Abstract The Malene supracrustal rocks of northwest Buksefjorden comprise approximately equal proportions of metavolcanic amphibolites and quartz—garnet—sillimanite and quartz—cordierite—anthophyllite gneisses. The amphibolites and quartz—garnet—sillimanite gneisses are locally intruded by metagabbros and amphibolite dykes. The supracrustal rocks occur as slices up to 500 m thick, tectonically interleaved with Amitsoq tonalitic—granitic gneisses (3750 Ma) and intruded by Nuk gneisses synchronous with intense deformation and high amphibolite facies metamorphism (2800 Ma). The Malene gneisses are divided into two principal units. The more extensive unit, here called the Qilangârssuit Malene Gneiss (QMG), is dominated by quartz—garnet—sillimanite gneisses which include local impersistent units of marble, fuchsite gneiss, quartz—plagioclase gneiss and gedrite—magnetite rock. The less extensive unit, here called the Simiutat Malene Gneiss (SMG), consists of quartz-rich cordierite—anthophyllite—mica gneisses with local pods and thin sheets of cordierite—anthophyllite—staurolite rock. Gneisses with a range of composition between those of the principal units are termed Transitional Malene Gneisses (TMG). Most primary structures, except bedding, have been obscured by the deformation and metamorphism. Relative proportions of major elements compared with Al and Ti suggest the original parents of the Malene gneisses were rich in SiO 2 (QMG, 70.63%; SMG, 75.48%), MgO (QMG, 4.60%; SMG, 6.51%) and tot. Fe (QMG, 7.00%; SMG, 2.84%), but contained low CaO (QMG, 0.66%; SMG, 0.20%) and alkalies (Na 2 O: QMG, 1.02%; SMG, 0.50%; K 2 O: QMG, 1.62%; SMG, 0.60%). Alkali metasomatism has affected some gneisses adjacent to concordant sheets of orthogneiss believed to correlate with Nuk gneisses. Comparisons with the chemical composition of common igneous and sedimentary rocks suggest the Malene gneisses had a sedimentary parentage but with unusually high MgO content. The Malene gneiss parents are considered to have been mixtures of detrital quartz and precipitated Mg-rich clay minerals such as palygorskite and attapulgite which occur in modern oceanic sediments. Detrital addition of quartz indicates a sialic provenance in accord with other lines of evidence which suggest that the Malene supracrustal rocks in northwest Buksefjorden were deposited on a sialic foundation of Amitsoq gneisses and older supracrustal amphibolites and metasediments represented by enclaves of the Akilia association. Some implications of these relations for the late Archaean evolution of West Greenland are discussed.