What does the cryptic crossword clue "A gas explosion involving Ross Sea (8)" mean?

The definition is "Sea". The wordplay uses an anagram. anagram of A + GAS + ROSS = SARGASSO; definition: "Sea" The answer is SARGASSO.

A gas explosion involving Ross Sea (8)

Guardian Cryptic #29036 | 25 Across | 2023-04-05 flower