title: Nature, Distribution, Origin and Economics of Glauconite in Carbonate-Phosphate-Glauconite Surficial Deposits on Central Chatham Rise, Southwest Pacific

authors: Lawless, Anna Shanti

subjects: Glauconite

abstract: Chatham Rise is a broad, elongated submarine platform that extends 1100 km out into the Southwest Pacific off eastern South Island. The surficial sediments on the central portion of the Rise at depths of 200-500 m include significant concentrations of the mineral glauconite (10-80 wt%) associated with skeletal carbonate, fine terrigenous material and locally abundant phosphatic nodules. This is the first study to fully analyse the nature, origin and economic potential of the glauconite component. Sub-bottom 3.5 kHz profiles have established the distribution, geometry and thickness (10-200 cm) of the surficial deposits, which overlie partially indurated Oligocene chalk of probable Whaingaroan age (~34-27 Ma). 137 grab, dredge or piston core samples have been analysed for their texture, mineralogy and geochemistry, which has produced a new surficial sediment map for the central Chatham Rise.

Glauconite most commonly occurs as dark green to black, very fine to fine sand-sized (0.2 mm), polished ovoidal and lobate pellets, and less commonly as infills within foraminiferal tests or as variably replaced rock fragments and phosphatic clasts. Full physical analysis reveals seven morphological types of glauconite including, in order of decreasing abundance, ovoidal, lobate, composite, internal molds, fossil casts, pigmentary, tabular and pellets within rock fragments. Their internal fabrics are dominated by random microcrystalline varieties with some oriented fibroradiating rim and skeletal infill types. Other notable features of some glauconite pellets include their expansion cracks, opaque inclusions and variable degrees of limonitisation. XRF/XRD analyses reveal mainly diagenetically mature varieties having elevated K2O (7-9 wt%) and Fe2O3 (19-23 wt%) values, and a dominant 10Å glauconitic mica structure involving from 10-20% expandable smectite layers.

K-Ar dates on pellets indicate a Late Miocene age (av. 5.75 Ma). This “old” age, as well as the clear evidence of reworking shown by the dominance of smooth polished ovoidal grains, mean that the central Chatham Rise glauconites are predominantly allogenic (i.e. derived/reworked), and neither strictly authigenic nor in situ, despite occurring in “modern” seafloor deposits. The formation of glauconite is linked to prominent upwelling within the Subtropical Front (STF) zone over the Rise in the Late Miocene, and the attendant heightened primary productivity, bacterial activity and nutrients associated with widespread biogenic blooms at that time. The source of the smectite required for glauconite formation could have been from the devitrification of volcanic ash from diverse eruptive centres, or through “neoformation”/authigenic precipitation within pore water solutions of carbonate-rich waters in the Oligocene/Miocene chalk substrate. Glauconite formation largely ceased after the Late Miocene due to an increase in terrigenous input, a reduced smectite source, and a major period of lowered sea level associated with Antarctic ice sheet growth. The “modern” Chatham glauconite pellets were sourced from submarine erosion of the former Late Miocene sediments and have been dispersed by intensified bottom current circulation at times of lowered sea level within the complex STF over Chatham Rise, and possibly ice scouring. Effectively there exists a widespread “Chatham unconformity” (mid-Oligocene to Recent) which cuts out most of the last 30 myr of the sedimentary record on central Chatham Rise, except for the highly condensed surficial deposits whose glauconite grains formed 5-6 Ma, in the Late Miocene. This long-lasting “Chatham unconformity” is a greatly extended version of the well documented Oligocene Marshall Paraconformity.

The thickness of the surficial sediment cover on central Chatham Rise ranges from 0.06-1.35 m. By using a conservative estimate of 0.5 m thick, and the wt% of glauconite within the sediment cover, a resource estimate of the glauconite has been made for various areas. In the most glauconite-rich area (>50 wt% glauconite) in the vicinity of Reserve Bank in 200-300 m water depths, which has an aerial extend of 4,500 km2, the glauconite resource amounts to about 2 Bt. The Chatham Rise glauconites have substantial economic potential as a potash fertiliser in support of the strong agricultural-based economy of New Zealand.

Glauconite is widespread in many Late Cretaceous-Cenozoic sedimentary deposits in the New Zealand rock record and the Chatham Rise occurrences provide a useful uniformitarian analogue for at least some of these.

text: Nature, Distribution, Origin and Economics of Glauconite in Carbonate-Phosphate-Glauconite Surficial Deposits on Central Chatham Rise, Southwest Pacific Chatham Rise is a broad, elongated submarine platform that extends 1100 km out into the Southwest Pacific off eastern South Island. The surficial sediments on the central portion of the Rise at depths of 200-500 m include significant concentrations of the mineral glauconite (10-80 wt%) associated with skeletal carbonate, fine terrigenous material and locally abundant phosphatic nodules. This is the first study to fully analyse the nature, origin and economic potential of the glauconite component. Sub-bottom 3.5 kHz profiles have established the distribution, geometry and thickness (10-200 cm) of the surficial deposits, which overlie partially indurated Oligocene chalk of probable Whaingaroan age (~34-27 Ma). 137 grab, dredge or piston core samples have been analysed for their texture, mineralogy and geochemistry, which has produced a new surficial sediment map for the central Chatham Rise.

Glauconite most commonly occurs as dark green to black, very fine to fine sand-sized (0.2 mm), polished ovoidal and lobate pellets, and less commonly as infills within foraminiferal tests or as variably replaced rock fragments and phosphatic clasts. Full physical analysis reveals seven morphological types of glauconite including, in order of decreasing abundance, ovoidal, lobate, composite, internal molds, fossil casts, pigmentary, tabular and pellets within rock fragments. Their internal fabrics are dominated by random microcrystalline varieties with some oriented fibroradiating rim and skeletal infill types. Other notable features of some glauconite pellets include their expansion cracks, opaque inclusions and variable degrees of limonitisation. XRF/XRD analyses reveal mainly diagenetically mature varieties having elevated K2O (7-9 wt%) and Fe2O3 (19-23 wt%) values, and a dominant 10Å glauconitic mica structure involving from 10-20% expandable smectite layers.

K-Ar dates on pellets indicate a Late Miocene age (av. 5.75 Ma). This “old” age, as well as the clear evidence of reworking shown by the dominance of smooth polished ovoidal grains, mean that the central Chatham Rise glauconites are predominantly allogenic (i.e. derived/reworked), and neither strictly authigenic nor in situ, despite occurring in “modern” seafloor deposits. The formation of glauconite is linked to prominent upwelling within the Subtropical Front (STF) zone over the Rise in the Late Miocene, and the attendant heightened primary productivity, bacterial activity and nutrients associated with widespread biogenic blooms at that time. The source of the smectite required for glauconite formation could have been from the devitrification of volcanic ash from diverse eruptive centres, or through “neoformation”/authigenic precipitation within pore water solutions of carbonate-rich waters in the Oligocene/Miocene chalk substrate. Glauconite formation largely ceased after the Late Miocene due to an increase in terrigenous input, a reduced smectite source, and a major period of lowered sea level associated with Antarctic ice sheet growth. The “modern” Chatham glauconite pellets were sourced from submarine erosion of the former Late Miocene sediments and have been dispersed by intensified bottom current circulation at times of lowered sea level within the complex STF over Chatham Rise, and possibly ice scouring. Effectively there exists a widespread “Chatham unconformity” (mid-Oligocene to Recent) which cuts out most of the last 30 myr of the sedimentary record on central Chatham Rise, except for the highly condensed surficial deposits whose glauconite grains formed 5-6 Ma, in the Late Miocene. This long-lasting “Chatham unconformity” is a greatly extended version of the well documented Oligocene Marshall Paraconformity.

The thickness of the surficial sediment cover on central Chatham Rise ranges from 0.06-1.35 m. By using a conservative estimate of 0.5 m thick, and the wt% of glauconite within the sediment cover, a resource estimate of the glauconite has been made for various areas. In the most glauconite-rich area (>50 wt% glauconite) in the vicinity of Reserve Bank in 200-300 m water depths, which has an aerial extend of 4,500 km2, the glauconite resource amounts to about 2 Bt. The Chatham Rise glauconites have substantial economic potential as a potash fertiliser in support of the strong agricultural-based economy of New Zealand.

Glauconite is widespread in many Late Cretaceous-Cenozoic sedimentary deposits in the New Zealand rock record and the Chatham Rise occurrences provide a useful uniformitarian analogue for at least some of these.

year: 2012

title: Discordance in perceptions of barriers to diabetes care between patients and primary care and secondary care

authors: Simmons, David

subjects: DAWN

abstract: OBJECTIVE—We sought to compare perceived barriers to diabetes care between people with diabetes and different health professional groups. 
RESEARCH DESIGN AND METHODS—This was a cross-sectional, postal, open-questionnaire survey conducted in the Waikato district, New Zealand. A total of 3,890 individuals with diabetes participated, as well as 436 primary and secondary health professionals. 
RESULTS—Barriers were reported in 69.7% of patients. Psychological barriers were most important (55.5%), followed by systems barriers (25.7%), and then knowledge as least important (15.3%). Psychological barriers were ranked first among general practitioners (91.0%), but systems barriers were ranked first by other health professionals (38.8–100%). General practitioner and patient barrier group rankings were similar (rT = 0.976, P < 0.05). Of specific barriers among individuals with diabetes, strictness of treatment regimen was the most frequently reported (42.3 vs. 0.1–16.8%) (P < 0.001) and 2.5 (95% CI 2.4–2.7)- to 3.4 (3.2–3.7)-fold more than the 2nd through 4th ranked barriers. Motivation was the most common specific barrier reported by general practitioners (86%), practice nurses (31.5%), and the diabetes team (85.7%). Practice and hospital nurse/dietitian rankings were most comparable with patients (rT = 0.457 and 0.466, respectively, both P < 0.05). A major area of patient–health professional discordance was the influence of other health problems, which was ranked 2nd among patients but 10th–18th among health professionals. 
CONCLUSIONS—The most important barriers to diabetes care perceived by patients are psychological and particularly relate to the strictness of the regimen. Discordance between patients and different health professionals exists in the perception of the importance of different barriers to diabetes care.

text: Discordance in perceptions of barriers to diabetes care between patients and primary care and secondary care OBJECTIVE—We sought to compare perceived barriers to diabetes care between people with diabetes and different health professional groups. 
RESEARCH DESIGN AND METHODS—This was a cross-sectional, postal, open-questionnaire survey conducted in the Waikato district, New Zealand. A total of 3,890 individuals with diabetes participated, as well as 436 primary and secondary health professionals. 
RESULTS—Barriers were reported in 69.7% of patients. Psychological barriers were most important (55.5%), followed by systems barriers (25.7%), and then knowledge as least important (15.3%). Psychological barriers were ranked first among general practitioners (91.0%), but systems barriers were ranked first by other health professionals (38.8–100%). General practitioner and patient barrier group rankings were similar (rT = 0.976, P < 0.05). Of specific barriers among individuals with diabetes, strictness of treatment regimen was the most frequently reported (42.3 vs. 0.1–16.8%) (P < 0.001) and 2.5 (95% CI 2.4–2.7)- to 3.4 (3.2–3.7)-fold more than the 2nd through 4th ranked barriers. Motivation was the most common specific barrier reported by general practitioners (86%), practice nurses (31.5%), and the diabetes team (85.7%). Practice and hospital nurse/dietitian rankings were most comparable with patients (rT = 0.457 and 0.466, respectively, both P < 0.05). A major area of patient–health professional discordance was the influence of other health problems, which was ranked 2nd among patients but 10th–18th among health professionals. 
CONCLUSIONS—The most important barriers to diabetes care perceived by patients are psychological and particularly relate to the strictness of the regimen. Discordance between patients and different health professionals exists in the perception of the importance of different barriers to diabetes care.

year: 2007

title: Māori loanwords: a corpus of New Zealand English tweets

authors: Trye, David

abstract: Māori loanwords are widely used in New Zealand English for various social functions by New Zealanders within and outside of the Māori community. Motivated by the lack of linguistic resources for studying how Māori loanwords are used in social media, we present a new corpus of New Zealand English tweets. We collected tweets containing selected Māori words that are likely to be known by New Zealanders who do not speak Māori. Since over 30% of these words turned out to be irrelevant (e.g., mana is a popular gaming term, Moana is a character from a Disney movie), we manually annotated a sample of our tweets into relevant and irrelevant categories. This data was used to train machine learning models to automatically filter out irrelevant tweets.

text: Māori loanwords: a corpus of New Zealand English tweets Māori loanwords are widely used in New Zealand English for various social functions by New Zealanders within and outside of the Māori community. Motivated by the lack of linguistic resources for studying how Māori loanwords are used in social media, we present a new corpus of New Zealand English tweets. We collected tweets containing selected Māori words that are likely to be known by New Zealanders who do not speak Māori. Since over 30% of these words turned out to be irrelevant (e.g., mana is a popular gaming term, Moana is a character from a Disney movie), we manually annotated a sample of our tweets into relevant and irrelevant categories. This data was used to train machine learning models to automatically filter out irrelevant tweets.

year: 2019