Publications by authors named "A A P Koppers"
Volcanic hotspots are thought to form by melting in an upwelling mantle plume head followed by melting of the plume tail. Plate motion then generates an age-progressive volcanic track originating from a large igneous province to a currently active hotspot. The most voluminous large igneous province, the approximately 120-million-year-old Ontong Java Nui Plateau (OJP-Nui) in the mid-Pacific, however, lacks an obvious volcanic track.
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- The subseafloor igneous basement contains a vast microbial habitat, but little is known about the life that exists there, especially in older sections over 65 million years old.
- Recent research tested this by analyzing samples from the Louisville Seamount Chain, finding varied cell biomass indicating the presence of microbial life in rocks older than 65 million years.
- The dominant bacterial genes found suggest active microbial processes related to nitrogen, sulfur, metal transformations, and hydrocarbon breakdown, highlighting a much broader range of subseafloor life than previously recognized.
The Easter mantle plume has produced one of the longest hotspot tracks in the Pacific Ocean. While previous studies have focused on the eastern side extending across the Nazca Plate, we use Ar/Ar isotopic and geochemical data to investigate the less explored western side around the Easter Microplate. We propose a dynamic model in which a deeper (600 km-depth), less buoyant mantle exerts a westward force on the East Pacific Rise (EPR), while a more buoyant plume region drives Easter hotspot volcanism and a localised acceleration in seafloor spreading.
View Article and Find Full Text PDFThe effects of the composition and angle of the subducting slab and mantle wedge flow on tectonic and magmatic processes in island arcs and associated back-arcs are poorly understood. Here we analyse the ages and compositions of submarine lavas from the flanks and the floor of the back-arc Futuna Trough some 50 km east of Tanna Island in the New Hebrides arc front. Whereas >2.
View Article and Find Full Text PDFThe submarine volcanic emplacement of the Ontong Java Plateau (OJP) is the suggested cause of Ocean Anoxic Event 1a (OAE 1a). However, no precise timing and duration exists for the formation of OJP, and its connection to OAE1a relies mainly on proxies in the sedimentary record. We provide high-precision Ar/Ar data from OJP drill and dredge sites that considerably improve OJP's eruptive history.
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