Genesis of self-organized zebra textures in burial dolomites : displacive veins, induced stress, and dolomitization
Merino, E. (Indiana University. Department of Geological Sciences)
Canals i Sabaté, Àngels (Universitat de Barcelona. Departament de Cristal·lografia, Mineralogia i Dipòsits Minerals)
Fletcher, R. C. (Pennsylvania State University. Department of Geosciences)

Data:	2006
Resum:	The dolomite veins making up rhythmites common in burial dolomites are not cement infillings of supposed cavities, as in the prevailing view, but are instead displacive veins, veins that pushed aside the host dolostone as they grew. Evidence that the veins are displacive includes a) small transform-fault-like displacements that could not have taken place if the veins were passive cements, and b) stylolites in host rock that formed as the veins grew in order to compensate for the volume added by the veins. Each zebra vein consists of crystals that grow inward from both sides, and displaces its walls via the local induced stress generated by the crystal growth itself. The petrographic criterion used in recent literature to interpret zebra veins in dolomites as cements - namely, that euhedral crystals can grow only in a prior void - disregards evidence to the contrary. The idea that flat voids did form in dolostones is incompatible with the observed optical continuity between the saddle dolomite euhedra of a vein and the replacive dolomite crystals of the host. The induced stress is also the key to the self-organization of zebra veins: In a set of many incipient, randomly-spaced, parallel veins just starting to grow in a host dolostone, each vein's induced stress prevents too-close neighbor veins from nucleating, or redissolves them by pressure-solution. The veins that survive this triage are those just outside their neighbors's induced stress haloes, now forming a set of equidistant veins, as observed.
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan aquestes es distribueixin sota la mateixa llicència que regula l'obra original i es reconegui l'autoria de l'obra original.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Rhythmite ; Zebra texture ; Breccia texture ; Displacive Veins ; Induced stress ; Self-organization ; Burial dolomitization
Publicat a:	Geologica acta, Vol. 4, Núm. 3 (2006) , p. 383-393, ISSN 1696-5728

Adreça alternativa: https://raco.cat/index.php/GeologicaActa/article/view/82338
Adreça alternativa: https://revistes.ub.edu/index.php/GEOACTA/article/view/105.000000352
DOI: 10.1344/105.000000352

11 p, 528.6 KB

El registre apareix a les col·leccions:
Articles > Articles publicats > Geologica acta
Articles > Articles de recerca