Weakening associated with the diaspore-corundum dehydration reaction in metabauxites: an example from Naxos (Greece)

Citation
Jl. Urai et A. Feenstra, Weakening associated with the diaspore-corundum dehydration reaction in metabauxites: an example from Naxos (Greece), J STRUC GEO, 23(6-7), 2001, pp. 941-950
Citations number
50
Categorie Soggetti
Earth Sciences
Journal title
JOURNAL OF STRUCTURAL GEOLOGY
ISSN journal
01918141 → ACNP
Volume
23
Issue
6-7
Year of publication
2001
Pages
941 - 950
Database
ISI
SICI code
0191-8141(200106/07)23:6-7<941:WAWTDD>2.0.ZU;2-9
Abstract
Metabauxite lenses embedded in marble on Naxos consist of diasporites below the 420 degreesC isograd, and dehydrate into corundum-rich rocks with incr easing grades of metamorphism. While the diasporites are essentially undefo rmed, the corundum-rich rocks are strongly deformed, even though both diasp orites and corundum-rich rocks are much stronger than the surrounding inten sely deformed marbles. The observed structures can be explained as an effec t of high fluid pressures during the prograde diaspore-corundum dehydration reaction, which causes dramatic temporary weakening of the metabauxites (t o a strength comparable to that of the surrounding deforming marbles). Defo rmation of the metabauxite is thus largely restricted to the time span the phase transformation occurred, allowing the dehydrating bauxite mass to def orm together with the surrounding marbles. (C) 2001 Elsevier Science Ltd. A ll rights reserved.