Fig. 4: Cross plots of Pb isotopic data.
From: Brief and intensive volcanic emissions from Ontong Java Nui heralded Oceanic Anoxic Event 1a
a 206Pb/204Pbi–207Pb/204Pbi, b 206Pb/204Pbi–208Pb/204Pbi, and c 207Pb/206Pbi–208Pb/206Pbi from DSDP Site 463 (this study), superposed on data fields of continental dust21,22, Shatsky Rise79,80, Hikurangi Plateau (HP)34, Kroenke (kr) type basalt of Ontong Java Plateau (OJP)81, Kwaimbaita (kw) type basalt of OJP81, Singgalo (sg) type basalt of OJP33,81, OJP eastern margin82, Lyra83, and Manihiki Plateau (MP)29,34,35,84,85. Because it is difficult to determine the Pb isotopic values of Cretaceous continental dust, we showed those modern Asian dust and potential South American dust source21,22 for reference. Pb isotopic ratios of Pacific Mid-Ocean Ridge Basalt (MORB) are based on ref. 86. The Pb isotopic data of dust have been corrected to 120 Ma by using U/Pb = 0.1315 and Th/Pb = 0.586187. The dashed lines in a and b represent mixing lines between average Pb isotopic compositions of sg-type OJP basalt and those of silicate fractions of pre-CIE sedimentary rocks from DSDP Site 463. See Figs. 2 and 3 for the data classification with respect to CIE.
