Diamond exploration and prospectivity of Greenland. Gov Greenland Department of Geology Record 1, 228 pp.

Greenland is dominated by cratonic blocks that provide conditions for the formation of diamonds. Pre-1.6 Ga rocks are exposed over 43% of ice-free land and many basins in younger areas evidence underlying Archean basement. Studies of mantle xenoliths reveal thick mantle lithosphere to 220 km in the North Atlantic Craton of western Greenland. Kimberlites, ultramafic lamprophyres and lamproites are known to be exposed abundantly, and span 1632 Ma of geological time. With carbonatites, 3029 discrete bedrock diamond-prospective occurrences have been identified. Known diamondiferous bodies are well represented over Greenland’s west coast, most notably the Garnet Lake 4 metre-thick composite aillikite / kimberlite sheet at Sarfartoq, and aillikite sheets at Qeqertaa, Disko Bay. Data from these, and other localities, demonstrate the potential for Greenland to host diamondiferous bodies with large, good quality diamonds in potentially economic concentrations. While preserved pipes may be discovered at higher elevations, the rarity of known pipes and diatremes evidences extensive glacial erosion and raises the potential for offshore and paleoplacer deposits. The Government of Greenland’s Diamond exploration data package is used to conduct a regional diamond prospectivity analysis. Most prior exploration targeted diamond indicator minerals in alluvial and glaciogenic samples averaging 10 kg in weight, and with inspection of recovered indicators concluding that sampling strategies have been adequate. Indicator minerals, including garnet, all reveal mineral chemistries consistent with deep mantle sources, often within the diamond stability field, and ilmenite compositions often support very high diamond preservation. All geographic subdivisions overlap chemistries of indicators from diamond-producing areas of Canada. The North Atlantic Craton of West Greenland and the Ketilidian Orogen of southern Greenland show particularly consistent diamond-prospective chemistries, while the Rae Craton of western Greenland is more variable. Quantitative prospectivity modelling incorporating geophysical data emphasises the importance of these regions but also highlights potential in the under-explored Inglefield Orogen and North Atlantic Craton of eastern Greenland. Historical data, compared with more regional, indirect prospectivity metrics show that further opportunities for diamond exploration exist in Greenland in selected areas of the west coast, as well as within less-explored areas such as eastern and northern regions, and offshore.

格陵兰岛以克拉通地块为主，这些地块为钻石的形成提供了条件。早于1.6亿年的岩石在超过43%的无冰土地上露出，而在较年轻地区的许多盆地中，也揭示了下伏的太古代基岩。对地幔捕掇体的研究揭示了在格陵兰岛西部的北大西洋克拉通中，地幔岩石圈厚度可达220公里。金伯利岩、超基性辉长岩和辉长岩广泛露出，地质年代跨度达16.32亿年。与碳酸盐岩一起，已识别出3029个具有钻石潜力的离散基岩点。在格陵兰岛的西海岸，已知的含钻石矿体得到了良好的代表，最著名的是位于Sarfartoq的Garnet Lake 4米厚的复合辉绿岩/金伯利岩层，以及Disko湾的辉绿岩层。这些数据以及其他地区的数据表明，格陵兰岛具有孕育大型、高质量钻石的潜在经济浓度的含钻石矿体的可能性。尽管在高海拔处可能发现保存的管道，但已知管道和裂隙的稀有性表明了广泛的冰川侵蚀，并提高了近海和古沉积物的可能性。格陵兰政府提供的钻石勘探数据包被用于进行区域钻石勘探潜力分析。大多数先前的勘探都针对了冲积和冰川样品中的钻石指示矿物，平均重量为10公斤，通过检查回收的指示矿物，得出采样策略是充分的。指示矿物，包括石榴石，其矿物化学成分均与深地幔来源一致，通常位于钻石稳定性场内，而钛铁矿的成分通常支持非常高的钻石保存率。所有地理分区都与加拿大钻石产出区的指示矿物化学成分重叠。西格陵兰的北大西洋克拉通和南格陵兰的凯蒂利迪安造山带显示出尤其一致的钻石勘探化学成分，而西格陵兰的雷克拉通则更为多变。结合地球物理数据的定量勘探潜力建模强调了这些地区的重要性，同时也突出了在不太开发的英格尔菲尔德造山带和东格陵兰北大西洋克拉通中的潜在价值。与更区域性的间接勘探潜力指标相比，历史数据显示，在格陵兰岛西海岸的选定区域以及东部和北部等较少开发的地区，以及近海地区，进一步探索钻石的机会仍然存在。