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• 1. [Article] Hotspots, mantle plumes, flood basalts, and true polar wander

  copyrighted by American Geophysical Union

  Citation × Citation Citation Abstract Copy Title: Hotspots, mantle plumes, flood basalts, and true polar wander Author: Duncan, Robert A., Richards, M. A. copyrighted by American Geophysical Union Title: Hotspots, mantle plumes, flood basalts, and true polar wander Author: Duncan, Robert A., Richards, M. A. copyrighted by American Geophysical Union Close

• 2. [Article] The timing and duration of the Karoo igneous event, southern Gondwana

  A volcanic event of immense scale occurred within a relatively short period in early Jurassic time over large regions of the contiguous Gondwana supercontinent. In southern Africa, associated remnants ...

  Citation × Citation Citation Abstract Copy Title: The timing and duration of the Karoo igneous event, southern Gondwana Author: Duncan, A.R., Duncan, Robert A., Marsh, J.S., Hooper, P.R., Rehacek, J. A volcanic event of immense scale occurred within a relatively short period in early Jurassic time over large regions of the contiguous Gondwana supercontinent. In southern Africa, associated remnants of thick volcanic successions of lava flows and extensive dike and sill complexes of similar composition have been grouped together as the Karoo Igneous Province. Correlative volcanic and plutonic rocks occur in Antarctica and Australia as the Ferrar Province. Thirty-two new Ar-40/Ar-39 incremental heating experiments on feldspars and whole rocks from Namibia, South Africa and East Antarctica produce highly resolved ages with a vast majority at 183 +/- 1 Ma and a total range of 184 to 179 Ma. These are indistinguishable from recent, high-resolution Ar-40/Ar-39 and U-Pb age determinations reported from the Antarctic portion of the province. Initial Karoo volcanism (Lesotho-type compositions) occurred across the entire South African craton. The ubiquitous distribution of a plexus of generally nonoriented feeder dikes and sills intruding Precambrian crystalline rocks and Phanerozoic sediments indicates that these magmas penetrated the craton over a broad region. Lithosphere thinning of the continent followed the main pulse of igneous activity, with volcanism focused in the Lebombo-Nuanetsi region, near the eventual split between Africa and Antarctica. Seafloor spreading and dispersion of east and west Gondwana followed some 10-20 m.y. afterward. The volume of the combined Karoo-Ferrar province (similar to 2.5 x 10(6) km(3)) makes it one of the largest continental flood basalt events. The timing of this event correlates with a moderate mass extinction (Toarcian-Aalenian), affecting largely marine invertebrates. This extinction event was not as severe as those recorded at the Permian-Triassic or Cretaceous-Tertiary boundaries associated with the Siberian and Deccan flood basalts events, respectively. The difference may be due to the high southerly latitude and somewhat lower eruption rates of the Karoo event. Title: The timing and duration of the Karoo igneous event, southern Gondwana Author: Duncan, A.R., Duncan, Robert A., Marsh, J.S., Hooper, P.R., Rehacek, J. A volcanic event of immense scale occurred within a relatively short period in early Jurassic time over large regions of the contiguous Gondwana supercontinent. In southern Africa, associated remnants of thick volcanic successions of lava flows and extensive dike and sill complexes of similar composition have been grouped together as the Karoo Igneous Province. Correlative volcanic and plutonic rocks occur in Antarctica and Australia as the Ferrar Province. Thirty-two new Ar-40/Ar-39 incremental heating experiments on feldspars and whole rocks from Namibia, South Africa and East Antarctica produce highly resolved ages with a vast majority at 183 +/- 1 Ma and a total range of 184 to 179 Ma. These are indistinguishable from recent, high-resolution Ar-40/Ar-39 and U-Pb age determinations reported from the Antarctic portion of the province. Initial Karoo volcanism (Lesotho-type compositions) occurred across the entire South African craton. The ubiquitous distribution of a plexus of generally nonoriented feeder dikes and sills intruding Precambrian crystalline rocks and Phanerozoic sediments indicates that these magmas penetrated the craton over a broad region. Lithosphere thinning of the continent followed the main pulse of igneous activity, with volcanism focused in the Lebombo-Nuanetsi region, near the eventual split between Africa and Antarctica. Seafloor spreading and dispersion of east and west Gondwana followed some 10-20 m.y. afterward. The volume of the combined Karoo-Ferrar province (similar to 2.5 x 10(6) km(3)) makes it one of the largest continental flood basalt events. The timing of this event correlates with a moderate mass extinction (Toarcian-Aalenian), affecting largely marine invertebrates. This extinction event was not as severe as those recorded at the Permian-Triassic or Cretaceous-Tertiary boundaries associated with the Siberian and Deccan flood basalts events, respectively. The difference may be due to the high southerly latitude and somewhat lower eruption rates of the Karoo event. Close

• 3. [Article] Post-K/PB younger ⁴⁰Ar–³⁹Ar ages of the Mandla lavas: Implications for the duration of the Deccan volcanism

  This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Elsevier and can be found at: http://www.journals.elsevier.com/lithos/

  Citation × Citation Citation Abstract Copy Title: Post-K/PB younger ⁴⁰Ar–³⁹Ar ages of the Mandla lavas: Implications for the duration of the Deccan volcanism Author: Shrivastava, J. P., Duncan, Robert A., Kashyap, Mamta This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Elsevier and can be found at: http://www.journals.elsevier.com/lithos/ Title: Post-K/PB younger ⁴⁰Ar–³⁹Ar ages of the Mandla lavas: Implications for the duration of the Deccan volcanism Author: Shrivastava, J. P., Duncan, Robert A., Kashyap, Mamta This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Elsevier and can be found at: http://www.journals.elsevier.com/lithos/ Close

• 4. [Article] Evolution of the Walvis Ridge-Rio Grande rise hot spot systen : implications for African and South American plate motions over plumes

  copyrighted by American Geophysical Union

  Citation × Citation Citation Abstract Copy Title: Evolution of the Walvis Ridge-Rio Grande rise hot spot systen : implications for African and South American plate motions over plumes Author: O'Connor, John M., Duncan, Robert A. copyrighted by American Geophysical Union Title: Evolution of the Walvis Ridge-Rio Grande rise hot spot systen : implications for African and South American plate motions over plumes Author: O'Connor, John M., Duncan, Robert A. copyrighted by American Geophysical Union Close

• 5. [Article] Geochronology of age-progressive volcanism of the Oregon High Lava Plains : implications for the plume interpretation of Yellowstone

  copyrighted by American Geophysical Union

  Citation × Citation Citation Abstract Copy Title: Geochronology of age-progressive volcanism of the Oregon High Lava Plains : implications for the plume interpretation of Yellowstone Author: Deino, Alan L., Grunder, Anita L., Duncan, Robert A., Jordan, Brennan T. copyrighted by American Geophysical Union Title: Geochronology of age-progressive volcanism of the Oregon High Lava Plains : implications for the plume interpretation of Yellowstone Author: Deino, Alan L., Grunder, Anita L., Duncan, Robert A., Jordan, Brennan T. copyrighted by American Geophysical Union Close

• 6. [Article] Asthenosphere–lithosphere interactions in Western Saudi Arabia: Inferences from ³He/⁴He in xenoliths and lava flows from Harrat Hutaymah

  To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Elsevier ...

  Citation × Citation Citation Abstract Copy Title: Asthenosphere–lithosphere interactions in Western Saudi Arabia: Inferences from ³He/⁴He in xenoliths and lava flows from Harrat Hutaymah Author: Kent, Adam J.R., Konrad, Kevin, Duncan, Robert A., Thornber, Carl R., Graham, David W., Al-Amri, Abdullah M. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Elsevier and can be found at: http://www.journals.elsevier.com/lithos/ Title: Asthenosphere–lithosphere interactions in Western Saudi Arabia: Inferences from ³He/⁴He in xenoliths and lava flows from Harrat Hutaymah Author: Kent, Adam J.R., Konrad, Kevin, Duncan, Robert A., Thornber, Carl R., Graham, David W., Al-Amri, Abdullah M. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Elsevier and can be found at: http://www.journals.elsevier.com/lithos/ Close