Martian meteorite launch: high-speed ejecta from small craters.

Transfer of mercurian impact ejecta to Earth and implications for mercurian meteorites

Introduction: The existence of lunar and especially martian meteorites in our collections proves that escape from the gravitational well of Mercury (with escape speed of about 4.2 km/sec, less than that of Mars) should be possible, presumably via impact of asteroids or comets into the mercurian surface. Once impact ejecta is liberated from Mercury, it finds itself in orbit around the Sun. What ...

Morphology of Martian Double Layered Ejecta Craters and the Speed of Ejecta

Role of Volatiles in the Emplacement of Ejecta Deposits around Martian Impact Craters

Introduction: Impact craters are a dominant geological landform on Mars, the most Earth-like planet in the Solar System. The martian impact cratering record is more diverse than for Earth and the other terrestrial planets [e.g., 1]. Of particular interest is the presence of multiple layers of lobate or fluidized proximal ejecta deposits surrounding martian impact craters. These are collectively...

Martian Impact Craters: the Normal and the Unusual

Introduction: Our group has conducted a number of studies investigating the characteristics of martian impact craters. Many of these studies have provided insights into the normal characteristics of martian impact craters, such as their ejecta extents, ratio of central pit diameters to crater diameters, and the distributions of specific ejecta and interior morphologies. Other characteristics ar...

Quantifying the Amount of Impact Ejecta at the Mer Landing Sites and Potential Paleolakes in the Southern Martian Highlands

Introduction: Martian paleolakes have been offered as landing sites for in situ and sample-return missions because of their high probability of containing climatic and hydrologic records and potential biomarkers. Prospective paleolake sites are identified in closed craters primarily based on discrepancies between the craters' expected and measured depths and interpretation of associated fluvial...