6. Wochenbericht SO208/2

SO208 Leg 2 PLUMEFLUX Wochenbericht Nr. 6 (19.08. – 25.08.2010

4. Wochenbericht SO208/2

SO208 Leg 2 PLUMEFLUX Wochenbericht Nr. 4 (05.08. – 11.08.2010

3. Wochenbericht M81/2A

FS Meteor Fahrtabschnitt M81/2A (Port of Spain, Trinidad & Tobago – Willemstad, Curaçao) 3. Wochenbericht 22.03.10-29.03.1

3. Wochenbericht SO199/1

Die F.S. Sonne-Expedition SO199 CHRISP (Merak Port/Indonesien - Singapur) findet vom 02.08. bis zum 22.09.2008 unter der Fahrtleitung von Prof. Kaj Hoernle (1. Fahrtabschnitt) und Dr. Reinhard Werner (2. Fahrtabschnitt) statt

2. Wochenbericht SO199/1

Die F.S. Sonne-Expedition SO199 CHRISP (Merak Port/Indonesien - Singapur) findet vom 02.08. bis zum 22.09.2008 unter der Fahrtleitung von Prof. Kaj Hoernle (1. Fahrtabschnitt) und Dr. Reinhard Werner (2. Fahrtabschnitt) statt

1. Wochenbericht M81/2A

FS Meteor Fahrtabschnitt M81/2A (Port of Spain, Trinidad & Tobago – Willemstad, Curaçao) 1. Wochenbericht 8.03.10-14.03.1

2. Wochenbericht M81/2A

FS Meteor Fahrtabschnitt M81/2A (Port of Spain, Trinidad & Tobago – Willemstad, Curaçao) 2. Wochenbericht 15.03.10-21.03.1

The Christmas Island Seamount Province, Indian Ocean: Origin of Intraplate Volcanism by Shallow Recycling of Continental Lithosphere?

The east-west-trending Christmas Island Seamount Province (CHRISP, 1800x600 km) in the northeastern Indian Ocean is elongated orthogonal to present-day plate motion, posing the question if a mantle plume formed this volcanic belt. Here we report the first age (Ar/Ar) and geochemical (Sr- Nd-Hf-Pb DS isotopic data) from the CHRISP seamount chain. A crude E-W age decrease from the Argo Basin (136 Ma), to the Eastern Wharton Basin (115-94 Ma) to the Vening-Meinesz seamounts (96-64 Ma) to the Cocos-Keeling seamounts (56-47 Ma) suggests spatial migration of melting. Christmas Island, however, yields much younger ages (44-4 Ma), inconsistent with an age progression. The isotopic compositions (e.g. 206Pb/204Pb = 17.3-19.3; 207Pb/204Pb = 15.49- 15.67; 143Nd/144Nd = 0.51220-0.51295; 176Hf/177Hf = 0.28246- 0.28319) range from enriched MORB (or “C”) to very enriched mantle (EM1) type compositions more typical of continental than oceanic volcanism. Lamproitic and kimberlitic rocks from western Australia, India and other continental areas, derived from metasomatized subcontinental lithospheric mantle, could serve as the EM1 type endmembers. The morphology, ages and chemical composition of the CHRISP, combined with plate tectonic reconstructions, cannot be easily explained within the framework of the mantle plume hypotheses. We therefore propose that the seamounts are derived through the recycling of continental lithosphere (mantle ± lower crust) delaminated during the breakup of Gondwana and brought to the surface at the former spreading centers separating Argoland (western Burma), Greater India and Australia