Interaction of microfractures: The mechanism of network building
2010 (English)In: Tectonophysics, ISSN 0040-1951, E-ISSN 1879-3266, Vol. 485, 215-230 p.Article in journal (Refereed) Published
Microscopic study of fractures in polished sections of Precambrian metamorphic sulphide ore reveals that distinct crack morphologies such as dimensions, orientation, shape and distribution are controlled by mineral associations and temperature conditions during failure. Microfractures developed in a regime of low differential stress where hydraulic pressure triggered the episodic crack opening by pressurized fluids. Fracture arrays consist of segments of varied orientation and width resulting from initially isolated cracks. Linear geometry of fracture systems is complicated by interaction of their segments. Three distinguished types of interaction include in-line propagation of two cracks tip-to-tip (type 1), propagation of two cracks along curved paths towards each other (type 2) and propagation of single crack obliquely towards the other crack (type 3). Different interaction types result from variation in fracture spacing and relative position of their tips and distinguished by the angle of propagation. The ratio of overlap/spacing for interacting fractures is negative (-0.25 to 0) for type 1 interaction and positive for type 2 (0 to 45), and type 3 (0 to 15) interactions. The mean value of the angle of fracture propagation in the onset of the interaction is obtained as 12 degrees for type 1, 25 degrees for type 2 and 38 degrees for type 3 interactions. The mean value of the angle of fracture propagation accommodating linkage is 4 degrees for type 1, 36 degrees for type 2 and 12 degrees for type 3 interactions. The initial crack distribution is crucial in determining whether their coalescence occurs resulting in mature fracture networks.
Place, publisher, year, edition, pages
2010. Vol. 485, 215-230 p.
Microfracture, Propagation, Interaction, Network, Ore
Research subject Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
IdentifiersURN: urn:nbn:se:uu:diva-119743DOI: 10.1016/j.tecto.2009.12.021ISI: 000277103300017OAI: oai:DiVA.org:uu-119743DiVA: diva2:300772