Make projections of additional ring in section of earth's crust (11)
I believe the answer is:
extrapolate
'make projections of additional ring in section of earth's crust' is the definition.
I can't judge whether this definition defines the answer.
'additional ring in section of earth's crust' is the wordplay.
'additional' becomes 'extra' (extra means additional or surplus).
'ring in section' becomes 'pola' (I can't explain this - if you can you should give a lot more credence to this answer).
'of earth' becomes 'terrene' (I've seen this before).
'crust' says to hollow out the word (remove centre letters) (the outside or crust of the word is used).
'terrene' with its middle removed is 'te'.
'extra'+'pola'+'te'='EXTRAPOLATE'
Can you help me to learn more?
(Other definitions for extrapolate that I've seen before include "Infer from what's known - to repeal tax (anag)" , "Infer further points from trends in data" , "forecast" , "Conclude from other data" .)