Table T4. Age assignments of biostratigraphic diatom zones used during Leg 181. 				
Zone	Reference	Top (Ma)	Base (Ma)	Datum used to define base
Neogene				
  Thalassiosira lentiginosa Subzone c	1	0	0.18	
  Thalassiosira lentiginosa Subzone b	1	0.18	0.42	
  Thalassiosira lentiginosa Subzone a	1	0.42	0.65	F. reinholdii  LO
  Actinocyclus ingens Subzone c	1	0.65	1.07	
  Actinocyclus ingens Subzone b	1	1.07	1.3	
  Actinocyclus ingens Subzone a	1	1.3	1.8	"P. barboi   LO,  ? T. elliptipora"
  Proboscia barboi	1	1.77	2	T. kolbei   LO
  Thalassiosira kolbei/Fragilariopsis matuyamae	1	2	2.5	"T. vulnifica   LO,   ? F. matuyamae"
  Thalassiosira vulnifica	1	2.5	3	"F. interfrigidaria   LO,   T. insigna  LO"
  Thalassiosira insigna  	2	2.63	3.26	T. vulnifica   FO
  Fragilariopsis interfrigidaria	2	3.26	3.8	F. interfrigidaria   FO
  Fragilariopsis barronii	2	8	4.44	"F. barronii   FO,  T. complicata  FO"
  Thalassiosira inura	2	4.44	4.92	T. inura   FO
  Thalassiosira oestrupii	2	4.92	0.56	T. oestrupii   FO			
  Fragilariopsis reinholdii  	2	5.56	8.1	F. reinholdii  FO			
  Actinocyclus ingens var. ovalis	2	8.1	8.68	"C. intersectus   FO,  A. ingens var. ovalis  FO"			
  Thalassiosira torokina	2	8.68	9.01	T. torokina   FO			
  Asteromphalus kennettii	2	9.01	10.23	T. kennettii   FO			
  Denticulopsis hustedtii	2	10.23	10.63	D. dimorpha  LO			
  Denticulopsis dimorpha	2	10.63	11.67	N. denticuloides  LO			 
  Denticulopsis dimorpha/Nitzschia denticuloides	2	11.67	12.2	D. dimorpha  FO			
  Denticulopsis praedimorpha	2	12.2	12.84	D. praedimorpha  FO			
  Nitzschia denticuloides	2	12.84	13.51	"N. grossepunctata  LO, N. denticuloides  FO"			
  Denticulopsis hustedtii/Nitzschia grossepunctata	2	13.51	14.17	D. hustedtii  FO			
  Actinocyclus ingens var. nodus	2	14.17	14.38	A. ingens var. nodus  FO		 	
  Nitzschia grossepunctata	2	14.38	15.38	N. grossepunctata  FO			
  A. ingens/D. maccollumii	2	15.38	16.2	A. ingens   FO			
  Denticulopsis maccollumii	2	16.2	16.75	D. maccollumii  FO			
  Crucidenticula kanayae	2	16.75	17.72	C. kanayae   FO			
  Thalassiosira fraga	2	17.72	20.79	T. fraga   FO
  Thalassiosira spumellaroides	2	20.79	22.58	T. spumellaroides   FO
Oligocene	2			
  Rocella gelida	2	22.58	26.5	R. gelida   FO
  Lisitzinia ornata	2	26.5	27.95	L. ornata   FO
  Azpeitia gombosii	2	27.95	28.35	A. gombosii   FO
  Rocella vigilans	2	28.35	30.24	R. vigilans (small form)   FO
  Cavitatus jouseanus	2	30.24	30.62	C. jouseanus   FO
  Rhizosolenia gravida/oligocaenica	2	30.62	33.22	R. oligocaenica   FO
Notes: Asterisks mark revised zones. 				
"References: 1 = Gersonde and Barcena (in press), 2 = Gersonde et al. (in press)."