The west Northland, lower miocene, carpet-bag formation, Manukau Breccia, is declared obsolete and replaced by the Waitakere Group (new). This group is established to contain the igneous and proximal sedimentary products of the lower to mid Miocene west Northland volcanic arc and is divided into three subgroups. The northern, Waipoua, Subgroup (new), consists of the Waipoua Basalt and associated volcaniclastic sediments of the Hokianga - Kaihu area. The central, Hukatere, Subgroup (new), contains volcaniclastic and igneous rocks of the Tokatoka – okahukura Peninsula area, Kaipara. The southern, Manukau, Subgroup, contains igneous rocks and associated volcaniclastic sediments of the Waitakere Hills and adjacent areas. The Waitakere Hills and their northern extension to Helensville (c.500 km2) have been systematically mapped at a scale of 1:25000 and found to consist of a number of tilted or gently folded blocks of Manukau Subgroup having a low, overall, west to north-west tilt. Five formations and thirteen members are established. The oldest sediments are volcanic-rich proximal turbidites (Cornwallis Formation, upper Po, lower Miocene) that overlie and interfinger with the more distal flysch of the Waitemata Group to the east. Cornwallis Formation, and many of the overlying sediments, accumulated at bathyal depths (800 – 3000 m+) on the western side of the Waitemata basin. The proximal turbidites were deposited by south-east flowing turbidity currents that passed down submarine canyons from the neritic Kaipara shelf in the north and north-west. Lenticular conglomerates (Albany Conglomerate, Helensville Conglomerate) accumulated in these canyons and distributary channels of the upper and mid fan regions. In uppermost Otaian to mid Altonian times (late lower Miocene), an apron of coarse volcaniclastic sediments (Piha Formation) spread eastwards over the Waitakere Hills area from a growing volcanic pile centred west of the present coastline. Piha Formation contains well-stratified rudites, subsidiary lenticular, cross-bedded and massive rudites, large slump deposits and peripheral submarine extrusions of and site flows, pillows and hyaloclastite. This coarse volcaniclastic belt was deposited on the neritic and upper.bathyal slopes of the volcanic pile and grades eastwards towards the centre of the basin into a fine volcaniclastic belt (Nihotupu Formation) containing well-bedded arenites and lutites, cross-bedded arenites, lenticular conglomerates, slump units and small piles of pillowed andesite. These were deposited at mid to lower bathyal depths. Substantial mid Altonian uplift in the Waitakere Hills was probably connected with eastwards advancing volcanism. The northern area around Muriwai remained marine for a time and several submarine canyons were eroded through the uplifted shelf and filled with pyroclastic-rich sediments (Tirikohua Formation). An extensive, predominantly terrestrial sheet of andesite flows and pyroclastics (Lone Kauri Formation) was erupted over the uplifted central Waitakere Hills area. This sheet vras possibly erupted from the two north-north-west trending, fault-controlled lineations of volcanic necks, craters, plugs, dyke swarms and intrusions that outcrop today along either side of the hills. Volcanian, strombolian and rare pelean eruptions from these centres produced mostly andesitic products plus one dacite dome (watchman Dacite); these were the last known phases of volcanism in the area (upper Pl - ?Sc, lower to mid Miocene). Macrofaunas have been collected from seventy-six localities in the Waitakere Hills. These can be divided into undisplaced bathyal biocoenoses and displaced thanatocoenoses in which neritic and bathyal faunas were mixed during subaqueous mass flow transport. Analysis of these faunas allows recognition of ten neritic and three bathyal macrofaunal biofacies. Remains of the crustacean Callianassa are recorded. From burrow networks (Thalassinoides) developed in bathyal sediments. Sparse ichnocoenoses composed entirely of feeding and dwelling structures produced by burrowing polychaetes, echinoids and possibly sipunculids occur in basin (mid - lower bathyal) and submarine canyon (outer neritic - upper bathyal) sediments around Maori Bay. A canyon wall ichnocoenosis (outer neritic – upper bathyal), produced in semi-consolidated sediments by burrowing polychaetes, decapod crustacea and possibly amphipods and other organisms, occurs south of Maori Bay. Twelve species from nine genera of hermatypic (reef-building) corals occur in mass flow deposits. They are inferred to have come from sporadically developed communities growing on shallow-water boulder banks around volcanic islands. Comparison of the total lower Miocene hermatypic coral fauna of Northland with present day reefs indicates that seasonal sea termperatures were 5 - 7°c warmer than now. Taxonomic descriptions of fossil corals, molluscs, polychaetes, benthonic foraminifera and trace fossils are given. Archesabella bartrumi gen. et sp. nov. is proposed for fossil tubes containing the body casts of sabellid-like worms. The hermatypic coral genus Goniastrea, trace fossil genus Rhizocorallium, and molluscan subgenera Dentalium (Gadilina), Solariella (Solaricida) and Turbo (Marmarostoma), are recorded from New Zealand for the first time. A new subgenus and species of the gastropod Monilea and new species of the gastropod genera Conacmea, Notoacmea (Parvacmea), Tecticrater, solariella (Solaricida), Turbo (Marmarostoma), Agathirses, "Bartrumella" and Vaqinella are described. A new genus and species of nuculanid bivalve, and new species of the mollusca Nucula, Saccella, Dentalium (Gadilina), Turbo (Marmarostoma), Agathirses, Argobuccinum (Ratifusus), Uttleya and Concholepas are but not named. The New Zealand species of the pteropod Vaginella are redescribed and figured, and the ontogeny of the oyster Crenostrea, discussed. The foraminiferal genus Sherbornina is recorded from New Zealand for the first time, together with thirty-nine overseas species. A further seventeen unnamed foraminiferal species are described. Planktonic foraminifera allow division of the Manukau Subgroup into three biostratigraphic units: upper otaian, lower altonian and mid Altonian. Three-fold subdivision of Scott's Altonian is shown to be possible in northern New Zealand. The lower - middle Altonian boundary is based on the Globorotalia (T.) zealandica zealandica datum, supported by both the temporary absence of Globoguadrina dehiscens and the measurements on the rate of chamber expansion in Globigerinoides t. trilobus populations. The middle – upper Altonian boundary is taken as the Globorotalia (G.) miozea miozea datum, supported by both the reappearance of G. dehiscens and the rate of chamber expansion measurements. Uniformitarian and computer approaches allow the thirty-one richest benthonic foraminiferal samples to be grouped into eight neritic and bathyal thanatotopes. Separate analysis of each thanatotope enables approximate depth limits to be placed on each and gives basin depths of 1500 - 3000 m+. Multidimensional scaling technique using Edwards Great Circle distances was found to be the most useful computer method in clustering the samples. Formations of the Waipoua Subgroup are summarised, and the paleogeography and eruptive history of the Waitakere Group is inferred.

This thesis examines the use of remote sensing techniques for the investigation and monitoring of geothermal areas in the Taupo volcanic zone of New Zealand. The research and development of a helicopter-borne video thermal infrared scanner technique and associated computer image processing methods constitutes the major portion of this study. In addition, preliminary results are presented from a related shallow ground temperature study conducted to investigate diurnal, seasonal and meteorological effects on temperatures in active thermal ground and results from a precursory assessment of SPOT-l satellite multispectral imagery obtained over the Waiotapu Geothermal Field for detecting, identifying and mapping characteristic geothermal surface features are also reported. The initial conduct of two video thermal IR scanner test surveys, one using an Inframetrics 525 over portions of the Rotorua Geothermal Field, the other using a FLIR 1000A over portions of the Wairakei-Tauhara Geothermal Field, demonstrated that imagery useful for basic geothermal feature mapping could be obtained in the late summer to early autumn period. Surveying during the hours around dusk was shown to be appropriate. Experimentation established instrument operating settings and defined nominal survey parameters. The real-time video imagery format proved useful as an aid to navigation and as a check on proper instrument set-up and operation- The helicopter platform provided valuable manoeuvrability and control. The results obtained from these two initial surveys aided development of survey design and conduct methodology. The video imagery obtained with both the Inframetrics and FLIR scanners was compatible with New Zealand's PAL standard- Visual TV-VCR inspection of the IR imagery allowed easy identification of a range of natural thermal features. Identification of cultural features aided location of the thermal anomalies. The Inframetrics imagery suffered from serious banding and other minor problems. The FLIR imagery was of a generally higher quality, though it exhibited problems. The fundamental ability to digitize images from the videotapes and apply powerful computer image processing techniques to aid interpretation and analysis was demonstrated. A methodology for pre-processing and enhancing the digitized Inframetrics and FLIR images was developed. Application of these image processing techniques brought out detail unavailable in the grey-level imagery and greatly increased interpretation ability. The demonstrated success of the first two test surveys led to the conduct of the first known large-scale video thermal IR scanner surveys of geothermal fields. Most details of the first of these ate confidential (at the client's request). A complete range of geothermal features was detected and easily recognised and their distribution established thus providing a much more detailed map of the geothermal activity than was previously available. The successful results attained confirmed the survey design and conduct methodology used. The second and largest survey covered the entire Rotorua Geothermal Field (l8 km2). Imagery was obtained with both the Inframetrics and FLIR IR scanners and a visible wavelength video camera. Extensive ground control measurements were made. This comprehensive survey of geothermal activity established a baseline from which change can be monitored The survey identified large scale seepage and submerged thermal input into Lake Rotorua which may be the source of known missing chloride. The first geothermal surface feature changes were identified, thus demonstrating the usefulness of the method for monitoring change. Preliminary image temperature calibration results were obtained and a procedure for constructing visible wavelength-thermal IR composite images was developed. The positive results demonstrated by this survey have led to the helicopter-borne video thermal IR technique being adopted for major geothermal feature mapping and monitoring programmes in New Zealand. Preliminary assessment of the high spatial resolution (20m) SPOT-1 multispectral imagery of the Waiotapu Geothermal Field. showed that the larger geothermal surface features can be detected and identified on a contrast stretched, 3-band colour composite image. A shallow (≤ 1m depth) ground temperature measurement site was established in an area extending from very active to near ambient conditions. Preliminary results show that temperature variations ranging from l-19 °C can occur in the most active ground. These temperature variations exhibit a strong negative correlation with atmospheric prcss111e changes and can introduce large, unexpected inaccuracies in ground temperature measurements.

In several areas of Auckland, urban development has resulted in flooding and siltation problems that have been both difficult and expensive to manage. This study investigates the fluvial processes of runoff and sediment generation with a pastoral catchment of the Albany Basin and assesses the potential hydrological impacts of urban development with its catchment area. During the study period this catchment was on the fringe of the urban development of Auckland's North Shore. By examining the factors that control runoff and sediment generation within a pastoral catchment, site information that may be useful for controlling runoff and sediment generation within an urbanised Albany Basin is gained. To assess the impacts of urban development, streamflows and suspended sediment yields from catchments representative of three different land uses are compared: pastoral, urban construction and developed urban. Stream channel enlargement indices for a number of nearby catchments with different proportions of urban land cover are also determined and compared. The study shows significant increases in stormflows and suspended sediment yields from catchments that are either fully developed or undergoing construction for urban use. But due to the relatively dry weather experienced during the study period these results are thought to underestimate the impact of urbanising the Albany Basin. The investigation of stream channel enlargement shows that for totally urban catchments stream channel cross-sectional areas may be nearly three times those for pastoral catchments. Methods for controlling the impact of urban development on streamflows, sediment yields and channel enlargement are discussed. It is proposed that by developing techniques where by storm runoff is dispersed and stored within the considerable soil moisture storage capacity of an urban land cover, of the type planned for the Albany Basin, that a considerable reduction in stormflow and sediment generation may be achieved. The study concludes that through careful land use planning and the use of appropriate control structure the impacts of urban development may be reduced to acceptable levels.

This dissertation presents the results of research of physical and biological processes of sedimentation on the shoreface and continental shelf in Pakiri Bay, on the east coast of the Northland Peninsu1a, New Zealand. These environments comprise the subtidal portion of the Pakiri sand body. Sand bodies that are contiguous with unconsolidated sediments of coastal barriers are characteristic of the embayed east coasts of the Auckland and Northland Regions, yet little is known of their geomorphology. Existing models of shoreface and shelf sedimentation afford limited assistance because they were developed in different environments. Factors that distinguish the study area from other coasts include tectonic stability, lack of modern (non-biogenic) sediment inputs, the predominance of currents related to shoaling surface waves, and a sea level stillstand for the last 6,500 years. The model of sedimentation developed is derived from intensive field investigation of the morphology, sedimentology and ecology of the Pakiri Bay shoreface and continental shelf. Investigations of sediment transport entail interpretations of the sediments and sedimentary structures of the seabed, application of existing sediment transport models and the analysis of morphodynamic data. The geomorphology of the Pakiri sediment body is characterized by a regular pattern of morphologic components and associated sediment types. Alongshore variation in these characteristics is generally minor compared with shore normal variation. The shoreface comprises a curvilinear concave surface, that extends offshore from the alongshore bar approximately 1500 m, to water depths of about 22 n. The inner continental shelf comprises an equally curvilinear, mostly convex, surface that slopes seaward to the relatively flat middle continental shelf. Secondary morphological variations result from the presence of large-scale bedforms on the middle continental shelf and landward margin of the inner shelf. The sediments of the shoreface are fine, very well sorted quartz-feldspathic sands of 2 ø mean grain size. The inner shelf sediments grade offshore from a medium sand to very coarse sands and fine gravels (mean grain size 0.0 to 0.5 ø). In contrast the sediments of the mid shelf are very fine sands (mean grain size 2.0 to 2.5 ø), with a mud content of 5 to l0 percent. Carbonate skeletal debris, derived mostly from molluscs, comprises a significant proportion of inner and mid shelf sediments. The concentration of carbonates in the sediments increases offshore from 0 to 5 percent on the shoreface to 30 percent at the base of the inner shelf. The carbonate fraction of the sediments is size graded on the inner shelf and mid shelf in accordance with the grain size characteristics of the non-carbonate fraction. A model of the distribution and abundance of living macrobenthos (mostly of the phyla mollusca) is derived from benthos surveys in Pakiri Bay. Species that are diagnostic of high and low energy environments are characteristic of the shoreface and middle continental shelf respectively. The pattern of carbonate concentration in the sediments of the subtidal sediment body does not correlate with the pattern of modern biogenic production. Highest levels of modern shell production occur across the shoreface, whereas carbonate concentrations are greatest at the base of the inner shelf. Hypotheses are advanced to explain this dichotomy. The geomorphology of the shoreface and inner continental shelf is seen as a response to modern processes of sedimentation. Sediment transport occurs primarily in response to currents related to shoaling waves. Two process regimes are recognized. During typically calm (swe11 wave) conditions the fine sands of the shoreface may be transported landward as a result of an onshore mass transport current. During severe storm events this process may transport bed sediments landward across the inner shelf and middle continental shelf forming the characteristic sediment and morphologic patterns observed. However, during such events this onshore flow is, probably counteracted by return flows that are able to transport eroded foreshore and inshore sediments seaward Key words: Sedimentation, shoreface, continental shelf, wave dominated, carbonated sedimentation, sediment body, facies.

The soil seed bank in Agathis australis (D. Don) Lindl. (kauri) forests of northern New Zealand is quantified, and its potential role in secondary successions examined. Seed bank data from a number of kauri forest sites stratified by successional time and distance from forest edges are summarized using Detrended Correspondence Analysis (ordination) and linear regression models. A number of issues concerning secondary successions and the soil seed bank are discussed. These include: 1. The relationship between the soil seed bank and extant vegetation. 2. The nature of the soil seed bank and successional time. 3. The nature of the soil seed bank and distance from forest edges. 4. The soil seed bank, canopy gaps and gap regeneration strategies. 5. The nature of the soil seed bank and soil properties. 6. The fruiting phenology, seed rain, and soil seed bank dynamics. The forest sites ranged from 50 years to over 1,000 years old, while distance from forest edges ranged from 0.2 km to 3.5 km. Soil seed bank densities under kauri forests were 134 - 5,388 seeds m-2 with a mean density of 1,320±217 seeds m-2 which is similar to estimates reported for temperate and tropical forest sites elsewhere. The spatial distribution of seeds in the seed bank both within and between sites is highly variable. A total of 6,062 seedlings emerged from the seed bank samples. This represented 62 vascular plant species, 26 (42%) native woody, 19 (30%) native weedy, 16 (26) adventive weedy and 1 (2%) native fern. The species composition of the soil seed bank was not closely related to extant vegetation and only 11%ot canopy and 13% of understorey species were represented in the soil seed bank. Thus, 77% of extant vegetation at any given site is floristically different from that of the soil seed bank. Ordination of the data by detrended correspondence analysis (DCA) suggested that extant vegetation (canopy and understorey) and the soil seed bank contain characteristic floras. The species composition of the seed bank is variable between sites. The viable seed pool is larger under young successional forests than under older mature forests. The number of species also declined with distance from forest edges. Adventive and native weedy species were found in seed banks under mature forests and sites of considerable distances from forest edges. However, the density of the weedy species component of the soil seed bank was at least partly determined by distance from forest edges where such species are common. While buried seed is likely to contribute to the early stages of secondary succession, evidence from canopy gaps suggested that the seedling bank (formerly suppressed understorey component) is more important in gap regeneration than the soil seed bank. DCA analysis revealed that seedling bank species composition of canopy gaps and forest sites were quite different from the soil seed banks, indicating that regeneration stemmed from formerly (suppressed) understorey seedlings. Phenology and seed rain study of a mature forest remnant and a regenerating forest community showed that as little as 5% of the seed input to the forest floor enters the soil seed bank and remains viable for more than one year. Evidence is presented to suggest that in a forest community, secondary succession after large-scale or localised disturbance, is achieved more so by suppressed seedlings and recent seed rain than the soil seed bank. The soil seed bank becomes significant in secondary succession when the subsoil is disturbed by the uprooting of trees or the forest floor is exposed by tree-fall (not covered by tree-fall debris).

The west Northland, lower miocene, carpet-bag formation, Manukau Breccia, is declared obsolete and replaced by the Waitakere Group (new). This group is established to contain the igneous and proximal sedimentary products of the lower to mid Miocene west Northland volcanic arc and is divided into three subgroups. The northern, Waipoua, Subgroup (new), consists of the Waipoua Basalt and associated volcaniclastic sediments of the Hokianga - Kaihu area. The central, Hukatere, Subgroup (new), contains volcaniclastic and igneous rocks of the Tokatoka – okahukura Peninsula area, Kaipara. The southern, Manukau, Subgroup, contains igneous rocks and associated volcaniclastic sediments of the Waitakere Hills and adjacent areas. The Waitakere Hills and their northern extension to Helensville (c.500 km2) have been systematically mapped at a scale of 1:25000 and found to consist of a number of tilted or gently folded blocks of Manukau Subgroup having a low, overall, west to north-west tilt. Five formations and thirteen members are established. The oldest sediments are volcanic-rich proximal turbidites (Cornwallis Formation, upper Po, lower Miocene) that overlie and interfinger with the more distal flysch of the Waitemata Group to the east. Cornwallis Formation, and many of the overlying sediments, accumulated at bathyal depths (800 – 3000 m+) on the western side of the Waitemata basin. The proximal turbidites were deposited by south-east flowing turbidity currents that passed down submarine canyons from the neritic Kaipara shelf in the north and north-west. Lenticular conglomerates (Albany Conglomerate, Helensville Conglomerate) accumulated in these canyons and distributary channels of the upper and mid fan regions. In uppermost Otaian to mid Altonian times (late lower Miocene), an apron of coarse volcaniclastic sediments (Piha Formation) spread eastwards over the Waitakere Hills area from a growing volcanic pile centred west of the present coastline. Piha Formation contains well-stratified rudites, subsidiary lenticular, cross-bedded and massive rudites, large slump deposits and peripheral submarine extrusions of and site flows, pillows and hyaloclastite. This coarse volcaniclastic belt was deposited on the neritic and upper.bathyal slopes of the volcanic pile and grades eastwards towards the centre of the basin into a fine volcaniclastic belt (Nihotupu Formation) containing well-bedded arenites and lutites, cross-bedded arenites, lenticular conglomerates, slump units and small piles of pillowed andesite. These were deposited at mid to lower bathyal depths. Substantial mid Altonian uplift in the Waitakere Hills was probably connected with eastwards advancing volcanism. The northern area around Muriwai remained marine for a time and several submarine canyons were eroded through the uplifted shelf and filled with pyroclastic-rich sediments (Tirikohua Formation). An extensive, predominantly terrestrial sheet of andesite flows and pyroclastics (Lone Kauri Formation) was erupted over the uplifted central Waitakere Hills area. This sheet vras possibly erupted from the two north-north-west trending, fault-controlled lineations of volcanic necks, craters, plugs, dyke swarms and intrusions that outcrop today along either side of the hills. Volcanian, strombolian and rare pelean eruptions from these centres produced mostly andesitic products plus one dacite dome (watchman Dacite); these were the last known phases of volcanism in the area (upper Pl - ?Sc, lower to mid Miocene). Macrofaunas have been collected from seventy-six localities in the Waitakere Hills. These can be divided into undisplaced bathyal biocoenoses and displaced thanatocoenoses in which neritic and bathyal faunas were mixed during subaqueous mass flow transport. Analysis of these faunas allows recognition of ten neritic and three bathyal macrofaunal biofacies. Remains of the crustacean Callianassa are recorded. From burrow networks (Thalassinoides) developed in bathyal sediments. Sparse ichnocoenoses composed entirely of feeding and dwelling structures produced by burrowing polychaetes, echinoids and possibly sipunculids occur in basin (mid - lower bathyal) and submarine canyon (outer neritic - upper bathyal) sediments around Maori Bay. A canyon wall ichnocoenosis (outer neritic – upper bathyal), produced in semi-consolidated sediments by burrowing polychaetes, decapod crustacea and possibly amphipods and other organisms, occurs south of Maori Bay. Twelve species from nine genera of hermatypic (reef-building) corals occur in mass flow deposits. They are inferred to have come from sporadically developed communities growing on shallow-water boulder banks around volcanic islands. Comparison of the total lower Miocene hermatypic coral fauna of Northland with present day reefs indicates that seasonal sea termperatures were 5 - 7°c warmer than now. Taxonomic descriptions of fossil corals, molluscs, polychaetes, benthonic foraminifera and trace fossils are given. Archesabella bartrumi gen. et sp. nov. is proposed for fossil tubes containing the body casts of sabellid-like worms. The hermatypic coral genus Goniastrea, trace fossil genus Rhizocorallium, and molluscan subgenera Dentalium (Gadilina), Solariella (Solaricida) and Turbo (Marmarostoma), are recorded from New Zealand for the first time. A new subgenus and species of the gastropod Monilea and new species of the gastropod genera Conacmea, Notoacmea (Parvacmea), Tecticrater, solariella (Solaricida), Turbo (Marmarostoma), Agathirses, "Bartrumella" and Vaqinella are described. A new genus and species of nuculanid bivalve, and new species of the mollusca Nucula, Saccella, Dentalium (Gadilina), Turbo (Marmarostoma), Agathirses, Argobuccinum (Ratifusus), Uttleya and Concholepas are but not named. The New Zealand species of the pteropod Vaginella are redescribed and figured, and the ontogeny of the oyster Crenostrea, discussed. The foraminiferal genus Sherbornina is recorded from New Zealand for the first time, together with thirty-nine overseas species. A further seventeen unnamed foraminiferal species are described. Planktonic foraminifera allow division of the Manukau Subgroup into three biostratigraphic units: upper otaian, lower altonian and mid Altonian. Three-fold subdivision of Scott's Altonian is shown to be possible in northern New Zealand. The lower - middle Altonian boundary is based on the Globorotalia (T.) zealandica zealandica datum, supported by both the temporary absence of Globoguadrina dehiscens and the measurements on the rate of chamber expansion in Globigerinoides t. trilobus populations. The middle – upper Altonian boundary is taken as the Globorotalia (G.) miozea miozea datum, supported by both the reappearance of G. dehiscens and the rate of chamber expansion measurements. Uniformitarian and computer approaches allow the thirty-one richest benthonic foraminiferal samples to be grouped into eight neritic and bathyal thanatotopes. Separate analysis of each thanatotope enables approximate depth limits to be placed on each and gives basin depths of 1500 - 3000 m+. Multidimensional scaling technique using Edwards Great Circle distances was found to be the most useful computer method in clustering the samples. Formations of the Waipoua Subgroup are summarised, and the paleogeography and eruptive history of the Waitakere Group is inferred.

This thesis examines the use of remote sensing techniques for the investigation and monitoring of geothermal areas in the Taupo volcanic zone of New Zealand. The research and development of a helicopter-borne video thermal infrared scanner technique and associated computer image processing methods constitutes the major portion of this study. In addition, preliminary results are presented from a related shallow ground temperature study conducted to investigate diurnal, seasonal and meteorological effects on temperatures in active thermal ground and results from a precursory assessment of SPOT-l satellite multispectral imagery obtained over the Waiotapu Geothermal Field for detecting, identifying and mapping characteristic geothermal surface features are also reported. The initial conduct of two video thermal IR scanner test surveys, one using an Inframetrics 525 over portions of the Rotorua Geothermal Field, the other using a FLIR 1000A over portions of the Wairakei-Tauhara Geothermal Field, demonstrated that imagery useful for basic geothermal feature mapping could be obtained in the late summer to early autumn period. Surveying during the hours around dusk was shown to be appropriate. Experimentation established instrument operating settings and defined nominal survey parameters. The real-time video imagery format proved useful as an aid to navigation and as a check on proper instrument set-up and operation- The helicopter platform provided valuable manoeuvrability and control. The results obtained from these two initial surveys aided development of survey design and conduct methodology. The video imagery obtained with both the Inframetrics and FLIR scanners was compatible with New Zealand's PAL standard- Visual TV-VCR inspection of the IR imagery allowed easy identification of a range of natural thermal features. Identification of cultural features aided location of the thermal anomalies. The Inframetrics imagery suffered from serious banding and other minor problems. The FLIR imagery was of a generally higher quality, though it exhibited problems. The fundamental ability to digitize images from the videotapes and apply powerful computer image processing techniques to aid interpretation and analysis was demonstrated. A methodology for pre-processing and enhancing the digitized Inframetrics and FLIR images was developed. Application of these image processing techniques brought out detail unavailable in the grey-level imagery and greatly increased interpretation ability. The demonstrated success of the first two test surveys led to the conduct of the first known large-scale video thermal IR scanner surveys of geothermal fields. Most details of the first of these ate confidential (at the client's request). A complete range of geothermal features was detected and easily recognised and their distribution established thus providing a much more detailed map of the geothermal activity than was previously available. The successful results attained confirmed the survey design and conduct methodology used. The second and largest survey covered the entire Rotorua Geothermal Field (l8 km2). Imagery was obtained with both the Inframetrics and FLIR IR scanners and a visible wavelength video camera. Extensive ground control measurements were made. This comprehensive survey of geothermal activity established a baseline from which change can be monitored The survey identified large scale seepage and submerged thermal input into Lake Rotorua which may be the source of known missing chloride. The first geothermal surface feature changes were identified, thus demonstrating the usefulness of the method for monitoring change. Preliminary image temperature calibration results were obtained and a procedure for constructing visible wavelength-thermal IR composite images was developed. The positive results demonstrated by this survey have led to the helicopter-borne video thermal IR technique being adopted for major geothermal feature mapping and monitoring programmes in New Zealand. Preliminary assessment of the high spatial resolution (20m) SPOT-1 multispectral imagery of the Waiotapu Geothermal Field. showed that the larger geothermal surface features can be detected and identified on a contrast stretched, 3-band colour composite image. A shallow (≤ 1m depth) ground temperature measurement site was established in an area extending from very active to near ambient conditions. Preliminary results show that temperature variations ranging from l-19 °C can occur in the most active ground. These temperature variations exhibit a strong negative correlation with atmospheric prcss111e changes and can introduce large, unexpected inaccuracies in ground temperature measurements.

In several areas of Auckland, urban development has resulted in flooding and siltation problems that have been both difficult and expensive to manage. This study investigates the fluvial processes of runoff and sediment generation with a pastoral catchment of the Albany Basin and assesses the potential hydrological impacts of urban development with its catchment area. During the study period this catchment was on the fringe of the urban development of Auckland's North Shore. By examining the factors that control runoff and sediment generation within a pastoral catchment, site information that may be useful for controlling runoff and sediment generation within an urbanised Albany Basin is gained. To assess the impacts of urban development, streamflows and suspended sediment yields from catchments representative of three different land uses are compared: pastoral, urban construction and developed urban. Stream channel enlargement indices for a number of nearby catchments with different proportions of urban land cover are also determined and compared. The study shows significant increases in stormflows and suspended sediment yields from catchments that are either fully developed or undergoing construction for urban use. But due to the relatively dry weather experienced during the study period these results are thought to underestimate the impact of urbanising the Albany Basin. The investigation of stream channel enlargement shows that for totally urban catchments stream channel cross-sectional areas may be nearly three times those for pastoral catchments. Methods for controlling the impact of urban development on streamflows, sediment yields and channel enlargement are discussed. It is proposed that by developing techniques where by storm runoff is dispersed and stored within the considerable soil moisture storage capacity of an urban land cover, of the type planned for the Albany Basin, that a considerable reduction in stormflow and sediment generation may be achieved. The study concludes that through careful land use planning and the use of appropriate control structure the impacts of urban development may be reduced to acceptable levels.

This dissertation presents the results of research of physical and biological processes of sedimentation on the shoreface and continental shelf in Pakiri Bay, on the east coast of the Northland Peninsu1a, New Zealand. These environments comprise the subtidal portion of the Pakiri sand body. Sand bodies that are contiguous with unconsolidated sediments of coastal barriers are characteristic of the embayed east coasts of the Auckland and Northland Regions, yet little is known of their geomorphology. Existing models of shoreface and shelf sedimentation afford limited assistance because they were developed in different environments. Factors that distinguish the study area from other coasts include tectonic stability, lack of modern (non-biogenic) sediment inputs, the predominance of currents related to shoaling surface waves, and a sea level stillstand for the last 6,500 years. The model of sedimentation developed is derived from intensive field investigation of the morphology, sedimentology and ecology of the Pakiri Bay shoreface and continental shelf. Investigations of sediment transport entail interpretations of the sediments and sedimentary structures of the seabed, application of existing sediment transport models and the analysis of morphodynamic data. The geomorphology of the Pakiri sediment body is characterized by a regular pattern of morphologic components and associated sediment types. Alongshore variation in these characteristics is generally minor compared with shore normal variation. The shoreface comprises a curvilinear concave surface, that extends offshore from the alongshore bar approximately 1500 m, to water depths of about 22 n. The inner continental shelf comprises an equally curvilinear, mostly convex, surface that slopes seaward to the relatively flat middle continental shelf. Secondary morphological variations result from the presence of large-scale bedforms on the middle continental shelf and landward margin of the inner shelf. The sediments of the shoreface are fine, very well sorted quartz-feldspathic sands of 2 ø mean grain size. The inner shelf sediments grade offshore from a medium sand to very coarse sands and fine gravels (mean grain size 0.0 to 0.5 ø). In contrast the sediments of the mid shelf are very fine sands (mean grain size 2.0 to 2.5 ø), with a mud content of 5 to l0 percent. Carbonate skeletal debris, derived mostly from molluscs, comprises a significant proportion of inner and mid shelf sediments. The concentration of carbonates in the sediments increases offshore from 0 to 5 percent on the shoreface to 30 percent at the base of the inner shelf. The carbonate fraction of the sediments is size graded on the inner shelf and mid shelf in accordance with the grain size characteristics of the non-carbonate fraction. A model of the distribution and abundance of living macrobenthos (mostly of the phyla mollusca) is derived from benthos surveys in Pakiri Bay. Species that are diagnostic of high and low energy environments are characteristic of the shoreface and middle continental shelf respectively. The pattern of carbonate concentration in the sediments of the subtidal sediment body does not correlate with the pattern of modern biogenic production. Highest levels of modern shell production occur across the shoreface, whereas carbonate concentrations are greatest at the base of the inner shelf. Hypotheses are advanced to explain this dichotomy. The geomorphology of the shoreface and inner continental shelf is seen as a response to modern processes of sedimentation. Sediment transport occurs primarily in response to currents related to shoaling waves. Two process regimes are recognized. During typically calm (swe11 wave) conditions the fine sands of the shoreface may be transported landward as a result of an onshore mass transport current. During severe storm events this process may transport bed sediments landward across the inner shelf and middle continental shelf forming the characteristic sediment and morphologic patterns observed. However, during such events this onshore flow is, probably counteracted by return flows that are able to transport eroded foreshore and inshore sediments seaward Key words: Sedimentation, shoreface, continental shelf, wave dominated, carbonated sedimentation, sediment body, facies.

The soil seed bank in Agathis australis (D. Don) Lindl. (kauri) forests of northern New Zealand is quantified, and its potential role in secondary successions examined. Seed bank data from a number of kauri forest sites stratified by successional time and distance from forest edges are summarized using Detrended Correspondence Analysis (ordination) and linear regression models. A number of issues concerning secondary successions and the soil seed bank are discussed. These include: 1. The relationship between the soil seed bank and extant vegetation. 2. The nature of the soil seed bank and successional time. 3. The nature of the soil seed bank and distance from forest edges. 4. The soil seed bank, canopy gaps and gap regeneration strategies. 5. The nature of the soil seed bank and soil properties. 6. The fruiting phenology, seed rain, and soil seed bank dynamics. The forest sites ranged from 50 years to over 1,000 years old, while distance from forest edges ranged from 0.2 km to 3.5 km. Soil seed bank densities under kauri forests were 134 - 5,388 seeds m-2 with a mean density of 1,320±217 seeds m-2 which is similar to estimates reported for temperate and tropical forest sites elsewhere. The spatial distribution of seeds in the seed bank both within and between sites is highly variable. A total of 6,062 seedlings emerged from the seed bank samples. This represented 62 vascular plant species, 26 (42%) native woody, 19 (30%) native weedy, 16 (26) adventive weedy and 1 (2%) native fern. The species composition of the soil seed bank was not closely related to extant vegetation and only 11%ot canopy and 13% of understorey species were represented in the soil seed bank. Thus, 77% of extant vegetation at any given site is floristically different from that of the soil seed bank. Ordination of the data by detrended correspondence analysis (DCA) suggested that extant vegetation (canopy and understorey) and the soil seed bank contain characteristic floras. The species composition of the seed bank is variable between sites. The viable seed pool is larger under young successional forests than under older mature forests. The number of species also declined with distance from forest edges. Adventive and native weedy species were found in seed banks under mature forests and sites of considerable distances from forest edges. However, the density of the weedy species component of the soil seed bank was at least partly determined by distance from forest edges where such species are common. While buried seed is likely to contribute to the early stages of secondary succession, evidence from canopy gaps suggested that the seedling bank (formerly suppressed understorey component) is more important in gap regeneration than the soil seed bank. DCA analysis revealed that seedling bank species composition of canopy gaps and forest sites were quite different from the soil seed banks, indicating that regeneration stemmed from formerly (suppressed) understorey seedlings. Phenology and seed rain study of a mature forest remnant and a regenerating forest community showed that as little as 5% of the seed input to the forest floor enters the soil seed bank and remains viable for more than one year. Evidence is presented to suggest that in a forest community, secondary succession after large-scale or localised disturbance, is achieved more so by suppressed seedlings and recent seed rain than the soil seed bank. The soil seed bank becomes significant in secondary succession when the subsoil is disturbed by the uprooting of trees or the forest floor is exposed by tree-fall (not covered by tree-fall debris).