کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1774512 1021167 2011 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Preservation of layered paleodeposits in high-latitude pedestal craters on Mars
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات علوم فضا و نجوم
پیش نمایش صفحه اول مقاله
Preservation of layered paleodeposits in high-latitude pedestal craters on Mars
چکیده انگلیسی

An outstanding question in Mars’ climate history is whether or not pedestal craters represent the armored remnants of ice-rich paleodeposits. We address this question using new high-resolution images; in a survey of several hundred high-latitude pedestal craters, we have identified 12 examples in which visible and/or topographically expressed layers are exposed on the marginal scarp of the pedestal. One example, located on the south polar layered deposits, preserves ice-rich layers that have otherwise been completely removed from the polar cap. These observations provide empirical evidence that the pedestal crater formation mechanism is capable of armoring and preserving ice-rich layered paleodeposits. Although layered exposures have not yet been observed in mid-latitude pedestal craters, high-latitude instances of discontinuous, partially covered layers suggest that layers can be readily concealed, likely through mantling and/or mass wasting processes along the marginal scarp. This interpretation is supported by the observation that high-latitude pedestals with exposed layers along their margins are, on average, taller than mid-latitude examples, and have larger, steeper marginal scarps, which may help to maintain layer exposures. These observations favor the interpretation that mid- to high-latitude pedestal craters represent the armored remnants of ice- and dust-rich paleodeposits, which occurred transiently due to changes in the climate regime. Preservation of fine-scale layering of ice and dust at these latitudes implies that the climate change did not involve regional melting conditions.


► Twelve high-latitude pedestal craters show exposed layers on their marginal scarps.
► One pedestal has preserved a local sequence of the south polar layered deposit.
► Layers are ice-rich paleodeposits preserved beneath armored pedestal surfaces.
► The rarity of visible layers along most pedestal margins is due to mantling.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Icarus - Volume 213, Issue 2, June 2011, Pages 443–450
نویسندگان
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