrated with energy dispersive X-ray analysis, the TIMA identified over 140 different HMs in the DCD area. The dataset, consisting of over 29 million individual mineral grains identified, was quality controlled and validated by an expert team. The data released here can be visualised, explored and downloaded using an online, bespoke mineral network analysis tool (MNA) built on a cloud-based platform. Accompanying this report are a data file of TIMA results and a mineralogy vocabulary file. When completed in 2023, it is hoped the HMMA project will positively impact mineral exploration and prospectivity modelling around Australia, as well as have other applications in earth and environmental sciences.

澳大利亚国家地球化学调查（National Geochemical Survey of Australia, NGSA）是澳大利亚唯一一套内部统一的大陆尺度地球化学图集与数据集。本数据集包含为支持澳大利亚重矿物图集（Heavy Mineral Map of Australia, HMMA）项目首次部分数据发布，从澳大利亚东南部达令-卡纳莫纳-德拉梅里安（Darling-Curnamona-Delamerian, DCD）区域选取的NGSA样品的额外矿物学数据。HMMA是由澳大利亚地球科学局（Geoscience Australia）与科廷大学（Curtin University）合作开展的项目，其可行性由试点项目奠定基础，隶属于澳大利亚政府资助的“未来勘探（Exploring for the Future, EFTF）”计划。本次选取的223份NGSA沉积物样品均位于DCD区域多边形范围内及周边约1度的缓冲区内。这些样品平均采自泛滥平原地貌下60至80厘米深度处，经干燥、筛分得到75至430微米的粒级组分，随后通过重液分离出其中的重矿物（heavy minerals, HMs，即比重＞2.9 g/cm³的矿物），并将其固定于圆柱形环氧树脂靶片之上。经抛光与碳镀膜处理后，靶片在泰思肯集成矿物分析仪（TESCAN® Integrated Mineral Analyzer, TIMA）上开展自动化矿物学分析。该设备集成扫描电子显微镜、背散射电子成像与能量色散X射线分析技术，在DCD区域内识别出140余种重矿物。本数据集共识别超2900万颗单矿物颗粒，已由专家团队完成质量控制与验证工作。本次发布的数据可通过基于云平台搭建的定制化矿物网络分析工具（mineral network analysis tool, MNA）实现可视化、探索与下载。本报告随附TIMA结果数据集文件与矿物学词汇表。该项目预计于2023年完成，有望为全澳范围内的矿产勘探与远景建模工作提供积极助力，同时亦可应用于地球与环境科学的其他研究领域。