Introduction to the special issue

Abstract

This special issue is the result of efforts by the Planetary Crater Consortium to engage the crater and broader planetary science community regarding the state of knowledge about impact craters. Impact craters are the most abundant landform on almost all solid surfaces in the solar system, observed on all bodies imaged closely to date except Jupiter's moon Io. Crater populations form the only known metric for modeling the surface ages of planetary bodies, and they are used to inform the underlying dynamics of the objects that generate them and the physics of the impacts themselves. Individual craters are used to understand local geology and geophysics, the environment in which they exist, and other important processes on the bodies upon which they form. In May 2015, the first-of-its-kind “Workshop on Issues in Crater Studies and the Dating of Planetary Surfaces” was convened at The Johns Hopkins University's Applied Physics Lab, where 50 community members presented talks and participated in discussions about the history of impact crater studies, where the field currently stands, and the most pressing questions and issues that are critical to advancing the field. This special issue arose from that conference. In this volume are 14 papers that span a wide range of topics. There are three review papers describing the state of knowledge of secondary impact craters, how large a counting surface needs to be for adequate crater statistics, and a survey of techniques and results of crater depth measurements for the last >50 years on solar system bodies. There are also new science papers, detailing crater morphometry and new methods and recommendations to measure them, terrestrial crater field work, models for types of craters and related features on the Moon and Mars, and implications of crater studies to Martian climate. Finally, there are three papers that describe new techniques and methods to analyze craters: a fast and robust way to determine crater saturation, a method to determine secondary crater clusters from those produced by atmospheric fragmentation, and a re-examination of classic size-frequency distribution techniques with new recommendations on how to display and analyze crater populations. Readers and editors alike thank the contributing authors and reviewers for their hard work on this valuable volume on impact craters. The editors and authors hope that the work in this volume will help pave the way for future research and studies into impact craters for many years to come.