Structure and kinematics of the Taupo Rift, New Zealand. Issue 6 (24th June 2014)

• Record Type: Journal Article
• Authors: Seebeck, Hannu; Nicol, Andrew; Villamor, Pilar; Ristau, John; Pettinga, Jarg
• Is Part Of: Tectonics. Volume 33:Issue 6(2014:Nov./Dec.)
• Page Start: 1178
• Page End: 1199
• Publication Date: 2014-06-24
• Subjects: Geology, Structural -- Periodicals; 551.8
• DOI: 10.1002/2014TC003569
• Languages: English
• ISSNs: 0278-7407

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <p>The structure and kinematics of the continental intra‐arc Taupo Rift have been constrained by fault‐trace mapping, a large catalogue of focal mechanisms (<italic>N</italic> = 202) and fault slip striations. The mean extension direction of ~137° is approximately orthogonal to the regional trend of the rift and arc front (<italic>α</italic> = 84° and 79°, respectively) and to the strike of the underlying subducting Pacific Plate. Bending and rollback of the subduction hinge strongly influence the location, orientation, and extension direction of intra‐arc rifting in the North Island. In detail, orthogonal rifting (<italic>α</italic> = 85–90°) transitions northward to oblique rifting (<italic>α</italic> = 69–71°) across a paleovertical‐axis rotation boundary where rift faults, extension directions, and basement fabric rotate by ~20–25°. Toward the south, extension is orthogonal to normal faults which are parallel to, and reactivate, steeply dipping basement fabric. Basement reactivation facilitates strain partitioning with a portion of margin‐parallel motion in the overriding plate mainly accommodated east of the rift by strike‐slip faults in the North Island Fault System (NIFS). Toward the north where the rift and NIFS intersect, ~4 mm/yr strike slip is transferred into the rift with net oblique extension accommodating a component of margin‐parallel motion. The trend and kinematics of the Taupo Rift are comparable to late Miocene‐Pliocene intra‐arc rifting in the Taranaki Basin, indicating that the northeast strike of the subducting plate and the southeast extension direction have been uniform since at least 4 Ma.</p> </abstract>