10,717 results for University of Waikato

  • Distinguishing between the concepts of steady state and dynamic equilibrium in geomorphology

    Abrahams, Athol D. (1968)

    Journal article
    University of Waikato

    The development of the concept of equilibrium in geomorphology over the past 15 years has been marked by linguistic difficulties due, in part, to the interchangeable use of the terms, dynamic equilibrium and steady state. It is here proposed that the range of steady state conditions constitute a sub-set of the range of conditions of dynamic equilibrium. The application of General Systems Theory is responsible for the introduction to geomorphology of the term steady state which in the strictest sense refers to the tendency for constant forms to develop. Gilbert understood dynamic equilibrium to mean an adjustment between the processes of erosion and the resistance of the bedrock. More recently, Leopold and Langbein described dynamic or quasi-equilibrium as a state of energy distribution which does not necessarily involve any regularity of form. However, dynamic equilibrium finds expression over space and time, in the evolving regularity and mutual adjustment of form elements. The development of regular erosional landforms reflects the tendency of the energy conditions of a system to make the final adjustment to the most probable state. If the manner of landform evolution is the point in question, the concepts of dynamic equilibrium and steady state become clearly distinguishable and system boundaries must be precisely defined. In field studies the theoretical approach is often superseded by the pragmatic approach. However, unless the logical distinction between the two concepts is made in the first place confusion will continue to persist in geomorphic analysis.

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  • Dating of recent low sea level and Maori rock carvings Ongari Point

    Schofield, J.C. (1968)

    Journal article
    University of Waikato

    A sea level of at least 1.5ft below the present one, and contemporaneous rock carvings have a radiocarbon date of 180±50 years B.P.

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  • Development of laboratory instrumentation for the study of soil erodibility

    Bryan, Rorke B. (1968)

    Journal article
    University of Waikato

    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.

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  • The effects of precipitation chemistry and catchment area lithology on the quality of river water in selected catchments in eastern Australia

    Douglas, Ian (1968)

    Journal article
    University of Waikato

    The results of partial chemical analyses of precipitation and river water samples from north-east Queensland and south-eastern New South Wales are presented. Comparisons of water quality in the two areas are made using ionic ratios. While the sodium and chloride contents of precipitation in the two areas are similar, higher concentrations of calcium, magnesium and potassium occur in precipitation samples collected in New South Wales. Precipitation supplies between 25% and 70% of the total solute loads of the rivers studied. In the Southern Tablelands of New South Wales more chloride is supplied to the catchment areas than is removed by the rivers. River water quality reflects catchment lithology more than the climatic contrasts between the two study areas. Nevertheless, precipitation chemistry exerts an influence on the ionic ratios of these Australian rivers with low total dissolved solids concentrations.

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  • Measurement of tide induced changes to water table profiles in coarse and fine sand beaches along Pegasus Bay, Canterbury

    Ericksen, Neil (1970)

    Journal article
    University of Waikato

    Measurements of changing water table profiles in beaches along Pegasus Bay, Canterbury, show an interchange of water between the sea and beach sand pores throughout a single semi-diurnal tidal cycle. The velocity of water escaping from the water table in response to an ebbing tide does not appear sufficient to elutriate material of silt size or larger from the beach. The low computed velocity is thought to be due to hydrostatic control, by sand dunes at the back of the beach, on water table amplitude. Fresh water and wave wash are considered important supplementary sources to that of tidal water in influencing water table profiles.

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  • A flume for studying the relative erodibility of soils and sediments

    Selby, Michael J. (1970)

    Journal article
    University of Waikato

    A flume has been built for studying the erodibility of soils and sediments by gullying. It consists of two boxes containing undisturbed soil samples. One box is set above the other and water from a stilling tank passes over the soil of the upper box and falls onto the soil of the lower box causing lip and channel scour and plunge-pool erosion. The sediment is collected and measured, and a measure of erodibility related to discharge, length of test and sediment yield is thus available.

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  • Contorted stratification with clay lobes in volcanic ash beds, Raglan-Hamilton region, New Zealand

    Tonkin, Philip J. (1970)

    Journal article
    University of Waikato

    Contorted stratification in basal volcanic ash beds of the Pleistocene Hamilton Ash Formation incorporates halloysitic clay lobes which project upward into a bed of predominantly allophanic material. The forms produced are similar to convolute laminations described in other marine and non-marine sedimentary sequences. The halloysitic clay lobes have been described previously as concretions and as the products of differential weathering processes. A third hypothesis is proposed to explain the formation of the clay lobes and associated contorted stratification of these basal ash beds, namely, that the beds were deformed by plastic flowage of halloysitic clay into a sensitive allophanic bed. This deformation was possibly a result of water-saturated beds rapidly losing strength as a result of cyclic reversals of stress and strain produced by earthquake shock waves.

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  • Complex belemnites of the Puaroan (lower-? middle Tithonian) stage in the Port Waikato Region of New Zealand

    Challinor, A.B. (1970)

    Journal article
    University of Waikato

    Belemnite guards range through 2700 feet of Puaroan strata in the Port Waikato region. All are Belemnopsis of the uhligi-complex. Belemnopsis aucklandica aucklandica (Hochstetter) in its most typical form may be restricted to the lower 700 feet of the sequence. Three species are described, together with what may be transitional forms. The morphology of juvenile guards is in marked contrast with that of mature specimens, and development of the adult guard is revealed by examination of internal sections. Some aspects of belemnite paleoecology are discussed. Belemnite biostratigraphy of the area is outlined and the more important fossil localities are described.

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  • An appraisal of nutrient supplies available for tree growth in a pumice soil

    Knight, P.J.; Will, G.M. (1970)

    Journal article
    University of Waikato

    Chemical analyses have confirmed and explained the results of an earlier pot trial in which the availability of major nutrients in six pumice ash layers of Kaingaroa silty sand was assessed by the growth of radiata pine seedlings. Almost all of the tree-available P is found in the present topsoil: the quantities-of P that occur in two buried soils (Waimihia and Rotoma ashes) are almost entirely in the form of organic P which is apparently very resistant to breakdown due to complexing with allophane. The N in these layers is similarly unavailable. The mineral layers, about 4 ft in thickness (Taupo pumice and lapilli), which lie between the present topsoil and the uppermost buried soil, are very low in total N and P and exchangeable Mg, but relatively high in exchangeable K. Only the lower buried soil contains a reasonable quantity of exchangeable Mg and has a Mg : K ratio in favour of Mg.

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  • Coverpage and Contents

    Waikato Geological Society (1970)

    Journal article
    University of Waikato

    Coverpage and Contents from Volume 4, Number 1, 1970 of Earth Science Journal.

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  • The movement of sediment in a channel in relation to magnitude and frequency concepts- a New Zealand example

    Pain, C.F.; Hosking, Peter L. (1970)

    Journal article
    University of Waikato

    In areas where surface wash contributes most of the debris to a channel network, the effect of events of moderate magnitude and frequency appear to be more important than catastrophic events for land form development. In previous studies this idea has been emphasised, largely as a result of the fact that the contribution of bedload to sediment yield has rarely been considered. Examination of these ideas under certain New Zealand conditions would seem to present a somewhat different picture. Where rapid mass movement is the main contributor of sediment to the channel, both the development of hill-slope form and the movement of sediment in channels must be related to the frequency of occurrence of mass movements. The evidence seems to suggest that most major mass movements are triggered during high-intensity, low-frequency storms. The Orere River catchment in the Hunua greywacke block of South Auckland, New Zealand, is examined to test these ideas. Although historical data are limited, the character of the sediments in the lower catchment would suggest a succession of major periods of deposition. High-intensity storms of 1966 and 1967 resulted in the deposition of large amounts of material in the channels throughout the catchment, with a gradual removal of material mainly from the upper catchment since that time. From the limited evidence that is available, a simple model of sediment movement through the catchment is presented.

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  • Coverpage and Contents

    Waikato Geological Society (1970)

    Journal article
    University of Waikato

    Coverpage and Contents from Volume 4, Number 2, 1970 of Earth Science Journal.

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  • Book reviews and Book notices

    Waikato Geological Society (1970)

    Journal article
    University of Waikato

    Book reviews and Book notices from Volume 4, Number 2, 1970 of Earth Science Journal.

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  • Quaternary warping at Gorge Saddle, western Southland

    Force, Eric R.; Force, Lucy M.; Thyne, Martin L. (1970)

    Journal article
    University of Waikato

    Gorge Saddle is one low point on a drainage divide between Fiordland and the Southland Plain. Eastward sloping Quaternary terraces east of the divide and westward sloping terraces to the west contain granitic pebbles which could have been derived only from the west. This suggests doming at the present divide concurrent with transport from the west.

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  • Coverpage and Contents

    Waikato Geological Society (1969)

    Journal article
    University of Waikato

    Coverpage and Contents from Volume 3, Number 2, 1969 of Earth Science Journal.

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  • The Sydney duricrusts: their terminology and nomenclature

    Faniran, Adetoye (1970)

    Journal article
    University of Waikato

    Two main duricrust types - laterites and ferricretes - and their underlying materials are mapped and described for the northern parts of the Sydney district, New South Wales. Laterites are by far the more widespread, being found both in the Wainamatta-Shales and in the Hawkesbury-Sandstone areas, particularly on the broad hilltops and interfiuves of the major divide between the three drainage systems - the north-flowing Hawkesbury-Broken Bay, the south-flowing Parramatta-Port Jackson and the east-flowing Pacific Ocean systems. The ferricretes occur mainly in the drier parts of the northwest, especially in the conglomeratic river gravels of the Maroota area. The two materials have similar profile characteristics but they are different in hand specimen, in textural and structural characteristics, and also in mineralogical composition. The duricrusts and their profiles have been widely destroyed and differentially truncated, so that their various zones and subzones are presently exposed at different places. These materials, especially in respect of laterites, are classified from field and laboratory evidence, according to their recognised, or assigned, position in the typical deep weathering profile. Names are assigned, depending on the area where the best examples were found.

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  • The soils of the southeastern sector of Egmont National Park

    Tonkin, Philip J. (1970)

    Journal article
    University of Waikato

    The soils of the southeastern slopes of Egmont National Park, Taranaki, are youthful in absolute age and also in soil development. They are classed as recent soils on a parent material basis: andesitic tephras, alluvium, and peat with interbedded tephra. Of these groups the former covers the greatest part of the surveyed area and was studied in the most detail. The recent soils from andesitic tephra have a profile form dominated by buried soil horizons and little weathered tephra layers, the youngest of which was erupted 210 years ago. Characteristic features are the very weak weathering of minerals in the upper soil layers, the variable depth of melanisation, the extremely leached state of the soil profile and lastly the marked similarity of the soil chemical parameters despite appreciably different biotic regimes and a range in slope and altitude. It is concluded that the extremely high rainfall, in excess of 150 inches per annum, so controls soil processes that the variables of site and vegetation are not expressed in the measured soil parameters.

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  • Input and output considerations in estimating rates of chemical denudation

    Goudie, Andrew (1970)

    Journal article
    University of Waikato

    Estimation of rates of solutional denudation in river basins necessitates some consideration of salt inputs as well as consideration of salt outputs. Recent work in nutrient cycling has stressed the complexity and importance of the input factor, particularly when throughfall chemistry is taken into account. Frequently the differences between rates of input and output of salt in a river basin are small, suggesting that many published rates of solutional denudation, which consider outputs alone, or inputs only in part, are excessive. The input of salts, which may take place in rain, snow, fog and throughfall are most important in coastal areas. Analysis of data, for both the semi-arid United States and the Cotswold Hills in England, illustrate the need for long-term sampling, and for a detailed spatial network of sampling points.

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  • Book reviews and Book notices

    Waikato Geological Society (1967)

    Journal article
    University of Waikato

    Book reviews and Book notice from Volume 1, Number 1, 1967 of Earth Science Journal.

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  • Notes on the hydrology of the Waikato River

    Ridall, G.T. (1967)

    Journal article
    University of Waikato

    The catchment area of the Waikato River is 5,500 square miles. If its source is accepted as being the Upper Waikato, then its distance to the sea at Port Waikato including its journey through Lake Taupo is 266 miles. It rises, together with the Whangaehu, the Rangitikei and the Wanganui, between the volcanic region of Ruapehu 9,000 ft. above sea level and the Kaimanawa Ranges 5,000 ft. above sea level. The river flows northwards for 34 miles into Lake Taupo, losing its identity into the Tongariro for the last 26 miles to the lake. It emerges from Lake Taupo resuming its proper name and, still flowing northwards, passes for more than 100 miles through a series of lakes formed by hydroelectric dams to Cambridge. From here it continues through a deeply incised channel to Ngaruawahia where it is joined by its major tributary, the Waipa River. From Ngaruawahia to the mouth, a distance of 60 miles, shallow lakes and peat swamps predominate on both sides of the river, many of them protected and drained and developed into rich dairy farms. From Mercer, 35 miles downstream of Ngaruawahia, where slight tidal effects are discernable at low flows, the river changes its general northerly direction to a westerly one and, still 9 miles from the mouth, enters the delta. Here it is fragmented into many channels before emptying into the broad expanse of Maioro Bay and finally emerges by two fairly narrow channels into the sea on the west coast, 25 miles south of Manukau Heads.

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