title: Using soil stratigraphy and tephrochronology to understand the origin, age, and classification of a unique Late Quaternary tephra-derived Ultisol in Aotearoa New Zealand

authors: Lowe, David J.

subjects: pedology

abstract: In this article, I show how an Ultisol, representative of a globally-important group of soils with clay-rich subsoils, low base saturation, and low fertility, in the central Waikato region in northern North Island, can be evaluated using soil stratigraphy and tephrochronology to answer challenging questions about its genesis, age and classification. The Kainui soil, a Typic Kandiudult (Soil Taxonomy) and Buried-granular Yellow Ultic Soil (New Zealand Soil Classification), occurs on low rolling hills of Mid-Quaternary age mainly in the Hamilton lowlands in, and north and northeast of, Hamilton city. It is a composite, multi-layered tephra-derived soil consisting of two distinct parts, upper and lower. The upper part is a coverbed typically c. 0.4–0.7 m in thickness (c. 0.6 m on average) comprising numerous late Quaternary rhyolitic and andesitic tephras that have been accumulating incrementally since c. 50 ka (the age of Rotoehu Ash at the coverbed’s base) whilst simultaneously being pedogenically altered (i.e., forming soil horizons) via developmental upbuilding pedogenesis during Marine Oxygen Isotope Stages (MOIS) 3-1. Any original depositional (fall) bedding has been almost entirely masked by pedogenic alteration. Sediments in lakes aged c. 20 ka adjacent to the low hills have preserved around 40 separate, thin, macroscopic tephra-fall beds mainly rhyolitic in composition, and equivalent subaerial deposits together form the upper c. 30 cm of the coverbed. Okareka (c. 21.8 ka), Okaia (c. 28.6 ka), Tahuna (c. 39.3 ka) and (especially) Rotoehu tephras make up the bulk of the lower c. 30 cm of the coverbed. Tephra admixing has occurred throughout the coverbed because of soil upbuilding processes. Moderately well drained, this upper profile is dominated by halloysite (not allophane) in the clay fraction because of limited desilication. In contrast, Otorohanga soils, on rolling hills to the south of Hamilton, are formed in equivalent but thicker (>c. 0.8 m) late Quaternary tephras ≤c. 50 ka that are somewhat more andesitic although predominantly rhyolitic overall. These deeper soils are well drained with strong desilication and thus are allophanic, generating Typic Hapludands. Ubiquitous redox features, together with short-lived contemporary reduction observed in the lower coverbed of a Kainui soil profile, indicate that the Kainui soil in general is likely to be saturated by perching for several days, or near saturation for several months, each year. The perching occurs because the coverbed overlies a slowly-permeable, buried, clay-rich paleosol on upper Hamilton Ash beds, >c. 50 ka in age, which makes up the lower part of the two-storeyed Kainui soil. The coverbed-paleosol boundary is a lithologic discontinuity (unconformity). Irregular in shape, it represents a tree-overturn paleosurface that may be c. 74 ka in age (MOIS 5/4 boundary). The buried paleosol is markedly altered and halloysitic with relict clay skins (forming paleo-argillic and/or paleo-kandic horizons) and redoximorphic features. It is inferred to have formed via developmental upbuilding pedogenesis during the Last Interglacial (MOIS 5e). The entire Hamilton Ash sequence, c. 3 m in thickness and overlain unconformably by Rotoehu Ash and underlain by c. 340-ka Rangitawa Tephra at the base, represents a thick composite (accretionary) set of clayey, welded paleosols developed by upbuilding pedogenesis from MOIS 10 to 5.

text: Using soil stratigraphy and tephrochronology to understand the origin, age, and classification of a unique Late Quaternary tephra-derived Ultisol in Aotearoa New Zealand In this article, I show how an Ultisol, representative of a globally-important group of soils with clay-rich subsoils, low base saturation, and low fertility, in the central Waikato region in northern North Island, can be evaluated using soil stratigraphy and tephrochronology to answer challenging questions about its genesis, age and classification. The Kainui soil, a Typic Kandiudult (Soil Taxonomy) and Buried-granular Yellow Ultic Soil (New Zealand Soil Classification), occurs on low rolling hills of Mid-Quaternary age mainly in the Hamilton lowlands in, and north and northeast of, Hamilton city. It is a composite, multi-layered tephra-derived soil consisting of two distinct parts, upper and lower. The upper part is a coverbed typically c. 0.4–0.7 m in thickness (c. 0.6 m on average) comprising numerous late Quaternary rhyolitic and andesitic tephras that have been accumulating incrementally since c. 50 ka (the age of Rotoehu Ash at the coverbed’s base) whilst simultaneously being pedogenically altered (i.e., forming soil horizons) via developmental upbuilding pedogenesis during Marine Oxygen Isotope Stages (MOIS) 3-1. Any original depositional (fall) bedding has been almost entirely masked by pedogenic alteration. Sediments in lakes aged c. 20 ka adjacent to the low hills have preserved around 40 separate, thin, macroscopic tephra-fall beds mainly rhyolitic in composition, and equivalent subaerial deposits together form the upper c. 30 cm of the coverbed. Okareka (c. 21.8 ka), Okaia (c. 28.6 ka), Tahuna (c. 39.3 ka) and (especially) Rotoehu tephras make up the bulk of the lower c. 30 cm of the coverbed. Tephra admixing has occurred throughout the coverbed because of soil upbuilding processes. Moderately well drained, this upper profile is dominated by halloysite (not allophane) in the clay fraction because of limited desilication. In contrast, Otorohanga soils, on rolling hills to the south of Hamilton, are formed in equivalent but thicker (>c. 0.8 m) late Quaternary tephras ≤c. 50 ka that are somewhat more andesitic although predominantly rhyolitic overall. These deeper soils are well drained with strong desilication and thus are allophanic, generating Typic Hapludands. Ubiquitous redox features, together with short-lived contemporary reduction observed in the lower coverbed of a Kainui soil profile, indicate that the Kainui soil in general is likely to be saturated by perching for several days, or near saturation for several months, each year. The perching occurs because the coverbed overlies a slowly-permeable, buried, clay-rich paleosol on upper Hamilton Ash beds, >c. 50 ka in age, which makes up the lower part of the two-storeyed Kainui soil. The coverbed-paleosol boundary is a lithologic discontinuity (unconformity). Irregular in shape, it represents a tree-overturn paleosurface that may be c. 74 ka in age (MOIS 5/4 boundary). The buried paleosol is markedly altered and halloysitic with relict clay skins (forming paleo-argillic and/or paleo-kandic horizons) and redoximorphic features. It is inferred to have formed via developmental upbuilding pedogenesis during the Last Interglacial (MOIS 5e). The entire Hamilton Ash sequence, c. 3 m in thickness and overlain unconformably by Rotoehu Ash and underlain by c. 340-ka Rangitawa Tephra at the base, represents a thick composite (accretionary) set of clayey, welded paleosols developed by upbuilding pedogenesis from MOIS 10 to 5.

year: 2019

title: A randomised crossover trial on the effects of foot starting position on calf raise test outcomes: Position does matter

authors: Hébert-Losier, Kim

subjects: Ankle

abstract: Background: This randomised crossover study with repeated measures examined the influence of the three most common foot starting positions used in conducting the calf raise test (CRT) on test outcomes. This study also accounted for the potential influence of gender, age, body mass index (BMI), and level of physical activity on test outcomes. Methods: Forty-nine healthy individuals (59 % female, 21 ± 4 years) performed single-leg calf raise repetitions in a human movement laboratory in three randomised foot starting positions: flat, 10° incline, and step. The validated Calf Raise application was used to track the vertical displacement of a marker placed on the foot using computer vision. The application extracted the following CRT outcomes from the vertical displacement curve: number of repetitions, peak vertical height, total vertical displacement, and total positive work. Data were analysed using mixed-effects models and stepwise regression. Results: There was a significant main effect (P < 0.001) of foot starting position on all outcomes, with all paired comparisons being statistically significant (P ≤ 0.023). Repetitions, total vertical displacement, and total positive work were greatest in flat and lowest in step, whereas peak vertical height was greatest in incline and lowest in step. Gender (P = 0.021; males>females) and BMI (P = 0.002; lower BMI>higher BMI) significantly influenced the number of repetitions. Gender (P < 0.001; males>females) also influenced total positive work. Age and physical activity levels did not significantly influence CRT outcomes. Conclusions: CRT foot starting position mattered and significantly affected all CRT outcomes. CRT foot starting position needs consideration when contrasting data in research and practice.

text: A randomised crossover trial on the effects of foot starting position on calf raise test outcomes: Position does matter Background: This randomised crossover study with repeated measures examined the influence of the three most common foot starting positions used in conducting the calf raise test (CRT) on test outcomes. This study also accounted for the potential influence of gender, age, body mass index (BMI), and level of physical activity on test outcomes. Methods: Forty-nine healthy individuals (59 % female, 21 ± 4 years) performed single-leg calf raise repetitions in a human movement laboratory in three randomised foot starting positions: flat, 10° incline, and step. The validated Calf Raise application was used to track the vertical displacement of a marker placed on the foot using computer vision. The application extracted the following CRT outcomes from the vertical displacement curve: number of repetitions, peak vertical height, total vertical displacement, and total positive work. Data were analysed using mixed-effects models and stepwise regression. Results: There was a significant main effect (P < 0.001) of foot starting position on all outcomes, with all paired comparisons being statistically significant (P ≤ 0.023). Repetitions, total vertical displacement, and total positive work were greatest in flat and lowest in step, whereas peak vertical height was greatest in incline and lowest in step. Gender (P = 0.021; males>females) and BMI (P = 0.002; lower BMI>higher BMI) significantly influenced the number of repetitions. Gender (P < 0.001; males>females) also influenced total positive work. Age and physical activity levels did not significantly influence CRT outcomes. Conclusions: CRT foot starting position mattered and significantly affected all CRT outcomes. CRT foot starting position needs consideration when contrasting data in research and practice.

year: 2024-09-01

title: Haumanu Hauora: Strengthening health institution responsiveness to climate change

authors: Masters-Awatere, Bridgette

abstract: The “Haumanu Hauora: Strengthening health institution responsiveness to climate change” project (Haumanu Hauora) is funded by the Deep South National Science Challenge. Our research team has 
been working to determine how health institutions (for example DHBs) develop Māori responsive policy as a preparatory step in anticipation of climate change impacts on Māori health. The project 
has involved several components, one of which involved speaking with tāngata whenua and DHB staff from the Bay of Plenty, Lakes and Waikato DHB regions about their experiences of climate 
change and involvement with health services. Another component was an environmental scan of available website information on the 17 other DHBs to ascertain the extent of policy that speaks to 
both the Treaty of Waitangi and climate change. This report presents an overview of the findings. 

This report begins with some context setting. We provide a summary of our literature reviews before a brief outline of the establishment of DHBs, which are the “health institution” of focus for 
this research. As the primary health provider and funders around the country, DHBs have been engaged as the site through which to understand the Māori health and climate change policy needs. 
Although DHBs were disestablished at the conclusion of our project, there are still lessons to learn from the ‘old’ health system. We present themes from tāngata whenua and rangatahi interviews as 
a way to foreground policy development information provided by DHB staff.

text: Haumanu Hauora: Strengthening health institution responsiveness to climate change The “Haumanu Hauora: Strengthening health institution responsiveness to climate change” project (Haumanu Hauora) is funded by the Deep South National Science Challenge. Our research team has 
been working to determine how health institutions (for example DHBs) develop Māori responsive policy as a preparatory step in anticipation of climate change impacts on Māori health. The project 
has involved several components, one of which involved speaking with tāngata whenua and DHB staff from the Bay of Plenty, Lakes and Waikato DHB regions about their experiences of climate 
change and involvement with health services. Another component was an environmental scan of available website information on the 17 other DHBs to ascertain the extent of policy that speaks to 
both the Treaty of Waitangi and climate change. This report presents an overview of the findings. 

This report begins with some context setting. We provide a summary of our literature reviews before a brief outline of the establishment of DHBs, which are the “health institution” of focus for 
this research. As the primary health provider and funders around the country, DHBs have been engaged as the site through which to understand the Māori health and climate change policy needs. 
Although DHBs were disestablished at the conclusion of our project, there are still lessons to learn from the ‘old’ health system. We present themes from tāngata whenua and rangatahi interviews as 
a way to foreground policy development information provided by DHB staff.

year: 2022-07-12