Bedrock geology of DFDP-2B, central Alpine Fault, New Zealand

<p>During the second phase of the Alpine Fault, Deep Fault Drilling Project (DFDP) in the Whataroa River, South Westland, New Zealand, bedrock was encountered in the DFDP-2B borehole from 238.5–893.2 m Measured Depth (MD). Continuous sampling and meso- to microscale characterisation of whole rock cuttings established that, in sequence, the borehole sampled amphibolite facies, Torlesse Composite Terrane-derived schists, protomylonites and mylonites, terminating 200–400 m above an Alpine Fault Principal Slip Zone (PSZ) with a maximum dip of 62°. The most diagnostic structural features of increasing PSZ proximity were the occurrence of shear bands and reduction in mean quartz grain sizes. A change in composition to greater mica:quartz + feldspar, most markedly below c. 700 m MD, is inferred to result from either heterogeneous sampling or a change in lithology related to alteration. Major oxide variations suggest the fault-proximal Alpine Fault alteration zone, as previously defined in DFDP-1 core, was not sampled.</p

Differences in Resilience and University Adjustment between School Leaver and Mature Entry University Students

Research shows that mature entry and school leaver students have vastly different experiences when transitioning to the university environment. It is suggested that the transition to university is a major life transition and thus is a period of great stress. For mature entry students and school leaver students, the impacts upon adjustment to university are varied during the transition to university study. It has been proposed that for successful university adjustment, high levels of resilience are needed. Three hypotheses were tested with a sample of undergraduate students (n = 63). Hypothesis one, that there is a relationship between resilience and adjustment was supported. This indicates that 31.9 percent of the variance in adjustment can be accounted for by resilience. Hypothesis two, that there is a difference in university adjustment between school leaver and mature entry students, and hypothesis three, that mature entry students would exhibit higher levels of resilience than school leavers, were both not supported. These findings imply that individual differences are more important in adjustment to university than group differences, and have the implication that universities may be better off considering these individual differences when accommodating new students

Grain growth of natural and synthetic ice at 0 degrees C

Abstract. Grain growth can modify the microstructure of natural ice, including the grain size and crystallographic preferred orientation (CPO). To better understand grain-growth processes and kinetics, we compared microstructural data from synthetic and natural ice samples of similar starting grain sizes that were annealed at the solidus temperature (0 ∘C) for durations of a few hours to 33 d. The synthetic ice has a homogeneous initial microstructure characterized by polygonal grains, little intragranular distortion, few bubbles, and a near-random CPO. The natural ice samples were subsampled from ice cores acquired from the Priestley Glacier, Antarctica. This natural ice has a heterogeneous microstructure characterized by a considerable number of air bubbles, widespread intragranular distortion, and a CPO. During annealing, the average grain size of the natural ice barely changes, whereas the average grain size of the synthetic ice gradually increases. These observations demonstrate that grain growth in natural ice can be much slower than in synthetic ice and therefore that the grain-growth law derived from synthetic ice cannot be directly applied to estimate the grain-size evolution in natural ice with a different microstructure. The microstructure of natural ice is characterized by many bubbles that pin grain boundaries. Previous studies suggest that bubble pinning provides a resisting force that reduces the effective driving force of grain-boundary migration and is therefore linked to the inhibition of grain growth observed in natural ice. As annealing progresses, the number density (number per unit area) of bubbles on grain boundaries in the natural ice decreases, whilst the number density of bubbles in the grain interiors increases. This observation indicates that some grain boundaries sweep through bubbles, which should weaken the pinning effect and thus reduce the resisting force for grain-boundary migration. Some of the Priestley ice grains become abnormally large during annealing. We speculate that the contrast of dislocation density amongst neighbouring grains, which favours the selected growth of grains with low dislocation densities, and bubble pinning, which inhibits grain growth, are tightly associated with abnormal grain growth. The upper 10 m of the Priestley ice core has a weaker CPO and better-developed second maximum than deeper samples. The similarity of this difference to the changes observed in annealing experiments suggests that abnormal grain growth may have occurred in the upper 10 m of the Priestley Glacier during summer warming. </jats:p

Supplementary Data to: &ldquo;Bedrock Geology of DFDP-2B, Central Alpine Fault, New Zealand&quot;

These data are supplementary material to &ldquo;Bedrock Geology of DFDP-2B, Central Alpine Fault, New Zealand&rdquo; (Toy et al., 2017, http://doi.org/10.1080/00288306.2017.1375533). The data tables SF3 and SF4 are provided as well as Excel as well as CSV and PDF versions (in the zip folder). The table numbers below are referring to Toy et al. (2017): Toy_SF1.pdf (Data Description): Supplementary Data to &ldquo;Bedrock Geology of DFDP-2B, Central Alpine Fault, New Zealand&rdquo;, including supplementary methods, Information on reference frames and corrections, and protocols for thin section preparation and scanning electron microscopic analyses. Toy_SF2: Table S1. Time vs. depth during drilling, with lag dip corrections Toy_SF3: Table S2. Energy dispersive spectroscopy (EDS) data acquired using a TESCAN Integrated Mineral Analyzer (TIMA) and phases detected by mineral liberation analysis (MLA) Toy_SF4: Table S3. Electron backscatter diffraction (EBSD) grain sizes.</span