What is exfoliation?
Twidale, C.R.; Bourne, J.A.
published: Dec 1, 2017
manuscript accepted: Nov 1, 2017
manuscript revision received: Oct 31, 2017
manuscript revision requested: Sep 10, 2017
manuscript received: Apr 15, 2015
ArtNo. ESP022006103005, Price: 29.00 €
Abstract At present the term ‘exfoliation’ (and its derivatives) is virtually meaningless because it is used to denote plates of rock ranging in thickness from a millimetre to several metres, which vary in origin. Yet it is an evocative word, for etymologically it suggests thin, leaf-like features. It is suggested that the word be used exclusively in this sense, that is, of laminae, scales or flakes, with qualifying adjectives to indicate origin, where known. Thick slabs though still widely attributed to erosional offloading, are named accordingly. This interpretation is disputed, and the genetically neutral sheet or sheeting fracture and structure are preferable terms. Slabs of a thickness intermediate between these extremes, and referred to by some as pseudo-bedding (which is a misleading term) pose problems. They are well represented in cold lands and are geometrically congruent with sheet fractures. Perhaps spall plates?