Jill England wrote:
The pertinent point of our paper was not to suggest a water origin, believe it or not

Alex writes:
I guess I was confused by the title, which starts out: "A Study of Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) Images Showing Probable Water Seepages..."

Jill England wrote:
The purpose of the paper was to find evidence supporting or rejecting a water formation conjecture.

The only evidence we found, which is THE central point of our paper is:

1. Efrain plotted the positions of Stain images and discovered there is a distinct distribution pattern where "stains/flows" occur only near the equator AND that they are bimodally distributed on Tharsis and 180 degrees away from Tharsis.

2. I wrote some software specifically to find overlapping images so that I could demonstrate if flows occur in a relatively short time frame. This was successful and I proved that flow features are currently forming geological features on Mars.

Alex writes:
As for (1), although I am not free to go into details, other workers will soon publish (in a peer-reviewed paper currently in press with JGR-Planets) that the "...dark slope streaks [are] distributed widely, but not uniformly, across the brighter equatorial regions..." Their relationship to near equatorial latitudes, which also happen to be areas of net dust influx is also supportive of the dust avalanche model. The concentrations around Tharis and its antipode is suggestive, but may also be a function of MOC NA targeting bias. Everyone I've spoken to says that the dark streaks are basically found in the equatorial regions "wherever we look for them." Since the vast majority of the MOC NA swaths are in fact targeted, and not randomly snapped, this may be a reflection that the targeting boxes themselves were concentrated on Tharsis and Arabia for other reasons (e.g, to study volcanism, crater counts on specific geologic units, etc.). In other words, the "bi-modal distribution" may be a biased dataset.

As for (2), as far as I know no one is disputing that these features are currently active, least of all Malin, who has stated as much on the MSSS web site and in LPSC abstracts.

Alex R. Blackwell
University of Hawaii