Isle found east of a geographical region, as explorer (4,6)

'explorer' is the definition.
(I know that Abel Tasman is a navigator)

'isle found east of a geographical region as' is the wordplay.
I cannot really see how this works, but
'isle' could be 'man' (the Isle of Man is an example) and 'man' is present in the answer.
'east' could be 'e' (abbreviation) and 'e' is present in the answer.
'a' is present in the answer.
'as' is present in the answer.
The remaining letters 'blt' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?