Thanks Artixan - I was amazed at the detail and the only thing I can attribute it to is that it truly was a "super moon".
The settings were as follows on that shot
Canon EF70-200mm f/4L IS USM lens
focal length: 200mm
Shutter speed: 1/1600 sec
I took other shots with varied apertures, iso and shutter speeds but this one came out the best, though they were all pretty similar.