Land splits at that tropical island (6)
I believe the answer is:
tobago
'tropical island' is the definition.
'Tobago' can be an answer for 'island' (Caribbean island). I am not certain of the 'tropical' bit.
'land splits at that' is the wordplay.
'land' becomes 'bag' (I've seen this in other clues).
'splits' is an insertion indicator (inserted letters split open the word).
'at that' becomes 'too' (used for emphasis eg 'and a cheap one at that').
'bag' placed within 'too' is 'TOBAGO'.
Can you help me to learn more?
(Other definitions for tobago that I've seen before include "Trinidad companion island" , "Island near Trinidad" , "Caribbean island" , "Trinidad and - (WI)" , "Section of WI" .)