I'd disagree there. Although the surface textures are diagnostic of flow of fluids, it isn't like any alluvial system that I know. Those scabby-surface textured units are characteristic of lava flows, and all the little cinder/phreatic cones are further evidence of high-temperature emplacement.

In my professional opinion, a series of lava flows is by far the most likely origin of the features we see in this large context image.

In practice, the feature may have been a partially-roofed lava channel, rather than a classic lava tube, but that's really only choosing a point on a spectrum, not a totally different beast from the menagerie...

As regards some of Michael's objections to lava tubes on Mars, I suspect that there are several issues that underly his problems in accepting a lava origin:-

1) In many cases the geometry of the collapse structures is more like a fracture than a tube. Of course, lava flows and lava tubes can be locked by the location of a pre-existing fracture, and in some circumstances a dyke can become a feeder for downstream flows and later be evacuated to leave a deep subsurface tube.

2) There is often a voilume problem with collapse features on Mars - it genrally seems that more material has been removed than would be appropriate for the nature of the feature causing it. In part, this may because the flows are such large scale on Mars, compared to Earth. Everything volcanic on Mars is bigger than on Earth. In part, it may be due to volatiles being lost from the subsurface, adding to the collapse volume, and finally, it maqy be due to the very long times involved on Mars - there is time for weak material to crumble to dust, and blow away, leaving surprisingly large cavities

3) Things on Mars are stacked. Lava tubes at one level may criss-cross with those at another, or with fractures, producing a complex pattern of cavities and weaknesses for later events to exploit.