부산대학교 도서관

We have produced regional geologic maps of the Zal, Hi'iaka, and Shamshu regions of Io s antijovian hemisphere based on Galileo mission data. Here we discuss the geologic features, summarize the map units and structures that are present, discuss the nature of volcanic activity, and give an analysis of the volcanic, tectonic, and gradational processes that affect the regions in order to better understand Io s geologic evolution. Zal Region: The Zal region (25-45degN, 65-85degW) consists of Zal Patera (120 km wide x 197 km long), two major mountains (north and south Zal Montes) which border Zal Patera to the west and south [1], and an unnamed patera ("Patera A") west of south Zal Montes. The Zal region includes at least two hotspots detected by Galileo: one along the western scarp of the Zal Patera volcano and one at the "Patera A" volcano. The floor of Zal Patera has been partly resurfaced by dark lava flows since Voyager imaging; portions of the patera floor appear unchanged during the Galileo mission. Mountains exhibit stages of degradation. The western bounding scarp of Zal Patera appears to be a fissure source vent for multiple silicate lava flows. The Zal Montes and Patera complex appears to be an example of volcano-tectonic interactions [1, 2]. Several of the flow units emanate from the fissure at the western scarp [2]. Hi'iaka Region: The Hi'iaka region (approx.12degS-5degN, 75-87degW) consists of Hi'iaka Patera, a large (60 km wide x 95 km long) patera, north and south Hi iaka Montes which border Hi'iaka Patera to the west and south and are L-shaped mirror-images of each other, west Hi'iaka Montes, a small isolated peak, and an unnamed patera ("Patera B") located south of north Hi'iaka Montes. The region includes one hotspot at Hi'iaka Patera. The floor of the patera exhibits flow deposits of differing ages. The eastern scarp of Hi'iaka Patera may be a fissure source vent for the patera floor materials. The Hi iaka Montes and Patera complex appears to be an example of volcano-tectonic interactions [1, 2]. Shamshu Region: The Shamshu region (approx.15degS-5degS, 55-77degW) consists of Shamshu Patera, three mountain units (west, north, and south Shamshu Mons), and a small unnamed patera ("Patera C") southwest of Shamshu Mons.