title: Late Holocene mud sedimentation and diagenesis in the Firth of Thames: Bentonites in the making

authors: Naish, Timothy R.

abstract: Late Holocene mud sedimentation in the southern Firth of Thames has been described from analysis of a number of shallow marine sediment cores. Three distinct lithofacies are distinguished on the basis of sediment texture and mineralogy. A laterally extensive greenish grey mud, typically bioturbated and massive, with sporadic uncorrelatable interbedded shell layers is termed the Firth of Thames mud facies. Nearer shore sediments are usually coarser and are subdivided into two facies: a siliciclastic sand facies (river mouth sand facies) comprising more prominent interbeds of sand in mud and associated with sedimentation at the mouth of the Waihou River; and a mixed terrigenous-carbonate gravel facies (delta fan gravel facies) associated with deposition on small delta fans adjacent to streams draining the Coromandel Range. The areal distribution of all three facies over the late Holocene has been controlled largely by northward progradation of the coastal Hauraki Lowland associated with the rapid sediment infilling of the Firth of Thames since sea level reached its present height 6500 y B.P. From seismic evidence the Holocene muds are up to 10m thick. The cores in this study penetrated only to 5.5m sub-bottom depth and yielded an oldest radiocarbon age of 5000 y B.P. The age data indicate an average rate of offshore vertical sediment accumulation of 1.5 mm/y. 

Up to 15 km of progradation of the southern shoreline of the coastal Hauraki Lowland has occurred over the late Holocene at an average rate of up to 2.5 m/y, notably from 3500 y B.P to 1200 y B.P. Progradation is evidenced by the occurrence of coarsening-upward sequences in nearer shore cores of the Firth of Thames, as well as their changing faunal composition, particularly the upward increase in abundance of the foraminifer Ammonia beccarri, a good indicator of brackish water conditions, which suggests a gradual seaward encroachment of the freshwater influence of the Waihou River over the late Holocene. Basal muds which are similar in composition to marine sediments of the Firth of Thames are overlain by peat dated at 6025 y B.P in a peat core from Kopouatai Peat Bog, and suggest that marine conditions existed in this inland region of the Hauraki Depression prior to 6025 y B.P. 

Muds range from silty clays to clayey silts and consist principally of volcanic glass, smectite and halloysite, with smaller amounts of other volcanic-derived siliciclasts and allophane and illite, as well as skeletal carbonate (mainly aragonite) and organic matter. A contemporaneous decrease in the abundance of volcanic glass (55-15 wt % down-core) and an increase in smectite concentration (8-45 wt % down-core) occurs with sub-bottom depth. Specific mineralogical analyses (XRD and IR) and evidence from scanning electron microscopy suggest the smectite is montmorillonitic in composition and authigenic in nature. Moreover, the absence of smectite in the bottom sediments of rivers draining the Hauraki Lowland precludes a detrital origin.

The diagenetic transformation of volcanic glass to smectite in sediments of the Firth of Thames is described by a sequential kinetic model which involves a parabolic dissolution coupled with a first order precipitation of smectite via the formation of an intermediate hydrated glass phase. The rate constant calculated from the sequential kinetic model is 3.35 x 10⁻⁴y⁻¹. The half-life of the glass is 1475 y, implying rapid early diagenetic alteration of volcanic glass to smectite to form late Holocene bentonitic deposits. Thermodynamic stability considerations imply that the first order precipitaion of smectite may be favoured by conditions of pH and Na⁺ activity typical of interstitial fluids having sea water salinity under mildly anoxic conditions.

text: Late Holocene mud sedimentation and diagenesis in the Firth of Thames: Bentonites in the making Late Holocene mud sedimentation in the southern Firth of Thames has been described from analysis of a number of shallow marine sediment cores. Three distinct lithofacies are distinguished on the basis of sediment texture and mineralogy. A laterally extensive greenish grey mud, typically bioturbated and massive, with sporadic uncorrelatable interbedded shell layers is termed the Firth of Thames mud facies. Nearer shore sediments are usually coarser and are subdivided into two facies: a siliciclastic sand facies (river mouth sand facies) comprising more prominent interbeds of sand in mud and associated with sedimentation at the mouth of the Waihou River; and a mixed terrigenous-carbonate gravel facies (delta fan gravel facies) associated with deposition on small delta fans adjacent to streams draining the Coromandel Range. The areal distribution of all three facies over the late Holocene has been controlled largely by northward progradation of the coastal Hauraki Lowland associated with the rapid sediment infilling of the Firth of Thames since sea level reached its present height 6500 y B.P. From seismic evidence the Holocene muds are up to 10m thick. The cores in this study penetrated only to 5.5m sub-bottom depth and yielded an oldest radiocarbon age of 5000 y B.P. The age data indicate an average rate of offshore vertical sediment accumulation of 1.5 mm/y. 

Up to 15 km of progradation of the southern shoreline of the coastal Hauraki Lowland has occurred over the late Holocene at an average rate of up to 2.5 m/y, notably from 3500 y B.P to 1200 y B.P. Progradation is evidenced by the occurrence of coarsening-upward sequences in nearer shore cores of the Firth of Thames, as well as their changing faunal composition, particularly the upward increase in abundance of the foraminifer Ammonia beccarri, a good indicator of brackish water conditions, which suggests a gradual seaward encroachment of the freshwater influence of the Waihou River over the late Holocene. Basal muds which are similar in composition to marine sediments of the Firth of Thames are overlain by peat dated at 6025 y B.P in a peat core from Kopouatai Peat Bog, and suggest that marine conditions existed in this inland region of the Hauraki Depression prior to 6025 y B.P. 

Muds range from silty clays to clayey silts and consist principally of volcanic glass, smectite and halloysite, with smaller amounts of other volcanic-derived siliciclasts and allophane and illite, as well as skeletal carbonate (mainly aragonite) and organic matter. A contemporaneous decrease in the abundance of volcanic glass (55-15 wt % down-core) and an increase in smectite concentration (8-45 wt % down-core) occurs with sub-bottom depth. Specific mineralogical analyses (XRD and IR) and evidence from scanning electron microscopy suggest the smectite is montmorillonitic in composition and authigenic in nature. Moreover, the absence of smectite in the bottom sediments of rivers draining the Hauraki Lowland precludes a detrital origin.

The diagenetic transformation of volcanic glass to smectite in sediments of the Firth of Thames is described by a sequential kinetic model which involves a parabolic dissolution coupled with a first order precipitation of smectite via the formation of an intermediate hydrated glass phase. The rate constant calculated from the sequential kinetic model is 3.35 x 10⁻⁴y⁻¹. The half-life of the glass is 1475 y, implying rapid early diagenetic alteration of volcanic glass to smectite to form late Holocene bentonitic deposits. Thermodynamic stability considerations imply that the first order precipitaion of smectite may be favoured by conditions of pH and Na⁺ activity typical of interstitial fluids having sea water salinity under mildly anoxic conditions.

year: 1990

title: To medicate or not to medicate? Exchange, identity and care in everyday household medication practices

authors: Hayward, Brooke Particia

subjects: Medication

abstract: In contemporary societies, medications are one of the most commonly used resources for the prevention, treatment, or cure of illness and disease (Shoemaker & de Oliveira, 2008). Despite this, there is a lack of understanding about how medications are used and understood by lay persons in private domestic dwellings. This research explores the medication experiences, understandings, and practices enacted by mothers caring for their chronically ill children. Four households containing children with chronic illness were involved in this qualitative interpretive research. Semi-structured interviews, mapping, diary keeping, and photo-production exercises were utilised to explore the ways in which medications are implicated in caring practices enacted by the mothers. Giddens’ (1984) structuration theory and the concept of ‘gift exchange’ provide the theoretical foundation for this thesis. This research indicates that the medication understandings and beliefs held by the participants are central to the construction of everyday caring medication practices. These beliefs and practices are not fixed or homogeneous, but complex and changeable; reflecting differing contexts, experiences, and forms of knowledge. The agency of parents as they conceptualise ‘care’ and choose to embrace or resist medication use, challenges the notion of ‘passive’ medication consumers. As the use of medication impacts many relationships within and outside of the confines of the household, this thesis highlights the social and symbolic nature of medications. The relationship between a parent and child is central to medication use, but medical decisions made by parents also implicate various other individuals, including health professionals and lay persons. The findings point to the need for health policy which acknowledges and is responsive to, the shifting health needs and understandings of the lay population.

text: To medicate or not to medicate? Exchange, identity and care in everyday household medication practices In contemporary societies, medications are one of the most commonly used resources for the prevention, treatment, or cure of illness and disease (Shoemaker & de Oliveira, 2008). Despite this, there is a lack of understanding about how medications are used and understood by lay persons in private domestic dwellings. This research explores the medication experiences, understandings, and practices enacted by mothers caring for their chronically ill children. Four households containing children with chronic illness were involved in this qualitative interpretive research. Semi-structured interviews, mapping, diary keeping, and photo-production exercises were utilised to explore the ways in which medications are implicated in caring practices enacted by the mothers. Giddens’ (1984) structuration theory and the concept of ‘gift exchange’ provide the theoretical foundation for this thesis. This research indicates that the medication understandings and beliefs held by the participants are central to the construction of everyday caring medication practices. These beliefs and practices are not fixed or homogeneous, but complex and changeable; reflecting differing contexts, experiences, and forms of knowledge. The agency of parents as they conceptualise ‘care’ and choose to embrace or resist medication use, challenges the notion of ‘passive’ medication consumers. As the use of medication impacts many relationships within and outside of the confines of the household, this thesis highlights the social and symbolic nature of medications. The relationship between a parent and child is central to medication use, but medical decisions made by parents also implicate various other individuals, including health professionals and lay persons. The findings point to the need for health policy which acknowledges and is responsive to, the shifting health needs and understandings of the lay population.

year: 2011

title: Ngā Hua a Tāne Rore: The Benefits of Kapa Haka.

authors: Pihama, Leonie

abstract: This report presentsthe findings of scoping research that is focused on developing a research agenda that will enable a greater understanding of the value and contribution of kapa haka to Aotearoa New Zealand society, and which explores the multiple ways in which we may view the value and contribution of kapa haka within cultural, social and economic contexts.
• There was a unanimous and resounding view that kapa haka does indeed make a valuable contribution to Aotearoa New Zealand society, but that its value is not fully understood or acknowledged within Aotearoa New Zealand.
• The most important components of kapa haka are its intrinsic link to culture and Māori identity, and the essential element of whanaungatanga, the importance of people and connectedness.
• Kapa haka has a dynamic role as a vehicle for the revitalisation and retention of te reo, tikanga, ritual processes and histories.
• It is perceived as a gateway into the culture for Māori who are disengaged from their marae/hapū/iwi, as well as as a safe, inclusive activity through which all New Zealanders can engage with Māori culture.
• Kapa haka is seen as a medium for fostering a richer, more cohesive and inclusive society in Aotearoa New Zealand. As such, it makes a major contribution to building and strengthening New Zealand’s nationhood.
• Kapa haka makes a significant contribution to New Zealand’s national identity and how we are represented and viewed internationally. It provides an effective platform for creating meaningful connections with other nations and peoples.
• Māori culture/kapa haka is increasingly utilised to add value to many forums, both formal and informal, within the public and government sectors. This was seen by some to reflect a more embracing attitude toward Māori cultural protocols as a normal part of New Zealand’s social fabric.
• Kapa haka is not, however, being given the status or respect it deserves as a cultural icon. Because its significance is not well understood by non-Māori, particularly at the level of government, it is often treated in a tokenistic way.
• A major component of kapa haka is its power to effect wellbeing, and to positively transform the lives of individuals and communities. A strength of the movement towards increased health and fitness within kapa haka is that it is achieved collectively.
• An important social benefit of kapa haka is that it provides a positive, disciplined, strength-based environment for rangatahi.
• Kapa haka is having a powerful, transformative impact on social outcomes through the BMPA (Māori performing arts degree), which enables people involved in kapa haka who would otherwise never have considered tertiary education as an option, to embark on that journey and exceed their
own expectations.
• An overall feeling of optimism about the future of kapa haka was tempered by the conviction that there was much more potential to be explored within the realm of kapa haka, particularly in terms of its social benefits.
• The myriad benefits of kapa haka within school environments, including improved learning outcomes, were clearly attested to. However, some barriers to realising those improved outcomes were also identified.
• Some participants were very sure ofthe economic value of kapa haka to Aotearoa. Whilemost of them were less able to articulate specific economic outcomes, they nonetheless had a definite sense of the link between the cultural, social and economic, and that that was ofsignificant value.
• The immense value of ‘culture-to-culture’ relationships was identified, with Maōri culture, including kapa haka, playing a significant role in laying the foundations for lasting trade relationships with other nations, and other cultures.
• Two significant and largely unacknowledged areas of economic contribution were identified: the ‘silent’ economy generated by kapa haka activities; and the extensive ‘productivity’ activity around voluntary workers involved in kapa haka.
• There was an overall view that the economic potential of kapa haka is underestimated and needs to be explored more fully, including the potential for engagement with New Zealand’s private sector.
• A recurrent theme that emerged around the value of kapa haka was to do with how we should go about measuring the value of culture, knowledge and art, and how ‘value’ itselfshould be defined and measured.
• Economic challenges were identified, especially in terms of financial hardship for those involved in kapa haka at the competitive level. It was also noted, however, that kapa haka communities are naturally adept and endlessly resourceful at generating funds.
• The issue of sustainability was raised by some participants who were concerned that kapa haka should be supported at every level into the future, and not just at the high-end competitive level.
• Of fundamental importance was that the growth and development of kapa haka should take place within the context of the acceptance and embracing of Māori culture as an integral component of New Zealand identity and nationhood.

text: Ngā Hua a Tāne Rore: The Benefits of Kapa Haka. This report presentsthe findings of scoping research that is focused on developing a research agenda that will enable a greater understanding of the value and contribution of kapa haka to Aotearoa New Zealand society, and which explores the multiple ways in which we may view the value and contribution of kapa haka within cultural, social and economic contexts.
• There was a unanimous and resounding view that kapa haka does indeed make a valuable contribution to Aotearoa New Zealand society, but that its value is not fully understood or acknowledged within Aotearoa New Zealand.
• The most important components of kapa haka are its intrinsic link to culture and Māori identity, and the essential element of whanaungatanga, the importance of people and connectedness.
• Kapa haka has a dynamic role as a vehicle for the revitalisation and retention of te reo, tikanga, ritual processes and histories.
• It is perceived as a gateway into the culture for Māori who are disengaged from their marae/hapū/iwi, as well as as a safe, inclusive activity through which all New Zealanders can engage with Māori culture.
• Kapa haka is seen as a medium for fostering a richer, more cohesive and inclusive society in Aotearoa New Zealand. As such, it makes a major contribution to building and strengthening New Zealand’s nationhood.
• Kapa haka makes a significant contribution to New Zealand’s national identity and how we are represented and viewed internationally. It provides an effective platform for creating meaningful connections with other nations and peoples.
• Māori culture/kapa haka is increasingly utilised to add value to many forums, both formal and informal, within the public and government sectors. This was seen by some to reflect a more embracing attitude toward Māori cultural protocols as a normal part of New Zealand’s social fabric.
• Kapa haka is not, however, being given the status or respect it deserves as a cultural icon. Because its significance is not well understood by non-Māori, particularly at the level of government, it is often treated in a tokenistic way.
• A major component of kapa haka is its power to effect wellbeing, and to positively transform the lives of individuals and communities. A strength of the movement towards increased health and fitness within kapa haka is that it is achieved collectively.
• An important social benefit of kapa haka is that it provides a positive, disciplined, strength-based environment for rangatahi.
• Kapa haka is having a powerful, transformative impact on social outcomes through the BMPA (Māori performing arts degree), which enables people involved in kapa haka who would otherwise never have considered tertiary education as an option, to embark on that journey and exceed their
own expectations.
• An overall feeling of optimism about the future of kapa haka was tempered by the conviction that there was much more potential to be explored within the realm of kapa haka, particularly in terms of its social benefits.
• The myriad benefits of kapa haka within school environments, including improved learning outcomes, were clearly attested to. However, some barriers to realising those improved outcomes were also identified.
• Some participants were very sure ofthe economic value of kapa haka to Aotearoa. Whilemost of them were less able to articulate specific economic outcomes, they nonetheless had a definite sense of the link between the cultural, social and economic, and that that was ofsignificant value.
• The immense value of ‘culture-to-culture’ relationships was identified, with Maōri culture, including kapa haka, playing a significant role in laying the foundations for lasting trade relationships with other nations, and other cultures.
• Two significant and largely unacknowledged areas of economic contribution were identified: the ‘silent’ economy generated by kapa haka activities; and the extensive ‘productivity’ activity around voluntary workers involved in kapa haka.
• There was an overall view that the economic potential of kapa haka is underestimated and needs to be explored more fully, including the potential for engagement with New Zealand’s private sector.
• A recurrent theme that emerged around the value of kapa haka was to do with how we should go about measuring the value of culture, knowledge and art, and how ‘value’ itselfshould be defined and measured.
• Economic challenges were identified, especially in terms of financial hardship for those involved in kapa haka at the competitive level. It was also noted, however, that kapa haka communities are naturally adept and endlessly resourceful at generating funds.
• The issue of sustainability was raised by some participants who were concerned that kapa haka should be supported at every level into the future, and not just at the high-end competitive level.
• Of fundamental importance was that the growth and development of kapa haka should take place within the context of the acceptance and embracing of Māori culture as an integral component of New Zealand identity and nationhood.

year: 2014