I guess the point being, the land masses were much closer together once upon a time??? It also looks to be near what would be the beginning of the Mid-Atlantic Ridge. In any case, the graphic itself also appears to be a an exaggerated depiction(for purposes of illustration?) of this:
Not nearly as exciting.
not nearly as exciting...
I agree with you, I can't remember now where I lifted that graphic from.
Perhaps it doesn't look as spectacular because the depth is missing.
Age of the Seafloor
EXCERPT:
...In the Atlantic, rock and sediment age should range from Cretaceous (120 million years) adjacent to the continents to very recent at the ridge crest. During legs 37 and 43 of the DSDP, Paleozoic and Proterozoic igneous rocks were recovered in cores on the Mid-Atlantic Ridge and the Bermuda Rise, yet not one of these occurrences of ancient rocks was mentioned in the Cruise Site Reports or Cruise Synthesis Reports (Meyerhoff et al., 1996a). Aumento and Loncarevic (1969) reported that 75% of 84 rock samples dredged from the Bald Mountain region just west of the Mid-Atlantic Ridge crest at 45°N consisted of continental-type rocks, and commented that this was a "remarkable phenomenon" – so remarkable, in fact, that they decided to classify these rocks as "glacial erratics" and to give them no further consideration. Another way of dealing with "anomalous" rock finds is to dismiss them as ship ballast. However, the Bald Mountain locality has an estimated volume of 80 km³, so it is hardly likely to have been rafted out to sea on an iceberg or dumped by a ship! It consists of granitic and silicic metamorphic rocks ranging in age from 1690 to 1550 million years, and is intruded by 785-million-year mafic rocks (Wanless et al., 1968). Ozima et al. (1976) found basalts of Middle Jurassic age (169 million years) at the junction of the rift valley of the Mid-Atlantic Ridge and the Atlantis fracture zone (30°N), an area where basalt should theoretically be extremely young, and stated that they were unlikely to be ice-rafted rocks. Van Hinte and Ruffman (1995) concluded that Paleozoic limestones dredged from Orphan Knoll in the northwest Atlantic were in situ and not ice rafted...
Washington, DC - Sediment cores retrieved from the Arctic's deep-sea floor by the Integrated Ocean Drilling Program's Arctic Coring Expedition (ACEX) have provided long-absent data to scientists who report new findings in the June 21 issue of Nature.
A team of ACEX researchers report that the Arctic Ocean changed from a landlocked body of water (a 'lake stage') through a poorly oxygenated 'estuarine sea' phase to a fully oxygenated ocean at 17.5 million years ago during the latter part of the early Miocene era. The authors attribute the change in Arctic conditions to the evolution of the Fram Strait into a wider, deeper passageway that allowed an inflow of saline North Atlantic water into the Arctic Ocean. Scientists believe that the deep-water connection between the northern Atlantic and Arctic Oceans is a key driver of global ocean circulation patterns...
