title: Sedimentology of Lake Taupo, Central North Island, New Zealand

authors: Lister, Guy Stafford

subjects: Lake Taupo

abstract: Lake Taupo, with an area of 616 km², is the largest of several lakes of volcano-tectonic origin in the Central Volcanic Region, North Island, New Zealand. In the past the lake has been affected by catastrophic volcanic events, the last being the Taupo Pumice eruptions of about 131 A.O. Since then the catchment has restabilised and sedimentation in the lake has diminished.
A number of depositional environments in Lake Taupo are characterised on the basis of surficial sediment texture and depositional processes. These environments include: shelf (sands, gravels, sand-gravel mixtures); slope (silty sands, sandy silts); rise (sandy silts, silts); basin (silts); sub-lacustrine talus slope and sub-lacustrine hill (gravel-sand-mud mixtures).
Close to existing or pre-existing river mouths, and on sub-lacustrine talus slopes, gravels typically include one or more types of catchment-derived rock fragments (andesite, rhyolite, ignimbrite, greywacke). In other parts of the lake, gravels are almost entirely pumice fragments derived from pumice tephras and breccias within the catchment. Shelf and slope sands consist of rock fragments, volcanic glass, quartz and plagioclase feldspar. Slope and rise sediments may also contain sand-sized benthic and aufwuch diatom tests (e.g. Synedra sp., Nitzschia sp., SurireZZa sp.). Basinal sediments include a minor,very fine-fine sand fraction of andesitic Ngauruhoe Ash. Silt in basinal sediments comprises planktic diatom tests (Melosira sp. » Cyclotella sp. ≃Epithemia sp.) and terrigenous grains (volcanic glass, rock fragments, quartz, plagioclase feldspar). Subordinate clay-sized material is dominated by diatomaceous and authigenic silica, detrital illite and kaolinite, and montmorillonite of probable hydrothermal origin.
The distribution and provenance of sediment components in the lake indicate that terrigenous material is derived mainly from southern catchment regions (greywacke and andesite lithologies) and to a lesser extent from the northeastern catchment (rhyolitic volcanics). Gravels and sands are deposited in shallow water where they may be re-worked by coastal processes; suspended silts and clays are transported offshore by surface or inter-flow currents, and deposited in basinal regions of the lake.
An extensive sub-bottom surface of sedimentary pumice, deposited in Lake Taupo during and soon after the Taupo Pumice eruptions, has been identified from sediment cores and seismic profiles of the lake bottom. Mud-layer thicknesses overlying this pumice surface indicate average basinal sedimentation rates of less than 30 mm/yr for central and northern lake regions, to more than 140 mm/yr in southern 1ake regions.
Areal distribution patterns of sediment texture and composition, together with depositional rates, form the basis for a proposed model of sedimentation in Lake Taupo.

text: Sedimentology of Lake Taupo, Central North Island, New Zealand Lake Taupo, with an area of 616 km², is the largest of several lakes of volcano-tectonic origin in the Central Volcanic Region, North Island, New Zealand. In the past the lake has been affected by catastrophic volcanic events, the last being the Taupo Pumice eruptions of about 131 A.O. Since then the catchment has restabilised and sedimentation in the lake has diminished.
A number of depositional environments in Lake Taupo are characterised on the basis of surficial sediment texture and depositional processes. These environments include: shelf (sands, gravels, sand-gravel mixtures); slope (silty sands, sandy silts); rise (sandy silts, silts); basin (silts); sub-lacustrine talus slope and sub-lacustrine hill (gravel-sand-mud mixtures).
Close to existing or pre-existing river mouths, and on sub-lacustrine talus slopes, gravels typically include one or more types of catchment-derived rock fragments (andesite, rhyolite, ignimbrite, greywacke). In other parts of the lake, gravels are almost entirely pumice fragments derived from pumice tephras and breccias within the catchment. Shelf and slope sands consist of rock fragments, volcanic glass, quartz and plagioclase feldspar. Slope and rise sediments may also contain sand-sized benthic and aufwuch diatom tests (e.g. Synedra sp., Nitzschia sp., SurireZZa sp.). Basinal sediments include a minor,very fine-fine sand fraction of andesitic Ngauruhoe Ash. Silt in basinal sediments comprises planktic diatom tests (Melosira sp. » Cyclotella sp. ≃Epithemia sp.) and terrigenous grains (volcanic glass, rock fragments, quartz, plagioclase feldspar). Subordinate clay-sized material is dominated by diatomaceous and authigenic silica, detrital illite and kaolinite, and montmorillonite of probable hydrothermal origin.
The distribution and provenance of sediment components in the lake indicate that terrigenous material is derived mainly from southern catchment regions (greywacke and andesite lithologies) and to a lesser extent from the northeastern catchment (rhyolitic volcanics). Gravels and sands are deposited in shallow water where they may be re-worked by coastal processes; suspended silts and clays are transported offshore by surface or inter-flow currents, and deposited in basinal regions of the lake.
An extensive sub-bottom surface of sedimentary pumice, deposited in Lake Taupo during and soon after the Taupo Pumice eruptions, has been identified from sediment cores and seismic profiles of the lake bottom. Mud-layer thicknesses overlying this pumice surface indicate average basinal sedimentation rates of less than 30 mm/yr for central and northern lake regions, to more than 140 mm/yr in southern 1ake regions.
Areal distribution patterns of sediment texture and composition, together with depositional rates, form the basis for a proposed model of sedimentation in Lake Taupo.

year: 1978

title: Acute hypophagia and changes in c-Fos immunoreactivity in adolescent rats treated with low doses of oxytocin and naltrexone.

authors: Head, Mitchell Antony

subjects: neuropeptides

abstract: A recent case report has shown that an adjunctive oxytocin + naltrexone (OT + NTX) treatment promoted more robust hypophagia and body weight reduction than OT alone in an adolescent male with hypothalamic obesity after craniopharyngioma resection. Thus far, there has been no basic research in adolescent laboratory animals that would examine whether the benefit of OT + NTX on appetite extends onto adolescent individuals without surgically induced overeating. Thus, here we examined whether low doses of combined OT + NTX acutely affect post-deprivation intake of energy-dense, standard chow; intake of energy-dense and palatable high-fat high-sugar (HFHS) diet; or calorie-dilute, palaTable 10% sucrose solution without deprivation in adolescent male rats. We assessed whether OT + NTX decreases water intake after water deprivation or produces a conditioned taste aversion (CTA). Finally, by using c-Fos immunoreactivity, we determined changes in activity of feeding-related brain areas after OT + NTX. We found that individual subthreshold doses of OT and NTX decreased feeding induced by energy and by palatability. Significant c-Fos changes were noted in the arcuate and dorsomedial hypothalamic nuclei. The hypophagic doses of OT + NTX did not suppress water intake in thirsty rats and did not cause a CTA, which suggests that feeding reduction is not a secondary effect of gastrointestinal discomfort or changes in thirst processing. We conclude that OT + NTX is an effective drug combination to reduce appetite in adolescent male rats.

text: Acute hypophagia and changes in c-Fos immunoreactivity in adolescent rats treated with low doses of oxytocin and naltrexone. A recent case report has shown that an adjunctive oxytocin + naltrexone (OT + NTX) treatment promoted more robust hypophagia and body weight reduction than OT alone in an adolescent male with hypothalamic obesity after craniopharyngioma resection. Thus far, there has been no basic research in adolescent laboratory animals that would examine whether the benefit of OT + NTX on appetite extends onto adolescent individuals without surgically induced overeating. Thus, here we examined whether low doses of combined OT + NTX acutely affect post-deprivation intake of energy-dense, standard chow; intake of energy-dense and palatable high-fat high-sugar (HFHS) diet; or calorie-dilute, palaTable 10% sucrose solution without deprivation in adolescent male rats. We assessed whether OT + NTX decreases water intake after water deprivation or produces a conditioned taste aversion (CTA). Finally, by using c-Fos immunoreactivity, we determined changes in activity of feeding-related brain areas after OT + NTX. We found that individual subthreshold doses of OT and NTX decreased feeding induced by energy and by palatability. Significant c-Fos changes were noted in the arcuate and dorsomedial hypothalamic nuclei. The hypophagic doses of OT + NTX did not suppress water intake in thirsty rats and did not cause a CTA, which suggests that feeding reduction is not a secondary effect of gastrointestinal discomfort or changes in thirst processing. We conclude that OT + NTX is an effective drug combination to reduce appetite in adolescent male rats.

year: 2021-12-23

title: Sport in the Waikato c.1897-1974: Narratives of Play, Identity and Belonging

authors: Buckley, Karen

subjects: sport

abstract: Regional identities and allegiances in New Zealand have most often been revealed at sporting events. From the colours worn, the slogans chanted, and even the ringing of cowbells, players, teams and supporters have presented facets of their collective character. This thesis engages with narratives of sport in the Waikato region over a period of eighty years to examine these representations as they produced meanings of sporting activities for local people. Informed by competing ideas about historical truth, the thesis interprets printed media as reconstructions of both recurring events, and belonging and membership, to investigate the place of sport in the region, and to decode the ways these stories of drama and contest contribute to the development of some components of a local identity.
Historically, the area now known as the ‘Waikato’ was part of the Auckland Province. The thesis argues that sport is at the centre of a notion of separation from the urban metropolis, and provided opportunities to demonstrate a growing independence. By examining examples of recurring sporting events such as the annual Ngāruawāhia Regatta, regular Auckland/Waikato rugby matches, Empire and Commonwealth Games participation, and regular lawn bowls tournaments, the place and function of sport in a regional space is able to be, in part, exposed. Uneven, often subtle, changes both in aspects of these events and in the representations of them, reveal underlying tensions and power relationships.
Local, if not exclusive, understandings of the place and role of Māori, and depictions of normative gender roles, are central to the analysis of these relationships. Sport is most often a social activity, and dissection of the newspaper texts has enabled the formation of ideas about the ways sports-men, and sometimes women, are collectively presented and organised. In much of the material used, these men and women are also the most recognisable and celebrated ‘heroes’. Consideration of the role of heroes in the formation of culturally constructed group identities informs the thesis, and the relationships between local sporting participants and groups are also important. Divisions, dissension, and competition for resources are all revealed in the reported activities of sports organisations, and changes in the importance afforded these endeavours are also apparent.
The focussed critical use of a local media source provides a consistent, if sometimes homogenous, group of historical narratives. The inclusion of local club and association histories, often produced with extensive use of newspaper archives, changes the perspective and enables a more nuanced examination of the place of different types of heroes, of gender norms and, most importantly, of the ways sporting organisations see and project themselves as part of the region. The stories they collectively choose to remember and tell are central to this narrative of the place of sport in the Waikato.

text: Sport in the Waikato c.1897-1974: Narratives of Play, Identity and Belonging Regional identities and allegiances in New Zealand have most often been revealed at sporting events. From the colours worn, the slogans chanted, and even the ringing of cowbells, players, teams and supporters have presented facets of their collective character. This thesis engages with narratives of sport in the Waikato region over a period of eighty years to examine these representations as they produced meanings of sporting activities for local people. Informed by competing ideas about historical truth, the thesis interprets printed media as reconstructions of both recurring events, and belonging and membership, to investigate the place of sport in the region, and to decode the ways these stories of drama and contest contribute to the development of some components of a local identity.
Historically, the area now known as the ‘Waikato’ was part of the Auckland Province. The thesis argues that sport is at the centre of a notion of separation from the urban metropolis, and provided opportunities to demonstrate a growing independence. By examining examples of recurring sporting events such as the annual Ngāruawāhia Regatta, regular Auckland/Waikato rugby matches, Empire and Commonwealth Games participation, and regular lawn bowls tournaments, the place and function of sport in a regional space is able to be, in part, exposed. Uneven, often subtle, changes both in aspects of these events and in the representations of them, reveal underlying tensions and power relationships.
Local, if not exclusive, understandings of the place and role of Māori, and depictions of normative gender roles, are central to the analysis of these relationships. Sport is most often a social activity, and dissection of the newspaper texts has enabled the formation of ideas about the ways sports-men, and sometimes women, are collectively presented and organised. In much of the material used, these men and women are also the most recognisable and celebrated ‘heroes’. Consideration of the role of heroes in the formation of culturally constructed group identities informs the thesis, and the relationships between local sporting participants and groups are also important. Divisions, dissension, and competition for resources are all revealed in the reported activities of sports organisations, and changes in the importance afforded these endeavours are also apparent.
The focussed critical use of a local media source provides a consistent, if sometimes homogenous, group of historical narratives. The inclusion of local club and association histories, often produced with extensive use of newspaper archives, changes the perspective and enables a more nuanced examination of the place of different types of heroes, of gender norms and, most importantly, of the ways sporting organisations see and project themselves as part of the region. The stories they collectively choose to remember and tell are central to this narrative of the place of sport in the Waikato.

year: 2016