The Napier Complex of East Antarctica has been recognised by the International Union of Geological Sciences (IUGS) as a Geological Heritage Site, following a proposal by a team of Earth scientists led by Professor Harley, Emeritus Professor in the School of GeoSciences. Trail Layering - Amundsen Bay: Mount Trail, with other mountains in the background. December 1979 The International Union of Geological Sciences (IUGS) has extended its list of the Earth's geological heritage sites with a selection of 100 sites, announced last week at the IUGS Geoheritage Event in Portugal, to add to the 200 sites designated by 2022. IUGS Geological Heritage Sites are recognised for their outstanding scientific value as exceptional examples of geological features, processes and discoveries. They represent some of the world’s most significant places for understanding the Earth and its history. Located across the globe, they offer an unsurpassed journey through the most important geological sites of the Earth. The Napier Complex Spanning 10,000 km², the Napier Complex is one of the oldest known pieces of Earth's crust, containing rocks and mineral grains - known as zircons - dating back between 2.4 and 3.85 billion years. Riiser Larsen view to summit - December 1979 Geoffrey Hills - view to the Raggatt Mountains, looking east (Simon Harley pictured on the foreground rocks). It is internationally renowned for having undergone metamorphism under extreme heat, with temperatures having reached up to 1050°C deep within the Earth's crust about 2.5 billion years ago. This intense heat and pressure produced rare mineral combinations that survive in very few other places on Earth, including sapphirine with quartz, garnet with osumilite, and orthopyroxene with sillimanite and rutile. These mineral combinations occur on a regional scale in the Napier Complex, making it the unsurpassed example of this type of extreme metamorphism.Chemical and isotopic analysis of 3.85-billion-year-old zircons found in some rocks of the Napier Complex, largely preserved despite the effects of the much younger – though still ancient – extreme metamorphism, offer scientists a rare window into how the planet's first crust formed and evolved. This is yet another reason for its recognition as Geological Heritage Site 243. IUGS Geological Heritage Site status The Napier Complex has been included in this prestigious list because it is recognised internationally, thanks to studies by Professor Harley and several other geoscientists, as the premier and type locality for ultrahigh temperature (UHT) crustal metamorphism. Being so remote, in a seldom-visited region of Antarctica, selection of the Napier Complex as one of the 300 Geological Heritage sites worldwide represents a major accolade for those who have studied its metamorphism and for Antarctic geoscience more broadly. The Napier Complex is currently only one of just 12 global sites now recognised for its metamorphic geology, and one of only 7 sites containing a record of the ancient Archaean Earth. The Napier Complex is also one of only 3 sites located in the continent of Antarctica – for comparison Scotland itself has 5 sites including Hutton’s unconformity at Siccar Point, Barrows Zones and the parallel roads of Glen Roy. Related linksIUGS News | The third 100 IUGS geological heritage sites have been announcedThe full list of IUGS Geological Heritage sites can be found here IUGS Heritage Sites list About the IUGS The International Union of Geological Sciences (IUGS) is a global scientific organisation that promotes international cooperation and advances the Earth sciences. Founded in 1961, it brings together geological organisations and researchers from around the world to support research, education and the development of geological science. This article was published on Monday 9 November 2026
