The Ancient Jade Mine Discovered in Dunhuang Hanxia of Northern Gansu Province: A Potential Important Source of Jade Material in Early Stage of China

The discovery of ancient jade mining sites is of great value for the confirmation of the origin of jade artifacts unearthed from archaeological sites. Dunhuang Hanxia ancient jade mining site is located in the southeast of Dunhuang city, and was discovered by the research team of Gansu Institute of Cultural Relics and Archaeology and the School of Earth Science and Engineering of Sun Yat-sen University jointly under the guidance of local amateur in September 2015. In the same year, 145 remains related to various types of mining on the ground were identified in Hanxia. The formal research supported by the National Natural Science Foundation of China on Dunhuang ancient jade mine and jade material transmission have been carried out since 2016. The site was officially excavated by the Gansu Institute of Cultural Relics and Archaeology in 2019. According to the dating of carbon isotope and cultural types of pottery, the earliest mining age of the site is confirmed to be 4 000 years ago. Based on the research with the scattered jade materials near the mine and the excavation jade materials, the main jade material of Hanxia jade mining sites in Dunhuang is nephrite, which can be divided into primary jade and Gobi material by their occurrence, and can be further grouped into white jade, green-white / yellow-white jade and other types by colour. According to the relationship between the occurrence of the mineralization and magmatic rocks, we confirm that the ancient jade deposits belong to the genesis of contact metasomatism. The jade materials can also be split into two types, i.e. metasomatic replacement jade material(R- type)and hydrothermal precipitation material(P-type). Initial evidence shows that in the late Neolithic period, the jade materials from the ancient jade mining (sites) in Northern Gansu Province entered the Central Plains of China and indicates that Mazongshan and Dunhuang Hanxia ancient jade deposits in Northern Gansu Province are potential important sources of jade materials in early stage of China.