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associated with the development of a major enlargement of the East Antarctic ice sheet in the middleMiocene and an intensification of vertical and horizontal thermal gradients (SHACKLETON andKENNElT, 1975; SAVIN, 1977). After this sharp drop, the temperatures stabilized for a while, butthey entered a period of greater climatic fluctuations in the late Neogene and Quaternary.The middle Miocene and younger circulation patterns look like their present day counterparts(Fig. 11). By middle Miocene the eastern limb of the Tethys was closed, but temporary connectionsmay have been established during periods of high seastands, e.g. in the early middle Miocene. TheIndo-Mediterranean link was-finally severed in the late Miocene (around 12-11 Ma), following aworldwide sea-level drop (ROGL and STEININGER, 1983). Early Pliocene patterns (Fig. 12) areessentially similar to the modern circulation patterns, with the exception of a open Central Americanpassage, which finally closed around 3 m.y. ago, leading to the present hydrographic patterns ofcentral Atlantic and Pacific regions.CONCLUDING REMARKSThe preceding discussion is only a very brief overview of the dynamic history of Indian Oceansince its genesis after the fragmentation of Gondwanaland. Aligned along its continental margins arevast old and new sedimentary basins that potentially could contain extensive hydrocarbon and mineralresources. Any meaningful exploitation of these resources requires that the details of the geologichistory of these margins must be deciphered. Unfortunately, marine geological/ geophysical researchis expensive and requires specialized personnel. Such undertakings are often beyond the reach ofindividual coastal states, which underscores the need for regional cooperation and sharing of researchresources, facilities and personnel. Both national and international scientific agencies need to fostersuch cooperation and promote research to help fullfil the national and regional aspirations for resourceself-sufficiency.ACKNOWLEDGEMENTSThe author is grateful to many colleagues for stimulating discussions about the history of theIndian Ocean, in particular to Ian Norton and John Sclater. Ian Norton also reviewed the manuscriptand provided the basemaps for the paleoceanographic/circulation reconstructions. The author is alsograteful to EPRCO for permission to publish this paper.REFERENCESBARRON, E.J. et al. (1981). Paleogeography, 180 millionHelv., 74, 443-470.years ago to present. Eclogae Geol.BARRON, E.J. and WASHINGTON, W.M. (1982). Cretaceous climate: a comparison ofatmospheric simulations and the geologic record. Paleogeogr., Paleoclimat., Paleoecol., 40,103-133.BENSON, R.H. (1975). The origin of the psychrosphere as recorded in changes of deep-seaostracode assemblages. Lethaia, 8,69-83.BRASS, G.W. et al. (1980). Ocean circulation, plate tectonics and climates. In: W. Berger and J.Crowell (eds.), Climates in Earth History. National Acad. Sci., p. 83-89.BRITISH ANTARCTIC SURVEY (1985). Tectonic map of Scotia Arc. Cambridge, Brit. Antarct.Surv. 1 map.64