Document Type

Article

Publication Title

Tectonics

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Publication Date

3-27-2009

Publication Number

TC2007

Volume Number

28

Abstract/ Summary

Long- and short-term strain variations along the Australian-Pacific plate boundary through the South Island of New Zealand, including a 300% increase in orogen width, coexistence of oblique thrusting on orthogonal structures, and variability in the locus of orogenic gold deposits, coincide with rheologically relevant geological variation. Our model investigates the consequences of thin, strong lower crust in the north and thick, weak lower crust in the south. Solution of the full 3-D mechanical equations reproduces the larger wavelength strain patterns of the orogen. A 3-D perturbation-based analytical solution leads to the identification of the sensitivity of displacement type to minor stress changes. Transition from boundary-normal thrusting to boundary-parallel thrusting occurs at the transition from strong to weak lower crust and is related to an increase in either tau(yz) (shear stress in the yz plane) or the ratio of the coordinate normal stresses, (sigma(yy)/sigma(xx)), where x and y are in the horizontal and z is vertical. Both mechanisms are compatible with the geologically dependent rheological variation employed in our model. Citation: Upton, P., P. O. Koons, D. Craw, C. M. Henderson, and R. Enlow (2009), Along-strike differences in the Southern Alps of New Zealand: Consequences of inherited variation in rheology, Tectonics, 28, TC2007, doi:10.1029/2008TC002353.

Citation/Publisher Attribution

Upton, P, Koons, PO, Craw, D, Henderson, CM, and Enlow, R, 2009, Along-Strike Differences in the Southern Alps of New Zealand: Consequences of Inherited Variation in Rheology: Tectonics, v. 28, TC2007. To view the published open abstract, go to http://dx.doi.org and enter the DOI.

Publisher Statement

© Copyright 2009 American Geophysical Union

DOI

10.1029/2008TC002353

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publisher's version of the published document

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