title: Volcanic geology of the early Pleistocene ignimbrite succession in the western Papamoa Region, Bay of Plenty

authors: Namaliu, Miriam Darusila Mangon

abstract: Volcanic activity in the Tauranga Volcanic Center (TgaVC) occurred between 2.95 to 1.9 Ma, some of the eruptions were explosive and led to the distribution of ignimbrites of varying volumes across the western Bay of Plenty Region (Tauranga Basin), North Island. The Papamoa Formation forms part of the landscape in this area. This study was aimed at determining the volcanic history and processes involved in the distribution of the Papamoa Formation within the eastern Tauranga Basin.

Stratigraphic, petrographic and geochemical investigations were undertaken in the field and from samples within the study area. Field observations of the ignimbrites involved stratigraphic logging and lateral relationships, component measurements and lithological descriptions. Ignimbrite petrography was undertaken by optical microscopy. To determine the geochemical characteristics of the source magmas for the ignimbrites, the following analyses were conducted: electron microprobe analysis (EMPA) on glass shards extracted from the ignimbrite matrices, glass from pumice, and on minerals in the pumice, x-ray fluorescence spectroscopy (XRF) on whole pumice clasts and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) on the same glass samples used for EMPA.

Five individual eruptions that led to the distribution of five ignimbrites have been identified within the ignimbrite succession of the Papamoa Formation: an early unnamed ignimbrite, followed by the Welcome Bay, Wharo, Arateka, and Otawera ignimbrites. The beige-brown, non-welded, pumice-rich, Welcome Bay Ignimbrite (2.4 Ma) is the most voluminous in the study area and also has an underlying pumice fall deposit. The dark brown to black, pumice-/fiamme-rich Wharo Ignimbrite (2.26 Ma, M. Prentice unpublished data, 2021) is the only moderate to densely welded ignimbrite. Both the Welcome Bay and Otawera ignimbrite contained black (andesitic-dacitic) and white (dacitic) pumice. The beige, non-welded Otawera Ignimbrite (2.21 Ma) is the least voluminous ignimbrite in the study area and comprises only white pumice. The beige-yellow brown Arateka ignimbrite is comprises of both the black and white pumice clasts. The unnamed Unit A ignimbrite, at the base of the succession has only one pumice population – grey pumice, but it is poorly exposed. All the ignimbrites are generally lithic poor. Petrographic analysis found that the main minerals occurring in the ignimbrites were: plagioclase, pyroxenes, hornblende and opaques. The main mineral in the black pumice was plagioclase and pyroxene. The white pumice, however, is mainly composed of plagioclase and hornblende. In terms of rock textures, the Welcome Bay Ignimbrite, Arateka Ignimbrite, Otawera Ignimbrite and Unit A-Unknown Ignimbrite had either a porphyritic or vitrophyric or a combination of both textures. The
Wharo Ignimbrite possessed a porphyritic and/or eutaxitic texture. Geochemical data showed that although the glass shards from each ignimbrite has a unique chemical composition, they were all rhyolitic. However, in terms of the two pumice types, the white pumice was dacitic while the black pumice was andesitic.

The presence of two pumice types (black and white) in the Welcome Bay, Wharo and Arateka Ignimbrites, supports the idea that the magma from which the ignimbrites were sourced, had a mixed andesitic to dacitic composition. The distribution and internal stratigraphy of the Papamoa Formation record a history of multiple ignimbrite-forming eruptions that were sourced locally, likely south of the study area; at least one ignimbrite (Welcome Bay Ignimbrite) was preceded by a sustained Plinian eruption column.

text: Volcanic geology of the early Pleistocene ignimbrite succession in the western Papamoa Region, Bay of Plenty Volcanic activity in the Tauranga Volcanic Center (TgaVC) occurred between 2.95 to 1.9 Ma, some of the eruptions were explosive and led to the distribution of ignimbrites of varying volumes across the western Bay of Plenty Region (Tauranga Basin), North Island. The Papamoa Formation forms part of the landscape in this area. This study was aimed at determining the volcanic history and processes involved in the distribution of the Papamoa Formation within the eastern Tauranga Basin.

Stratigraphic, petrographic and geochemical investigations were undertaken in the field and from samples within the study area. Field observations of the ignimbrites involved stratigraphic logging and lateral relationships, component measurements and lithological descriptions. Ignimbrite petrography was undertaken by optical microscopy. To determine the geochemical characteristics of the source magmas for the ignimbrites, the following analyses were conducted: electron microprobe analysis (EMPA) on glass shards extracted from the ignimbrite matrices, glass from pumice, and on minerals in the pumice, x-ray fluorescence spectroscopy (XRF) on whole pumice clasts and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) on the same glass samples used for EMPA.

Five individual eruptions that led to the distribution of five ignimbrites have been identified within the ignimbrite succession of the Papamoa Formation: an early unnamed ignimbrite, followed by the Welcome Bay, Wharo, Arateka, and Otawera ignimbrites. The beige-brown, non-welded, pumice-rich, Welcome Bay Ignimbrite (2.4 Ma) is the most voluminous in the study area and also has an underlying pumice fall deposit. The dark brown to black, pumice-/fiamme-rich Wharo Ignimbrite (2.26 Ma, M. Prentice unpublished data, 2021) is the only moderate to densely welded ignimbrite. Both the Welcome Bay and Otawera ignimbrite contained black (andesitic-dacitic) and white (dacitic) pumice. The beige, non-welded Otawera Ignimbrite (2.21 Ma) is the least voluminous ignimbrite in the study area and comprises only white pumice. The beige-yellow brown Arateka ignimbrite is comprises of both the black and white pumice clasts. The unnamed Unit A ignimbrite, at the base of the succession has only one pumice population – grey pumice, but it is poorly exposed. All the ignimbrites are generally lithic poor. Petrographic analysis found that the main minerals occurring in the ignimbrites were: plagioclase, pyroxenes, hornblende and opaques. The main mineral in the black pumice was plagioclase and pyroxene. The white pumice, however, is mainly composed of plagioclase and hornblende. In terms of rock textures, the Welcome Bay Ignimbrite, Arateka Ignimbrite, Otawera Ignimbrite and Unit A-Unknown Ignimbrite had either a porphyritic or vitrophyric or a combination of both textures. The
Wharo Ignimbrite possessed a porphyritic and/or eutaxitic texture. Geochemical data showed that although the glass shards from each ignimbrite has a unique chemical composition, they were all rhyolitic. However, in terms of the two pumice types, the white pumice was dacitic while the black pumice was andesitic.

The presence of two pumice types (black and white) in the Welcome Bay, Wharo and Arateka Ignimbrites, supports the idea that the magma from which the ignimbrites were sourced, had a mixed andesitic to dacitic composition. The distribution and internal stratigraphy of the Papamoa Formation record a history of multiple ignimbrite-forming eruptions that were sourced locally, likely south of the study area; at least one ignimbrite (Welcome Bay Ignimbrite) was preceded by a sustained Plinian eruption column.

year: 2021

title: Are international real interest rate linkages characterized by asymmetric adjustments?

authors: Holmes, Mark J.

subjects: real interest parity

abstract: This study tests for asymmetries in the adjustment mechanism towards real interest parity using monthly data over the period 1973–2004 for the U.S. and a sample of other OECD economies. There is stronger evidence of long-run cointegrating relationships when an explicit distinction is made between decreasing and increasing deviations from equilibrium. The speed of mean-reversion tends to be fastest when momentum gathers for increasing rather than decreasing deviations. This evidence is consistent with asymmetric monetary policy responses where close linkages with respect to the U.S. are likely to be less prevalent in a regime of rising nominal interest rates and falling inflation.

text: Are international real interest rate linkages characterized by asymmetric adjustments? This study tests for asymmetries in the adjustment mechanism towards real interest parity using monthly data over the period 1973–2004 for the U.S. and a sample of other OECD economies. There is stronger evidence of long-run cointegrating relationships when an explicit distinction is made between decreasing and increasing deviations from equilibrium. The speed of mean-reversion tends to be fastest when momentum gathers for increasing rather than decreasing deviations. This evidence is consistent with asymmetric monetary policy responses where close linkages with respect to the U.S. are likely to be less prevalent in a regime of rising nominal interest rates and falling inflation.

year: 2006

title: What is the difference? What factors contribute to the variation of achievement for Year 7 and 8 Māori students in high decile, full primary schools?

authors: McLocklan, Sue

subjects: Maori student achievement

abstract: The educational disparity between indigenous Māori students and those of the majority continue to be a major issue in New Zealand. Attempting to bridge the gap for Māori students has generated focus on Māori student engagement in the classroom, the actions and understanding of the teacher and the relationship and interactions between the teacher and students in their learning environment. Elements of culturally responsive pedagogy have been identified as positive contributing factors to accelerating academic achievement for secondary Māori mainstream students. 
This small-scale cross-cultural exploratory qualitative research project seeks to identify the factors that contribute to student achievement variation for Year 7 and 8 students in high decile full primary schools and the integration of teacher’s cultural competencies in high quality learning opportunities. Within a kaupapa Māori research process, this study uses empirical data collected from a purposive sample through a semi-structured individual interview and a for self-assessment. Voluntary research participants were twelve students and six teachers in three schools in the Bay of Plenty, Waikato and Wellington regions. This research examines the engagement of student and teacher in pedagogical practice, learning variables, cultural knowledge and practices attributable to positive academic achievement for Māori. 
The findings reveal that when teachers place themselves in an agentic position; adopt a professional commitment and willingness to engage in effective relations, interactions and reciprocal practices to support Māori learners, high levels of relational trust and expectations prevail through mutual respect and interdependence to attain successful educational outcomes.
Further teacher professional learning is essential to enlighten and deepen teachers' understanding of culturally responsive pedagogy to enable Māori learners to reach their potential to participate and contribute in their world of choice.

text: What is the difference? What factors contribute to the variation of achievement for Year 7 and 8 Māori students in high decile, full primary schools? The educational disparity between indigenous Māori students and those of the majority continue to be a major issue in New Zealand. Attempting to bridge the gap for Māori students has generated focus on Māori student engagement in the classroom, the actions and understanding of the teacher and the relationship and interactions between the teacher and students in their learning environment. Elements of culturally responsive pedagogy have been identified as positive contributing factors to accelerating academic achievement for secondary Māori mainstream students. 
This small-scale cross-cultural exploratory qualitative research project seeks to identify the factors that contribute to student achievement variation for Year 7 and 8 students in high decile full primary schools and the integration of teacher’s cultural competencies in high quality learning opportunities. Within a kaupapa Māori research process, this study uses empirical data collected from a purposive sample through a semi-structured individual interview and a for self-assessment. Voluntary research participants were twelve students and six teachers in three schools in the Bay of Plenty, Waikato and Wellington regions. This research examines the engagement of student and teacher in pedagogical practice, learning variables, cultural knowledge and practices attributable to positive academic achievement for Māori. 
The findings reveal that when teachers place themselves in an agentic position; adopt a professional commitment and willingness to engage in effective relations, interactions and reciprocal practices to support Māori learners, high levels of relational trust and expectations prevail through mutual respect and interdependence to attain successful educational outcomes.
Further teacher professional learning is essential to enlighten and deepen teachers' understanding of culturally responsive pedagogy to enable Māori learners to reach their potential to participate and contribute in their world of choice.

year: 2013