Fluvial transport dynamics in the Rangitikei River (New Zealand) unravelled through single-grain feldspar luminescence

2020 ◽  
Author(s):  
Anne Guyez ◽  
Stephane Bonnet ◽  
Tony Reimann ◽  
Jakob Wallinga
Keyword(s):  
New Zealand ◽  
Light Exposure ◽  
River Sediments ◽  
High Ratio ◽  
Sediment Flux ◽  
Fluvial Terraces ◽  
The Past ◽  
Transport Distance ◽  
Fluvial Transport ◽  
Single Grain

<p>Over the past decades, luminescence has been widely used for dating sedimentary deposits. Several recent publications suggest luminescence signals can also be used to investigate fluvial transport. Here we explore what information luminescence signals yield in past and present sediment dynamics in the Rangitikei River (RR), New Zealand (Bonnet et al., 2019).</p><p>We present a dataset of 30 samples from fluvial terraces and modern river sediments of the RR. For each of the samples, we measured pIRIR luminescence signals of 300 individual sand-sized grains of feldspar (Reimann et al., 2012). We interpret results to evaluate differences between past and modern transport conditions, and to infer information on lateral input of bedrock particles in different river sections.</p><p>The information obtained from the single-grain analysis is incredibly rich, and requires new metrics for interpretation. To quantify the percentage of grains that were eroded from bedrock (or very old deposits) and re-deposited with minimal light-exposure, we identified grains for which the pIRIR signal is above 85% of full saturation (Wintle, 2006). For grains below this saturation threshold, we used the bootstrapped minimum age model (Galbraith et al.,1999; Cunningham and Wallinga, 2012) to determine the palaeodose, the best estimate of the natural radiation dose received by grains since their last deposition and burial event. For the modern deposits, we interpret the palaeodose to indicate the light-exposure of the best-bleached grains. Thereby, it provides a proxy of fluvial transport distance of the sediment grains.</p><p>For the modern river sediments we obtain palaeodoses between 2 and 6 Gy. A decreasing trend in palaeodose downstream suggests that part of the grains are transported through the entire system and are gradually bleached through light exposure during this process. The downstream trend in palaeodose of the RR is influenced by the connection of a major tributary, the Kawhatau River (KR), characterized by higher palaeodoses. Based on the observed trends, we estimate that the KR contributes three times more to modern sediment flux down the confluence than the upstream RR. Moreover, we observe that downstream of the confluence the percentage of saturated grains increase, which implies significant local input of bedrock particles from valley sides.</p><p>Data from recent (Holocene) autogenic fluvial terraces were acquired downstream the RR/KR confluence. They show a high to very high ratio of saturated grains (30-70%). We also document a downstream increasing trend of the percentage of saturated grains in these fluvial terraces, much stronger than for modern deposits. The maximum is observed for terraces at elevation of +28/+34 m, with an input of saturated grains that doubles over a distance of 100 km. As a consequence, saturated grains represent up to 70 % of the grain population in the most downstream sample. This implies a stronger lateral input of bedrock particles in the past, during recent incision of the river and a significant contribution of valley walls to the sediment flux of the RR, probably through landslides and/or lateral fluvial erosion.</p>

Source, sea level and circulation effects on the sediment flux to the deep ocean over the past 15 ka off eastern New Zealand

2002 ◽  
Vol 33 (3-4) ◽  
pp. 339-355 ◽  
Author(s):  
Lionel Carter ◽  
Barbara Manighetti ◽  
Mike Elliot ◽  
Noel Trustrum ◽  
Basil Gomez
Keyword(s):  
New Zealand ◽  
Sea Level ◽  
Deep Ocean ◽  
Sediment Flux ◽  
The Past

scholarly journals Neotectonics and Paleoseismicity of a Major Junction Between Two Strands of the Awatere Fault, South Island, New Zealand

2021 ◽  
Author(s):  
◽  
Dougal P M Mason
Keyword(s):  
New Zealand ◽  
Magnitude Estimate ◽  
Strike Slip ◽  
Fault System ◽  
Rupture Propagation ◽  
Coseismic Slip ◽  
The West ◽  
Fluvial Terraces ◽  
The Past ◽  
Earthquake Ruptures

<p><b>In northeastern South Island, New Zealand, obliquely-convergent relativemotion between the Pacific and Australian plates is accommodated by slip acrossactive dextral-oblique faults in the Marlborough fault system. The Awatere Fault isone of four principal active strike-slip faults within this plate boundary zone, andincludes two sections (the eastern and Molesworth sections) that have differentstrikes and that join across a complex fault junction in the upper Awatere Valley.</b></p> <p>Detailed mapping of the fault traces and measurement of 97 geomorphicdisplacements along the Awatere Fault in the vicinity of the fault junction show thatthe eastern and Molesworth sections of the fault intersect one another at a low angle(10-15º), at the eastern end of an internally faulted, elongate, ~15 km long and up to3 km wide fault wedge or sliver. The region between the fault sections is split by aseries of discontinuous, en-echelon scarps that are oriented from ~10º to 20-30ºclockwise from the principal fault sections. Based on other observations ofdiscontinuities in strike-slip earthquake ruptures around the globe, this low-angleintersection geometry suggests that the junction between these fault sections may notact as a significant barrier to earthquake rupture propagation. This interpretation ofthe mechanical significance of the fault junction to earthquake ruptures is counter toprevious suggestions, but is supported by new paleoseismic data from fourpaleoseismic trenches excavated on each side of the junction. In a new paleoseismictrench on the Molesworth section at Saxton River, 18 km to the west of the junction,up to ten surface-rupturing events in the past ~15 ka are recognised from 12radiocarbon ages and 1 optically stimulated luminescence age. In two new trencheson the eastern section near to Upcot Saddle, 12 km northeast of the fault junction,five events took place in the past 5.5 ka, based on 21 radiocarbon ages. Thischronology from Upcot Saddle is combined with data from two previous trencheslocated ~55 km to the northeast at Lake Jasper, to infer nine events on the easternsection since 8330-8610 cal. years B.P. These well-dated events on the easternsection are compared to those on the Molesworth section to the west of the faultjunction. At 95% confidence, five events on both sections have occurred withstatistical contemporaneity since ~6 ka B.P. These five events may have rupturedboth the eastern and Molesworth sections simultaneously, in accordance with the interpretation that the fault section junction does not arrest rupture propagation.</p> <p>Alternatively, these events may have been separate earthquakes that occurred withinthe statistical resolution provided by radiocarbon dating.</p> <p>The most recent event to rupture the eastern section was the Mw ~7.5 1848Marlborough earthquake. The coseismic slip distribution and maximum traceablelength of this surface rupture are calculated from the magnitude and distribution ofsmall, metre-scale geomorphic displacements attributable to this earthquake. Thesedata suggest this event ruptured >100-110 km of the eastern section, with meansurface displacement of 5.3 ±1.6 m. Based on these parameters, the momentmagnitude of this earthquake would be Mw 7.4-7.7. This magnitude estimate isindistinguishable from previous calculations that were based on attenuation ofshaking intensity isoseismals that were assigned from contemporary historicalaccounts of that earthquake. On the basis of similar rupture lengths and coseismicdisplacements, it is inferred that the penultimate event had a similar momentmagnitude to the 1848 earthquake.</p> <p>Horizontal displacement of a flight of 6 fluvial terraces at Saxton River by theMolesworth section of the Awatere Fault is constrained to have occurred at a nearconstantrate of 5.5 ±1.5 mm/a since ~15 ka B.P. These rates are based on two newoptically stimulated luminescence ages for the highest terrace treads of 14.5 ±1.5 and6.69 ±0.74 ka B.P. These rates are indistinguishable from recent strike-slip rateestimates for the eastern section of 5.6 ±1.1 and 6 ±2 mm/a. Comparing themagnitudes and ages of the terrace riser displacements at Saxton River to the timingof paleoearthquakes on the Molesworth section implies a mean per-eventdisplacement of 4.4 ±0.2 m since ~15 ka. The new terrace ages also record twoperiods of aggradation that post-date the Last Glacial Maximum.</p>

scholarly journals Neotectonics and Paleoseismicity of a Major Junction Between Two Strands of the Awatere Fault, South Island, New Zealand

2021 ◽  
Author(s):  
◽  
Dougal P M Mason
Keyword(s):  
New Zealand ◽  
Magnitude Estimate ◽  
Strike Slip ◽  
Fault System ◽  
Rupture Propagation ◽  
Coseismic Slip ◽  
The West ◽  
Fluvial Terraces ◽  
The Past ◽  
Earthquake Ruptures

<p><b>In northeastern South Island, New Zealand, obliquely-convergent relativemotion between the Pacific and Australian plates is accommodated by slip acrossactive dextral-oblique faults in the Marlborough fault system. The Awatere Fault isone of four principal active strike-slip faults within this plate boundary zone, andincludes two sections (the eastern and Molesworth sections) that have differentstrikes and that join across a complex fault junction in the upper Awatere Valley.</b></p> <p>Detailed mapping of the fault traces and measurement of 97 geomorphicdisplacements along the Awatere Fault in the vicinity of the fault junction show thatthe eastern and Molesworth sections of the fault intersect one another at a low angle(10-15º), at the eastern end of an internally faulted, elongate, ~15 km long and up to3 km wide fault wedge or sliver. The region between the fault sections is split by aseries of discontinuous, en-echelon scarps that are oriented from ~10º to 20-30ºclockwise from the principal fault sections. Based on other observations ofdiscontinuities in strike-slip earthquake ruptures around the globe, this low-angleintersection geometry suggests that the junction between these fault sections may notact as a significant barrier to earthquake rupture propagation. This interpretation ofthe mechanical significance of the fault junction to earthquake ruptures is counter toprevious suggestions, but is supported by new paleoseismic data from fourpaleoseismic trenches excavated on each side of the junction. In a new paleoseismictrench on the Molesworth section at Saxton River, 18 km to the west of the junction,up to ten surface-rupturing events in the past ~15 ka are recognised from 12radiocarbon ages and 1 optically stimulated luminescence age. In two new trencheson the eastern section near to Upcot Saddle, 12 km northeast of the fault junction,five events took place in the past 5.5 ka, based on 21 radiocarbon ages. Thischronology from Upcot Saddle is combined with data from two previous trencheslocated ~55 km to the northeast at Lake Jasper, to infer nine events on the easternsection since 8330-8610 cal. years B.P. These well-dated events on the easternsection are compared to those on the Molesworth section to the west of the faultjunction. At 95% confidence, five events on both sections have occurred withstatistical contemporaneity since ~6 ka B.P. These five events may have rupturedboth the eastern and Molesworth sections simultaneously, in accordance with the interpretation that the fault section junction does not arrest rupture propagation.</p> <p>Alternatively, these events may have been separate earthquakes that occurred withinthe statistical resolution provided by radiocarbon dating.</p> <p>The most recent event to rupture the eastern section was the Mw ~7.5 1848Marlborough earthquake. The coseismic slip distribution and maximum traceablelength of this surface rupture are calculated from the magnitude and distribution ofsmall, metre-scale geomorphic displacements attributable to this earthquake. Thesedata suggest this event ruptured >100-110 km of the eastern section, with meansurface displacement of 5.3 ±1.6 m. Based on these parameters, the momentmagnitude of this earthquake would be Mw 7.4-7.7. This magnitude estimate isindistinguishable from previous calculations that were based on attenuation ofshaking intensity isoseismals that were assigned from contemporary historicalaccounts of that earthquake. On the basis of similar rupture lengths and coseismicdisplacements, it is inferred that the penultimate event had a similar momentmagnitude to the 1848 earthquake.</p> <p>Horizontal displacement of a flight of 6 fluvial terraces at Saxton River by theMolesworth section of the Awatere Fault is constrained to have occurred at a nearconstantrate of 5.5 ±1.5 mm/a since ~15 ka B.P. These rates are based on two newoptically stimulated luminescence ages for the highest terrace treads of 14.5 ±1.5 and6.69 ±0.74 ka B.P. These rates are indistinguishable from recent strike-slip rateestimates for the eastern section of 5.6 ±1.1 and 6 ±2 mm/a. Comparing themagnitudes and ages of the terrace riser displacements at Saxton River to the timingof paleoearthquakes on the Molesworth section implies a mean per-eventdisplacement of 4.4 ±0.2 m since ~15 ka. The new terrace ages also record twoperiods of aggradation that post-date the Last Glacial Maximum.</p>

Enterococci in the New Zealand environment: implications for water quality monitoring

1997 ◽  
Vol 35 (11-12) ◽  
pp. 325-331 ◽  
Author(s):  
S. A. Anderson ◽  
S. J. Turner ◽  
G. D. Lewis
Keyword(s):  
Water Quality ◽  
New Zealand ◽  
Water Quality Monitoring ◽  
Epidemiological Studies ◽  
High Ratio ◽  
Quality Data ◽  
Considerable Proportion ◽  
Multiple Sources ◽  
Water Quality Data ◽  
Bathing Water Quality

Faecal enterococci ecology outside the host is of great relevance when using these organisms as indicators of water quality. As a complement to New Zealand epidemiological studies of bathing water quality and health risk, a study of the environmental occurrence of these organisms has been undertaken. Specific concerns over the use of enterococci derive from the unique situation in New Zealand which has few chlorinated sewage effluents, a high ratio of grazing animals to humans, and significant inputs of animal processing effluents into the environment. Human and animal faecal wastes are the main sources, with 106–107cfu/100ml found in human sewage. Analysis of domestic and feral animal faeces found enterococci in the range of 101–106cfu/g with considerable variation between species. The latter observations support the notion that a considerable proportion of the load in urban/rural catchments and waterways (typically 102–103 enterococci cfu/100ml) is derived from non-human sources. Previous studies of enterococci quiescence in marine/fresh waters indicate that they enter a non-growth phase, exposure to sunlight markedly reducing culturability on selective and non-selective media. Enterococci were also found to survive/multiply within specific non-faecal environments. Enterococci on degrading drift seaweed at recreational beaches exceeded seawater levels by 2–4 orders of magnitude, suggesting that expansion had occurred in this permissive environment with resultant potential to contaminate adjacent sand and water. These studies suggest that multiple sources, environmental persistence, and environmental expansion of enterococci within selected niches add considerable complexity to the interpretation of water quality data.

scholarly journals Knowledge and perceptions of cardiopulmonary resuscitation amongst New Zealand podiatrists: a web-based survey

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Angela Brenton-Rule ◽  
Daniel Harvey ◽  
Kevin Moran ◽  
Daniel O’Brien ◽  
Jonathon Webber
Keyword(s):  
New Zealand ◽  
Cardiopulmonary Resuscitation ◽  
Life Support ◽  
Survival Rates ◽  
Sudden Cardiac Arrest ◽  
Cross Sectional Study ◽  
Trial Registration ◽  
Cross Sectional ◽  
Web Based ◽  
The Past

Abstract Background Podiatrists in New Zealand have a duty of care to assist patients in an emergency, and current cardiopulmonary resuscitation (CPR) certification is a requirement for registration. However, it is unknown how competent and confident podiatrists are in administering CPR and how they would respond in an emergency. Having a health professional who has a competent knowledge of CPR and skills in basic life support, can improve survival rates from sudden cardiac arrest. Therefore, the aim of this study was to survey New Zealand podiatrists to determine their CPR knowledge and qualifications; beliefs about the application of CPR; and perceptions of their competency in CPR. Methods This cross-sectional study used a web-based survey. Participants were New Zealand registered podiatrists with a current annual practising certificate. The 31-item survey included questions to elicit demographic information, CPR practice and attitudes, and CPR knowledge. Responses were collected between March and August 2020. Results 171 podiatrists responded to the survey. 16 % of the podiatrists (n = 28) had performed CPR in an emergency, with a 50 % success rate. Participants were predominantly female (n = 127, 74 %) and working in private practice (n = 140,82 %). Nearly half of respondents were younger than 40 years (n = 75,44 %) and had less than 10 years of clinical experience (n = 73, 43 %). Nearly all (n = 169,97 %) participants had received formal CPR training in the past two years, with 60 % (n = 105) receiving training in the past 12 months. Most respondents (n = 167,98 %) self-estimated their CPR ability as being effective, very effective, or extremely effective. Participants’ knowledge of CPR was variable, with the percentage of correct answers for CPR protocol statements ranging between 20 and 90 %. Conclusions This study provides the first insight into New Zealand podiatrists’ CPR knowledge and perceptions. Podiatrists were found to have high levels of CPR confidence but demonstrated gaps in CPR knowledge. Currently, New Zealand registered podiatrists require biennial CPR re-certification. However, resuscitation authorities in New Zealand and overseas recommend an annual update of CPR skills. Based on this study’s findings, and in line with Australia and the United Kingdom, the authors recommend a change from biennial to annual CPR re-certification for podiatrists in New Zealand. Trial registration The study was registered with the Australian New Zealand Clinical Trials Registry (ACTRN12620001144909).

scholarly journals Asexuals negotiate the ‘onslaught of the heteronormative’

Sexualities ◽  
2021 ◽  
pp. 136346072199338
Author(s):  
Tiina Vares
Keyword(s):  
New Zealand ◽  
Everyday Life ◽  
Cultural Context ◽  
Emotional Responses ◽  
Emotional Impact ◽  
Individual Interviews ◽  
The Past ◽  
Aotearoa New Zealand ◽  
The Everyday ◽  
Research Gap

Although theorizing and research about asexuality have increased in the past decade, there has been minimal attention given to the emotional impact that living in a hetero- and amato-normative cultural context has on those who identify as asexual. In this paper, I address this research gap through an exploration of the ‘work that emotions do’ (Sara Ahmed) in the everyday lives of asexuals. The study is based on 15 individual interviews with self-identified asexuals living in Aotearoa New Zealand. One participant in the study used the phrase, ‘the onslaught of the heteronormative’ to describe how he experienced living as an aromantic identified asexual in a hetero- and amato-normative society. In this paper I consider what it means and feels like to experience aspects of everyday life as an ‘onslaught’. In particular, I look at some participants’ talk about experiencing sadness, loss, anger and/or shame as responses to/effects of hetero- and amato-normativity. However, I suggest that these are not only ‘negative’ emotional responses but that they might also be productive in terms of rethinking and disrupting hetero- and amato-normativity.

CPT-based liquefaction case histories compiled from three earthquakes in Canterbury, New Zealand

2021 ◽  
pp. 875529302199636
Author(s):  
Mertcan Geyin ◽  
Brett W Maurer ◽  
Brendon A Bradley ◽  
Russell A Green ◽  
Sjoerd van Ballegooy
Keyword(s):  
New Zealand ◽  
Case History ◽  
Prediction Models ◽  
Free Field ◽  
Case Histories ◽  
Cone Penetration ◽  
History Data ◽  
The Past ◽  
Surface Manifestation ◽  
The Many

Earthquakes occurring over the past decade in the Canterbury region of New Zealand have resulted in liquefaction case-history data of unprecedented quantity. This provides the profession with a unique opportunity to advance the prediction of liquefaction occurrence and consequences. Toward that end, this article presents a curated dataset containing ∼15,000 cone-penetration-test-based liquefaction case histories compiled from three earthquakes in Canterbury. The compiled, post-processed data are presented in a dense array structure, allowing researchers to easily access and analyze a wealth of information pertinent to free-field liquefaction response (i.e. triggering and surface manifestation). Research opportunities using these data include, but are not limited to, the training or testing of new and existing liquefaction-prediction models. The many methods used to obtain and process the case-history data are detailed herein, as is the structure of the compiled digital file. Finally, recommendations for analyzing the data are outlined, including nuances and limitations that users should carefully consider.

Primary Exploration on Opportunities for the Formation of New Zealand’s Creative Film & TV Industry

2013 ◽  
Vol 311 ◽  
pp. 334-338
Author(s):  
Qi Li
Keyword(s):  
New Zealand ◽  
Radiation Effects ◽  
International Markets ◽  
Rapid Rise ◽  
Market Environment ◽  
Sharp Rise ◽  
The Past ◽  
Labor Division ◽  
Technology Market ◽  
Production Industry

Over the past two decades, New Zealand has seen rapid and sharp rise of film & TV industry, developed competitive edges of film production industry, participated in labor division in the international markets and shaped creative film &TV industry with radiation effects. This paper analyzes the historical opportunities for the rapid rise of film & TV industry in Zealand from the perspectives of changes to the market environment of technology, market, industry labor division, etc.

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