The volcanoes described in the previous chapters are either unique on Io or are class types of silicate eruptions. Many other volcanic centers display diverse styles of eruption, and colors and geomorphologies indicative of other lava compositions. The tour of Io's volcanoes continues with a closer look at some of these features.

Tupan Patera

Tupan Patera (141°W, 19°S) (Plate 12b) is one of Io's most colorful features. The patera is 75 km × 50 km in area and about 900 m deep (Turtle et al., 2004). Bright red material, probably short-chain sulphur allotropes, colors most of the patera floor and diffuse deposits are seen on the surface southeast of the patera (Keszthelyi et al., 2001a; Turtle et al., 2004). Black silicates cover the floor of the eastern half of the patera and appear in patches in the western half. In NIMS data these dark areas are the warmest areas, whereas the central “island” is cold (Lopes et al., 2004). A relatively uniform black line traces the edge of the patera floor in the western half of the patera and may be a tide line like that seen at Emakong (Turtle et al., 2004; see Section 14.5). The appearance of bright material in patches on the eastern patera floor is consistent with the melting of sulphur from the patera walls and patera margins; the sulphur then flows and pools on cooling silicates on the floor of the patera.