title: Towards a Better Understanding of Coastal Cliff Erosion in Waitemata Group Rock; Auckland, New Zealand.

authors: Bell, Jessica Emily

subjects: Waitemata Group

abstract: The soft sedimentary deposits of the Waitemata Group which outcrop on the eastern coastline of the Auckland region are a coastal cliff erosion hazard. The determination of the rate that these cliffs erode for hazard zonation purposes still requires research. A database has been collated of a range of structural, geological, geomorphic and climate parameters from 16 representative cliff sites in order to statistically assess what parameters influence cliff erosion and why erosion rates vary within the relatively uniform geology. 

Four different lithological units have been defined: sandstone beds of turbidites; sandstone beds of densites (contain rip-up clasts); sand to gravel beds of debrites; and siltstone beds. Cliff rock has very weak to weak intact rock strength; apertures of 0.1 to 15 mm; infill types are soft clay and grit, and hard calcite and iron; spacing of discontinuities are smaller in siltstone beds (≥ 5 mm), and up to 5 m in sandstone and debrite beds; bedding and fault planes are continuous, joints are non-continuous; block size is dictated by bed thickness and non-continuous joints. Shore platform widths were used to determine long-term erosion rates which range from 1.2 to 53.0 mm y-1. Platform morphologies are either sloping or horizontal or are a combination of both. Higher platform benches found at some sites are considered to be the result of a higher period of sea-level or are high-tide benches. Intact and rock mass strength increases northwards. Cliff heights are 8 to 38 m; cliff angles are 51 to 79 . Conditions for sporadic planar and wedge failure were determined at some sites; frittered siltstone and low durability sandstone allow smaller-scale, continual erosion. Castor Bay, Army Bay, Waiwera Beach and Leigh Marine Reserve have the lowest rock mass quality. Musick Point, Narrowneck Beach and Waiake Bay have good rock mass quality.

A conceptual model for coastal cliff erosion has been developed for Waitemata Group coastal cliffs, based on the dominant processes that act on the cliffs determined from statistical analysis (student t-test, correlation and regression) and field observations. The primary factor for cliff erosion is bed dip, whereby seaward dipping beds have higher erosion rates than landward dipping beds. The secondary factors for cliff erosion include: the intact and rock mass strength of the rock; the rock mass quality; strength of the siltstone beds; strength and structure of the sandstone beds; and orientation of the bedding planes with respect to the cliff face. Shear stresses are enhanced when beds dip seaward and thus shear failure along continuous surfaces is achievable. When beds dip landward the influence of shear stresses along bedding planes, and their contribution to the removal of individual blocks of rock, is severely inhibited resulting in reduced rates of erosion.  There is no relationship between cliff height and erosion rates and cliff heights are mainly controlled by the pre-existing landscape. Cliff angle is controlled by the proportion of sandstone and siltstone (whereby lower cliff angles are more siltstone-dominated), rock mass strength and weathering.  Erosion rates do vary in Waitemata Group rock of the Auckland region because of the variation in structural and geomorphic conditions of the cliff, most strongly controlled by the dip angle of bedding planes.

text: Towards a Better Understanding of Coastal Cliff Erosion in Waitemata Group Rock; Auckland, New Zealand. The soft sedimentary deposits of the Waitemata Group which outcrop on the eastern coastline of the Auckland region are a coastal cliff erosion hazard. The determination of the rate that these cliffs erode for hazard zonation purposes still requires research. A database has been collated of a range of structural, geological, geomorphic and climate parameters from 16 representative cliff sites in order to statistically assess what parameters influence cliff erosion and why erosion rates vary within the relatively uniform geology. 

Four different lithological units have been defined: sandstone beds of turbidites; sandstone beds of densites (contain rip-up clasts); sand to gravel beds of debrites; and siltstone beds. Cliff rock has very weak to weak intact rock strength; apertures of 0.1 to 15 mm; infill types are soft clay and grit, and hard calcite and iron; spacing of discontinuities are smaller in siltstone beds (≥ 5 mm), and up to 5 m in sandstone and debrite beds; bedding and fault planes are continuous, joints are non-continuous; block size is dictated by bed thickness and non-continuous joints. Shore platform widths were used to determine long-term erosion rates which range from 1.2 to 53.0 mm y-1. Platform morphologies are either sloping or horizontal or are a combination of both. Higher platform benches found at some sites are considered to be the result of a higher period of sea-level or are high-tide benches. Intact and rock mass strength increases northwards. Cliff heights are 8 to 38 m; cliff angles are 51 to 79 . Conditions for sporadic planar and wedge failure were determined at some sites; frittered siltstone and low durability sandstone allow smaller-scale, continual erosion. Castor Bay, Army Bay, Waiwera Beach and Leigh Marine Reserve have the lowest rock mass quality. Musick Point, Narrowneck Beach and Waiake Bay have good rock mass quality.

A conceptual model for coastal cliff erosion has been developed for Waitemata Group coastal cliffs, based on the dominant processes that act on the cliffs determined from statistical analysis (student t-test, correlation and regression) and field observations. The primary factor for cliff erosion is bed dip, whereby seaward dipping beds have higher erosion rates than landward dipping beds. The secondary factors for cliff erosion include: the intact and rock mass strength of the rock; the rock mass quality; strength of the siltstone beds; strength and structure of the sandstone beds; and orientation of the bedding planes with respect to the cliff face. Shear stresses are enhanced when beds dip seaward and thus shear failure along continuous surfaces is achievable. When beds dip landward the influence of shear stresses along bedding planes, and their contribution to the removal of individual blocks of rock, is severely inhibited resulting in reduced rates of erosion.  There is no relationship between cliff height and erosion rates and cliff heights are mainly controlled by the pre-existing landscape. Cliff angle is controlled by the proportion of sandstone and siltstone (whereby lower cliff angles are more siltstone-dominated), rock mass strength and weathering.  Erosion rates do vary in Waitemata Group rock of the Auckland region because of the variation in structural and geomorphic conditions of the cliff, most strongly controlled by the dip angle of bedding planes.

year: 2007

title: Afterword—Geographies of Sexuality and Gender ‘Down Under’

authors: Longhurst, Robyn

abstract: The specialist sessions on ‘Geographies of Sexuality and Gender ‘‘Down Under’’’at the Australian Geographers’ conference in Melbourne in July 2007, and the subsequent publication of the essays presented here, is long overdue. The editors, in their introduction, explain that the aims of the sessions and this subsequent themed issue are (1) to showcase specifically Australasian-based research on spaces, places and scales of sexuality and gender; and (2) to offer Australasian perspectives on disciplinary debates about sexuality and gender. Undoubtedly these aims have been fulfilled. These essays have been written by scholars in a range of disciplines. Some are emerging scholars, others more senior. It is an eclectic collection containing essays on topics as diverse as young men who surf, and women who ‘come out’ as lesbian only to then ‘come out’ again as heterosexual, and yet key questions about identity, difference, gender, and sexuality underpin all the contributions, which give it a useful cohesion. When I first saw the call for papers for the specialist sessions at the Melbourne conference I was keen to take part. Over the past 15 years or so I have attended a number of New Zealand and Australian geography conference sessions on gender but I cannot recall attending sessions specifically on sexuality, or even on sexuality and gender. The conference in Melbourne, therefore, was a great opportunity but unfortunately it was one I missed (although I co-authored a paper with Lynda Johnston). The blow of this missing out, however, was lessened by an invitation to write the ‘Afterword’ for this collection. I really enjoyed reading the essays. They represent the burgeoning and exciting work on gay, lesbian, queer, feminist and gender geographies currently being carried out by scholars working in and on New Zealand and Australia. Undoubtedly they make a very significant empirical, theoretical and political contribution to the discipline. In the paragraphs that follow I address each of these contributions in turn.

text: Afterword—Geographies of Sexuality and Gender ‘Down Under’ The specialist sessions on ‘Geographies of Sexuality and Gender ‘‘Down Under’’’at the Australian Geographers’ conference in Melbourne in July 2007, and the subsequent publication of the essays presented here, is long overdue. The editors, in their introduction, explain that the aims of the sessions and this subsequent themed issue are (1) to showcase specifically Australasian-based research on spaces, places and scales of sexuality and gender; and (2) to offer Australasian perspectives on disciplinary debates about sexuality and gender. Undoubtedly these aims have been fulfilled. These essays have been written by scholars in a range of disciplines. Some are emerging scholars, others more senior. It is an eclectic collection containing essays on topics as diverse as young men who surf, and women who ‘come out’ as lesbian only to then ‘come out’ again as heterosexual, and yet key questions about identity, difference, gender, and sexuality underpin all the contributions, which give it a useful cohesion. When I first saw the call for papers for the specialist sessions at the Melbourne conference I was keen to take part. Over the past 15 years or so I have attended a number of New Zealand and Australian geography conference sessions on gender but I cannot recall attending sessions specifically on sexuality, or even on sexuality and gender. The conference in Melbourne, therefore, was a great opportunity but unfortunately it was one I missed (although I co-authored a paper with Lynda Johnston). The blow of this missing out, however, was lessened by an invitation to write the ‘Afterword’ for this collection. I really enjoyed reading the essays. They represent the burgeoning and exciting work on gay, lesbian, queer, feminist and gender geographies currently being carried out by scholars working in and on New Zealand and Australia. Undoubtedly they make a very significant empirical, theoretical and political contribution to the discipline. In the paragraphs that follow I address each of these contributions in turn.

year: 2008

title: Beyond structuralism: Exploring a semantic based approach for describing the Māori language in grammar books and textbooks for pedagogical purposes

authors: Taiapa, Michael William

subjects: Māori

abstract: Since the 1950s, the advancements and developments in English language studies has had a profound impact on its description that has made it less syntactically driven and more communicatively oriented. This has the potential to influence language description moving it from a purely structurally focused orientation to a more semantically focused one that could influence pedagogic outcomes in more meaningful and useful ways. Nevertheless, in the case of the Māori language, its description has largely focused on structure linguistics that was prevalent in the 19th and early 20th centuries. There has been very little focus on a semantic description and this, in turn, is reflected in grammar books and textbooks on te reo. This thesis set out to explore a semantic approach to describe te reo and to rethink how this type of description may be realized and included in the design of grammar books and textbooks for the teaching and learning of te reo in the broader field of second language pedagogy and acquisition. The thesis also includes a practical component in which a small sample of Māori language teachers were interviewed to determine how linguistic and/ or semantic approaches to describe te reo may have or have impacted on their own beliefs, attitudes, and teaching practices (See, Chapter 7). Thus, it is argued here that research-based studies, advancements, and developments in language descriptions over the past five decades (See, for example, Council of Europe, 1949; Fillmore, 1967; Longacre, 1968; & Crombie, 1985b) should play central roles in the design of a semantic based description of the Māori language from which a linguistic based description can significantly benefit.

text: Beyond structuralism: Exploring a semantic based approach for describing the Māori language in grammar books and textbooks for pedagogical purposes Since the 1950s, the advancements and developments in English language studies has had a profound impact on its description that has made it less syntactically driven and more communicatively oriented. This has the potential to influence language description moving it from a purely structurally focused orientation to a more semantically focused one that could influence pedagogic outcomes in more meaningful and useful ways. Nevertheless, in the case of the Māori language, its description has largely focused on structure linguistics that was prevalent in the 19th and early 20th centuries. There has been very little focus on a semantic description and this, in turn, is reflected in grammar books and textbooks on te reo. This thesis set out to explore a semantic approach to describe te reo and to rethink how this type of description may be realized and included in the design of grammar books and textbooks for the teaching and learning of te reo in the broader field of second language pedagogy and acquisition. The thesis also includes a practical component in which a small sample of Māori language teachers were interviewed to determine how linguistic and/ or semantic approaches to describe te reo may have or have impacted on their own beliefs, attitudes, and teaching practices (See, Chapter 7). Thus, it is argued here that research-based studies, advancements, and developments in language descriptions over the past five decades (See, for example, Council of Europe, 1949; Fillmore, 1967; Longacre, 1968; & Crombie, 1985b) should play central roles in the design of a semantic based description of the Māori language from which a linguistic based description can significantly benefit.

year: 2023