in one of those d'oh! moments, i dd'd a 16mb image to my 320gb disk instead
of the intended usb key...

i've copied off the 320gb disk image to another drive and tried a bunch of
things to try to correct this (hopefully trivial) hiccup, but havent had any
success. things tried so far:
-restored the partition table from an identical disk, this alone has worked
for me in past but fails to mount
-mounting using alternate superblock ignoring errors gives IO errors
-fscking using alternate superblock generates a LOT of errors and hangs
before returning the prompt

all advice greatly appreciated

decom