Buried ice in Kennar Valley: a late Pleistocene remnant of Taylor Glacier
Buried ice in Kennar Valley: a late Pleistocene remnant of Taylor Glacier
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肯纳尔谷的埋冰：泰勒冰川晚更新世的遗迹
作者：
Kate M. Swanger
摘要埋藏的冰川冰在麦克默多干旱河谷中很常见，在理想的气候和地貌条件下，可以保存数百万年。这项研究的重点是分析约300平方米的埋藏冰川冰在肯纳山谷，夸特梅因山脉。绘制的冰是干净的，厚度<10 m，被~25 cm的桑迪漂移覆盖。肯纳山谷的入口被泰勒冰川的一个裂片占据，泰勒冰川是泰勒圆顶的出口冰川。根据冰沉积物特征，气泡浓度和稳定同位素分析，从三个冰芯，较低的肯纳谷冰是冰川的起源。这些数据加上先前报道的暴露年龄年表表明，埋藏的冰是由泰勒冰川的晚更新世推进沉积的，可能是在间冰期期间。埋藏的冰川冰的表面呈现出图案化的地面形态，其特征是带有深槽的小圆顶形多边形。这种形状可能反映了冰损失的最后阶段，因为停滞，孤立的冰尖升华到位。这项研究强调了多边形形态学如何用于推断整个南极洲以及其他寒冷干旱景观中的干净埋藏冰的厚度及其地貌稳定性。
Abstract Buried glacier ice is common in the McMurdo Dry Valleys and under ideal climatic and geomorphological conditions may be preserved for multimillion-year timescales. This study focuses on the analysis of ~300 m2 of buried glacier ice in lower Kennar Valley, Quartermain Range. The mapped ice is clean,<10 m thick and covered by a~25 cm sandy drift. The mouth of Kennar Valley is occupied by a lobe of Taylor Glacier, an outlet glacier from Taylor Dome. Based on ice–sediment characteristics, air bubble concentrations and stable isotopic analyses from three ice cores, the lower Kennar Valley ice is glacial in origin. These data coupled with a previously reported exposure age chronology indicate that the buried ice was deposited by a late Pleistocene advance of Taylor Glacier, probably during an interglacial interval. The surface of the buried glacier ice exhibits a patterned ground morphology characterized by small, dome-shaped polygons with deep troughs. This shape possibly reflects the final stages of ice loss, as stagnant, isolated ice pinnacles sublimate in place. This study highlights how polygon morphology can be used to infer the thickness of clean buried ice and its geomorphological stability throughout Antarctica, as well as other in cold, arid landscapes.