New Zealand Journal of Geology and Geophysics abstracts

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Note: Haumurian (c. 66-80 Ma) half-graben development and deformation, mid Waipara, North Canterbury, New Zealand

ANDREW NICOL

Department of Geology
University of Canterbury
Private Bag 4800
Christchurch, New Zealand*

*Present address: Fault Analysis Group, Department of Earth Sciences, University of Liverpool, P.O. Box 147, Liverpool L69 3BX, United Kingdom.

Abstract In mid Waipara, North Canterbury, geological mapping has defined the outcrop distribution of Haumurian-aged (c. 66-80 Ma) sedimentary rocks, which locally thicken adjacent to the ESE-striking Birch Fault and are interpreted to have been deposited in a half-graben. Late Cretaceous strata fine upwards from basal conglomerate to muddy quartzose sandstone and reflect a transgressive transition from fluvial to shallow marine environments. These data are in accord with basins documented on the Chatham Rise and suggest that Late Cretaceous extension in Canterbury developed at least as far west as the foothills of the Southern Alps. Locally, in mid Waipara, half-graben development was associated with mild NNE extension (c. 2-3%). Crustal stretching occurred in Canterbury up to c. 30 Ma after continental separation of Gondwana, which is anomalous with respect to the continental breakup model and warrants further investigation.

Keywords Late Cretaceous; half-graben; extension; mid Waipara; Gondwana

Received 22 July 1992; published 13 April 1993
New Zealand Journal of Geology & Geophysics, 1991, Vol. 36: 127—130
0028Ð8306/06/3601—0127 ©The Royal Society of New Zealand 1991

PDF file of entire paper: medium quality (413K); (scanned from paper original: notes about this process). Digitisation of this article from the printed journal was kindly facilitated by the Geological Society of New Zealand

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