115 research outputs found
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
Origin of pyroxenite component in the source of the Canary shield stage magmas constrained from olivine phenocryst -radiogenic isotope relationships
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