TY - JOUR AU - Nielsen, Troels F.D. AU - Jebens, Martin AU - Jensen, Sven M. AU - Secher, Karsten PY - 2006/11/29 Y2 - 2024/03/28 TI - Archetypal kimberlite from the Maniitsoq region, southern West Greenland and analogy to South Africa JF - GEUS Bulletin JA - GEUS Bulletin VL - 10 IS - SE - RESEARCH ARTICLE | SHORT DO - 10.34194/geusb.v10.4906 UR - https://geusbulletin.org/index.php/geusb/article/view/4906 SP - 45-48 AB - <p>Ultramafic dyke rocks with kimberlitic megacrysts and mantle nodules have been known for decades from the northern part of the Archaean block and adjacent Proterozoic terranes in southern West Greenland (Fig. 1; Escher &amp; Watterson 1973; Goff 1973; Scott 1981; Larsen &amp; Rex 1992; Mitchell <em>et al.</em> 1999). Some of the dykes have proved to be diamondiferous (see Jensen <em>et al.</em> 2004a, b, for exploration results, diamond contents, and references). The <em>c.</em> 600 Ma old dykes werecalled ‘kimberlitic’ by Larsen &amp; Rex (1992), but Mitchell <em>et al.</em> (1999) concluded that they were best referred to a ‘carbonatiteultramafic lamprophyre’ suite (aillikites or melnoites). Mitchell <em>et al.</em> (1999) further suggested that the West Greenland province represents “one of the few bona fide examples of ultramafic lamprophyre which contain diamonds”. Reports on indicator mineral assemblages (Jensen <em>et al.</em> 2004b) and diamond contents (e.g. Hudson Resources Inc. 2005) have re-opened the discussion on the classification of the dykes. The results of an investigation of the Majuagaa dyke (Nielsen &amp; Jensen 2005) are summarised below, together with the preliminary results of a regional investigation of the groundmass minerals of the dykes. It is concluded that dykes in the Maniitsoq region are similar to archetypal, South African, on-craton, Type 1 kimberlites, and that all regions of the West Greenland province of ultramafic magmatism are favourable for diamond exploration.</p> ER -