Crater Population and Resurfacing of the Martian North Polar Layered Deposits
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ion and Resurfacing of the Martian North Polar L • Present-day accumulation in the north polar layered deposits (NPLD) is thought to occur via deposition on the north polar residual cap (NRC). •Understanding current mass balance in relation to current climate would provide insight into the climatic record of the NPLD. •~132 craters have been identified on the NPLD (black and white dots), 97 of which are located within a region defined to represent recent accumulation (black dots). •HiRISE images reveal a morphological sequence of crater degradation that provides a qualitative understanding of processes involved in crater removal. •Temporal and spatial distribution of crater degradation is interpreted to be close to uniform. •Through comparison of the size- frequency distribution of these craters with the expected production function, the craters are interpreted to be an equilibrium population with a crater of diameter D meters having a lifetime of ~30.75D 1.14 years. •Accumulation rates within these craters are estimated at 7.2D -0.14 mm/year, which corresponds to values of ~3-4 mm/year, and are much higher than rates thought to apply to the surrounding flat terrain. •Current crater population is estimated to have accumulated in the last ~20,000 years (kyr) or Cumulative size-frequency distribution Differential size-frequency distribution 20 Kyr isochron [Hartmann, 2005] 20 Kyr isochron [Hartmann, 2005]
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Crater Population and Resurfacing of the Martian North Polar Layered Deposits. Present-day accumulation in the north polar layered deposits (NPLD) is thought to occur via deposition on the north polar residual cap (NRC). - PowerPoint PPT Presentation
Transcript of Crater Population and Resurfacing of the Martian North Polar Layered Deposits
Crater Population and Resurfacing of the Martian North Polar Layered Deposits
• Present-day accumulation in the north polar layered deposits (NPLD) is thought to occur via deposition on the north polar residual cap (NRC).
•Understanding current mass balance in relation to current climate would provide insight into the climatic record of the NPLD.
•~132 craters have been identified on the NPLD (black and white dots), 97 of which are located within a region defined to represent recent accumulation (black dots).
•HiRISE images reveal a morphological sequence of crater degradation that provides a qualitative understanding of processes involved in crater removal. •Temporal and spatial distribution of crater degradation is interpreted to be close to uniform.
•Through comparison of the size-frequency distribution of these craters with the expected production function, the craters are interpreted to be an equilibrium population with a crater of diameter D meters having a lifetime of ~30.75D1.14 years. •Accumulation rates within these craters are estimated at 7.2D-0.14 mm/year, which corresponds to values of ~3-4 mm/year, and are much higher than rates thought to apply to the surrounding flat terrain. •Current crater population is estimated to have accumulated in the last ~20,000 years (kyr) or less.
Cumulative size-frequency distribution Differential size-frequency distribution
20 Kyr isochron [Hartmann, 2005]
20 Kyr isochron [Hartmann, 2005]
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