Fault-zone weakening processes along the reactivated Outer Hebrides Fault Zone, Scotland
-
- J. IMBER
- Department of Geological Sciences, University of Durham, South Road, Durham DH1 3LE, UK
-
- R. E. HOLDSWORTH
- Department of Geological Sciences, University of Durham, South Road, Durham DH1 3LE, UK
-
- C. A. BUTLER
- Department of Geological Sciences, University of Durham, South Road, Durham DH1 3LE, UK
-
- G. E. LLOYD
- Department of Earth Sciences, University of Leeds, Leeds LS2 9JT, UK
書誌事項
- 公開日
- 1997-01
- 権利情報
-
- https://doi.org/10.15223/policy-002
- DOI
-
- 10.1144/gsjgs.154.1.0105
- 公開者
- Geological Society of London
この論文をさがす
説明
<jats:p>The Outer Hebrides Fault Zone is a major reactivated structure cutting amphibolite-grade Lewisian basement gneisses in NW Scotland. During a regionally important phase of sinistral strike-slip movements, the influx of chemically active hydrous fluids along the fault zone was associated with the formation of a network of greenschist-facies phyllonitic shear zones. Later ESE-directed extensional strain was preferentially focused into these pre-existing zones of weakness. The syn-tectonic alteration of a relatively strong, feldspar/hornblende-dominated load-bearing framework microstructure to an interconnected weak layer microstructure of fine-grained, strongly aligned phyllosilicate aggregates leads to the long-term weakening in the fault zone. Comparison with experimental data suggests that this produces a shallowing of the frictional-viscous creep ('brittle-ductile') transition and a substantial reduction in total crustal strength. Similar processes may account for the apparent weakness of many long-lived fault zones.</jats:p>
収録刊行物
-
- Journal of the Geological Society
-
Journal of the Geological Society 154 (1), 105-109, 1997-01
Geological Society of London