Railsback's Some Fundamentals of Mineralogy and Geochemistry Straits II: connections of the major ocean basins 100 500 1000 5000 10,000 10,000 10,000 The Bab-al-Mandeb Southern Ocean straits connecting the Red Sea Atlantic-Indian to the Indian Ocean is 5000 not appropriate to this Pacific-Atlantic 5000 plot but, as a strait over (Drake Passage) an incipient mid-ocean Indian-Pacific ridge, it illustrates how a lesser strait over a Atlantic-Arctic divergent plate boundary can through time Connections migrate across this “Connectivity gap” in the seemingly plot to join the group Pacific-Indian: connections between the most critical to at upper right. oceans (Arctic, Atlantic, 1000 Palau Atauro – Alor strait, deep ocean 1000 Indian, Pacific, Southern). circulation north of Timor The passages to the upper right are huge in both width and depth, and mature mid-ocean 500 500 ridges pass through them. They Time are thus the major conduits of ocean Pacific-Indian: Sape Strait circulation. The straits to the left are Sea level during (Sumbawa-Kimodo) considerably smaller, have other Pleisto- tectonic origins, and are much less cene Pacific-Indian: Lombok Strait significant to global-scale ocean circu- glacial (Bali-Lombok) lation. The bottom two are so shallow maxima that they limit commercial shipping: Pacific-Arctic: “Malaccamax” is the technical term Depthstrait (m) of 100 100 Bering Strait for the maximum size of ship that (Siberia-Alaska) can pass through the Strait of Malacca (which is a critical strait 50 Innumerable small straits for global shipping), and the 50 between islands of the Torres Strait is useless for Indonesian archipelago, Pacific-Indian: and elsewhere, would Strait of Malacca major shipping. plot in this region. (Sumatra-Malaysia) Pacific-Indian: Torres Strait (Australia – Papua New Guinea) 10 10 0.5 1.0 5 10 50 100 500 1000 5000 10,000 Width of strait or channel (km) LBR SFMGStraitsPartII01.odg 5/2014.