کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8133643 | 1523475 | 2019 | 37 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Glaciation on Mercury: Accumulation and flow of ice in permanently shadowed circum-polar crater interiors
ترجمه فارسی عنوان
انجماد در جیوه: انباشت و جریان یخ در فضای داخلی دهانه قطبهای دائمی سایه
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
علوم فضا و نجوم
چکیده انگلیسی
Radar-bright deposits that coincide with regions in permanent shadow typically found within impact craters at and near the poles of Mercury have been interpreted as being composed of water ice. We investigate the dynamic properties of these solid water-ice deposits (glaciers) with the goal of constraining their movement, flow rates, possible deformation, and related structures and deposits. As an end-member, we treat the extreme case of maximum ice accumulation where these deposits fill the crater to the shadow line, an event we would only expect following maximum accumulation conditions such as a large cometary impact or a comet shower. We find that, given the extremely cold conditions and the limited thickness of glaciers, even under the most favorable accumulation conditions, glaciation is cold-based, ice flow velocities are very low (4â¯Ãâ¯10â8â¯m/yr) and, with the exception of a sublimation lag deposit, glaciation is unlikely to leave any significant impact on the terrain. An important accelerator of ice flow is found to be the contribution of lateral heat conduction from the surrounding extremely hot surface terrain (â¼225â¯K average with up to 450â¯K maximums), which for 55â¯km craters yields velocities of 10â3â¯m/yr while for smaller 10â¯km craters velocities may exceed 1â¯m/yr, enough to leave a detectable ice deformation imprint such as drop moraines. However given that the observed deposits are substantially below their maximum fill capacities these estimates are unlikely to be attained.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Icarus - Volume 317, 1 January 2019, Pages 81-93
Journal: Icarus - Volume 317, 1 January 2019, Pages 81-93
نویسندگان
James L. Fastook, James W. Head, Ariel N. Deutsch,