About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract

AAPG Bulletin, V. 95, No. 8 (August 2011), P. 13691381.

Copyright copy2011. The American Association of Petroleum Geologists. All rights reserved.

DOI:10.1306/01031110118

Diagenetic control of deformation mechanisms in deformation bands in a carbonate grainstone

Alexander Rath,1 Ulrike Exner,2 Cornelius Tschegg,3 Bernhard Grasemann,4 Richard Laner,5 Erich Draganits6

1Department of Geodynamics and Sedimentology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria; [email protected]
2Department of Geodynamics and Sedimentology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria; [email protected]
3Department of Lithospheric Research, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria; [email protected]
4Department of Geodynamics and Sedimentology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria; [email protected]
5Department of Geodynamics and Sedimentology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria; [email protected]
6Department of Geodynamics and Sedimentology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria; [email protected]

ABSTRACT

Deformation bands are commonly found in porous silicilastic sediments, where strain is accommodated by rotation, translation, and fracturing of individual grains instead of by the formation of a sharp discontinuity. We investigated deformation bands in a high-porosity carbonate rock from the Eisenstadt-Sopron Basin, on the border between Austria and Hungary, using a combination of microstructural and petrophysical methods. We used cathodoluminescence and electron microprobe analyses to assess the distribution and chemical composition of the carbonate particles, deformation bands, and cements. The earliest deformation bands formed before the cementation of the limestone, mainly by rotation of elongated bioclasts to an orientation parallel to the deformation bands. Further movement along the bands after the generation of blocky cement around the bioclasts resulted in cataclastic deformation of both allochems and cement. Moreover, we documented a reduction of porosity from 22 to 35% in the host rock to 2 to 5% in the deformation bands by microcomputed tomography and conventional helium porosimetry. Permeability is reduced as much as three orders of magnitude relative to the host rock, as documented by pressure decay probe permeametry. The observations indicate a change in physical properties of the rock caused by cementation during the generation of deformation bands, which results in a change of deformation mechanism from grain rotation and compaction to cataclastic deformation along a single band. The reduction of porosity and permeability, which is even stronger than observed in most silicilastic rocks, affects the migration of fluids in groundwater or hydrocarbon reservoirs.

Pay-Per-View Purchase Options

The article is available through a document delivery service. Explain these Purchase Options.

Protected Document: $10
Internal PDF Document: $14
Open PDF Document: $24

AAPG Member?

Please login with your Member username and password.

Members of AAPG receive access to the full AAPG Bulletin Archives as part of their membership. For more information, contact the AAPG Membership Department at [email protected].