Weird!

[Fergus]

 

[Norman_E]

Unusual but not so weird really. Volcanic "ash" made from pumice floats, and spreads out in to a thin layer on the water surface. I believe that Pliny recorded a similar phenomenon from the Versuvius eruption in AD72. (did I get the date right?)

 

[aknight]

AD 79 apparently

 

[SilverBreeze]

It's been here before, nice cruising here.