title: Using a tephrostratigraphic framework to determine the past 40,000 yrs of fault rupture and paleohydrothermal activity on the east strand of the Whirinaki Fault, Ngakuru Graben, central Taupo Volcanic Zone

authors: Loame, Remedy Charlotte

subjects: seismology

abstract: The Ngakuru Graben in the central Taupo Volcanic Zone, North Island, New Zealand, is largely thermally inactive, but several fossil geothermal systems have been mapped throughout the area parallel to the Whirinaki Fault (WF). A fossil geothermal system was identified on the northeast section of the east strand of the WF at a location on Hossack Road hereafter referred to as the Meade-Hossack site. The aim of this study was to establish a history of fault rupture and sinter development at the Meade-Hossack site, and to relate the observed faulting and paleogeothermal activity to that at other locations on the WF. The objectives were to (i) describe the stratigraphy exposed in a trench and outcrop, (ii) identify (correlate) tephras using stratigraphic principles, ferromagnesian mineralogical assemblages, and electron microprobe-determined major-element compositions of glass shards, and (iii) restore tectonic deformation at the site using tephrochronology to date the timing of fault movement and the development of sinter formation.

A paleoseismic trench was excavated across the northeast section of the east strand of the WF. The stratigraphy and deformation in the trench were logged. Samples of tephras were taken for mineral and glass shard analysis by microscope petrography and electron microprobe analysis, respectively. Eight tephras were identified, namely the Kaharoa (AD 1314 ± 12 or 636 ± 12 cal. yr. BP) (95% probability age range), Taupo (AD 232 ± 10 or 1718 ± 10 cal. yr. BP), Rotoma (9423 ± 120 cal. yr. BP), Rotorua (15635 ± 412 cal. yr. BP), Okareka (21858 ± 290 cal. yr. BP), Kawakawa (25358 ± 162 cal. yr. BP), Poihipi (28446 ± 670 cal. yr. BP), and Tahuna (c. 40 ka), as well as the Ohakuri Ignimbrite (c. 240 ka).

Five fault rupture events were identified in the trench (MH1–5). The trench logs were used to reconstruct earlier stages of the stratigraphic succession at the site prior to deformation by each rupture events. The tephra ages were used to constrain the timing of fault movement. The slip rates and the vertical displacement measurements were also calculated using tephrochronology, and correlated with trends (fast-slow-fast) for events of similar ages observed in other trenches on the WF.

Rupture event MH1 occurred between the Taupo and Kaharoa eruption episodes at a slip rate of 0.87 ± 0.37 mm/yr, MH2 between the Rotoma and Taupo eruptions at a rate of 0.11 ± 0.20 mm/yr, MH3 between the Rotorua and Rotoma eruptions at a rate of 0.20 ± 0.22 mm/yr, MH4 between the Okareka and Rotorua eruptions at a rate of 0.13 ± 0.27 mm/yr, and MH5 between the Ohakuri and Okareka eruptions at a rate of 0.53 ± 0.24 mm/yr. The recurrence interval during the last 21.8 kyrs was calculated to be 1.8–5.4 kyrs, which fits within recurrence intervals calculated for other trenches on the WF.

The rupture events at the Meade-Hossack site show evidence of stress transfer from the southeast section of the east strand as well as the northwest section of the west strand of the WF, indicating that the strands are connected at depth. Sinter deposition mirrors that on the west strand from ~40–10 ka, indicating that the paleogeothermal fields were fed by the same source at depth.Sinter deposition mirrors that on the west strand from ~40–10 ka, indicating that the paleogeothermal fields were fed by the same source at depth. Fault rupture MH3 at the Meade-Hossack site altered the local fluid flow regime, leading to the cessation of sinter development on the east strand by 9423 ± 120 cal. yr. BP.

text: Using a tephrostratigraphic framework to determine the past 40,000 yrs of fault rupture and paleohydrothermal activity on the east strand of the Whirinaki Fault, Ngakuru Graben, central Taupo Volcanic Zone The Ngakuru Graben in the central Taupo Volcanic Zone, North Island, New Zealand, is largely thermally inactive, but several fossil geothermal systems have been mapped throughout the area parallel to the Whirinaki Fault (WF). A fossil geothermal system was identified on the northeast section of the east strand of the WF at a location on Hossack Road hereafter referred to as the Meade-Hossack site. The aim of this study was to establish a history of fault rupture and sinter development at the Meade-Hossack site, and to relate the observed faulting and paleogeothermal activity to that at other locations on the WF. The objectives were to (i) describe the stratigraphy exposed in a trench and outcrop, (ii) identify (correlate) tephras using stratigraphic principles, ferromagnesian mineralogical assemblages, and electron microprobe-determined major-element compositions of glass shards, and (iii) restore tectonic deformation at the site using tephrochronology to date the timing of fault movement and the development of sinter formation.

A paleoseismic trench was excavated across the northeast section of the east strand of the WF. The stratigraphy and deformation in the trench were logged. Samples of tephras were taken for mineral and glass shard analysis by microscope petrography and electron microprobe analysis, respectively. Eight tephras were identified, namely the Kaharoa (AD 1314 ± 12 or 636 ± 12 cal. yr. BP) (95% probability age range), Taupo (AD 232 ± 10 or 1718 ± 10 cal. yr. BP), Rotoma (9423 ± 120 cal. yr. BP), Rotorua (15635 ± 412 cal. yr. BP), Okareka (21858 ± 290 cal. yr. BP), Kawakawa (25358 ± 162 cal. yr. BP), Poihipi (28446 ± 670 cal. yr. BP), and Tahuna (c. 40 ka), as well as the Ohakuri Ignimbrite (c. 240 ka).

Five fault rupture events were identified in the trench (MH1–5). The trench logs were used to reconstruct earlier stages of the stratigraphic succession at the site prior to deformation by each rupture events. The tephra ages were used to constrain the timing of fault movement. The slip rates and the vertical displacement measurements were also calculated using tephrochronology, and correlated with trends (fast-slow-fast) for events of similar ages observed in other trenches on the WF.

Rupture event MH1 occurred between the Taupo and Kaharoa eruption episodes at a slip rate of 0.87 ± 0.37 mm/yr, MH2 between the Rotoma and Taupo eruptions at a rate of 0.11 ± 0.20 mm/yr, MH3 between the Rotorua and Rotoma eruptions at a rate of 0.20 ± 0.22 mm/yr, MH4 between the Okareka and Rotorua eruptions at a rate of 0.13 ± 0.27 mm/yr, and MH5 between the Ohakuri and Okareka eruptions at a rate of 0.53 ± 0.24 mm/yr. The recurrence interval during the last 21.8 kyrs was calculated to be 1.8–5.4 kyrs, which fits within recurrence intervals calculated for other trenches on the WF.

The rupture events at the Meade-Hossack site show evidence of stress transfer from the southeast section of the east strand as well as the northwest section of the west strand of the WF, indicating that the strands are connected at depth. Sinter deposition mirrors that on the west strand from ~40–10 ka, indicating that the paleogeothermal fields were fed by the same source at depth.Sinter deposition mirrors that on the west strand from ~40–10 ka, indicating that the paleogeothermal fields were fed by the same source at depth. Fault rupture MH3 at the Meade-Hossack site altered the local fluid flow regime, leading to the cessation of sinter development on the east strand by 9423 ± 120 cal. yr. BP.

year: 2016

title: Exiting the closet daily: Examining the repetitive nature of minority gender and sexual identity self-disclosures.

authors: Stanley, Jessica

subjects: identity

abstract: The process of minority gender and sexual identity self-disclosure is inherently complex. The act of ‘coming out’ is often perceived as a significant, singular event; however, those with lived experiences recognise that it is an ongoing, repetitive experience influenced by varying social contexts—a concept referred to within this research as identity maintenance. Understanding this phenomenon is paramount in addressing the psychosocial realities of LGBTQIA+ people—both individually and collectively—as they navigate the decision to disclose their minority identity in a range of environments, contexts, and interactions. Specifically, this thesis seeks to illuminate the processes of identity maintenance within the context of Aotearoa New Zealand, providing a foundational understanding of the lived experiences of LGBTQIA+ individuals. To do so, five research questions were constructed, these include: 1. How do participants interpret their experiences of identity self-disclosure or non-disclosure? 2. What social factors influence the decision to self-disclose minority gender and/or sexual identity? 3. How does the repetitive nature of identity self-disclosure affect participants? 4. How does identity self-disclosure vary in different social environments? and 5. How does language shape identity self-disclosure? This research utilises Interpretive Phenomenological Analysis (IPA) to analyse qualitative data gathered from a cohort of 10 self-identifying LGBTQIA+ participants. By focusing on lived experiences, the research captures the psychosocial factors involved in self-disclosure practices. Participants were selected through a purposive sampling method, ensuring a range of backgrounds and identities were represented, including age, ethnicity, neurological and physical ability, and religious status. Semi-structured face-to-face interviews were conducted with each of the 10 participants, and five participants elected to complete a diary entry task following their interview. Participants described navigating their LGBTQIA+ identities across different contexts, drawing on a range of psychosocial tools in their day-to-day practice of identity maintenance. Four themes arose from the findings. Firstly, The Temporality of Identity highlighted how the LGBTQIA+ identity is experienced over time, from early identity development to the long-term, ongoing practice of identity maintenance. Secondly, The Tax of Identity theme identified how participants experienced mental, emotional, and educational taxes as a result of their LGBTQIA+ identity. Thirdly, The Ecology of Identity theme identified the ways in which participants experienced effects from distal and proximal environments on the development and embodiment of their LGBTQIA+ identities. Finally, The Language of Identity theme highlighted how participants engaged with both verbal and non-verbal forms of communication to disclose their LGBTQIA+ identity as well as the social monitoring tools they utilised in disclosure decision-making. The findings of this thesis contribute to existing discourse on LGBTQIA+ identities and form the first known literature on the identity maintenance experiences of Aotearoa’s LGBTQIA+ community. Ultimately, this research highlights the ways in which identity maintenance serves as a beneficial tool for restoring the agency of LGBTQIA+ people in choosing when, where, how, why, and to whom identity self-disclosures will be made.

text: Exiting the closet daily: Examining the repetitive nature of minority gender and sexual identity self-disclosures. The process of minority gender and sexual identity self-disclosure is inherently complex. The act of ‘coming out’ is often perceived as a significant, singular event; however, those with lived experiences recognise that it is an ongoing, repetitive experience influenced by varying social contexts—a concept referred to within this research as identity maintenance. Understanding this phenomenon is paramount in addressing the psychosocial realities of LGBTQIA+ people—both individually and collectively—as they navigate the decision to disclose their minority identity in a range of environments, contexts, and interactions. Specifically, this thesis seeks to illuminate the processes of identity maintenance within the context of Aotearoa New Zealand, providing a foundational understanding of the lived experiences of LGBTQIA+ individuals. To do so, five research questions were constructed, these include: 1. How do participants interpret their experiences of identity self-disclosure or non-disclosure? 2. What social factors influence the decision to self-disclose minority gender and/or sexual identity? 3. How does the repetitive nature of identity self-disclosure affect participants? 4. How does identity self-disclosure vary in different social environments? and 5. How does language shape identity self-disclosure? This research utilises Interpretive Phenomenological Analysis (IPA) to analyse qualitative data gathered from a cohort of 10 self-identifying LGBTQIA+ participants. By focusing on lived experiences, the research captures the psychosocial factors involved in self-disclosure practices. Participants were selected through a purposive sampling method, ensuring a range of backgrounds and identities were represented, including age, ethnicity, neurological and physical ability, and religious status. Semi-structured face-to-face interviews were conducted with each of the 10 participants, and five participants elected to complete a diary entry task following their interview. Participants described navigating their LGBTQIA+ identities across different contexts, drawing on a range of psychosocial tools in their day-to-day practice of identity maintenance. Four themes arose from the findings. Firstly, The Temporality of Identity highlighted how the LGBTQIA+ identity is experienced over time, from early identity development to the long-term, ongoing practice of identity maintenance. Secondly, The Tax of Identity theme identified how participants experienced mental, emotional, and educational taxes as a result of their LGBTQIA+ identity. Thirdly, The Ecology of Identity theme identified the ways in which participants experienced effects from distal and proximal environments on the development and embodiment of their LGBTQIA+ identities. Finally, The Language of Identity theme highlighted how participants engaged with both verbal and non-verbal forms of communication to disclose their LGBTQIA+ identity as well as the social monitoring tools they utilised in disclosure decision-making. The findings of this thesis contribute to existing discourse on LGBTQIA+ identities and form the first known literature on the identity maintenance experiences of Aotearoa’s LGBTQIA+ community. Ultimately, this research highlights the ways in which identity maintenance serves as a beneficial tool for restoring the agency of LGBTQIA+ people in choosing when, where, how, why, and to whom identity self-disclosures will be made.

year: 2024

title: Te tuangi (the clam): A metaphor for teaching, learning and the key competencies

authors: Simpson, Mary Louisa

subjects: Early childhood

abstract: This article explores the shift from “essential skills” to “key competencies” in the school curriculum. Drawing on information gathered from teacher interviews and observations at a New Zealand primary school, this article suggests that culture and context strongly shape and influence the interpretation of key competencies. The authors develop a metaphor—te tuangi—to theorise the relationship between a learner (akonga) and a teacher (kaiako) in a cultural and social context.

text: Te tuangi (the clam): A metaphor for teaching, learning and the key competencies This article explores the shift from “essential skills” to “key competencies” in the school curriculum. Drawing on information gathered from teacher interviews and observations at a New Zealand primary school, this article suggests that culture and context strongly shape and influence the interpretation of key competencies. The authors develop a metaphor—te tuangi—to theorise the relationship between a learner (akonga) and a teacher (kaiako) in a cultural and social context.

year: 2011