2019 Planetary Geologic Mappers 2019 (LPI Contrib. No. 2154) 7016.pdf CAN THE INTERCRATER PLAINS UNIT ON MERCURY BE MEANINGFULLY SUBDIVIDED?: CHARACTERIZATION OF THE DERAIN (H-10) QUADRANGLE INTERCRATER PLAINS. J. L. Whit- ten1, C. I. Fassett2, and L. R. Ostrach3, 1Department of Earth and Environmental Sciences, Tulane University, New Orleans, LA 70118, (
[email protected]), 2NASA Marshall Space Flight Center, Huntsville, AL 35805, 3U.S. Ge- ological Survey, Astrogeology Science Center, 2255 N. Gemini Dr., Flagstaff, AZ 86001. IntroDuction: The intercrater plains are the most little agreement about the definition of intercrater and complex and extensive geologic unit on Mercury [1, 2]. intermediate plains. Generally, the intercrater plains are identified as gently It appears that previous researchers were looking for rolling plains with a high density of superposed craters a way to divide up the massive intercrater plains unit by <15 km in diameter [1]. Analyses of the current crater mapping an intermediate unit. This seems like a good population indicate that the intercrater plains experi- idea, however, there was no quantitative measure or de- enced a complex record of ancient resurfacing [3, 4] finitive characteristic used to divide the intercrater (i.e., craters 20–100 km in diameter are missing). This plains from the intermediate plains. Qualitatively, these dearth of larger impact craters could have been caused two geologic units differ in their density of secondary by volcanism or impact-related processes. Various for- craters and their morphology. Intermediate plains have mation mechanisms have been proposed for the inter- a more muted appearance and have been interpreted as crater plains, including volcanic eruptions and basin older smooth plains [13].