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| Titel |
Critical Mineralising Plumbing Systems - Analysis Using Wavelets |
| VerfasserIn |
Alison Ord, Bruce Hobbs |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250077891
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| Zusammenfassung |
| Crustal plumbing systems consist of an interconnected set of fractures. Recently, fracture
systems have been viewed as examples of critical systems (Perez-Reche et al., 2008). Various
styles of critical systems can be distinguished. The classical form of critical behaviour occurs
when some tuning parameter (such as elastic modulus or stress) reaches a critical value that
initiates fracture. This is expressed as a single catastrophic event which is repeated as the
system reloads. Another extreme in behaviour is self-organised criticality (SOC) where
the system fails through the development of small avalanches of fractures with
continuous forcing. Perez-Reche et al. (2008) discuss systems that can evolve from
classical criticality to self-organised criticality or to other regimes. Each regime is
characterised spatially by a range in the fractal dimension, D. Massive catastrophic
behaviour (called SNAP), in two dimensions, is characterised by1 -¤ D -¤ 1.5. SOC
has D - 1.5whereas distributed small avalanches (called POP) are characterised
by1.5 -¤ D -¤ 2. The aim is to distinguish SNAP terrains from POP terrains which seem
highly probable mineralising plumbing systems based on previous modelling (Miller
and Nur, 2000) and work by Sibson (1992), Cox (1999) and Cox et al. (2001) that
portrays the evolution of the plumbing system as a swarm of seismic aftershocks; this
constitutes a typical POP regime. We explore whether or not the plumbing systems
for hydrothermal systems have fractal dimensions in the POP-range for critical
systems, and whether or not there is more diagnostic information to be obtained
from the multi-fractal spectrum. The hypothesis is that fracture systems analysed
using wavelets define multifractal patterns which are diagnostic of hydrothermal
systems.
References
Cox SF. Deformational controls on the dynamics of fluid flow in mesothermal
gold systems. In: McCaffrey K, Lonergan L, Wilkinson J, editors. Fractures, Fluid
Flow and Mineralization: Geological Society of London, Special Publications;
1999;123-39.
Cox SF, Braun J, Knackstedt MA. Principles of structural control on permeability and
fluid flow in hydrothermal systems. Reviews in Economic Geology. 2001; 14:1-24.
Miller SA, Nur A. Permeability as a toggle switch in fluid-controlled crustal processes.
Earth and Planetary Sci. Lett.. 2000; 183:133-46.
Perez-Reche F-J, Truskinovsky, L, Zanzotto, Driving-induced crossover: From classical
criticallity to self-organised criticality. Phys. Rev. Let. 2008; 101: 230601.
Sibson RH. Fault-valve behavior and the hydrostatic lithostatic fluid pressure interface.
Earth-Science Reviews. 1992; 32:141-4. |
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