Diamonds

The geology of the northern two-thirds of the Northern Territory (NT) is dominated by the North Australian Craton which hosts all of Australia’s producing diamond mines. 

Diamond exploration over the past 30 years has identified an extensive swathe of microdiamonds and diamond indicator minerals that extends from the Nicholson River area near the NT/Queensland border to the Kimberley region of WA. A number of diamond-bearing kimberlite fields have been discovered in the NT, some of which - Merlin and Timber Creek - have been commercially mined. 

A review of the diamond occurrences and prospectivity of the NT is in NTGS Record 2012-001.

Production

At the Merlin field, open cut mining between 1999 and 2006 produced more than 457 339 carats of diamonds. The largest diamond ever found in Australia, a 104.73 ct white gem-quality stone, was recovered from Merlin. 

Geology

The Merlin field contains 13 kimberlite pipes that have been dated at 367 million years old - Devonian - and intrude rocks of the southern McArthur and northern Georgina basins.

Diamond-bearing kimberlite dykes have also intruded sedimentary rocks of the McArthur Basin at the Packsaddle and Blackjack prospects, north east of Mataranka. 

Jurassic-age  -179 million years old - diamond-bearing kimberlite pipes and dykes intrude the Victoria Basin rocks near Timber Creek.

Last updated: 13 October 2017