Question

During what geologic period did the Atlantic start to open?

Answer 1

Answer:-

Rifting in the central Atlantic occurred 220–198 Million years ago (Ma), with seafloor spreading beginning ca. 200 Ma in the south (GA-Carolinas) and 180 Ma in the north (MA-Nova Scotia). The South Atlantic began to open 120 Ma and the Norwegian-Greenland Sea opened 55 Ma. Scotian Sea and Drake Passage opened about 34 Ma.

Simple terms, most date the birth of the Atlantic as 180 Ma