Unbeknownst to NASA at the time, the waters that long ago carved Pathfinder’s landing site spilled out from a previously undocumented inland sea nearby, new research shows.
Image: J. A. P. Rodriguez et al., 2019/Scientific Reports The key to the discovery was the detection and characterization of the Simud Interior Basin—a large basin about 155 miles (250 km) south and upstream of the Pathfinder landing site.
This basin is roughly the size of California, and at an elevation slightly higher than the hypothesized Northern Ocean, a former body of water just north and downstream of the Pathfinder landing site.
Eventually, the waters in the inland sea spilled over, flooding the land barrier and creating the spillover surface features observed by Pathfinder.
Also, debris or lava flows couldn’t have formed the features seen at the Pathfinder site, the researchers argue, as such flows would have completely obliterated any sign of the basin; as a flowing liquid, lava or fluidized debris flows would have behaved just like water, filling up the Simud Interior Basin prior to spilling over into land barrier.