title: Mapping lithology and hydrothermal alteration in geothermal systems using portable X-ray fluorescence (pXRF): A case study from the Tauhara geothermal system, Taupo Volcanic Zone

authors: Mauriohooho, Kate

subjects: pXRF

abstract: Portable x-ray fluorescence (pXRF) analyzers are widely used in the environmental and mineral exploration fields. pXRF analyzers can rapidly and inexpensively provide chemical concentrations on a variety of elements, often with detection limits of ∼1–5 ppm. We compared portable XRF results from untreated geothermal drill cuttings with laboratory XRF results from pressed pellet and lithium borate fused beads prepared from powders crushed from the same samples. It is demonstrated that the portable XRF results are accurate for many elements, particularly for those with atomic numbers greater than 17. 304 cutting samples from three drillholes in the Tauhara geothermal field were subsequently analyzed by pXRF. Downhole elemental concentrations plotted against lithological units defined on geological well logs indicate that significant variations in elemental concentrations occur, some of which correlate with logged lithology boundaries. Other chemical variations appear to define previously unrecognized subunits, as well as areas of hydrothermal alteration. We suggest that pXRF should become a routine part of the characterization of geothermal cuttings during geothermal exploration and well drilling, as the chemical results are accurate, rapid and inexpensive, and the results can be used to define lithological boundaries and potentially correlate between drillholes, therefore improving geologic, stratigraphic and hydrothermal alteration models of the geothermal field.

text: Mapping lithology and hydrothermal alteration in geothermal systems using portable X-ray fluorescence (pXRF): A case study from the Tauhara geothermal system, Taupo Volcanic Zone Portable x-ray fluorescence (pXRF) analyzers are widely used in the environmental and mineral exploration fields. pXRF analyzers can rapidly and inexpensively provide chemical concentrations on a variety of elements, often with detection limits of ∼1–5 ppm. We compared portable XRF results from untreated geothermal drill cuttings with laboratory XRF results from pressed pellet and lithium borate fused beads prepared from powders crushed from the same samples. It is demonstrated that the portable XRF results are accurate for many elements, particularly for those with atomic numbers greater than 17. 304 cutting samples from three drillholes in the Tauhara geothermal field were subsequently analyzed by pXRF. Downhole elemental concentrations plotted against lithological units defined on geological well logs indicate that significant variations in elemental concentrations occur, some of which correlate with logged lithology boundaries. Other chemical variations appear to define previously unrecognized subunits, as well as areas of hydrothermal alteration. We suggest that pXRF should become a routine part of the characterization of geothermal cuttings during geothermal exploration and well drilling, as the chemical results are accurate, rapid and inexpensive, and the results can be used to define lithological boundaries and potentially correlate between drillholes, therefore improving geologic, stratigraphic and hydrothermal alteration models of the geothermal field.

year: 2016

title: Clean lakes - What value? What cost?

authors: Mueller, Hannah

abstract: Kia ora everyone and thank you so much for making it back to the last session of this wonderful symposium. Thank you so much to the LakesWater Quality Society for inviting me here to speak today. I am excited by the opportunity to share with you some of the findings of my PhD research that I finished earlier this year.

text: Clean lakes - What value? What cost? Kia ora everyone and thank you so much for making it back to the last session of this wonderful symposium. Thank you so much to the LakesWater Quality Society for inviting me here to speak today. I am excited by the opportunity to share with you some of the findings of my PhD research that I finished earlier this year.

year: 2017

title: Popoia te reo kia penapena: Nurture the language

authors: Berryman, Mere

subjects: Maori language

abstract: Research to develop a Māori language screening tool (Specialist Education Services, 2001), identified that students entering Māori Medium at five, could be classified into one of four Māori language competency, groups. Concurrently, teachers raised their need to identify the Māori language proficiency of five year olds entering Māori Medium so that more appropriate teaching strategies could be incorporated in preparation for literacy.
Accordingly, three Māori oral-language assessment tools, to help identify the Māori language competency of students entering Māori Medium settings at five years of age and provide formative information, were developed in response to this need. This paper details the development and trial of these tools.

text: Popoia te reo kia penapena: Nurture the language Research to develop a Māori language screening tool (Specialist Education Services, 2001), identified that students entering Māori Medium at five, could be classified into one of four Māori language competency, groups. Concurrently, teachers raised their need to identify the Māori language proficiency of five year olds entering Māori Medium so that more appropriate teaching strategies could be incorporated in preparation for literacy.
Accordingly, three Māori oral-language assessment tools, to help identify the Māori language competency of students entering Māori Medium settings at five years of age and provide formative information, were developed in response to this need. This paper details the development and trial of these tools.

year: 2009