气候变化领域集成服务门户(CCPortal): Surface boulder banding indicates Martian debris-covered glaciers formed over multiple glaciations

CCPortal

DOI	10.1073/pnas.2015971118
	Surface boulder banding indicates Martian debris-covered glaciers formed over multiple glaciations
	Levy J.S.; Fassett C.I.; Holt J.W.; Parsons R.; Cipolli W.; Goudge T.A.; Tebolt M.; Kuentz L.; Johnson J.; Ishraque F.; Cvijanovich B.; Armstrong I.
发表日期	2021
ISSN	00278424
卷号	118 期号:4
英文摘要	Glacial landforms, including lobate debris aprons, are a global water ice reservoir on Mars preserving ice from past periods when high orbital obliquity permitted nonpolar ice accumulation. Numerous studies have noted morphological similarities between lobate debris aprons and terrestrial debris-covered glaciers, an interpretation supported by radar observations. On Earth and Mars, these landforms consist of a core of flowing ice covered by a rocky lag. Terrestrial debris-covered glaciers advance in response to climate forcing driven by obliquity-paced changes to ice mass balance. However, on Mars, it is not known whether glacial landforms emplaced over the past 300 to 800 formed during a single, long deposition event or during multiple glaciations. Here, we show that boulders atop 45 lobate debris aprons exhibit no evidence of monotonic comminution but are clustered into bands that become more numerous with increasing latitude, debris apron length, and pole-facing flow orientation. Boulder bands are prominent at glacier headwalls, consistent with debris accumulation during the current Martian interglacial. Terrestrial glacier boulder bands occur near flow discontinuities caused by obliquity-driven hiatuses in ice accumulation, forming internal debris layers. By analogy, we suggest that Martian lobate debris aprons experienced multiple cycles of ice deposition, followed by ice destabilization in the accumulation zone, leading to boulder-dominated lenses and subsequent ice deposition and continued flow. Correlation between latitude and boulder clustering suggests that ice mass-balance works across global scales on Mars. Lobate debris aprons may preserve ice spanning multiple glacial/interglacial cycles, extending Mars climate records back hundreds of millions of years. © 2021 National Academy of Sciences. All rights reserved.
英文关键词	Climate; Glaciers; Ice Age; Mars; Obliquity
语种	英语
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/180912
作者单位	Department of Geology, Colgate University, Hamilton, NY 13346, United States; NASA Marshall Space Flight Center, Huntsville, AL 35801, United States; Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, United States; Department of Geosciences, University of Arizona, Tucson, AZ 85721, United States; Earth and Geographic Sciences Department, Fitchburg State University, Fitchburg, MA 01420, United States; Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, TX 78712, United States
推荐引用方式 GB/T 7714	Levy J.S.,Fassett C.I.,Holt J.W.,et al. Surface boulder banding indicates Martian debris-covered glaciers formed over multiple glaciations[J],2021,118(4).
APA	Levy J.S..,Fassett C.I..,Holt J.W..,Parsons R..,Cipolli W..,...&Armstrong I..(2021).Surface boulder banding indicates Martian debris-covered glaciers formed over multiple glaciations.Proceedings of the National Academy of Sciences of the United States of America,118(4).
MLA	Levy J.S.,et al."Surface boulder banding indicates Martian debris-covered glaciers formed over multiple glaciations".Proceedings of the National Academy of Sciences of the United States of America 118.4(2021).