GEUS fieldwork 2006 increases diamond potential of Greenland
The Geological Survey of Denmark and Greenland (GEUS) and the Bureau of Minerals and Petroleum (BMP) have worked together for several years with kimberlites and other alkaline rocks with the aim of throwing more light on the diamond potential of Greenland. In 2006, field work on kimberlite and carbonatite were finished by 8 August with good results.
Exploration east of Maniitsoq revealed an eastward extension of known kimberlite dyke systems and located zones rich in garnet xenocrysts and in nodules of peridotite and eclogite. The new dyke sections are similar in appearance and composition to the microdiamond-bearing Majuagaa dyke to the west.
A completely new and exciting discovery of kimberlite was made during investigations of supracrustal rocks on a 10 km2 large nunatak in the Inland Ice, c. 140 km south-east of Nuuk. Here GEUS geologists discovered a large number of kimberlite boulders in a side moraine along the northern side of the nunatak. The kimberlite erratics occur over a distance of 300 m and are from one cubic centimetre up to 0.5 cubic metre in size. They have a greyish-greenish appearance with abundant fragments and many nodules of crustal, mantle and eclogitic origin. The source of the boulders is unknown, as no in situ kimberlite has yet been seen on the nunatak. Kimberlites have not previously been recorded in this part of Greenland, thus the discovery opens a completely new area for diamond exploration.
Mapping and gamma-spectrometric surveys in the c. 160 Ma old (Jurassic) Tikiusaaq carbonatite complex, (found last year) have confirmed that the complex has a size and structure similar to the coeval Qaqarssuk complex, east of Maniitsoq. The Tikiusaaq complex is rich in apatite and comprises alteration zones expected to be rich in rare earth elements and niobium.
Samples from all the above areas will be analysed during the autumn of 2006, and the results will clarify the importance of the new finds. Final reports of results can be expected during the first half of 2007.
GEUS-geologists Anders Scherstén and Henrik Stendal with the largest kimberlite block they found in the moraine along a nunatak, c. 140 km south-east of Nuuk.