Impacts Focus Group
Currently Inactive

Introduction

Peter Ward, Co-Chair
University of Washington
argo@u.washington.edu

Frank Kyte, Co-Chair
University of California, Los Angeles
kyte@igpp.ucla.edu

The Impacts Focus Group (IFG) has been assembled to examine how impacts of asteroids, comets, and other materials have influenced the origin, evolution, and extinction of life on Earth. A major goal of the Impacts Focus Group is to accumulate samples from a wide variety of temporal and geographical research locales. The geochemical and paleontological analysis of these samples will also be a major thrust of their efforts. Impacts, as a geological process, have affected landscapes of every rocky or icy planet in the solar system. If life ever existed on astrobiological points of interest such as Mars or Europa, then impacts have likely affected the biota on these bodies as they have done on Earth.

Background

Until recently, impact cratering has been viewed primarily as a geological process. Research in this area has been involved with questions regarding the relationship between impactor size and crater size. However, impact sites such as the K/T boundary at Chicxulub have demonstrated that impacts can have profound biological consequences as well. The Impacts Focus Group seeks to understand how impact cratering as a geological process affects the surrounding environment and its biota. Members will concentrate primarily on field-based hypothesis testing, and secondarily, on the utilization of theoretical models.

While the IFG is a relative newcomer to the NAI’s growing list of Focus Groups, its members have already convened and addressed many relevant areas of interest. Topics that are planned for investigation include impacts as the cause of mass extinctions, impacts as a mechanism for delivering biological materials to early Earth, and impacts as a mechanism for delivering water to Earth. This Focus Group may also examine many of the physical attributes of cratering such as crater morphology and geology, geological signatures of craters, dynamics of formation, and frequency of impacts. By studying these various aspects of impact and cratering processes, the Impacts Focus Group will provide the astrobiological community with a greater understanding of how the physics and geology of impacts translates to biological perturbation and adaptation.

Activities
2003

A UCLA-sponsored Rubey Colloquium entitled “Impacts and the Origin, Evolution, and Extinction of Life” provided the first opportunity for those interested in the Impacts Focus Group to voice their interests and opinions about possible areas of study. Approximately 30 experts were invited to speak on topics such as impacts as links to catastrophic mass extinctions, impacts and their environmental effects, and impacts as a mechanism for dispersal of life within the solar system or across interstellar space. This colloquium brought together key players in the field, helped to elucidate important questions that could be addressed by the IFG, and brought more of the astrobiological perspective into this already mature field. The Rubey Colloquium book of abstracts is available on-line at: http://www.ess.ucla.edu/rubey/abstract.pdf. In addition, as described in the May 29 Issue of the NAI Newsletter, many papers generated from this colloquium were published in the Spring 2003 issue of Astrobiology.

The acquisition, distribution, and analysis of samples are expected to begin as soon as the research objectives of the IFG have been refined and finalized; and when the target samples have been identified and prioritized. A first year summary meeting will discuss progress, cooperative efforts, and a new prioritization of sample areas and/or their identification.