DOI: 10.1002/2017JE005432
Scopus记录号: 2-s2.0-85040735041
论文题名: Timing and Distribution of Single-Layered Ejecta Craters Imply Sporadic Preservation of Tropical Subsurface Ice on Mars
作者: Kirchoff M.R. ; Grimm R.E.
刊名: Journal of Geophysical Research: Planets
ISSN: 21699097
出版年: 2018
卷: 123, 期: 1 起始页码: 131
结束页码: 144
语种: 英语
英文关键词: absolute model ages
; layered ejecta craters
; spatial distribution
; subsurface ice
; subsurface volatiles
Scopus关键词: ejecta
; geological survey
; ice cover
; Mars
; planetary atmosphere
; planetary surface
; spatial distribution
; spatiotemporal analysis
英文摘要: Determining the evolution of tropical subsurface ice is a key component to understanding Mars's climate and geologic history. Study of an intriguing crater type on Mars—layered ejecta craters, which likely form by tapping subsurface ice—may provide constraints on this evolution. Layered ejecta craters have a continuous ejecta deposit with a fluidized-flow appearance. Single-layered ejecta (SLE) craters are the most common and dominate at tropical latitudes and therefore offer the best opportunity to derive new constraints on the temporal evolution of low-latitude subsurface ice. We estimate model formation ages of 54 SLE craters with diameter (D) ≥ 5 km using the density of small, superposed craters with D < 1 km on their continuous ejecta deposits. These model ages indicate that SLE craters have formed throughout the Amazonian and at a similar rate expected for all Martian craters. This suggests that tropical ice has remained at relatively shallow depths at least where these craters formed. In particular, the presence of equatorial SLE craters with D ~ 1 km indicates that ice could be preserved as shallow as ~100 m or less at those locations. Finally, there is a striking spatial mixing in an area of highlands near the equator of layered and radial (lunar-like ballistic) ejecta craters; the latter form where there are insufficient concentrations of subsurface ice. This implies strong spatial heterogeneity in the concentration of tropical subsurface ice. ©2017. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/114769
Appears in Collections: 气候减缓与适应
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作者单位: Southwest Research Institute, Boulder, CO, United States
Recommended Citation:
Kirchoff M.R.,Grimm R.E.. Timing and Distribution of Single-Layered Ejecta Craters Imply Sporadic Preservation of Tropical Subsurface Ice on Mars[J]. Journal of Geophysical Research: Planets,2018-01-01,123(1)