Imagine it's night; you're aboard an airplane, looking downward. All you see is complete darkness.
Now, put on your IR glasses. Imagine you see this:
link
What do you think you are looking at?!?
You are flying over a volcanic region, so I think is quite normal to suppose we are looking at hot spots.
Now, move your cursor over -5.224 N, 243.17 E.
See that white stripe?
Now, switch to daytime IR view (from listbox above): you see that? The black area?
What is it?
What is cold during day and warm during night?!?
Any idea if HiIRISE images exists for this region?
Here around, exactly at -5.636 N, -118.751 E , there's also the "strange anomaly" known as "mars hole" in thse days;
this is an hi-res picture. I can't find similar resolution pictures for "my" anomaly. Any help?