title: Formation of magnetite-enriched zones in and offshore of a mesotidal estuarine lagoon: An environmental magnetic study of Tauranga Harbour and Bay of Plenty, New Zealand

authors: Badesab, Firoz

subjects: environmental magnetism

abstract: Magnetic iron minerals are widespread and indicative sediment constituents in estuarine, coastal and shelf systems. We combine environmental magnetic, sedimentological and numerical methods to identify magnetite-enriched placer-like zones in a complex coastal system and delineate their formation mechanisms. Magnetic susceptibility and remanence measurements on 245 surficial sediment samples collected in and around Tauranga Harbour, the largest barrier-enclosed tidal estuary of New Zealand, reveal several discrete enrichment zones controlled by local hydrodynamic conditions. Active magnetite enrichment takes place in tidal channels, which feed into two coast-parallel nearshore magnetite-enriched belts centered at water depths of 6–10 m and 10–20 m. A close correlation between magnetite content and magnetic grain size was found, where higher susceptibility values are associated within coarser magnetic crystal sizes. Two key mechanisms for magnetite enrichment are identified. First, tide-induced residual currents primarily enable magnetite enrichment within the estuarine channel network. A coast-parallel, fine sand magnetite enrichment belt in water depths of less than 10 m along the barrier island has a strong decrease in magnetite content away from the southern tidal inlet and is apparently related to active coast-parallel transport combined with mobilizing surf zone processes. A second, less pronounced, but more uniform magnetite enrichment belt at 10–20 m water depth is composed of non-mobile, medium-coarse-grained relict sands, which have been reworked during post-glacial sea level transgression. We demonstrate the potential of magnetic methods to reveal and differentiate coastal magnetite enrichment patterns and investigate their formative mechanisms.

text: Formation of magnetite-enriched zones in and offshore of a mesotidal estuarine lagoon: An environmental magnetic study of Tauranga Harbour and Bay of Plenty, New Zealand Magnetic iron minerals are widespread and indicative sediment constituents in estuarine, coastal and shelf systems. We combine environmental magnetic, sedimentological and numerical methods to identify magnetite-enriched placer-like zones in a complex coastal system and delineate their formation mechanisms. Magnetic susceptibility and remanence measurements on 245 surficial sediment samples collected in and around Tauranga Harbour, the largest barrier-enclosed tidal estuary of New Zealand, reveal several discrete enrichment zones controlled by local hydrodynamic conditions. Active magnetite enrichment takes place in tidal channels, which feed into two coast-parallel nearshore magnetite-enriched belts centered at water depths of 6–10 m and 10–20 m. A close correlation between magnetite content and magnetic grain size was found, where higher susceptibility values are associated within coarser magnetic crystal sizes. Two key mechanisms for magnetite enrichment are identified. First, tide-induced residual currents primarily enable magnetite enrichment within the estuarine channel network. A coast-parallel, fine sand magnetite enrichment belt in water depths of less than 10 m along the barrier island has a strong decrease in magnetite content away from the southern tidal inlet and is apparently related to active coast-parallel transport combined with mobilizing surf zone processes. A second, less pronounced, but more uniform magnetite enrichment belt at 10–20 m water depth is composed of non-mobile, medium-coarse-grained relict sands, which have been reworked during post-glacial sea level transgression. We demonstrate the potential of magnetic methods to reveal and differentiate coastal magnetite enrichment patterns and investigate their formative mechanisms.

year: 2012

title: Students' Perceptions of the Secondary Numeracy Project

authors: Thereesha, Fathimath

subjects: Secondary Numeracy Project

abstract: This thesis explores the perceptions and experiences of twenty four Year 9 students from two schools in New Zealand who had participated in the Secondary Numeracy Project. The two schools were in their first year of SNP at the time of data collection. The main focus was on four areas of mathematics learning: group work, equipment, communication and teachers. Data was collected mainly by using semi-structured and clinical interviews. Findings revealed that equipment was particularly important and were used more frequently by students in Low ability group. Students liked using equipment, working in groups and sharing multiple solutions. However, communication was not used much as a means of making sense of mathematics in these classrooms. Furthermore the students' responses depended on the ability groups. These findings complemented the work of other researchers who have explored students' perspectives at the primary level. These findings suggest that the SNP would be more successful if students were explicitly taught good communication and cooperative learning skills.

text: Students' Perceptions of the Secondary Numeracy Project This thesis explores the perceptions and experiences of twenty four Year 9 students from two schools in New Zealand who had participated in the Secondary Numeracy Project. The two schools were in their first year of SNP at the time of data collection. The main focus was on four areas of mathematics learning: group work, equipment, communication and teachers. Data was collected mainly by using semi-structured and clinical interviews. Findings revealed that equipment was particularly important and were used more frequently by students in Low ability group. Students liked using equipment, working in groups and sharing multiple solutions. However, communication was not used much as a means of making sense of mathematics in these classrooms. Furthermore the students' responses depended on the ability groups. These findings complemented the work of other researchers who have explored students' perspectives at the primary level. These findings suggest that the SNP would be more successful if students were explicitly taught good communication and cooperative learning skills.

year: 2007

title: Book review:  Ikawai: freshwater fishes in Māori culture and economy

authors: Hicks, Brendan J.

abstract: This article reviews the book : “Ikawai: freshwater fishes in Māori culture and economy”, by RM McDowall.

text: Book review:  Ikawai: freshwater fishes in Māori culture and economy This article reviews the book : “Ikawai: freshwater fishes in Māori culture and economy”, by RM McDowall.

year: 2012