Structure of the Hanmer strike-slip basin, Hope fault, New Zealand

Abstract

Research Article| November 01, 1994 Structure of the Hanmer strike-slip basin, Hope fault, New Zealand RAY A. WOOD; RAY A. WOOD 1Institute of Geological and Nuclear Sciences Ltd., P.O. Box 1320, Wellington, New Zealand Search for other works by this author on: GSW Google Scholar JARG R. PETTINGA; JARG R. PETTINGA 2Department of Geology, University of Canterbury, Christchurch, New Zealand Search for other works by this author on: GSW Google Scholar STEPHEN BANNISTER; STEPHEN BANNISTER 1Institute of Geological and Nuclear Sciences Ltd., P.O. Box 1320, Wellington, New Zealand Search for other works by this author on: GSW Google Scholar G. LAMARCHE; G. LAMARCHE 1Institute of Geological and Nuclear Sciences Ltd., P.O. Box 1320, Wellington, New Zealand Search for other works by this author on: GSW Google Scholar TIMOTHY J. McMORRAN TIMOTHY J. McMORRAN 2Department of Geology, University of Canterbury, Christchurch, New Zealand Search for other works by this author on: GSW Google Scholar GSA Bulletin (1994) 106 (11): 1459–1473. https://doi.org/10.1130/0016-7606(1994)106<1459:SOTHSS>2.3.CO;2 Article history first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation RAY A. WOOD, JARG R. PETTINGA, STEPHEN BANNISTER, G. LAMARCHE, TIMOTHY J. McMORRAN; Structure of the Hanmer strike-slip basin, Hope fault, New Zealand. GSA Bulletin 1994;; 106 (11): 1459–1473. doi: https://doi.org/10.1130/0016-7606(1994)106<1459:SOTHSS>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract Hanmer basin (10 x 20 km), located in northern South Island, New Zealand, is evolving where two major segments of the dextral strike-slip Hope fault are projected to converge across a 6- to 7-km-wide releasing step-over. The structural geometry and development of Hanmer basin does not conform to traditional pull-apart basin models.The respective fault segments do not overlap but are indirectly linked along the southwest margin of the basin by an oblique normal fault. The Hope River segment terminates in an array of oblique normal faults along the northwestern basin range front, and east-west-striking normal faults on the west Hanmer Plain. Faulted Holocene alluvial-fan surfaces indicate west Hanmer basin is actively subsiding evolving under north-south extension. The Conway segment along the southeastern margin of the basin terminates in a complex series of active fault traces, small pop-up ridges, and graben depressions. Early basin-fill sediments of Pleistocene age are being folded, elevated, and dissected as the eastern part of Hanmer basin is progressively inverted and destroyed by north-south contraction.The north margin of the basin is defined by a series of topographic steps caused by normal faulting outside of the area of the releasing step-over. These normal faults we interpret to reflect large-scale upper crustal collapse of the hanging-wall side of the Hope fault.New seismic reflection data and geologic mapping reveal a persistent longitudinal and lateral asymmetry to basin development. Four seismic stratigraphic sequences identified in the eastern sector of the basin thicken and are tilted southward, with insequence lateral onlaps occurring to the north and east, and also onto basement near the fault-controlled basin margins. The basin depocenter currently contains >1000 m of sediment adjacent to the south margin and is disrupted by faulting only at depth. In the western part of the basin, the sediment fill is thinner (<500 m) and is intensely faulted across the entire basin width.Today the rate of basin deepening under transtension at the western end is matched by its progressive inversion and destruction under transpression in the eastern sector, with the oldest basin fill now being recycled. We propose a hybrid model for Hanmer strike-slip basin, one in which geometric elements of a fault-wedge basin (downward and upward tipped, spindle-shaped ends) are combined with those of a pull-apart basin (step-over region between the major fault segments). We also conclude that changes in fault geometry (releasing and restraining bends and step-overs) at a variety of scales and over short distances control the development of the extensile and contractile parts of the basin and three-dimensional basin asymmetry. Strain partitioning is complex and cannot be related simply to local reorientation of the regional stress field. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.