Distribution of kimberlite and aillikite in the Diamond Province of southern West Greenland: A regional perspective based on groundmass mineral chemistry and bulk compositions

摘要: A regional study of dike and sill occurrences kimberlitic rocks in terms xenolith megacryst assemblages from the diamond province southern West Greenland demonstrates very systematic variation composition melts across margin Archaean core North Atlantic craton. Melt derived window lithospheric mantle below Archean is kimberlitic. Toward Palaeoproterozoic Nagssugtoqidian orogen (also window) gradually change to ultramafic lamprophyre compositions evolving toward an end-member akin aillikites penecontemporaneous Torngat region Canada. The identification types based on groundmass paragenesis including presence or absence clinopyroxene chromite, ilmenite, spinel, phlogopite. also shown, although somewhat blurred, by bulk rock major trace element compositions. melt not a reflection depth initial melting, but relates deep SCLM. Kimberlite craton are suggested be reaction products between carbonate-rich astenospheric orthopyroxene-bearing phlogopite-poor depleted SCLM, whereas aillikite type similar asthenospheric subducted SCLM that had previously been subjected metasomatism veining.