Caulking Gaps Between Plank Floor Boards?

[tomsteve]

Insulate, draft seal and vapour barrier the basement.

if not this, im thinkin something like done on boat decks

http://www.boat-building.org/learn-skill...and-hulls/

[David Stone]

Thanks everyone.  
I'll see what I can do to attack it from the bottom.

[Snipe Hunter]

Insulate, draft seal and vapour barrier the basement.

This

That wood shouldn't be moving that much. I'm thinking poor insulation beneath it. Paper towards the conditioned side of the house.

[Robert Adams]

I have never seen any other filler used in those gaps other than good old dirt and it takes decades of accumulated dirt to fill and pack hard in those gaps.

[Stwood_]

Looks like a super old old floor. And the junk in there, by the color on my monitor, looks like concrete or mortar.

[rwe2156]

I would try to caulk it with a roofing type caulking.  I've used some that are extremely flexible.

There are also rubber-type caulks that might work as well.