1978 Edition

Mélange; melange

Reference work entry

Mélange (spelled melange in much English-language literature) describes heterogeneous rock units that contain blocks, typically of hard or structurally competent lithologies, surrounded and supported by a fine-grained matrix of shale, slate, or serpentinite. Considerable controversy has surrounded the term mélange since its first use by Greenly (1919), in the description of a unit from Anglesey in the British Isles. Interest in mélanges was revived during the development of plate tectonics, when mélanges were identified as tectonic products of subduction (e.g., Hsu, 1968). Controversy has surrounded both the definition of the term mélange, and the interpretation and origin of units so described.


Almost all definitions of mélange include as critical components the presence of blocks of varied sizes and lithologies, not in contact with each other, and surrounded by a finer-grained matrix. Most geologists have also agreed that a mélange has to be a unit that is mappable,...

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© Dowden, Hutchinson & Ross, Inc. 1978

Authors and Affiliations

  1. 1.Department of Earth and Atmospheric Sciences, 1–26 Earth Sciences BuildingUniversity of AlbertaEdmontonCanada