Manihiki Plateau, southwestern Pacific: Archive of multi-phase magmatism, anoxic environment and modifications in ocean circulation and climate


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Gabriele.Uenzelmann-Neben [ at ] awi.de

Abstract

The Cretaceous was characterised by a dramatic increase in ocean crust production and abnormal intraplate volcanism. Many Large Igneous Provinces (LIPs) were formed during this period. The south western Pacific is dominated by three LIPs: the Ontong-Java Plateau (> 1.5 106 km2), the Manihiki Plateau (~0.8 106 km2), and the Hikurangi Plateau (0.35 106 km2). The formation of LIPs in the equatorial western Pacific is still a matter of debate. For example, are they the product of a single “mega (Greater Ontong Java)” or of multiple, smaller volcanic events? Another important question is the time interval over which this volcanism took place: within a few million years or over tens of millions of years? This has implications for our understanding of mantle processes and climate variability. During the eruption of such huge amounts of magma large quantities of CO2 are emitted into the ocean-atmosphere system. LIPs are thus considered to have been responsible for global environmental modifications and ecosystem adaptations. We propose to drill on Manihiki Plateau to recover a complete sedimentary and the upper (1-2 km) basement volcanic rock sequences. The sediments preserved on this plateau record an 120 My-long history of extreme climates , global anoxia, perturbation of geochemical cycles and major changes in marine biota. The overall goal is a quantitative characterisation and understanding of biogeochemical cycles and marine ecosystem reactions to environmental and climate changes at the onset, during and after major greenhouse episodes. We want to determine the spatial and temporal variability of the lysocline carbonate compensation depth (CCD), oxygen minimum zone (OMZ), and primary productivity during the .Cretaceous. The proximity of Manihiki to Ontong Java Plateau and the Galapagos hotspots offers the opportunity to investigate reactions of the ocean/atmosphere system, as well as geochemical fluxes in an area close to emplacement of LIPs.



Item Type
Conference (Invited talk)
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Primary Division
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Not peer-reviewed
Publication Status
Published
Event Details
IODP Cretaceous Climate workshop, 15 Apr 2013 - 17 Apr 2013, London, UK.
Eprint ID
32708
Cite as
Uenzelmann-Neben, G. , Erba, E. , Duncan, R. , Hoernle, K. , Werner, R. , Gohl, K. , Hauff, F. , Nuernberg, D. and Geldmacher, J. (2013): Manihiki Plateau, southwestern Pacific: Archive of multi-phase magmatism, anoxic environment and modifications in ocean circulation and climate , IODP Cretaceous Climate workshop, London, UK, 15 April 2013 - 17 April 2013 .


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