Combining geomorphic observations with in situ cosmogenic isotope measurements to study anticline growth and fault propagation in Central Otago, New Zealand

Bennett, E. and Youngson, J. and Jackson, J. A. and Norris, R. and Raisbeck, G. and Yiou, F. (2006) Combining geomorphic observations with in situ cosmogenic isotope measurements to study anticline growth and fault propagation in Central Otago, New Zealand. New Zealand Journal of Geology and Geophysics, 49. pp. 217-231. ISSN 0028–8306

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Abstract

Measurements of 10Be concentrations in quartz-rich boulders exposed by the uplift of anticlinal ranges in Central Otago, New Zealand, are used to investigate the fault propagation styles and rates for the underlying blind reverse faults. 10Be ages along Little Rough Ridge reveal the propagation rate for this fault to be between zero (i.e., not propagating at all, if the ages reflect emergence of a fault of fixed length through a sloping surface) and a maximum of 8.1 mm/yr, if the ages reflect true lateral growth. Regardless of the propagation rate, Little Rough Ridge has established its length rapidly compared with the rate at which it has accumulated displacement. On Raggedy Range, the 10Be ages, together with structural data, imply that the ridge reached its current length by the merging of several small fault segments. This study emphasises the importance of combining 10Be measurements with geomorphic observations. Without understanding the geomorphological context, 10Be exposure ages are difficult to interpret at all; but even with geomorphic data, the interpretation of these ages can still be ambiguous.

Item Type: Article
Uncontrolled Keywords: 2006 AREP 2006 P IA51
Subjects: 02 - Geodynamics, Geophysics and Tectonics
Divisions: 02 - Geodynamics, Geophysics and Tectonics
Journal or Publication Title: New Zealand Journal of Geology and Geophysics
Volume: 49
Page Range: pp. 217-231
Depositing User: Sarah Humbert
Date Deposited: 16 Feb 2009 13:01
Last Modified: 23 Jul 2013 10:01
URI: http://eprints.esc.cam.ac.uk/id/eprint/141

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