title: Morphology and geochemistry of glauconite from the Te Kuiti Group, South Auckland region, New Zealand

authors: Compton, Martyn Stephen

abstract: The late Eocene - Oligocene Te Kuiti Group comprises calcareous mudstone, calcareous sandstone and skeletal or sandy limestone formed in marginal marine to fully marine shelf settings. Glauconite is ubiquitous in all sedimentary units in low concentration (5-10%), but at unconformities or near formation boundaries can attain concentrations > 75%.
Binocular microscope studies show· the following morphological form abundances: ovoidal(40-55%) > fragmentary(20-40%) > lobate(5-15%) > casts (0-5%) with trace quantities of tabular, capsule, and vermicular grains. The abundance of ovoidal and fragmentary glauconite suggests the glauconite is dominantly allogenic. Only the highly fragile cast and lobate grains are considered reliable indicators of authigenic glauconite.
Because distinction of morphological types using the binocular microscope is subjective, an alternative classification based on measured variables using image analysis was attempted. Seven measurements (area, formfactor, convexicity, length, fractal, aspect, and fibre) were made for each grain image. Seven glauconite morphological types were investigated: capsule, cauliflower, fragmentary, lobate, ovoidal, tabular, and vermicular. Measurement data were analysed using canonical variate analysis. The calculated discriminating vectors were then used to distinguish the seven morpological forms. Using two canonical variates 81.5% of the variability within the database was accounted for.
X-ray diffraction studies shows a predominance of poorly crystalline glauconite. Many difficulties were encountered when applying previous literature techniques for calculating the expandable content of glauconite. An alternative technique based on the relationship between %K₂0 and % expandables is favoured for the calculation of % expandables. A relationship between host sediment lithology and glauconite expandable content was found; siltstone = 20-32%. expandables in the glauconite, sandstone = 8-15% expandables in the glauconite.
Major element data were obtained with the electron microprobe for 327 individual glauconite grain centres of 70 samples from 45 sites and 7 formations in the Te Kuiti. Group. The. chemical data were analysed using canonical variate analysis and the seven formations were clearly distinguished. Because only a small glauconite sample size is required (4-5 grains) the technique has potential for determining the stratigraphic correlation of drill core samples and small hand specimens of Te Kuiti Group material containing glauconite.
The range composition of Te Kuiti Group glauconite calculated from EMP major element data using the "Clayform" program is:
(Si ₃.₄₀₋₃.₆₈ Al ₀.₃₂₋₀.₆₀) (Al ₀.₀₈₋₀.₄₁ Fe ₁.₀₀³⁺₋₁.₃₆ Fe ₀.₁₉²⁺₋₀.₂₆ Mg ₀.₄₀₋₀.₆₀) (Ca ₀.₀₂₋₀.₁₆ Na ₀.₀₀₋₀.₀₄ K₀.₄₉₋₀.₆₇) O₁₀(OH₂)
The Te Kuiti Group passes stratigraphically upward from terrigenous and mixed terrigenous-skeletal carbonate deposits to very pure limestones. Early post-depositional diagenetic processes probably released Mg from the carbonate lattice of accumulating skeletal grains. Some of the released Mg was incorporated into the glauconite lattice as evidenced by the increase in Mg content of glauconite stratigraphically upward, parallel with the increased carbonate content of the rocks.
Major and trace element data were obtained using X-ray fluorescence for 29 bulk glauconite concentrates from 21 sites and 5 formations. Notably there were anomalous Mg, Pb and Ni concentrations in glauconite from the Otorohanga - Waitomo -Te Kuiti area. This suggests the area existed as a small semi-enclosed embayment, with a significantly higher terrigenous input compared with adjacent depocentres.
A strong correlation between the La/Ce ratio of glauconite and paleontological and oxygen isotope-derived sea-water temperatures suggests glauconite La/Ce ratio may be a useful paleotemperature indicator. The data collected in this study show no single previously suggested process adequately decribes the development of glauconite. Rather, glauconite should be considered polygenetic.

text: Morphology and geochemistry of glauconite from the Te Kuiti Group, South Auckland region, New Zealand The late Eocene - Oligocene Te Kuiti Group comprises calcareous mudstone, calcareous sandstone and skeletal or sandy limestone formed in marginal marine to fully marine shelf settings. Glauconite is ubiquitous in all sedimentary units in low concentration (5-10%), but at unconformities or near formation boundaries can attain concentrations > 75%.
Binocular microscope studies show· the following morphological form abundances: ovoidal(40-55%) > fragmentary(20-40%) > lobate(5-15%) > casts (0-5%) with trace quantities of tabular, capsule, and vermicular grains. The abundance of ovoidal and fragmentary glauconite suggests the glauconite is dominantly allogenic. Only the highly fragile cast and lobate grains are considered reliable indicators of authigenic glauconite.
Because distinction of morphological types using the binocular microscope is subjective, an alternative classification based on measured variables using image analysis was attempted. Seven measurements (area, formfactor, convexicity, length, fractal, aspect, and fibre) were made for each grain image. Seven glauconite morphological types were investigated: capsule, cauliflower, fragmentary, lobate, ovoidal, tabular, and vermicular. Measurement data were analysed using canonical variate analysis. The calculated discriminating vectors were then used to distinguish the seven morpological forms. Using two canonical variates 81.5% of the variability within the database was accounted for.
X-ray diffraction studies shows a predominance of poorly crystalline glauconite. Many difficulties were encountered when applying previous literature techniques for calculating the expandable content of glauconite. An alternative technique based on the relationship between %K₂0 and % expandables is favoured for the calculation of % expandables. A relationship between host sediment lithology and glauconite expandable content was found; siltstone = 20-32%. expandables in the glauconite, sandstone = 8-15% expandables in the glauconite.
Major element data were obtained with the electron microprobe for 327 individual glauconite grain centres of 70 samples from 45 sites and 7 formations in the Te Kuiti. Group. The. chemical data were analysed using canonical variate analysis and the seven formations were clearly distinguished. Because only a small glauconite sample size is required (4-5 grains) the technique has potential for determining the stratigraphic correlation of drill core samples and small hand specimens of Te Kuiti Group material containing glauconite.
The range composition of Te Kuiti Group glauconite calculated from EMP major element data using the "Clayform" program is:
(Si ₃.₄₀₋₃.₆₈ Al ₀.₃₂₋₀.₆₀) (Al ₀.₀₈₋₀.₄₁ Fe ₁.₀₀³⁺₋₁.₃₆ Fe ₀.₁₉²⁺₋₀.₂₆ Mg ₀.₄₀₋₀.₆₀) (Ca ₀.₀₂₋₀.₁₆ Na ₀.₀₀₋₀.₀₄ K₀.₄₉₋₀.₆₇) O₁₀(OH₂)
The Te Kuiti Group passes stratigraphically upward from terrigenous and mixed terrigenous-skeletal carbonate deposits to very pure limestones. Early post-depositional diagenetic processes probably released Mg from the carbonate lattice of accumulating skeletal grains. Some of the released Mg was incorporated into the glauconite lattice as evidenced by the increase in Mg content of glauconite stratigraphically upward, parallel with the increased carbonate content of the rocks.
Major and trace element data were obtained using X-ray fluorescence for 29 bulk glauconite concentrates from 21 sites and 5 formations. Notably there were anomalous Mg, Pb and Ni concentrations in glauconite from the Otorohanga - Waitomo -Te Kuiti area. This suggests the area existed as a small semi-enclosed embayment, with a significantly higher terrigenous input compared with adjacent depocentres.
A strong correlation between the La/Ce ratio of glauconite and paleontological and oxygen isotope-derived sea-water temperatures suggests glauconite La/Ce ratio may be a useful paleotemperature indicator. The data collected in this study show no single previously suggested process adequately decribes the development of glauconite. Rather, glauconite should be considered polygenetic.

year: 1989

title: Huts and heartache: The affordance of playground huts for legal debate in early childhood social organisation

authors: Bateman, Amanda

subjects: education

abstract: This article discusses the way in which four-year-old children engaged in the complex co-production of rules and social governance in their primary school playground in Wales, UK. Through an inductive investigation into children's everyday social interactions at morning break time the child's view of their spatial affordances can be revealed. These affordances are the spaces the children talk into being (Heritage, 1978) and to what end. By making explicit reference to the wooden huts in their co-production of playground rules and governance the children talked those spaces into being and made them noticeable as important places for the practice of such agency in their everyday social organisation process.

text: Huts and heartache: The affordance of playground huts for legal debate in early childhood social organisation This article discusses the way in which four-year-old children engaged in the complex co-production of rules and social governance in their primary school playground in Wales, UK. Through an inductive investigation into children's everyday social interactions at morning break time the child's view of their spatial affordances can be revealed. These affordances are the spaces the children talk into being (Heritage, 1978) and to what end. By making explicit reference to the wooden huts in their co-production of playground rules and governance the children talked those spaces into being and made them noticeable as important places for the practice of such agency in their everyday social organisation process.

year: 2011

title: Wāhine Māori engagement with literacies

authors: Masters-Awatere, Bridgette

subjects: Literacy

abstract: Wāhine Māori engagement with literacies (2023) is a case study report in collaboration with Te Whakaruruhau. It has been undertaken as part of a larger project, The expression, experience and transcendence of low skills in Aotearoa New Zealand (2019–2024), the aim of which is to provide policy recommendations to improve life-course trajectories and socio-economic outcomes for adults with low literacy and numeracy skills in Aotearoa New Zealand. Broadly speaking, Wāhine Māori engagement with literacy examines the framing and application of literacy measures in contemporary New Zealand culture. More specifically, it is about the lives and learning of wāhine (women) Māori (the indigenous peoples of Aotearoa New Zealand) within that culture and their attitudes towards, and complex relationships with, literacy as it is defined in their own lives and in the current setting. The study aims for a holistic understanding of lived literacies in driving the development of educational policies by public institutions and private groups. Reframing literacy as literacies is posited as a means to empower marginalised groups and to challenge the dominance of the Eurocentric education paradigm. Formal learning in English-language schools cannot be the extent of national literacy standards as it disregards Māori epistemological and ontological realities and can discount wāhine, many of whom may prioritise other modes of literacy. Centring their perspectives will bring about a more culturally inclusive future, one that makes space for the development of emotional and cultural literacies—as well as other forms such as digital, media, visual, financial, and health literacies—alongside the conventional version of literacy that has a monopoly in the present system.

text: Wāhine Māori engagement with literacies Wāhine Māori engagement with literacies (2023) is a case study report in collaboration with Te Whakaruruhau. It has been undertaken as part of a larger project, The expression, experience and transcendence of low skills in Aotearoa New Zealand (2019–2024), the aim of which is to provide policy recommendations to improve life-course trajectories and socio-economic outcomes for adults with low literacy and numeracy skills in Aotearoa New Zealand. Broadly speaking, Wāhine Māori engagement with literacy examines the framing and application of literacy measures in contemporary New Zealand culture. More specifically, it is about the lives and learning of wāhine (women) Māori (the indigenous peoples of Aotearoa New Zealand) within that culture and their attitudes towards, and complex relationships with, literacy as it is defined in their own lives and in the current setting. The study aims for a holistic understanding of lived literacies in driving the development of educational policies by public institutions and private groups. Reframing literacy as literacies is posited as a means to empower marginalised groups and to challenge the dominance of the Eurocentric education paradigm. Formal learning in English-language schools cannot be the extent of national literacy standards as it disregards Māori epistemological and ontological realities and can discount wāhine, many of whom may prioritise other modes of literacy. Centring their perspectives will bring about a more culturally inclusive future, one that makes space for the development of emotional and cultural literacies—as well as other forms such as digital, media, visual, financial, and health literacies—alongside the conventional version of literacy that has a monopoly in the present system.

year: 2023-09-28