the gulf of mexico is a marginal sea.
the gulf of mexico is a marginal sea.
is the gulf of mexico an ocean or sea?
a marginal sea
geologists and other earth scientists agree in general that the present gulf of mexico basin originated in late triassic time as the result of rifting within pangea. the rifting was associated with zones of weakness within pangea, including sutures where the laurentia, south american, and african plates collided to create it. first, there was a late triassic-early jurassic phase of rifting during which rift valleys formed and filled with continental red beds. second, as rifting progressed through early and middle jurassic time, continental crust was stretched and thinned. this thinning created a broad zone of transitional crust, which displays modest and uneven thinning with block faulting, and a broad zone of uniformly thinned transitional crust, which is half the typical 40 kilometer thickness of normal continental crust. it was at this time that rifting first created a connection to the pacific ocean across central mexico and later eastward to the atlantic ocean. this flooded the opening basin to create the gulf of mexico as an enclosed marginal sea. while the gulf of mexico was a restricted basin, the subsiding transitional crust was blanketed by the widespread deposition of louann salt and associated anhydrite evaporites. during the late jurassic, continued rifting widened the gulf of mexico and progressed to the point that sea-floor spreading and formation of oceanic crust occurred. at this point, sufficient circulation with the atlantic ocean was established that the deposition of louann salt ceased. seafloor spreading stopped at the end of jurassic time, about 145-150 million years ago.
gulf of mexico
the atlantic seaboard basin in eastern north america drains to the atlantic ocean; the great lakes-st. lawrence basin in central and eastern north america drains to the gulf of st. lawrence on the atlantic ocean or to the labrador sea; the gulf of mexico basin in the southern united states drains to the gulf of mexico, a basin of the atlantic ocean; the pacific basin in western north america drains to the pacific ocean or the gulf of california on the pacific ocean; the arctic basin in northwestern north america drains to the beaufort sea of the arctic ocean or directly to the arctic ocean; the hudson bay basin in central northern north america drains to hudson bay on the labrador sea (which may be considered part of either the arctic ocean or atlantic ocean), or to the arctic sea via foxe basin and fury and hecla strait; the great basin in western united states is an endorheic basin which does not drain to any ocean.
watersheds of north america