'06 EC 300 Marzocchi fork leg leaking all over floor

[brider]

Hope this pic is visible;

I'm laying on my back looking up at the right fork leg. You can see the drip forming, it's lost a LOT of fluid all over the floor. This happened spontaneously this last week, can I assume that the insane cold weather we had recently just caused the internal o-ring seals to shrink and now fail? Since there's oil surrounding the larger hex nut, I'll assume the leak is coming from a larger o-ring sealing the nut.

I don't have a manual for the Marzocchi fork, but I assume the small screw is the compression damping adjuster, and the large hex nut attaches to the underside of the damping cartridge?

I know I'll have to pull the top cap off to re-fill with fluid, but can I remove that large nut (and the adjuster screw with it) under spring load to replace an o-ring seal?