Browsing by Author "Katsui, Yoshio"
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Item Contribución al conocimiento geológico de la península Byers de la isla Livingston; islas Shetland del sur, Antártica(1970) Gonzalez-Ferran, Oscar; Katsui, Yoshio; Tavera, JuanThe first finding of ammonite fossil remains, in epiclastic and pyroclastic beds of the southwestern end of the Byers Peninsula, Livingston Island, South Shetland Islands Group, Antarctica, is reported, and the structural geology and petrology of the area is briefly described. The species present, Spiticeras (Spiticeras) ef, spitiensis Blandford and Blandfordiceras (Pseudoblandfordiceras) patagorniensis (Favre) Feruglio, indicate upper Titonian to Neocomian. Lava flows are intercalated in the upper levels of the formation, which is also cut by dikes, sills, and conoliths of diorite and basaltic andesite. Six new chemical analyses of the igneous rocks are given.Item Estudio integral del volcanismo cenozoico superior de las Islas Shetland del Sur, Antártica(1970) Gonzalez-Ferran, Oscar; Katsui, YoshioPresent paper discusses the petrographic characteristics and distribution of the volcanic rocks of the late Cenozoic in the South Shetland Islands Antarctica. The geology of the Copper Mine Peninsula, Robert Island, Potter in King George Island, Bridgeman, Penguin and Deception Islands is described, recognizing a displacement of the volcanic activity approximately from north to south. The evolution of the volcanic Pleistocene-recent centers associated with tectonic depression of the Bransfield Strait is analized. Recent eruptions in Deception Island are also discussed. Petrographic and chemical analises permit to conclude that the volcanic rocks of the South Shetland Islands, of Miocene to Recent age, are probably derived mainly from a basaltic-aluminous magma rich in soda. Its Peacok alkali-calcium index is 56.5, defining the calc-alkaline character of this volcanic Series in the South Shetland Islands.