Popigai, Siberia - well preserved giant impact structure, national treasury, and world's geological heritage

The about 35-Ma old Popigai impact structure is located on the northern edg e of the Anbar shield in sub-polar Siberia. Among the terrestrial "impact r ing basins", the 100 km diameter Popigai represents the best preserved exam ple with excellent outcrops. In addition, a large number of drill holes and geophysical surveys helped to constrain the sub-surface nature of the crat er making Popigai a three-dimensional model for similar impact structures o n other terrestrial planetary bodies. Moreover, this crater is the type loc ality for impact diamonds surpassing there in their total mass that at all other known diamond deposits together; alone this fact makes Popigai a nati onal treasury. The structure which is most probably linked to ejecta horizo ns occurring in marine sequences of Late Eocene age, has been designated by UNESCO authorities as part of the world's geological heritage. Due to econ omic reasons, exploration work in this quite remotely area has ceased more than a decade ago, making new field studies in this crater virtually imposs ible. We outline the basic characteristics of this world-class site for imp act research, the history of discovery and mineral exploration, and report on IPEX 1997, the first International scientific Popigai Expedition.