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Discovery of Early Cretaceous rocks in New Caledonia; new geochemical and U-Pb zircon age constraints on the transition from subduction to marginal breakup in the Southwest Pacific
- Source :
- Journal of Geology, Journal of Geology, University of Chicago Press, 2010, 118 (4), pp.381-397
- Publication Year :
- 2010
- Publisher :
- HAL CCSD, 2010.
-
Abstract
- International audience; New U-Pb dating of detrital zircon and geochemical features of Permian-Mesozoic arc-derived volcanic rocks and volcaniclastic turbidites (greywackes), when compared to the volcanic rocks associated with unconformable Late Cretaceous shallow-water sediments, reveal that subduction in New Caledonia, once thought to be extinct in the Late Jurassic (ca. 150 Ma), was still active at least from ca. 130 Ma to 95 Ma. The accumulation of volcanic arc-derived sediments during the late Early Cretaceous suggests that, as in New Zealand, active margin activity went on for a short time in spite of the assumed subduction jamming by the Hikurangi plateau at ca.100 Ma. Meanwhile, the rift-related magmatic activity that preceded the marginal breakup migrated eastward: from ca. 130 Ma (130-95 Ma) in eastern Australia, 110 Ma (110-82 Ma) in New Zealand, and finally ca. 89 Ma (89-83 Ma) in New Caledonia, and generated large volumes of silicic magma. In contrast, marginal basins opened synchronously at ca. 83 Ma when the stretched continental crust finally broke out. In general, intraplate and volcanic-arc signatures coexisted in Cretaceous syn-rift magmas. Therefore, the Australian marginal breakup appears to be the final effect of continuous southward unzipping of Gondwana that interfered with the subduction-modified mantle wedge of the Mesozoic active margin. The occurrence of lateral flow of the upper asthenospheric mantle due to the rapidly eastward migrating Australian plate margin possibly prevented the formation of a volcanic arc at the eastern end of the system.
- Subjects :
- U-Pb geochronology
010504 meteorology & atmospheric sciences
[SDE.MCG]Environmental Sciences/Global Changes
greywacke
Pyroclastic rock
Silicic
010502 geochemistry & geophysics
01 natural sciences
Paleontology
active margin
New Caledonia
marginal basin
detrital zircon
14. Life underwater
0105 earth and related environmental sciences
geochemistry
[SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics
geography
geography.geographical_feature_category
Gondwana
Subduction
Australia
Geology
15. Life on land
Cretaceous
Volcanic rock
volcaniclastic turbidite
Magma
Zircon
New Zealand
Mesozoic
Subjects
Details
- Language :
- English
- ISSN :
- 00221376 and 15375269
- Database :
- OpenAIRE
- Journal :
- Journal of Geology, Journal of Geology, University of Chicago Press, 2010, 118 (4), pp.381-397
- Accession number :
- edsair.doi.dedup.....6c3bd6535fc2256dd644d7a2c3d50df4