Volume 2, Number 1, 1968

This collection contains all the articles from Volume 2, Number 1, 1968 of the Earth Science Journal.

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Now showing 1 - 5 of 9
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    Coverpage and Contents
    (Journal Article, Waikato Geological Society, The University of Waikato, 1968) Waikato Geological Society
    Coverpage and Contents from Volume 2, Number 1, 1968 of Earth Science Journal.
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    Chronology of fans and terraces in the Galatea Basin
    (Journal Article, Waikato Geological Society, The University of Waikato, 1968) Pain, C.F.; Pullar, W.A.
    Air-borne volcanic ash beds are used to date fans and terraces in the Galatea Basin and to outline the depositional history of this part of the Rangitaiki Valley. The basin is interpreted as a fault-angle depression formed by a downwarped sheet of ignimbrite and an upthrusted block of greywacke which forms the Ikawhenua Range. It is from this range that much of the detritus has been derived to fill the basin, deposited mainly in the form of fans and terraces. The larger fans cover a wide area and their surfaces are older than the Rotoma eruption of c. 8000 years B.P. The widespread occurrence of these fans indicates a major erosion interval between c. 11,000 and c. 8,000 years ago. The younger fans are distributed in a particular order with fans of the Pre-Taupo surface north of the Horomanga Stream and those of the Pre- and Post-Kaharoa surfaces south of the same stream. This ordered distribution of the younger fans suggests a climatic control of fan building. Aggradation and degradation phases in the Rangitaiki and Whirinaki Rivers have formed a pronounced meander trough containing terraces of the Pre-Taupo, Pre-Kaharoa, and Post-Kaharoa surfaces. The terrace of the Pre-Kaharoa surface, largely of Taupo Pumice alluvium, is the most common. Degradation, however, is controlled by a local base level at the ignimbrite rapids on the Rangitaiki River just north of the Galatea Basin.
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    The role of mass-movement in shore platform development along the Gisborne coastline, New Zealand
    (Journal Article, Waikato Geological Society, The University of Waikato, 1968) McLean, R.F.; Davidson, C.F.
    Tidal shore platforms form a conspicuous part of the coastal scenery north of Gisborne, New Zealand. Some of these platforms are being extended landward under present-day conditions. Present widening results primarily from cliff-retreat by mass-movement. The coincidence in distribution of areas of wave convergence, mass-movement and shore platforms suggests a genetic connection between these marine and subaerial process and response elements. Various types of mass-movement are involved in cliff-retreat, notably slumps, flows, debris slides and soil and rock falls. While the products of such mass-movement forms are removed by wave action, extensive boulder fields on some shore platforms indicate that removal is not always complete. Not all of the shore platforms on this coast are being widened at present. Widening has ceased where active mass-movement is not occurring.
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    Bioerosion on shore platforms developed in the Waitemata Formation, Auckland
    (Journal Article, Waikato Geological Society, The University of Waikato, 1968) Healy, Terry R.
    Bioerosion - the removal of lithic substrate by the erosive activities of living organisms- has not previously been discussed for New Zealand shore platforms. This paper aims at drawing attention to bioerosion as a process active in shore platform development. Detailed reference is made to bioerosion occurring on the alternating sandstones and siltstones of the Waitemata Formation found outcropping on the coastline around Auckland. In this area several facets of shore platform morphology may be attributed to the direct effects of boring and browsing marine organisms. A classification of animals causing bioerosion, based on mechanism of erosion, is presented, and the geomorphic significance of the various groups discussed.
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    Development of laboratory instrumentation for the study of soil erodibility
    (Journal Article, Waikato Geological Society, The University of Waikato, 1968) Bryan, Rorke B.
    In order to carry out a study of the relative efficiency of various erodibility indices, and of the relative erodibility of soils developed in the Peak District of Derbyshire (England), three instruments were developed. These instruments were: a wet-sieve aggregate analyser of the Yoder pattern, a compact laboratory rainfall simulator using spray nozzles, a radiant drying unit using infra-red lamps. The efficiency of the instruments and the validity of the operating -techniques are critically evaluated and suggestions for improvement are advanced.
© 1968 Waikato Geological Society, The University of Waikato. All items in Research Commons are provided only to permit fair dealing for the purposes of research or private study. They are protected by copyright with all rights reserved unless otherwise indicated.