Featured Image - 11/11/2008
Lava Terraces in Bowditch
Bowditch (25 ° S, 103.1 ° E) is an irregularly-shaped depression NW of Lacus Solitudinis (Figure 1) and is approximately 25-km wide. Bowditch has a ring that resembles those in a dirty bathtub. Much like water in a bathtub, this ring is a marker of the highest level of liquid lava within Bowditch (Figure 2). The Bowditch depression filled with lava like many craters on the Moon; as the lava cooled and solidified, it subsided into the center of the depression (Masursky et al. 1978). This image of Bowditch is exceptional because the lava terraces are clearly visible; however, further study of the lunar surface with LROC's narrow-angle camera (NAC) will provide scientists with more evidence of lava cooling, contraction, and subsidence at the scale of 50 cm/pixel. The LROC NAC can search the margins of mare ponds and lava-filled craters for more evidence of lava terracing. Lava terraces provide important clues about the thickness, viscosity, composition, and cooling rate of lunar lavas and will help us better understand volcanism on the Moon.
Figure 1: Bowditch (AS15-M-2357) and Lacus Solitudinis.
(Apollo Image AS15-M-2357 [NASA/JSC/Arizona State University])
Figure 2: Portion of AS15-M-2357 showing detail in Bowditch and surrounding region. White arrows highlight the lava terraces in Bowditch. Yellow arrows point to fractures from which lava may have erupted. Red arrow points to a partially-flooded crater.
(Portion of Apollo Image AS15-M-2357 [NASA/JSC/Arizona State University])
Apollo Over the Moon: A View From Orbit (1978) H. Masursky, G. W. Colton, F. El-Baz, eds. NASA SP-362. http://www.hq.nasa.gov/office/pao/History/SP-362/contents.htm