The Makara Basin: A Miocene Slope-Basin along the New Zealand Sector of the Australian-Pacific Obliquely Convergent Plate Boundary

  1. Peter F. Ballance and
  2. Harold G. Reading
  1. Gerrit J. van der Lingen1 and
  2. Jarg R. Pettinga2,†

Published Online: 20 APR 2009

DOI: 10.1002/9781444303735.ch11

Sedimentation in Oblique-Slip Mobile Zones

Sedimentation in Oblique-Slip Mobile Zones

How to Cite

van der Lingen, G. J. and Pettinga, J. R. (1980) The Makara Basin: A Miocene Slope-Basin along the New Zealand Sector of the Australian-Pacific Obliquely Convergent Plate Boundary, in Sedimentation in Oblique-Slip Mobile Zones (eds P. F. Ballance and H. G. Reading), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444303735.ch11

Author Information

  1. 1

    Sedimentology Laboratory, New Zealand Geological Survey, University of Canterbury, Christchurch, New Zealand

  2. 2

    Geology Department, University of Auckland, Auckland, New Zealand

  1. Department of Geology, University of Canterbury, Christchurch, NZ

Publication History

  1. Published Online: 20 APR 2009
  2. Published Print: 11 SEP 1980

ISBN Information

Print ISBN: 9780632006076

Online ISBN: 9781444303735

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Keywords:

  • Makara Basin - a Miocene slope-basin along New Zealand sector;
  • basin sediments, consisting flysch strata;
  • ichnofossils - Helminthoida crassa, Zoophycos, and Chondrites;
  • Elsthorpe Anticline, developing during late Pliocene and Pleistocene times;
  • Oligocene to early Miocene sequence, containing sediment gravity flow deposits;
  • ‘piercement structures’

Summary

The Miocene Makara Basin in the Hawke's Bay area is one of a series of small Neogene flysch basins within the North Island oblique subduction system. It forms part of the East Coast Deformed Belt, which, together with the Axial Ranges to the west, is situated between the Taupo Volcanic Zone (volcanic arc) and the Hikurangi Trough (subduction trench).

The basin is bounded by narrow zones of highly deformed Upper Cretaceous to Lower Tertiary strata, the Waimarama–Mangakuri Coastal High to the east, and the Otane Anticlinal Complex to the west. These zones were active structural highs during flysch sedimentation. A third structural high, the Elsthorpe Anticline, developed late in the history of the basin, and divided the basin sediments into eastern and western asymmetric synclines.

Basin sediments consist of flysch strata, pebbly mudstones, tuff beds, and hemipelagic mudstones, up to 2200 m thick. The flysch strata, subdivided into four subfacies, are frequency graded, display modified Bouma divisions of sedimentary structures, and have a constant maximum grain size. One subfacies, the Ponui Sandstone, consists of thick units of amalgamated, non-graded, mainly structureless sandstone beds. All these strata were probably deposited by a spectrum of sediment gravity flows, ranging from turbidity currents to fine-grained debris flows, which originated higher up the slope. The local occurrence of pebbly mudstones, deposited by gravelly debris flows and by slumps, reflects derivation from the structural highs. Rhyolitic tuff beds, intercalated in the flysch sequence, and forming the top of the basin fill, were deposited both by sediment gravity flows and ash-falls.

The Makara Basin (and similarly the other Neogene flysch basins in the East Coast Deformed Belt) is interpreted as a small basin (about 30 by 20 km) which originated on the inner slope of the Hikurangi subduction trench. The flysch sediments were ponded in between thrust ridges (the structural highs), formed by imbricate thrust faulting and deformation of the leading edge of the upper plate. The volcanogenic sediments were probably derived from the Coromandel Arc, which was active to the west in Miocene time. The hemipelagic mudstones represent normal slope sedimentation.

Although subduction is taking place obliquely to the trend of the East Coast Deformed Belt, deformation is by compressive folding and thrust faulting only. Strike-slip movements probably were located further to the west.