GPR reflection profiles of Clark and Commonwealth Glaciers, Dry Valleys, Antarctica
GPR reflection profiles of Clark and Commonwealth Glaciers, Dry Valleys, Antarctica
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南极洲干谷克拉克冰川和联邦冰川的探地雷达反射剖面
作者：
S. Arcone;K. Kreutz
摘要：我们在南极干谷地区的克拉克冰川和联邦冰川上记录的 100MHz 探地雷达 (GPR) 表面剖面中不存在深度超过 100m 的冰川地平线。两座冰川均显示出长达 280 m 的连续底部地平线，底部信噪比接近 30 dB。密度层应在 50 m 深度以下消失，因为 36 m 处出现不透水冰。联邦冰川内的折叠可能会阻碍约 80 m 深度以下的雷达地层，但克拉克冰川内没有明显的折叠。我们的浅冰芯中存在着强烈的硫酸盐浓度和对比。然而，似乎高背景浓度水平以及可能随深度降低的浓度对比度将其相应的反射系数置于我们系统灵敏度的极限或低于约 77m 深度。这一结论的进一步验证有待我们的深核化学剖面的处理。
Abstract Englacial horizons deeper than 100m are absent within 100MHz ground-penetrating radar (GPR) surface profiles we recorded on Clark and Commonwealth Glaciers in the Antarctic Dry Valleys region. Both glaciers show continuous bottom horizons to 280 m, with bottom signal-to-noise ratios near 30 dB. Density horizons should fade below 50 m depth because impermeable ice occurred by 36 m. Folding within Commonwealth Glacier could preclude radar strata beneath about 80 m depth, but there is no significant folding within Clark Glacier. Strong sulfate concentrations and contrasts exist in our shallow ice core. However, it appears that high background concentration levels, and possible decreased concentration contrasts with depth placed their corresponding reflection coefficients at the limit of, or below, our system sensitivity by about 77m depth. Further verification of this conclusion awaits processing of our deep-core chemistry profiles.