title: Volcanology of the Owharoa and Waikino ignimbrites, Waihi, Coromandel Volcanic Zone

authors: Julian, Hannah Alice

subjects: ignimbrites

abstract: The Waihi Caldera (Coromandel Volcanic Zone) is defined by a 15 km diameter gravity anomaly, which was active during the Pliocene and has been infilled by a 1.5 km-thick succession of volcanic deposits and lake sediments. The Owharoa and Waikino ignimbrites are both suspected to have been a product of the Waihi Caldera (Brathwaite & Christie, 1996). The aim of this study was to determine and compare the eruption and emplacement processes of the Owharoa and Waikino ignimbrites.
The ignimbrites were characterised in the field by facies analysis and dated by U-Pb zircon dating using laser ablation inductively coupled plasma mass spectrometry. Their petrographic characteristics were described by optical microscopy, scanning electron microscopy and X-ray powder diffraction. Geochemical characteristics were identified by electron microprobe analysis (on minerals and glass shards) and X-ray fluorescence spectrometry (on pumice and bulk ignimbrite).
The Owharoa Ignimbrite (3.76 ± 0.05 Ma, Vincent, 2012) is poorly sorted with variable degrees of welding degrees. Facies identified include pumice-rich and lithic-rich facies (O1), flattened pumice rich facies (O2), lithic rich, pumice poor facies (O3), dark grey, densely welded, fiamme rich facies (O4) and pumice rich facies (O5). Juvenile clasts include creamy rounded woody-textured pumice in the east, and dark to black, lensoidal, glassy fiamme in the west with quartz and plagioclase phenocrysts. Lithic clasts include volcanic lithics (rhyolite, andesite, and ignimbrite), and occasional sedimentary lithics (sandstone/siltstone).
The Waikino Ignimbrite (3.48 +/- 0.19 Ma) is a finer-grained, relatively well sorted, massive, glass shard matrix-rich (~93%) ignimbrite that is separated into two facies, W1, a softer, massive yellow basal facies; and W2 a grey, well welded, massive facies. The pumice within the Waikino Ignimbrite (1%) was no larger than coarse ash-sized, white fragments. The Waikino Ignimbrite had plagioclase, quartz, biotite (larger than the Owharoa Ignimbrite) and opaque minerals. Geochemically the Waikino Ignimbrite was rhyolitic with higher alkali content than the Owharoa Ignimbrite.
The Owharoa Ignimbrite represents the deposit of an intra-caldera, pulsating depositional pyroclastic flow that shows subtle variations in pumice and lithic abundance. The massive nature of the Waikino Ignimbrite indicates a consistent, steady pyroclastic flow, derived from an intensely fragmented magma to form a glass shard-rich, pumice-poor deposit. Both ignimbrites were sourced from the Waihi Caldera due to their proximity to the caldera, the lithic characteristics and their similar geochemistry and mineralogy. The closeness in age of the ignimbrites signifies the relationship between the deposits, and relationship they have with the Waihi Caldera. It is possible that the Waikino Ignimbrite was the last major eruption from the Waihi Caldera, therefore the end of the duration of the caldera can be identified as after the Waikino Ignimbrite eruption at 3.48 +/- 0.19 Ma.

text: Volcanology of the Owharoa and Waikino ignimbrites, Waihi, Coromandel Volcanic Zone The Waihi Caldera (Coromandel Volcanic Zone) is defined by a 15 km diameter gravity anomaly, which was active during the Pliocene and has been infilled by a 1.5 km-thick succession of volcanic deposits and lake sediments. The Owharoa and Waikino ignimbrites are both suspected to have been a product of the Waihi Caldera (Brathwaite & Christie, 1996). The aim of this study was to determine and compare the eruption and emplacement processes of the Owharoa and Waikino ignimbrites.
The ignimbrites were characterised in the field by facies analysis and dated by U-Pb zircon dating using laser ablation inductively coupled plasma mass spectrometry. Their petrographic characteristics were described by optical microscopy, scanning electron microscopy and X-ray powder diffraction. Geochemical characteristics were identified by electron microprobe analysis (on minerals and glass shards) and X-ray fluorescence spectrometry (on pumice and bulk ignimbrite).
The Owharoa Ignimbrite (3.76 ± 0.05 Ma, Vincent, 2012) is poorly sorted with variable degrees of welding degrees. Facies identified include pumice-rich and lithic-rich facies (O1), flattened pumice rich facies (O2), lithic rich, pumice poor facies (O3), dark grey, densely welded, fiamme rich facies (O4) and pumice rich facies (O5). Juvenile clasts include creamy rounded woody-textured pumice in the east, and dark to black, lensoidal, glassy fiamme in the west with quartz and plagioclase phenocrysts. Lithic clasts include volcanic lithics (rhyolite, andesite, and ignimbrite), and occasional sedimentary lithics (sandstone/siltstone).
The Waikino Ignimbrite (3.48 +/- 0.19 Ma) is a finer-grained, relatively well sorted, massive, glass shard matrix-rich (~93%) ignimbrite that is separated into two facies, W1, a softer, massive yellow basal facies; and W2 a grey, well welded, massive facies. The pumice within the Waikino Ignimbrite (1%) was no larger than coarse ash-sized, white fragments. The Waikino Ignimbrite had plagioclase, quartz, biotite (larger than the Owharoa Ignimbrite) and opaque minerals. Geochemically the Waikino Ignimbrite was rhyolitic with higher alkali content than the Owharoa Ignimbrite.
The Owharoa Ignimbrite represents the deposit of an intra-caldera, pulsating depositional pyroclastic flow that shows subtle variations in pumice and lithic abundance. The massive nature of the Waikino Ignimbrite indicates a consistent, steady pyroclastic flow, derived from an intensely fragmented magma to form a glass shard-rich, pumice-poor deposit. Both ignimbrites were sourced from the Waihi Caldera due to their proximity to the caldera, the lithic characteristics and their similar geochemistry and mineralogy. The closeness in age of the ignimbrites signifies the relationship between the deposits, and relationship they have with the Waihi Caldera. It is possible that the Waikino Ignimbrite was the last major eruption from the Waihi Caldera, therefore the end of the duration of the caldera can be identified as after the Waikino Ignimbrite eruption at 3.48 +/- 0.19 Ma.

year: 2016

title: Planification economique et migration en Polynesie Francaise.

authors: d'Hauteserre, Anne-Marie

subjects: migratory patterns

abstract: Economic Planning and Migration in French Polynesia. This article discusses possible ties between migratory patterns in French Polynesia and policies drafted by the French state and the local government concerning the territory’s economic development. The goals are to diversify the economic production of the outer archipelagos based on their natural resources and to encourage the return of out-migrants. The structures of production that the new cultural economy has systemically articulated at the global scale should also encourage the return migration that the economic policies seek to establish. Contemporary patterns of mobility differ little from those of times past. Polynesians have always moved and had thus established multiple support networks for migrants across the Pacific. The responses gathered during recent research trips to French Polynesia indicate that the large investments in infrastructure by the two governments in the outer archipelagos are not convincing most out-migrants to return. This infrastructure might, however, attract migrants from other parts of French Polynesia even if only temporarily, as is already the case for some foreigners.

text: Planification economique et migration en Polynesie Francaise. Economic Planning and Migration in French Polynesia. This article discusses possible ties between migratory patterns in French Polynesia and policies drafted by the French state and the local government concerning the territory’s economic development. The goals are to diversify the economic production of the outer archipelagos based on their natural resources and to encourage the return of out-migrants. The structures of production that the new cultural economy has systemically articulated at the global scale should also encourage the return migration that the economic policies seek to establish. Contemporary patterns of mobility differ little from those of times past. Polynesians have always moved and had thus established multiple support networks for migrants across the Pacific. The responses gathered during recent research trips to French Polynesia indicate that the large investments in infrastructure by the two governments in the outer archipelagos are not convincing most out-migrants to return. This infrastructure might, however, attract migrants from other parts of French Polynesia even if only temporarily, as is already the case for some foreigners.

year: 2004

title: "More than bloods and obs" - Whānau Māori discuss health and hospital care

authors: Masters-Awatere, Bridgette

abstract: The impact of colonisation on Māori, the Indigenous people of Aotearoa New Zealand, combined with negative interactions with health workers, has contributed to insufficient resources and reduced access to primary health care. The purpose of this report is to share narratives of whānau Māori who have experienced a child’s hospital admission in order to highlight the common aspects (good and bad) of their stay at Waikato Hospital. The overarching aim of the Harti Hauora Tamariki (HHT) tool trial, within which this report is located, is to demonstrate the measurable impact of a developed screening tool (referred to throughout as the Harti tool). The Harti tool is a comprehensive approach to assessing and addressing holistic health needs for hospitalised children and their whānau. Our recruitment strategy gave priority to those whose kōrero would capture the realities of those living in situations of few resources. This report presents findings from conversational interviews with whānau of tamariki Māori admitted to the paediatrics ward of Waikato Hospital. We have purposefully presented the interview findings as narratives to allow the reader to engage in their own interpretation of commonalities of experiences. Each case study follows the same format: an overview, their hospital experience, and their description of everyday health. Across all the cases, similarities of experience emerge; financial stressors and strain; hunger and isolation; concern for their child(ren); and families that are actively engaged in caring for their children’s health and well-being. The Harti tool, when administered by a culturally competent Harti Research Assistant (Harti RA), appears to work to counteract previous alienating experiences. Being treated with dignity, respect and value had a positive impact. Participants spoke at length regarding how wonderful it was to be able to engage with the Harti RA’s as Māori and in a culturally appropriate way.

text: "More than bloods and obs" - Whānau Māori discuss health and hospital care The impact of colonisation on Māori, the Indigenous people of Aotearoa New Zealand, combined with negative interactions with health workers, has contributed to insufficient resources and reduced access to primary health care. The purpose of this report is to share narratives of whānau Māori who have experienced a child’s hospital admission in order to highlight the common aspects (good and bad) of their stay at Waikato Hospital. The overarching aim of the Harti Hauora Tamariki (HHT) tool trial, within which this report is located, is to demonstrate the measurable impact of a developed screening tool (referred to throughout as the Harti tool). The Harti tool is a comprehensive approach to assessing and addressing holistic health needs for hospitalised children and their whānau. Our recruitment strategy gave priority to those whose kōrero would capture the realities of those living in situations of few resources. This report presents findings from conversational interviews with whānau of tamariki Māori admitted to the paediatrics ward of Waikato Hospital. We have purposefully presented the interview findings as narratives to allow the reader to engage in their own interpretation of commonalities of experiences. Each case study follows the same format: an overview, their hospital experience, and their description of everyday health. Across all the cases, similarities of experience emerge; financial stressors and strain; hunger and isolation; concern for their child(ren); and families that are actively engaged in caring for their children’s health and well-being. The Harti tool, when administered by a culturally competent Harti Research Assistant (Harti RA), appears to work to counteract previous alienating experiences. Being treated with dignity, respect and value had a positive impact. Participants spoke at length regarding how wonderful it was to be able to engage with the Harti RA’s as Māori and in a culturally appropriate way.

year: 2019