Aspects of material transport and polycrystal growth in fractures

The thesis investigates fracture sealing processes from micro- to basin scale. Chapter 2 describes the microstructural evolution of fracture sealing using a self-designed see-through apparatus. Analogue material is used to visualize and model sealing processes on a microscale, which is quantified with a numerical model and extended to fracture sealing of quartz. Chapter 3 describes hydrothermal fracture sealing experiments at hydrothermal conditions carried out in a Paterson rig. A temperature gradient induces a concentration gradient and precipitation in a pre-split quartzite samples, which can be used to qualitatively prediction the sealing potential of natural systems. Chapter 4 describes antitaxial fibrous veins (calcite, gypsum, quartz / Tiger's eye) in different sedimentary environments. A new type of sinusoidal solid host rock inclusion is described, and conclusions are drawn on the vein opening mechanism. The arrangement of solid host rock inclusions do not favour the crack-seal mechanism, but more likely suggest a continuous growth process. The force of crystallisation may have contributed to vein formation. Chapter 5 presents microstructural, stable (d13C, d18O) and radiogenic (87Sr/86Sr) isotope of antitaxial fibrous calcite veins from the Swiss Alps and New York State, USA. At least some veins are isolated in three dimensions, vein formation is initated by transgranular fracturing. Isotope data indicate that the fluid precipitatinig the vein was derived from an external source. Chapter 6 describes fracture sealing processes in Mesozoic limestonee, Jabal Akdhar anticline, Oman mountains. Seven different vein generations were distinguished and correlated with tectonic deformation phases of the Oman mountains. Stable isotope analysis (d13C, d18O) shows a early rock-buffered fluid system, and the influx of exotic waters with the onset of large normal faulting. The veins are correlated with the geomechanical evolution during the different fracture sealing phases, and fluid overpressure compartment is proposed forming the early veins.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2006

Author dc:creator

• Hilgers, Christoph

Contributors dc:contributor

• Urai, Janos
• Cox, Stephen F.
• Bons, Paul

• info:eu-repo/classification/ddc/550
• fluid overpressure
• fracture sealing
• sedimentary rocks
• veins
• Bruchversiegelung
• Fluidüberdruck
• Kluftfüllungen
• Sedimentgesteine
• Geowissenschaften

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

eng

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-112129%22

OAI record oai:identifier

https://publications.rwth-aachen.de/oai2d?verb=GetRecord&metadataPrefix=oai_dc&identifier=oai%3Apublications.rwth-aachen.de%3A46475