ALBERT

Description: Author Posting. © Oceanography Society, 2019. This article is posted here by permission of Oceanography Society for personal use, not for redistribution. The definitive version was published in Neal, C.R., M.F. Coffin, and W.W. Sager. Contributions of scientific ocean drilling to understanding the emplacement of submarine large igneous provinces and their effects on the environment. Oceanography 32(1), (2019):176–192, doi:10.5670/oceanog.2019.142.

Description: The Ontong Java Plateau (OJP), Shatsky Rise (SR), and Kerguelen Plateau/Broken Ridge (KP/BR) represent three large igneous provinces (LIPs) located in oceanic settings. The basement lavas have been investigated through scientific ocean drilling and, in the case of the OJP, fieldwork on the emergent obducted portions of the plateau in the Solomon Islands. Such studies show that these three LIPs have very different characteristics. For example, the KP/BR still has an active hotspot, whereas the OJP and the SR do not. The OJP is remarkable in its compositional monotony across the plateau (the Kwaimbaita geochemical type), with minor compositional variation found at the margins (the Kroenke, Singgalo, and Wairahito types). Shatsky Rise shows more compositional variation and, like the OJP, has a dominant lava type (termed the “normal” type) in the early stages (Tamu Massif), but subsequent eruptions at the Ori and Shirshov massifs comprise isotopically and trace element enriched lavas, likely reflecting a change in mantle source over time. The KP/BR has highly variable basement lava compositions, ranging from lavas slightly enriched above that of normal mid-ocean ridge basalt in the northern portion (close to the South East Indian Ridge) to more enriched varieties to the south and on Broken Ridge, with a continental crust signature present in lavas from the southern and central KP/BR. The OJP and the KP/BR appear to have formed through punctuated magmatic events, whereas the SR was formed by one relatively long, drawn out event. The formation of oceanic LIPs has in many (but not all) cases been synchronous with oceanic anoxic events. This paper focuses on three oceanic plateaus to emphasize the debate surrounding the environmental impact such LIPs may have had, and also highlights the contributions of scientific ocean drilling to our knowledge of oceanic LIP formation and evolution. This new knowledge allows planning for future oceanic LIP drilling.

Description: Many thanks to the crew and operators of the scientific ocean drilling vessel JOIDES Resolution without whom the understanding of oceanic flood basalts would be severely limited. We also thank the US National Science Foundation for continued support of scientific ocean drilling. We are indebted to Jörg Geldmacher, Paul Wallace, Carlotta Escutia, and Anthony Koppers for reviews of this paper that were insightful and extremely helpful in making it much better than the initial submission.