title: Proglacial sedimentation of late Wisconsin age in Miers Valley, Antarctica

authors: Clayton-Greene, Jan Maree

subjects: Miers Valley

abstract: Miers Valley is an ice free valley in the Koettlitz Region of Victoria Land, Antarctica. The eastern basin of this valley has extensive coverage of gypsum and laminated calcite overlying fine silts and sands, while Lake Miers occupies the western basin. Mapping of the surficial sediments has shown that a proglacial lake at least 80m deep extended up the valley (Glacial Lake Trowbridge), dammed to the east by a glacial tongue extending from the coast, C-14 and U/Th dating of the lacustrine carbonates has shown that this lake occupied Miers Valley between 10,000 and 20,000 yrs BP and was at its maximum between 18,000 and 19,000 yrs BP.
Dating of individual lamina has shown that calcite deposition was not continuous, but proceeded in at least three pulses. This is supported by stable isotope analyses which show an enrichment in ¹⁸O with time, suggesting the possible concentration through evaporation of ¹⁸O during the lake's history. Impressions within the calcite plates indicate that a crystalline material, possibly gypsum, was crystallizing contemporaneously with the calcite. This salt was subsequently flushed from the system on the draining of the eastern basin. At the final stages of occupation, large quantities of gypsum were deposited into the eastern basin from the glacier terminus and draining of the lake resulted in a surface coverage of gypsum throughout the eastern basin.
Shallow mounds of coarse basalt rich drift overlie the carbonate, gypsum and silt beds in places throughout the eastern basin. On the surface ice cover of Lake Miers, similar mounds occur. The ice beneath these mounds is virtually sediment free and the sediment on the surface differs from that on the lake bed. It is suggested that the mounds on the ice raft and the mounds in the eastern basin share a common origin. Supraglacial and englacial sediments carried into the valley with the Ross Ice Tongue were deposited onto the floating ice cover of Glacial Lake Trowbridge. This material was then rafted across the valley as the lake ice was pushed forward by ice fed from the glacial tongue. The sediments remained supported on the lake until they reached the annual melt out moat or the lake drained. They were then deposited on top of the lacustrine sediments, thereby preserving them (as occurred in the eastern basin), or in the case of the western basin a lake remained so the mounds were preserved on the ice cover which had then become immobile.
Once the proglacial lake drained, most of the lacustrine sediments were then exposed to the environment. Scanning Electron Microscope studies have shown that the exposed lacustrine carbonates have undergone chemical weathering. These carbonates are pitted and weathered compared to much older and less exposed carbonates in neighbouring Marshall Valley.

text: Proglacial sedimentation of late Wisconsin age in Miers Valley, Antarctica Miers Valley is an ice free valley in the Koettlitz Region of Victoria Land, Antarctica. The eastern basin of this valley has extensive coverage of gypsum and laminated calcite overlying fine silts and sands, while Lake Miers occupies the western basin. Mapping of the surficial sediments has shown that a proglacial lake at least 80m deep extended up the valley (Glacial Lake Trowbridge), dammed to the east by a glacial tongue extending from the coast, C-14 and U/Th dating of the lacustrine carbonates has shown that this lake occupied Miers Valley between 10,000 and 20,000 yrs BP and was at its maximum between 18,000 and 19,000 yrs BP.
Dating of individual lamina has shown that calcite deposition was not continuous, but proceeded in at least three pulses. This is supported by stable isotope analyses which show an enrichment in ¹⁸O with time, suggesting the possible concentration through evaporation of ¹⁸O during the lake's history. Impressions within the calcite plates indicate that a crystalline material, possibly gypsum, was crystallizing contemporaneously with the calcite. This salt was subsequently flushed from the system on the draining of the eastern basin. At the final stages of occupation, large quantities of gypsum were deposited into the eastern basin from the glacier terminus and draining of the lake resulted in a surface coverage of gypsum throughout the eastern basin.
Shallow mounds of coarse basalt rich drift overlie the carbonate, gypsum and silt beds in places throughout the eastern basin. On the surface ice cover of Lake Miers, similar mounds occur. The ice beneath these mounds is virtually sediment free and the sediment on the surface differs from that on the lake bed. It is suggested that the mounds on the ice raft and the mounds in the eastern basin share a common origin. Supraglacial and englacial sediments carried into the valley with the Ross Ice Tongue were deposited onto the floating ice cover of Glacial Lake Trowbridge. This material was then rafted across the valley as the lake ice was pushed forward by ice fed from the glacial tongue. The sediments remained supported on the lake until they reached the annual melt out moat or the lake drained. They were then deposited on top of the lacustrine sediments, thereby preserving them (as occurred in the eastern basin), or in the case of the western basin a lake remained so the mounds were preserved on the ice cover which had then become immobile.
Once the proglacial lake drained, most of the lacustrine sediments were then exposed to the environment. Scanning Electron Microscope studies have shown that the exposed lacustrine carbonates have undergone chemical weathering. These carbonates are pitted and weathered compared to much older and less exposed carbonates in neighbouring Marshall Valley.

year: 1986

title: Evaluation of STOP Children’s Service 2020-2021: Parents/caregivers and teachers’ perspectives on the effectiveness of the STOP Children’s Service

authors: Flanagan, Paul G.

subjects: child behaviour

abstract: This project explored the effectiveness of STOP’s Children’s Service through interviews with parents/caregivers and principals/teachers of child clients who accessed the Service during 2020-2021. This time frame included experience of the effects of Covid-19, providing the possibility of learning areas for improvement of the service to families in remote rural areas where access to in-person clinical services are limited.

text: Evaluation of STOP Children’s Service 2020-2021: Parents/caregivers and teachers’ perspectives on the effectiveness of the STOP Children’s Service This project explored the effectiveness of STOP’s Children’s Service through interviews with parents/caregivers and principals/teachers of child clients who accessed the Service during 2020-2021. This time frame included experience of the effects of Covid-19, providing the possibility of learning areas for improvement of the service to families in remote rural areas where access to in-person clinical services are limited.

year: 2023

title: Indigenous voices

authors: Daya-Winterbottom, Trevor

abstract: Indigenous people and their communities have a vital role in environmental management and development, and states should (in accordance with principle 22 of the Rio Declaration 1992) recognize and duly support their identity, culture and interests and enable their effective participation in the achievement of sustainable development. This paper will critically analyse the normative influence of tikanga Māori, non-doctrinal methods for discovering tikanga Māori, the special rules for interpretation of tikanga, and the wider application of customary values.

text: Indigenous voices Indigenous people and their communities have a vital role in environmental management and development, and states should (in accordance with principle 22 of the Rio Declaration 1992) recognize and duly support their identity, culture and interests and enable their effective participation in the achievement of sustainable development. This paper will critically analyse the normative influence of tikanga Māori, non-doctrinal methods for discovering tikanga Māori, the special rules for interpretation of tikanga, and the wider application of customary values.

year: 2022-07-11