TY - JOUR
T1 - Formation of Central Pits in Impact Craters on Mars
T2 - A Statistical Investigation of Proposed Mechanisms
AU - Peel, Samantha E.
AU - Burr, Devon M.
AU - Tran, Liem
N1 - Funding Information:
The Robbins and Hynek () crater database, and revised versions thereof, are available at webgis.wr.usgs.gov/pigwad/down/mars_crater_consortium.htm. The image data sets are accessible through the Orbital Data Explorer (ode.rsl.wustl.edu) and PILOT (pilot.wr.usgs.gov). The HRSC DEMs are accessible at maps.planet.fu-berlin.de. MOLA PEDR data are available through ode.rsl.wustl.edu/mars/datapointsearch.aspx. CTX DEMs were constructed using MarsSI (emars.univ-lyon1.fr) and Ames Stereo Pipeline (ti.arc.nasa.gov/tech/asr/groups/intelligent-robotics/ngt/stereo). The specific craters identified as appropriate for this work and the sample sets utilized for each of the tests discussed above, as well as the results of the volume measurements, are available as online supporting information from this journal website. S.E.P was funded through graduate assistantships from the University of Tennessee. L.T. and D.M.B. were funded through professorships at the University of Tennessee.
Publisher Copyright:
©2019. American Geophysical Union. All Rights Reserved.
PY - 2019/2
Y1 - 2019/2
N2 - Central pit craters (CPCs) are complex craters that exhibit depressions within their floors or central uplifts. Some proposed models for central pit formation can be grouped by similar mechanism: (A) explosive volatile release, (B) central peak collapse, and (C) drainage of subsurface melted volatiles. We test these groups of mechanisms for central pit formation on Mars based on morphometries expected from each mechanism. Volatiles in the target (A and C) would be expected to result in a correlation with layered ejecta, also formed from volatiles, for CPCs over non-CPCs. Central peak collapse (B) should result in larger diameters for pit rims than central peaks due to outward flow. Explosive volatile release (A) should yield smaller volumes for pit rims than pits due to mass loss. Data were collected on Context Camera images and digital elevation models for random samples of CPCs to assess the presence of these expected morphologies. Results of a Fisher exact test showed no preference in layered ejecta with CPCs over non-CPCs, inconsistent with volatiles in the target. Results of an independent t test showed that central pit rim diameters are larger than central peak diameters, supporting some component of central peak collapse, although measurement uncertainty makes this interpretation tentative. Central pit rim volumes were not found to be statistically smaller than their pits, weighing against formation by explosive volatile release. Thus, our findings do not support any single group of formation mechanism tested here, although they allow for formation by some combination of these (or other) processes.
AB - Central pit craters (CPCs) are complex craters that exhibit depressions within their floors or central uplifts. Some proposed models for central pit formation can be grouped by similar mechanism: (A) explosive volatile release, (B) central peak collapse, and (C) drainage of subsurface melted volatiles. We test these groups of mechanisms for central pit formation on Mars based on morphometries expected from each mechanism. Volatiles in the target (A and C) would be expected to result in a correlation with layered ejecta, also formed from volatiles, for CPCs over non-CPCs. Central peak collapse (B) should result in larger diameters for pit rims than central peaks due to outward flow. Explosive volatile release (A) should yield smaller volumes for pit rims than pits due to mass loss. Data were collected on Context Camera images and digital elevation models for random samples of CPCs to assess the presence of these expected morphologies. Results of a Fisher exact test showed no preference in layered ejecta with CPCs over non-CPCs, inconsistent with volatiles in the target. Results of an independent t test showed that central pit rim diameters are larger than central peak diameters, supporting some component of central peak collapse, although measurement uncertainty makes this interpretation tentative. Central pit rim volumes were not found to be statistically smaller than their pits, weighing against formation by explosive volatile release. Thus, our findings do not support any single group of formation mechanism tested here, although they allow for formation by some combination of these (or other) processes.
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U2 - 10.1029/2018JE005738
DO - 10.1029/2018JE005738
M3 - Article
AN - SCOPUS:85061932781
SN - 2169-9097
VL - 124
SP - 437
EP - 453
JO - Journal of Geophysical Research: Planets
JF - Journal of Geophysical Research: Planets
IS - 2
ER -