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Brown University-Vernadsky Institute Microsymposium 43

"The Martian Time Scale:
Craters, Meteorites, Processes and Stratigraphy"

March 11-12, 2006
Lecture Hall
The Lunar and Planetary Institute, Center for Advanced Space Studies
3600 Bay Area Boulevard
Houston Texas 77058

In the year 2000 the International Space Science Institute held a workshop on the "Chronology and Evolution of Mars". From this meeting a new view emerged of impact cratering chronology and age-dating of martian meteorites (SNCs). Continuing analysis of new spacecraft data (MGS, MO, MER, MEX) has provided the data necessary to extend and assess this chronology to a host of geological units and environments. Images from orbit and the surface have revealed the significant role of exhumation in the geological evolution of surfaces. New insights are emerging concerning impact fluxes and the influence of secondary cratering processes in impact cratering chronology. Finally, new analyses of SNC meteorites2 and their context have raised fundamental questions about the interpretation of the absolute chronologic basis of the time scale.

For these reasons, the Microsymposium 43 workshop "The Martian Time Scale: Craters, Meteorites, Processes and Stratigraphy" will focus on the discussion of several of these major issues. Each discussion topic will be prefaced by a presentation from an expert in the field, followed by ample time for discussion of the issues. The purpose of the workshop will be to 1) identify the most fundamental unknowns associated with our knowledge of the martian time scale and 2) outline the ways in which we might resolve these questions (new observations, experiments, laboratory analyses, etc.). A product of the Microsymposium will be a written assessment of these points.

Final Program:

Saturday: March 11, 2006
LPI Lecture Hall

1:00 PM
1) Introduction: What new developments in Mars cratering chronology have occurred since the ISSI Conference? Bill Hartmann, PSI.

1:30 PM: Discussion.

1: 45 PM
2) What are the real crystallization ages of the SNC meteorites and what role does alteration play? Larry Nyquist, NASA JSC.

2:15 PM: Discussion and Commentary (5 minutes each).

Commentary: The ordeal of dating igneous rocks in wet planetary and terrestrial environments. Francis Albarede, ENS Lyon.

Commentary: U/Pb data are the solution? Yes, Nd is a red herring. Emil Jagoutz, Max Planck Institute, Mainz.

2:45 PM
3) What new insights do we have about Mars cratering chronology from new flux estimates and a better understanding of the impact cratering process? Boris Ivanov, RAS.

3:15 PM: Discussion.

3:30 PM
4) The characteristics of the impact crater production size-frequency distribution on Solar System planetary bodies, their relationships to asteroidal and cometary impacts, and the question of secondary-cratering contributions. Gerhard Neukum, Stephanie Werner, and Boris Ivanov; Freie Universitat Berlin, RAS.

4:00 PM: Discussion.

4:30 PM
5) Origins of small impact craters on Mars: Primaries and secondaries. Alfred McEwen, University of Arizona.

5:00 PM: Discussion and Commentary (5 minutes each).

Commentary: Secondary cratering, asteroids and martian chronology. Clark Chapman, Southwest Research Institute.

Commentary: The statistics of small numbers of craters can be useful for constraining ages. Misha Kreslavsky, Kharkov Institute and Brown University.

Commentary: Comparing secondary crater production on the Moon and Mars." Nadine Barlow, Northern Arizona University.

5:30 PM: Reception and Posters.

Posters: An instrument for Rb/Sr geochronology. Scott Anderson, University of Hawai'i. Rampart craters in Thaumasia Planum. Dennis Reiss, DLR. Gravitational focusing and the computation of an accurate Moon/Mars cratering ratio. Mark Matney, NASA JSC. Numerical simulation of heating of target at crater-field-forming impact events. Jens Orm and Alain Lepinette, INTA.

Sunday: March 12, 2006
LPI Lecture Hall

8:00 AM
6) What are the implications for Mars Noachian cratering chronology of the detection of additional craters and basins with MOLA data? Herb Frey, NASA GSFC.

8:30 AM: Discussion.

8:45 AM
7) Sequence of events for the geological history of Mars. Stephanie Werner and Gerhard Neukum: Freie Universitat Berlin).

9:15 AM: Discussion and Commentary (5 minutes each)

Commentary: Evidence of the decreasing impact rate over the last 3 Gy from the martian geological record. Cathy Quantin, National Air and Space Museum.

Commentary: The morphology of very fresh large impact craters on Mars from THEMIS and MOC images. Peter Mouginis-Mark, University of Hawai'i.

9:45 AM
8) Observations of crater morphometry and landscape development from the Mars Exploration Rover: Implications for the origin of small impact craters as secondaries and for deriving ages from the small crater population. Matt Golombek, JPL.
10:15 AM: Discussion.

10:30 AM
9) How have the new data for Mars changed our perceptions of Mars stratigraphy and geological history? Ken Tanaka, USGS Flagstaff.

11:00 AM: Discussion.

11:15 AM
10) What is the importance of in situ analysis and Mars sample return in improving and solidifying Mars cratering chronology? Glenn MacPherson, Smithsonian Institution.

11:45 AM: Discussion and Commentary (5 minutes each)

Commentary: Potential for in situ noble gas chronology. Tim Swindle, LPL.

12 Noon: Closing Remarks and Adjourn. James Head and Alexander Basilevsky

Abstracts from previous Microsymposia:

Micro 42, October 2005