TypeA&TypeB

Offshores Type 1 & Type 2

Using the Bally's classification of the sedimentary basins it is easy to classify the offshores. Two types can be proposed :

(i) Offshores Type 1 , which are not associated with the formation of megasutures.

(ii) Offshores Type 2, which are associated with the formation of megasutures.

Offshores Type 1 are, mainly, associated with Atlantic-type divergent continental margins (Atlantic offshores), rift-type basins (e.g., Marajo offshore, Brazil) and cratonic basins (e.g., North Sea).

Offshores Type 2 are, mainly, associated with convergent margins either with episutural or perisutural basins. The west of Sumatra or Java offshores, in Indonesia, are associated with forearc basins, while the offshores west of USA are associated with the mediterranean-type basins. The majority of the offshores in SE Asia are associated with backarc basins. However, as we have seen before ,due to the rifting, some of these offshores evolved into non Atlantic-type divergent margins, since the lithosphere broke-up and seafloor spreading created a marginal sea. Mediterranean-type basin offshore are frequent in Mediterranean sea in association with breakup of the lithosphere in A-type subduction context.