Investigation of the process of debris entrainment and till deposition of the Taylor Glacier

Investigations into the processes of debris entrainment and the formation of a debris layer within glacial ice was conducted. The glacial ice velocity at various points on the Taylor Glacier was conducted over several seasons to establish a model of entrainment, transport and deposition of glacial debris by polar ice. In the 1975-1976 season, three rows of poles (18) were placed on the lower 800 m of the Taylor Glacier (ice velocity and ablation network). The poles were accurately located using theodolite and tellurometer from three trig stations established on the sides of the valley. The height of each pole above the ice was also measured. In the 1976-1977 season, the network was extended and the poles were remeasured twice for approximate movement and ablation measurements, early and late in the expedition. Ice temperature measurements were taken from two holes in the glacier to depths of 17.5 and 15m. Supraglacial pebble sampling was undertaken at 33 sites on the glacier in an attempt to determine whether various lithologies have differing rates of breakdown under the processes of fast shattering and freeze thaw. Englacial and proglacial pebble samples were collected to determine the degree of rounding and/or facetting on pebbles of different lithologies. Ice samples were collected and sectioned and described to determine general trends in the petrography between various types of ice, which will be related to the origins of englacial debris and clean ice layers. Gravity profiles were carried out perpendicular to the flow the Taylor Glacier with 90 stations occupied. In the 1977-1978 season, ice velocity, ablation and temperature measurements were again measured. A study of basal ice along the margins of the Taylor Glacier revealed englacial sediment concentrations ranging from 0.4 to 60 percent. Movement of this basal debris-rich ice was measured. Further englacial and proglacial sediment sampling was undertaken and basic textural sediment analysis was completed to determine different sedimentary environments from sedimentological characteristics. In the 1978-1979 season, an early trip was made to the Taylor Glacier to complete the englacial sediment sampling and to observe englacial structures before the melt bagan. This was extended to investigate the dry valley alpine glaciers including the Rhone, Sykes, Albreich and Sandy Glaciers. Comparisons were made of the englacial sediment textures, ice structures and the products of deposition and these indicate that the mechanisms of debris incorporation for these glaciers differ from the Taylor Glacier.

本研究针对冰川冰内碎屑裹挟过程及碎屑层形成机制开展了系统调查。研究团队在多个季节内对泰勒冰川（Taylor Glacier）各点位的冰流速进行观测，旨在构建极地冰裹挟、搬运与沉积冰川碎屑的理论模型。1975-1976年季，研究团队在泰勒冰川下段800米区域布设3排共18根测杆，搭建冰流速与消融监测网络；研究人员依托山谷两侧布设的3个三角测量站，通过经纬仪与微波测距仪精准测定各测杆位置，并同步测量测杆高出冰面的高度。1976-1977年季，研究团队对监测网络进行扩容，并在考察前期与后期分别对测杆开展两次复测，以获取冰川运动与消融的近似观测数据。研究人员在冰川上钻取2个钻孔，分别测量至17.5米与15米深度的冰温。本研究在冰川33个点位开展冰面砾石采样，以探究不同岩性（lithology）的砾石在快速破碎与冻融作用下的风化速率是否存在差异；同时采集冰内与冰缘砾石样品，分析不同岩性砾石的磨圆度与/或刻面发育程度。研究人员采集冰样并进行切片与描述，以明确不同类型冰的岩石学特征总体变化规律，该规律将与冰内碎屑与洁净冰层的成因建立关联。研究沿垂直于泰勒冰川流向的方向布设90个测点，开展重力剖面测量。1977-1978年季，研究团队再次开展冰流速、消融与冰温监测。对泰勒冰川边缘底冰的研究显示，冰内沉积物含量介于0.4%至60%之间，同时研究人员对该富碎屑底冰的运动情况进行了测量。本团队进一步开展冰内与冰缘沉积物采样，并完成基础沉积物结构分析，以通过沉积学特征区分不同沉积环境。1978-1979年季，研究团队先期前往泰勒冰川，在冰川消融前完成冰内沉积物采样与冰内结构观测，随后将考察范围扩展至干谷区域的阿尔卑斯型冰川，包括罗纳冰川（Rhone Glacier）、赛克斯冰川（Sykes Glacier）、阿尔布雷希特冰川（Albreich Glacier）与桑迪冰川（Sandy Glacier）。研究团队对上述冰川的冰内沉积物结构、冰体结构与沉积产物进行对比分析，结果表明这些冰川的碎屑裹挟机制与泰勒冰川存在显著差异。