One of the above images is from Mars and the other is from eastern Washington.
Basalt ring dikes just north of I-90 and Denekas Road northeast of Ritzville
Jaeger etal 2007 recognized these features as analogs to some features on Mars. Eastern Washington has large tracts of flood basalt lava and large tracts of huge water floods from the ice age floods. Landforms that look very similar and possibly formed in similar manners are present on Mars and hence eastern Washington geology and landscapes have been compared to Martian landscapes to understand the Mars features.
As best as I can tell there is a leaning towards the ring structures being the result of lava flowing over water or wet ground or perhaps springs. Lillquist and Powell (2013) discuss and present various ideas about the ring structures near Odessa, Washington in a guide to the geology of upper Crab Creek.
An interesting note on these features is that they are apparently rare. But I suspect that they may not be so much rare as rarely exposed in a way that they can be observed.
While there are similarities, there still is some debate regarding the interpretations of scenarios of lava flow, flooding, ice and meteor impacts on Mars (Page, 2008) and (Jaeger etal, 2008).
1 comment:
This is so cool.
I have vivid and pleasant memories of such a structure just outside Odessa, where my cousin lived. More recently, someone in an academic work not in front of me now, points out what might be a cross-section of one in the west wall of the Grand Coulee--just below where the channel widens, a couple miles S of Steamboat Rock. It looks kind of like a distorted funnel, a symmetrical warping of one flow, as I seem to recall. I will check the article you link to.
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