Times	*Authors (Denotes Presenter)**	Abstract Title and Summary
10:00 a.m.	Kirchoff M. R. *	Introduction and Welcome; Brief Remembrance of Nadine Barlow
10:10 a.m.	Robbins S. J. *	Meeting Logistics
10:15 a.m.	Kirchoff M. R. *	PCC Business: New Charter, New Council Member, New Chair, New Secretary

Wednesday, August 11, 2021

COMPUTER APPLICATIONS TO IMPACT CRATER STUDIES

10:30 a.m. CDT

Chair: Michelle Kirchoff

Times	*Authors (Denotes Presenter)**	Abstract Title and Summary
10:30 a.m.	Purohit S. P. * Gandhi S. G. Dubey N. B.	Automatic Classification of Floor-Fractured Craters Using Machine Learning [#2018] Recorded Presentation This study aims at applying supervised machine learning based classification algorithms in automatically predicting the class of a Floor-Fractured craters (FFC) using the attributes derived from its DEM.
11:00 a.m.	Salvino C. S. * Burt D. M.	Objectively Quantifying Martian Lobate Crater Ejecta Patterns [#2025] Recorded Presentation Asymmetric ejecta patterns are seen with some craters on Mars; the etiology is unknown but may be related to the volatiles in the subsurface. Three methods of analytical modeling were developed to objectively quantify the degree of asymmetry.
11:30 a.m.		Break

Wednesday, August 11, 2021

CRATER-BASED SURFACE AGES

11:45 a.m. CDT

Chair: Lillian Ostrach

Times	*Authors (Denotes Presenter)**	Abstract Title and Summary
11:45 a.m.	Rossignoli N. L. * Di Sisto R. P.	Cratering Model for the Mid-Sized Satellites of Uranus [#2020] Recorded Presentation We model the crater distribution on the five mid-sized Uranian satellites considering impacts by Centaur objects. The comparison of our results with observational crater counts allows us to further explore the impact history of these satellites.
12:15 p.m.	Burkhard L. M. * Costello E. S. Cameron M. E.	Uncovering Ganymede’s Past: Crater Size Frequency Distributions on Nippur/Philus Sulci [#2033] Recorded Presentation We digitized more than 15,000 craters on Ganymede down to 100 m diameter. Here, we investigate the area of Nippur/Philus Sulci, where geologic units align on a single line of longitude, eliminating possible leading/trailing hemisphere disparities.
12:45 p.m.	Giguere T. A. * Boyce J. M. Gillis-Davis J. J. Rowland S. K. Stopar J. D.	Aspects of Crater Rim Crests: Improving the Accuracy of Absolute Model Ages [#2036] Recorded Presentation The use of high-resolution LROC NAC Digital Elevation Model (DEM) data to determine crater rim crests based on the change in aspect leads to improved diameter measurements, which directly improves the accuracy of absolute model ages.
1:15 p.m.		Break

Wednesday, August 11, 2021

LIGHTNING SESSION

1:30 p.m. CDT

Chair: Kassandra Martin-Wells

Times	*Authors (Denotes Presenter)**	Abstract Title and Summary
1:30 p.m.	Sit E. C. L. *	Exploring the Landing Site of Lunar Craters After Meeting NASA Apollo Astronaut [#2010] To demonstrate the process of studying the location of Apollo landing sites and equipment required for lunar crater photography. Then will provide case studies regarding observational astronomy and lunar photography by story-telling and examples.
1:40 p.m.	Burgener J. A. *	Are the Fireball Orbits Associated with the Perseid Meteor Shower an Indication of a Previous Low Angle Skip Impact by Comet 109P/Swift-Tuttle? [#2017] Recorded Presentation The Perseid meteor shower due to Comet Swift-Tuttle has an exceptional number of fireballs each year. The orbits of the fireballs ranges widely. Results from software simulating a Skip Impact by Swift-Tuttle match the fireball pattern.
1:50 p.m.	Burt D. M. *	Were Impactoclastic features on Mars Mistaken for Feature Deposited by Water or Wind? [#2009] Recorded Presentation Features in layered rocks on Mars that have been attributed to deposition by water or wind appear to have been mistaken for those caused by impact cratering and sedimentation. Examples are given from pyroclastic deposits on Earth.

Wednesday, August 11, 2021

DISCUSSION AND NADINE BARLOW IN MEMORIAM

2:00 p.m. CDT

Chair: Michelle Kirchoff

Times	*Authors (Denotes Presenter)**	*Abstract Title and Summary*
2:00 p.m.		DISCUSSION
3:00 p.m.		In Memoriam for Nadine Barlow

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Thursday, August 12, 2021

INTRODUCTION AND WELCOME; PCC ELECTION SPEECHES

10:00 a.m. CDT

Chair: Michelle Kirchoff

Times	*Authors (Denotes Presenter)**	Abstract Title and Summary
10:00 a.m.	Kirchoff M. R. *	Introduction and Welcome; Election Speeches

Thursday, August 12, 2021

CRATER STUDIES VIA REMOTE SENSING DATASETS

10:15 a.m. CDT

Chairs: Jamie Riggs and Kassandra Martin-Wells

Times	*Authors (Denotes Presenter)**	Abstract Title and Summary
10:15 a.m.	Thaker A. D. * Neish C. D. Blewett D. T. Zheng Y. C.	An Analysis of Radar-Dark Haloed Craters Using Chang’E-2 Passive Radiometry Data [#2016] Recorded Presentation We study lunar impact craters with ring-shaped structures surrounding them, having distinctive low radar returns, known as the ‘dark-halo craters.’ We use passive microwave emissions to characterize their regolith properties and evolution over time.
10:45 a.m.	Powers L. T. * Martin-Wells K. S.	The Spatial Relationship Between Tycho Secondary Craters and Distal Impact Melt Deposits [#2027] Recorded Presentation Analysis of Tycho secondary craters and distal impact melt locations in ray systems to the northeast and northwest of Tycho.
11:15 a.m.	Martin-Wells K. S. *	The Relationship Between Diviner Rock Abundance and Local Slope at Tycho Distal Impact Melt Deposits [#2038] Recorded Presentation The relationship between maximum Diviner Rock Abundance and local slope is investigated at 111 regions of distal Tycho impact melt.
11:45 a.m.		Break
12:00 p.m.	Chertok M. A. * Lucey P. G. Costello E. S.	Rocky Ejecta Blankets of the Lunar Mare [#2023] Recorded Presentation We examine craters with rocky ejecta at the Chang’E 5 landing site and compare with an older Mare study area. We find that rock abundance has a unique relationship with the mechanical properties of regolith.
12:30 p.m.	Jodhpurkar M. J. * Ostrach L. R. Zellner N. E. B.	Characterizing Moulton Crater and Its Immediate Surroundings [#2019] Recorded Presentation What mysteries lie / On the farside of the Moon / Moulton shows a glimpse.
1:00 p.m.	Boatwright B. D. * Head J. W.	Mars Crater Modification in the Late Noachian II: Updated Criteria for Identifying Cold-Based Crater Wall Glaciation [#2028] Recorded Presentation We provide updated criteria for identifying cold-based crater wall glaciation on Mars based upon new findings of cross-cutting fluvial stratigraphy and transverse aeolian ridges.
1:30 p.m.		Break
1:45 p.m.	Landis M. E. * Dundas C. M. Hayne P. O. McEwen A. S. Daubar I. J. Byrne S. Sutton S. S. Britton A. Herkenhoff K. E.	Two Dated Small Impacts on the South Polar Layered Deposits, Mars, and Implications for Near-Surface Properties [#2030] Recorded Presentation We present results from observations of two dated impacts on the South Polar Layered Deposits, Mars. We preliminarily report depths to icier material buried below an SPLD dust mantling layer.
2:15 p.m.	Robbins S. J. *	Initial Work Building a Next-Generation Mars Crater Database: A Case-Study of MC-09 (Tharsis) Craters in Context Camera Images Versus THEMIS [#2037] Recorded Presentation Discussion of a new effort at building a wide-ranging Mars impact crater database, including methods (those used and some experimental), lessons learned from before, and comparisons with past work.
2:45 p.m.	Boyce J. M. *	The Pitted Ramparts of Large Multi-Layered Craters on Mars: Their Possible Formation Mechanisms and Their Implications [#2039] Recorded Presentation The rampart of the outer ejecta layer of large (i.e., > 25 km dia.) martian multi-layered ejecta craters typically exhibit closely spaced pits. These pits are likely due to degassing of impact melt-rich breccia concentrated in these ramparts.

Thursday, August 12, 2021

PCC NOMENCLATURE COMMITTEE REPORT AND OPEN DISCUSSION

3:15 p.m. CDT

Chair: Michelle Kirchoff

Times	*Authors (Denotes Presenter)**	Abstract Title and Summary
3:15 p.m.	Boyce J. M. *	Nomenclature Committee Report
3:20 p.m.		DISCUSSION

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Friday, August 13, 2021

FIELD AND LABORATORY STUDIES

10:00 a.m. CDT

Chair: Michelle Kirchoff

Times	*Authors (Denotes Presenter)**	Abstract Title and Summary
10:00 a.m.	Kirchoff M. R. *	Introduction and Welcome
10:05 a.m.	Mitchell C. D. * James P. B. Kring D. A.	A Novel Approach to Bulk Density Estimation with Gravity Gradients at Meteor Crater, Arizona [#2034] Recorded Presentation This abstract outlines a new technique for determining shallow sub-surface densities utilizing gravity gradients at Meteor Crater. We outline the methodology for this technique and compare sampled densities against the calculated values.
10:35 a.m.	Horn M. * Heinrich P. V. Hood D. Herr A. Webb A. James P. Karunatillake S. Ermakov A. Lorenzo J.	Possible Pleistocene Impact in Louisiana as an Analog for Craters in Martian Duststone Settings [#2035] Petrography and geophysics are used to analyze a 2km circular depression in non-consolidated fine-grained sediment in SE Louisiana. Results encourage consideration of the feature as a terrestrial analog for martian duststone craters.
11:05 a.m.	Patton R. L. * Watkinson A. J.	Impactite and Shatter Cone Genesis via Super-Shearing Crack Propagation [#2012] Recorded Presentation Stress-energy balance in non-linear elastic media predicts a novel regime of super-shearing crack propagation. Impactite and shatter cone genesis can be understood in this context, as can size-morphology transitions in crater forms.
11:35 a.m.		Break

Friday, August 13, 2021

LABORATORY AND COMPUTER MODELING OF IMPACT CRATERS

11:50 a.m. CDT

Chair: Jamie Riggs

Times	*Authors (Denotes Presenter)**	Abstract Title and Summary
11:50 a.m.	Alsemgeest J. * Brouwer F. M.	Thermodynamic Modelling of Hydrothermal Alteration in the Vista Alegre Impact Structure (Brazil) to Distinguish Between Different Alteration Stages [#2008] Recorded Presentation Thermodynamic modelling was used to constrain the evolution of hydrothermal vein sets in the Vista Alegre impact structure, Brazil. Together with other indications, this suggests that the dominant set results from excavated, pre-existing alteration.
12:20 p.m.	Suarez Cortes A. D. * Flandes A. Durand Manterola H. J.	Study of Planetary Impact Craters and Their Ejection Material Based on Low Impact Speed Laboratory Models [#2031] Recorded Presentation We introduce impact experiments at low impact speeds (10 m/s≥ vp ≤70 m/s) with a low-cost experimental setup and apply a similar analysis used by divers authors as in the case of laboratory impact experiments at much larger speeds.
12:50 p.m.	Robertson D. K. * Pokorný P. Granvik M. M. S. Wheeler L. C. Rumpf C. M.	Latitude Variation of Flux and Impact Angle of Asteroid Collisions with Earth and the Moon [#2013] Recorded Presentation Flux to the poles is greater than the flux at the equator, by 22% for Earth and 55% for the Moon. Impacts near the equator are shallower and those at the poles steeper. Validation with observations is examined and risk to people is determined.
1:20 p.m.		Break

Friday, August 13, 2021

WRAP-UP DISCUSSION AND PLANETARY CRATER CONSTORTIUM BUSINESS

1:35 p.m. CDT

Chairs: Michelle Kirchoff and Jamie Riggs

Times	*Authors (Denotes Presenter)**	*Abstract Title and Summary*
1:35 p.m.		DISCUSSION
2:35 p.m.		PCC Business: Election Speeches Part 2; Voting on a New Chair, Council Member, Charter; Selection of Secretary; 2022’s PCC Meeting
3:00 p.m.		Adjourn

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*Authors (Denotes Presenter)**	Abstract Title and Summary
Ernstson K. Poßekel J. Kurtz J.	The Enigmatic Sachsendorf Bay Structure (Oderbruch, Northeast Germany): Evidence of a Pleistocene/Holocene Meteorite Impact Event [#2022] A previously postulated major impact structure in northern Germany finds support from high-resolution Digital Terrain Models. Previous hypotheses of the formation of this geologically alien structure by glacial and tectonic processes are rejected.
Poßekel J. Ernstson K.	The So-Called “Sölle” Late Pleistocene Circular Formations in the Brandenburg and Mecklenburg-Vorpommern Federal States (Northern Germany): Evidence of Meteorite Impact Crater Strewn Fields [#2024] The theory of dead-ice formation of the so-called Sölle, which, in the tens of thousands, characterize large areas in northern Germany, is rejected, and at least for a large part of the circular structures a meteorite impact genesis is assumed.
Rappenglück M. A. Poßekel J. Ernstson K.	Mars and Moon on Earth: Formation of Small Terraced Impact Craters and Ground Penetrating Radar Investigations [#2021] Small terraced impact craters on the Moon and Mars have comparable equivalents on Earth, occurring in large numbers in the Chiemgau impact crater strewn field in Germany. They are described in high-resolution Digital Terrain Models and with detailed GPR measurements.
Schmidt G.	Evidence for a Metallic Asteroid Source from Chicxulub Impact Crater Sediments at the Yucatán Peninsula in Mexico: A Re-Interpretation of Literature Data [#2002] The most likely source for the PGE signature (literature data) in Chicxulub Crater sediments is an iron asteroid. The source crater responsible for the global Ir distribution associated with the mass extinction has therefore not yet been identified.

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