Initial Reports Volume 186 Chapter 4, Table T8. Stratigraphic occurrences and chronology of datum levels of diatoms, Site 1150. Note: LO = last occurrence, LCO = last common occurrence, FO = first occurrence, NPD = North Pacific diatom zones. Upper sample Lower sample Datum event Zone Age (Ma) Core, section, interval (cm) Depth (mbsf) Core, section, interval (cm) Depth (mbsf) (base) 186-1150A- 186-1150A- LO Proboscia curvirostris NPD 12 0.3 6H-CC 55.73 7H-4, 65-69 60.35 LCO Actinocyclus oculatus NPD 11 1.01-1.46 11H-CC 102.66 12H-1, 140-144 104.10 LO Neodenticula koizumii NPD 10 2 14H-3, 70-72 120.10 14H-5, 71-73 123.11 LCO Neodenticula kamtschatica NPD 9 2.61-2.68 21X-CC 192.01 22X-3, 140-144 197.70 FO N. koizumii NPD 8 3.53-3.95 28X-CC 260.33 29X-3, 63-67" 264.43 FO Thalassiosira latimarginata 5.07 45X-CC 424.33 46X-CC 428.83 FO Thalassiosira oestrupii sensu lato NPD 7Bb 5.49 56X-CC 527.49 57X-1, 70-74 531.30 186-1150B- 186-1150B- LCO Rouxia californica NPD 7Ba 6.65 20R-CC 893.02 21R-3, 70-72 896.44 LO Cavitatus jouseanus 6.7-6.8 23R-CC 919.73 24R-CC 923.46 FO N. kamtschatica 7.3-7.4 28R-CC 968.83 29R-3, 75-78 972.88 LO Thalassionema schraderi NPD 7A 7.6 31R-CC 992.31 32R-1, 60-63 998.90 LO Denticulopsis katayamae 8.5 39R-CC 1070.80 40R-CC 1079.21 LCO Denticulopsis simonsenii NPD 6B 8.6 40R-CC 1079.21 41R-1, 68-71 1085.98 LO Denticulopsis dimorpha NPD 6A 9.16 43R-1, 69-71 1105.29 43R-3, 71-72 1108.26 FO D. katayamae 9.26 45R-CC 1129.85 46R-CC 1138.94 FO T. schraderi 9.5 46R-CC 1138.94 47R-CC 1147.36 FO D. dimorpha NPD 5D 9.9 50R-CC 1180.23