title: Late Holocene cool climate episodes, recorded on Lake Bonney, an Antarctic amplifier lake

authors: Croall, Jacob Grant

abstract: Chemical, stable isotope and natural abundance radionuclide analysis of cores taken through sediments below Lake Bonney, Taylor Valley, Antarctica, show evidence of multiple episodes of flooding by meltwaters from Taylor Glacier and desiccation to brines sufficiently concentrated to produce ice free conditions. The last three identified desiccation events date 1550 ± 40, 800 ± 100 and 450 ± 160 yr B.P. and match the last three periods of sustained cooling identified by isotope changes in the Taylor Dome ice core. Similar cooling events have been identified by other authors elsewhere in Antarctica.

The desiccation events have produced dramatic changes in the sediment character of Lake Bonney East Lobe, but show little impact in the West Lobe. In East Lobe halite, hydrohalite, gypsum, and aragonite are precipitated and extreme isotopic enrichment of carbon (up to 813C of +12.0%0) occurred as aragonite was forced from solution by rapid freezing of the brine over winter. Reflooding events were often associated with algal blooms and resulted in radical changes in the 180/1 60 ratio in the water column.

It is speculated that Taylor Glacier retreated to expose a 250 m deep subglacial depression during the last glacial maximum allowing Glacial Lake Washburn to extend westwards to perhaps Cavendish Rocks. The reduced Taylor Glacier enabled Taylor Dome to lower causing deposition of more 180 enriched ice than would otherwise have been expected. Taylor Glacier and Taylor Dome have continued to advance throughout the Holocene.

text: Late Holocene cool climate episodes, recorded on Lake Bonney, an Antarctic amplifier lake Chemical, stable isotope and natural abundance radionuclide analysis of cores taken through sediments below Lake Bonney, Taylor Valley, Antarctica, show evidence of multiple episodes of flooding by meltwaters from Taylor Glacier and desiccation to brines sufficiently concentrated to produce ice free conditions. The last three identified desiccation events date 1550 ± 40, 800 ± 100 and 450 ± 160 yr B.P. and match the last three periods of sustained cooling identified by isotope changes in the Taylor Dome ice core. Similar cooling events have been identified by other authors elsewhere in Antarctica.

The desiccation events have produced dramatic changes in the sediment character of Lake Bonney East Lobe, but show little impact in the West Lobe. In East Lobe halite, hydrohalite, gypsum, and aragonite are precipitated and extreme isotopic enrichment of carbon (up to 813C of +12.0%0) occurred as aragonite was forced from solution by rapid freezing of the brine over winter. Reflooding events were often associated with algal blooms and resulted in radical changes in the 180/1 60 ratio in the water column.

It is speculated that Taylor Glacier retreated to expose a 250 m deep subglacial depression during the last glacial maximum allowing Glacial Lake Washburn to extend westwards to perhaps Cavendish Rocks. The reduced Taylor Glacier enabled Taylor Dome to lower causing deposition of more 180 enriched ice than would otherwise have been expected. Taylor Glacier and Taylor Dome have continued to advance throughout the Holocene.

year: 2005

title: Characterization of synthetic and commercial trisiloxane surfactant materials

authors: Bonnington, L. S.

subjects: organosilicone surfactant

abstract: The organosilicone surfactant Silwet L-77® (L-77), used as an agrochemical adjuvant, is a mixture comprised predominantly of [(CH₃)₃SiO]₂ (CH₃)Si (CH₂)₃ (OCH₂CH₂)n OCH₃ oligomers (n = 3-16, average n  7.5). The commercially available L-77 mixture was purified by reversed-phase high-performance liquid chromatography (HPLC) to obtain individual trisiloxane surfactant components. Pure oligomers (n = 3, 6 and 9) were also synthesized. Synthesis was achieved by hydrosilylation of monomeric ethoxylate monomethyl ether starting reagents. Pure hexa- and nona-ethylene glycols were produced by condensation of smaller oligomers. Atmospheric-pressure ionization mass spectrometry (MS) methods were used to characterize fully the commercial L-77 product and synthesized or isolated components. The application of Fourier-transform ion cyclotron resonance MS and online HPLC-electrospray ionization MS techniques to the analysis of this surfactant are described here. The application of these analytical techniques also enabled elucidation of the synthetic by-products present in the commercial formulation.

text: Characterization of synthetic and commercial trisiloxane surfactant materials The organosilicone surfactant Silwet L-77® (L-77), used as an agrochemical adjuvant, is a mixture comprised predominantly of [(CH₃)₃SiO]₂ (CH₃)Si (CH₂)₃ (OCH₂CH₂)n OCH₃ oligomers (n = 3-16, average n  7.5). The commercially available L-77 mixture was purified by reversed-phase high-performance liquid chromatography (HPLC) to obtain individual trisiloxane surfactant components. Pure oligomers (n = 3, 6 and 9) were also synthesized. Synthesis was achieved by hydrosilylation of monomeric ethoxylate monomethyl ether starting reagents. Pure hexa- and nona-ethylene glycols were produced by condensation of smaller oligomers. Atmospheric-pressure ionization mass spectrometry (MS) methods were used to characterize fully the commercial L-77 product and synthesized or isolated components. The application of Fourier-transform ion cyclotron resonance MS and online HPLC-electrospray ionization MS techniques to the analysis of this surfactant are described here. The application of these analytical techniques also enabled elucidation of the synthetic by-products present in the commercial formulation.

year: 2004

title: Discussing future directions in the Maori legal environment

authors: Te Aho, Linda

abstract: The next few years are likely to be exciting in terms of law changes, parliament getting ready for the next election cycle and the end of historical claims settlements. This presentation will look at the future of the Maori legal environment

text: Discussing future directions in the Maori legal environment The next few years are likely to be exciting in terms of law changes, parliament getting ready for the next election cycle and the end of historical claims settlements. This presentation will look at the future of the Maori legal environment

year: 2016