Caledonian (435–425 Ma) and “Grenvillian” (950–900 Ma) S-type leucogranites and augen gneisses are prominent in the thrust units that form the southern half of the East Greenland Caledonian orogen, south of 76°N. Such rocks do not occur further north (76°N–81°N), where the bedrock is dominated by Paleoproterozoic orthogneisses and metagranitoid rocks (2000–1750 Ma). More mafic Caledonian granitoid rocks (quartz diorites, granodiorites, quartz monzonites, syenites, etc.) are found only in the southernmost parts of the orogen (∼71°N), side by side with S-type leucogranites. The S-type granites were formed by partial fusion of “fertile” lithologies within the late Mesoproterozoic Krummedal supracrustal sequence...