Process of mountain formation is gory on environment primarily; shattering (7)
I believe the answer is:
orogeny
'process of mountain formation' is the definition.
The definition suggests a singular noun which matches the answer.
'gory on environment primarily shattering' is the wordplay.
'primarily' suggests taking the first letters.
'shattering' is an anagram indicator.
The first letter of 'environment' is 'e'.
'gory'+'on'+'e'='goryone'
'goryone' anagrammed gives 'OROGENY'.
'is' is the link.
Can you help me to learn more?
(Another definition for orogeny that I've seen is " origin of mountains".)