Siliceous Microfossil Abundance in IODP Expedition 342 Sediments1 Christopher J

Norris, R.D., Wilson, P.A., Blum, P., and the Expedition 342 Scientists Proceedings of the Integrated Ocean Drilling Program, Volume 342

Data report: siliceous microfossil abundance in IODP Expedition 342 sediments1 Christopher J. Hollis2

Chapter contents Abstract

Abstract ...... 1 Siliceous microfossils exhibit an interesting pattern of occurrence in Integrated Ocean Drilling Program Expedition 342 sediments. Introduction ...... 1 A review of shipboard data from smear slides and microfossil pro- Methods and materials ...... 2 cessing notes was combined with shore-based investigations to Results ...... 2 provide a revised summary of this occurrence pattern. A review of Discussion ...... 4 radiolarian biostratigraphy was also undertaken for all sites. In Acknowledgments...... 5 general, siliceous microfossils (diatoms and radiolarians) are References ...... 5 abundant and well preserved in lower Miocene and upper Oligo- Figures ...... 7 cene drift sediments on the J-Anomaly Ridge (Sites U1404, U1405, Tables...... 16 and U1406) but are otherwise rare in Neogene to upper Eocene sediments from all sites. Siliceous microfossils (mainly radiolarians) are also abundant in middle Eocene to upper lower Eo- cene sediments at several sites, tending to be more persistent in the deeper J-Anomaly Ridge sites (U1403 and U1404) than in the shallower sites (U1406 and U1407) and all southeast Newfound- land ridge sites (U1408, U1409, and U1410). No siliceous microfossils were encountered at Site U1411. Sediments are chert rich through the Paleocene–Eocene transition at Sites U1403 and U1407, and as a consequence siliceous microfossils are frequently abundant but always poorly preserved. Well-preserved radiolarians occur in the upper and middle Paleocene at Sites U1403 and U1406–U1409. Hopefully, this record of siliceous microfossil abundance will be helpful in ongoing studies of biosiliceous sedimentation.

Introduction A robust record of the regional variation in biogenic sediment accumulation rates is needed to understand how climatic and oce- anic changes through the Cenozoic may have affected biological productivity and export processes and to better resolve the rela- tionships between climate change and the global carbon cycle. 1Hollis, C.J., 2017. Data report: siliceous microfossil Biogenic opal is a widely used proxy for primary production (e.g., abundance in IODP Expedition 342 sediments. In Moore et al., 2008) but is often hard to reliably distinguish from Norris, R.D., Wilson, P.A., Blum, P., and the other sources of silica in hemipelagic sediments. Moreover, bio- Expedition 342 Scientists, Proceedings of the genic silica accumulation is a function of nutrient availability and Integrated Ocean Drilling Program, 342: College opal preservation on the seafloor, both of which may vary inde- Station, TX (Integrated Ocean Drilling Program). doi:10.2204/iodp.proc.342.201.2017 pendently over time (Moore et al., 2014). As with all proxies, it is 2GNS Science, PO Box 30-368, Lower Hutt 5040, inadvisable to use this proxy in isolation. Biogenic silica accumu- New Zealand. [email protected] lation rate may prove to be a complementary guide to productiv-

Proc. IODP | Volume 342 doi:10.2204/iodp.proc.342.201.2017 C.J. Hollis Data report: siliceous microfossil abundance ity when combined with other proxies, such as trace verted and gently placed on a slide bearing 8–10 element geochemistry and benthic foraminifers. drops of Canada balsam. Radiolarian abundance, This report combines shipboard data from smear preservation, and zonal assignment are listed for slides with shipboard and shore-based data from Holes U1403A–U1410A in Table T2. radiolarian micropaleontology to provide a general Semiquantitative abundance estimates of the radio- guide to the occurrence and abundance of siliceous larian assemblage are derived from the number of microfossils (radiolarians and diatoms) in the cores radiolarians in a 5 cm3 sample: recovered during Integrated Ocean Drilling Program A = abundant (>10,000). (IODP) Expedition 342 (see the “Expedition 342 C = common (2,000–10,000). summary” chapter [Norris et al., 2014b]). Expedi- F = few (100–1,999). tion 342 investigated the Cretaceous–Cenozoic R = rare (<100). ocean history of the northwest Atlantic (latitude B = barren. ~41°N) through the recovery of expanded sequences of sedimentary drift deposits deposited in the flanks Preservation of the radiolarian assemblage is re- of J-Anomaly and southeast Newfoundland Ridges corded as (Fig. F1). It is hoped that this overview will improve G = good (most specimens complete, fine struc- our understanding of the general controls on biosili- tures preserved). ceous sedimentation in this region through the Ce- M = moderate (minor dissolution and/or break- nozoic and serve to guide future studies into trends age). in biogenic sediment accumulation patterns. P = poor (common dissolution, recrystallization, The correlation with radiolarian zones has also been and/or breakage). reviewed and updated for Sites U1403–U1410 (Figs. The radiolarian biostratigraphy has been reviewed F2, F3, F4, F5, F6, F7, F8, F9). for all samples assigned to radiolarian zones in Table T2. This review was used to refine correlations with radiolarian zones in the stratigraphic summaries Methods and materials (Figs. F2, F3, F4, F5, F6, F7, F8, F9) and age-depth The procedure for the description of smear slides is plots (Fig. F10). Radiolarian biostratigraphy is based outlined in the “Methods” chapter (Norris et al., on the low-latitude zonation outlined by Sanfilippo 2014a). The following categories are used to quantify and Nigrini (1998) and revised by Kamikuri et al. the abundance of diatoms and radiolarians in Holes (2012). Age estimates for radiolarian datums have U1403A–U1410A (Table T1): been recalibrated to the GTS2012 timescale (Grad- stein et al., 2012). 0 = absent (0%). P = present (<1%). F = few (1%–10%). Results C = common (>10%–25%). The abundance and preservation of radiolarians in A = abundant (>25%–50%). microfossil residues and the abundance of diatoms VA = very abundant (>50%). and radiolarians in smear slides is plotted for Sites Shipboard processing of radiolarian samples is also U1403–U1410 in Figures F2, F3, F4, F5, F6, F7, F8, outlined in the “Methods” chapter (Norris et al., F9. These data are also recorded in Tables T1 and T2. 2014a). Shore-based processing followed a similar The key features for each site are summarized below. method, except that acid digestion preceded clean- ing with H2O2 and Calgon. Samples were oven dried Site U1403 at 40°C, weighed, and leached in 10% hydrochloric acid until the reaction ceased. The spent acid solu- Site U1403 was drilled on the J-Anomaly Ridge in a tion was decanted, and the sample was then cleaned water depth of 4946.5 m. It was the deepest site drilled during Expedition 342. A poorly dated upper by heating on a hot plate in a solution of 10% H2O2 and Calgon. After effervescence subsided, the sample Cenozoic sequence is underlain by a highly siliceous was washed through a 63 µm sieve. If the residue was sequence of middle Eocene to Maastrichtian age (Fig. not fully clean, the drying, acid leaching, and clean- F2). ing steps were repeated. Residues were oven dried at Radiolarians are abundant and well preserved in the 40°C and strewn onto one or more microscope cov- middle Eocene and upper part of the lower Eocene erslips coated in gum tragacanth. The surface of the (Cores 342-U1403A-9H through 17H; Zones RP13 coverslip was moistened by a gentle breath, and the through RP9). In the underlying lower Eocene and loose residue was tapped off. The coverslip was in- Paleocene interval (Cores 18X through 25X; Zones

Proc. IODP | Volume 342 2 C.J. Hollis Data report: siliceous microfossil abundance

RP8 through RP6), radiolarian abundance fluctuates Siliceous microfossils are generally abundant and from few to abundant and preservation is moderate well preserved in three intervals within Hole to poor. Radiolarians are rare but moderately pre- U1406A: a lower Miocene to upper Oligocene inter- served in the lower Paleocene–upper Maastrichtian val (Cores 342-U1406A-2H through 15H; Zones RN3 interval (Cores 26X through 29X). Diatoms are not through RP21a), a short middle Eocene interval recorded in smear slides or microfossil residues from (Core 29X; Zones RP11 through RP12), and a simi- this site. larly short upper Paleocene interval (Core 31X; Zone RP7). Radiolarians dominate the siliceous microfossil Site U1404 assemblage, but diatoms are persistent, albeit rare, in both the upper and the Paleocene intervals. As at Site Site U1404 was drilled on the J-Anomaly Ridge in a U1404, siliceous microfossils are absent from the Eo- water depth of 4746 m. The sediments comprise a cene–Oligocene transition interval (Cores 16H condensed, poorly dated, upper Neogene interval through 27X). underlain by an expanded interval of lower Miocene to middle Eocene drift sediments (Fig. F3). Site U1407 Siliceous microfossils are abundant in two intervals in Hole U1404A: a lower Miocene to upper Oligo- Site U1407 was drilled on the southeast Newfound- cene interval (Cores 342-U1404A-3H through 19H; land ridge in a water depth of 3074 m. The sedi- Zones RN2 through RP21), in which both radio- ments comprise a highly condensed Neogene and larians and diatoms are common to abundant, and a upper Paleogene succession underlain by a relatively middle Eocene interval (Cores 28H through 36X expanded middle Eocene to upper Paleocene succes- [bottom of hole]; Zones RP16 through RP14), in sion. The lower ~130 m of core is a condensed suc- which radiolarians are generally abundant but dia- cession that extends from the lower Paleocene to the toms are absent. Significantly, siliceous microfossils upper Albian (Fig. F6). are rare or absent through the Eocene–Oligocene Siliceous microfossils are largely restricted to two in- transition at this site. tervals in Hole U1407A: a short lower Eocene interval (Cores 342-U1407A-10H through 11H; Zone Site U1405 RP11) and a relatively expanded upper Paleocene in- Site U1405 was drilled on J-Anomaly Ridge in a water terval (Cores 16X through 22X; Zones RP7 through depth of 4286 m. The sediments comprise a short RP6a). Radiolarians are abundant and well preserved upper Neogene interval underlain by a highly ex- in these two intervals. Diatoms are rare in Hole panded succession of lower Miocene to upper Oligo- U1407A and are restricted to these two intervals. cene drift sediments (Fig. F4). Siliceous microfossils are absent from the upper Neo- Site U1408 gene interval but are generally abundant to common Site U1408 was drilled on southeast Newfoundland and uniformly well preserved in the lower Miocene ridge in a water depth of 3022 m. It is the shallowest to upper Oligocene sediments (Cores 342-U1405A- site drilled during this expedition. The sediments 4H through 29X; Zones RN4 through RP22). Radio- comprise a condensed Neogene and upper Paleogene larians decrease in abundance in the lower part of succession underlain by middle Eocene drift sedi- the upper Oligocene interval (Cores 22H through ments, which are in turn underlain by a relatively 29X; Zone RP22) but remain well preserved. Diatoms condensed succession of lower Eocene and upper Pa- are persistent in Cores 4H through 29X and peak in leocene sediments (Fig. F7). abundance through the Oligocene–Miocene transi- Siliceous microfossils are restricted to two short in- tion (Cores 19H through 24H). Siliceous microfossils tervals in Hole U1408A. Abundant and well-pre- are rare or absent from the lower cores (Cores 30X served radiolarians occur in two cores within the ex- through 33X). panded middle Eocene sequence (Cores 342- U1408A-16H and 17H; Zone RP13) and two cores in Site U1406 the uppermost Paleocene (Cores 26X and 27X; Site U1406 was drilled on J-Anomaly Ridge in a water Zone RP7). Although not recorded in smear slides, depth of 3814 m. It was the shallowest site drilled on radiolarians were also noted in microfossil assem- J-Anomaly Ridge and recovered an expanded se- blages directly above these two intervals, but preser- quence of lower Miocene to middle to upper Eocene vation is too poor to confidently identify biostrati- drift sediments, which are capped by a condensed se- graphic marker species. Diatoms are rare in Hole quence of Pliocene–Pleistocene sediments and un- U1408A sediments and are restricted to the two derlain by Paleocene sediments (Fig. F5). radiolarian-rich intervals.

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Site U1409 composition in intervals where siliceous microfossils were not recorded. Site U1409 was drilled on southeast Newfoundland ridge in a water depth of 3501.5 m. It is the deepest There is a consistent pattern in the distribution of si- site drilled at this location. The sediments comprise a liceous microfossil-rich intervals in Expedition 342 relatively condensed Neogene and upper Paleogene sediment cores (Fig. F10). Siliceous microfossils are succession underlain by middle Eocene drift sedi- common in the Pleistocene in the two deepest sites ments, which are in turn underlain by a succession on southeast Newfoundland ridge (Sites U1409 and of lower Eocene and upper to middle Paleocene sedi- U1410; >3300 m water depth) but are otherwise rare ments (Fig. F8). in the upper Neogene. Both diatoms and radiolarians Diatoms and radiolarians are common in the upper- are abundant and well preserved in lower Miocene most two cores in Hole U1409A (342-U1409A-1H and upper Oligocene drift sediments on the J-Anom- and 2H), which are of Pleistocene age. Deeper in aly Ridge (Sites U1404, U1405, and U1406) but are Hole U1409A, siliceous microfossils are restricted to absent from sediments of this age on southeast New- two intervals. Radiolarians are generally common foundland ridge. Significantly, siliceous microfossils and moderately well preserved in the lower Eocene are absent from all sites for ~10 My spanning the Eo- (Cores 12H through 17X; Zones RP11 through RP8) cene–Oligocene transition, from lower Oligocene to and are abundant and well preserved in the upper- uppermost middle Eocene. Radiolarians are abun- most Paleocene (Cores 20X and 21X; Zones RP7 and dant from middle Eocene to upper lower Eocene sed- RP6c). Diatoms are rare in both intervals and absent iments at several sites, tending to be more persistent from other pre-Pleistocene sediments in Hole in the deeper J-Anomaly Ridge sites (U1403 and U1409A. U1404) than in shallower sites on J-Anomaly Ridge (U1406 and U1407) and all sites on southeast New- Site U1410 foundland ridge (U1408, U1409, and U1410). Radio- larians are poorly preserved in a chert-rich interval Site U1410 was drilled on southeast Newfoundland in the lower Eocene and spanning the Paleocene/Eo- ridge in a water depth of 3387 m. The sediments cene boundary, notably at Sites U1403 and U1407. comprise a condensed Neogene and upper Paleogene In contrast, very well preserved, abundant, and di- succession underlain by middle to lower Eocene drift verse radiolarians occur in the upper Paleocene cal- sediments (Fig. F9). careous ooze, which is present at Sites U1406– Diatoms and radiolarians are common in the upper- U1409. Indeed, all sites that penetrated the Paleo- most two cores in Hole U1410A (342-U1410A-1H cene in this region encountered a radiolarian-rich in- and 2H), which are of undifferentiated Pliocene– terval that encompassed portions of Zones RP6 and Pleistocene age. Deeper in Hole U1410A, siliceous RP7, an interval that is also rich in radiolarians at microfossils are restricted to a single lower Eocene Deep Sea Drilling Project (DSDP) Site 384 interval. Radiolarians are abundant and well pre- (Nishimura, 1992). Preservation is excellent at the served in Cores 23X through 26X and span the same shallower sites, where radiolarians occur within the Eocene radiolarian zones as in Hole U1409A: Zones Paleocene nannofossil ooze, but is variable at Site RP11 through RP8. Diatoms are rare in this interval U1403, where sediments are more siliceous. and absent from other pre-Pleistocene sediments in Diatoms are rare in the lower Paleogene and are re- Hole U1410A. stricted to intervals where radiolarians are abundant in the middle to lower Eocene and upper Paleocene. Site U1411 A similar record of siliceous microfossil abundance Site U1411 was drilled on southeast Newfoundland was recorded at DSDP Site 384, which was drilled on ridge in a water depth of 3299 m. Siliceous micro- J-Anomaly Ridge at a water depth of 3909 m fossils are very rare and sporadically distributed at (Tucholke, Vogt, et al., 1979), where radiolarians are this site. abundant and well preserved from middle to upper lower Eocene (Zones RP11 through RP9) and from upper to lower Paleocene (Zones RP7 through RP6a; Discussion Nishimura, 1992). The Paleocene–Eocene transition There is good agreement between paleontological is not preserved at this site. and sedimentological methods for assessing the This distribution pattern indicates that siliceous abundance of siliceous microfossils in Expedition microfossil accumulation is greatest during the two 342 sediments. It is highly unlikely that biogenic main phases of drift sedimentation, particularly the opal makes a significant contribution to sediment Miocene–Oligocene drifts of J-Anomaly Ridge but

Proc. IODP | Volume 342 4 C.J. Hollis Data report: siliceous microfossil abundance also in the middle Eocene drifts on southeast New- IODP Consortium (ANZIC). My participation in this foundland ridge and at Sites U1403 and U1404. Ra- expedition and preparation of this report was sup- diolarians tend to occur more regularly at deep-water ported by ANZIC and the New Zealand government sites (U1403 and U1404) in the Eocene. In the shal- through the GNS Science Global Change through lower sites, there is a weak trend toward shorter in- Time Program (540GCT62) and Marsden Fund Grant tervals of abundant radiolarian with shoaling. In the (12-GNS-001). Eocene, abundant radiolarians occur over ~3.5 My at Site U1406 (3814 m), over ~4 My at Sites U1409 (3502 m) and U1410 (3387 m), over ~2 My at Site References U1407 (3074 m), and over ~0.5 My at Site U1408 Bohrmann, G., and Stein, R., 1989. Biogenic silica at ODP (3022 m). Site 647 in the southern Labrador Sea: occurrence, dia- In addition to this depth relationship, it also seems genesis, and paleoceanographic implications. In Srivas- likely that the distribution of siliceous microfossil as- tava, S.P., Arthur, M.A., Clement, B., et al., Proceedings of semblages may be related to the evolution of north- the Ocean Drilling Program, Scientific Results, 105: College west Atlantic circulation patterns. Siliceous sedi- Station, TX (Ocean Drilling Program), 155–170. http:// dx.doi.org/10.2973/odp.proc.sr.105.121.1989 ments are restricted to the northeast margin of the southeast Newfoundland ridge in the Pleistocene, Gradstein, F.M., Ogg, J.G., Schmitz, M.D., and Ogg, G.M. suggesting that the ridge may mark the oceano- (Eds.), 2012. The Geological Time Scale 2012: Amsterdam (Elsevier). graphic boundary between Subantarctic and temper- ate waters and perhaps the southern limit of the Lab- Kamikuri, S., Moore, T.C., Ogane, K., Suzuki, N., Pälike, H., and Nishi, H., 2012. Early Eocene to early Miocene rador Current at this site (Bohrmann and Stein, radiolarian biostratigraphy for the low-latitude Pacific 1989). The two main intervals of abundant siliceous Ocean. Stratigraphy, 9(1):77–108. http://www.micro- microfossils correspond with periods of relatively press.org/micropen2/articles/1/7/27546_articles_ar- warm climate (i.e., the Oligocene–Miocene transi- ticle_file_1785.pdf tion and the lower to middle Eocene) (Zachos et al. Jin, Y., van Peer, T., Xuan, C., and Hollis, C.J., 2015. Late 2008). These time intervals may have been associ- Oligocene to early Miocene radiolarian events recorded ated with greater mixing of subantarctic and sub- in the mid-latitude North Atlantic [presented at the tropical waters, which may have promoted biosili- 14th INTERRAD: International Conference on Fossil ceous productivity at these sites. This scenario is and Recent Radiolarians, Antalya, Turkey, 22–26 March consistent with the low-latitude affinities of the 2015]. radiolarian assemblages (C.J. Hollis et al., unpubl. Moore, T.C., Jr., Jarrard, R.D., Olivarez Lyle, A., and Lyle, data; Jin et al., 2015) and may explain why a time of M., 2008. Eocene biogenic silica accumulation rates at relatively cooler climatic conditions, from the early the Pacific equatorial divergence zone. Paleoceanography, Oligocene to late Eocene, is not associated with en- 23(2):PA2202. http://dx.doi.org/10.1029/ hanced biosiliceous productivity in this midlatitude 2007PA001514 setting. The scarcity of siliceous microfossils at Site Moore, T.C., Jr., Wade, B.S., Westerhold, T., Erhardt, A.M., U1411 supports this hypothesis. An expanded suc- Coxall, H.K., Baldauf, J., and Wagner, M., 2014. Equato- cession of drift sediments spans the Eocene/Oligo- rial Pacific productivity changes near the Eocene-Oligo- cene boundary. Paleoceanography, 29(9):825–844. http:/ cene boundary. Therefore, high burial rates alone /dx.doi.org/10.1002/2014PA002656 cannot account for preservation of siliceous microfossils. Nishimura, A., 1992. Paleocene radiolarian biostratigraphy in the northwest Atlantic at Site 384, Leg 43, of the Deep Sea Drilling Project. Micropaleontology, 38(4):317– 362. http://dx.doi.org/10.2307/1485764 Acknowledgments Norris, R.D., Wilson, P.A., Blum, P., Fehr, A., Agnini, C., I thank Expedition 342 science and sampling party Bornemann, A., Boulila, S., Bown, P.R., Cournede, C., members and IODP for providing the data and sam- Friedrich, O., Ghosh, A.K., Hollis, C.J., Hull, P.M., Jo, K., ples used in this report. I thank Kazuyoshi Moriya Junium, C.K., Kaneko, M., Liebrand, D., Lippert, P.C., and Haruka Takagi for their shipboard compilations Liu, Z., Matsui, H., Moriya, K., Nishi, H., Opdyke, B.N., Penman, D., Romans, B., Scher, H.D., Sexton, P., Takagi, of siliceous microfossil abundance and Sonja Bermu- H., Turner, S.K., Whiteside, J.H., Yamaguchi, T., and dez for shore-based processing of radiolarian samples Yamamoto, Y., 2014. Methods. In Norris, R.D., Wilson, at GNS Science. Ted Moore and Dick Norris provided P.A., Blum, P., and the Expedition 342 Scientists, Pro- helpful comments on the draft manuscript. Shore- ceedings of the Integrated Ocean Drilling Program, 342: Col- based processing was funded through a postcruise re- lege Station, TX (Integrated Ocean Drilling Program). search grant from the Australian and New Zealand http://dx.doi.org/10.2204/iodp.proc.342.102.2014

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Norris, R.D., Wilson, P.A., Blum, P., Fehr, A., Agnini, C., 33(1–2):109–117, 121–156. http://dx.doi.org/10.1016/ Bornemann, A., Boulila, S., Bown, P.R., Cournede, C., S0377-8398(97)00030-3 Friedrich, O., Ghosh, A.K., Hollis, C.J., Hull, P.M., Jo, K., Tucholke, B.E., Vogt, P.R., et al., 1979. Initial Reports of the Junium, C.K., Kaneko, M., Liebrand, D., Lippert, P.C., Deep Sea Drilling Project, 43: Washington, DC (U.S. Govt. Liu, Z., Matsui, H., Moriya, K., Nishi, H., Opdyke, B.N., Printing Office). http://dx.doi.org/10.2973/ Penman, D., Romans, B., Scher, H.D., Sexton, P., Takagi, dsdp.proc.43.1979 H., Turner, S.K., Whiteside, J.H., Yamaguchi, T., and Zachos, J.C., Dickens, G.R., and Zeebe, R.E., 2008. An early Yamamoto, Y., 2014b. Expedition 342 summary. In Nor- Cenozoic perspective on greenhouse warming and car- ris, R.D., Wilson, P.A., Blum, P., and the Expedition 342 bon-cycle dynamics. Nature, 451(7176):279–283. http:/ Scientists, Proceedings of the Integrated Ocean Drilling Pro- /dx.doi.org/10.1038/nature06588 gram, 342: College Station, TX (Integrated Ocean Drill- ing Program). http://dx.doi.org/10.2204/ iodp.proc.342.101.2014 Initial receipt: 4 February 2016 Sanfilippo, A., and Nigrini, C., 1998. Code numbers for Acceptance: 16 February 2017 Cenozoic low latitude radiolarian biostratigraphic zones Publication: 2 May 2017 and GPTS conversion tables. Marine Micropaleontology, MS 342-201

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Figure F1. Expedition 342 drill sites.

42˚ N Titanic U1411 U1408

U1407 U1410 U1409 41˚ SSE Newfoundland Ridge E N ew DSDP 384 f ou U1406 nd U1405 ge la id nd 40˚ U1404 R R y U1403 al id m ge no A JJ-Anomaly- Ridge

39˚ 52˚W 51˚ 50˚ 49˚ 48˚47˚ 46˚ 45˚

Proc. IODP | Volume 342 7 C.J. Hollis Data report: siliceous microfossil abundance

Figure F2. Radiolarian zones, radiolarian abundance and preservation, and siliceous microfossil abundance in smear slides, Hole U1403A.

Radiolarian Biosilica in U1403A U1403B U1403A Core Core Radiolarian CaCO 3 (wt%) abundance Smear slides

recovery recovery Image Lith. unit 0255075 B R F C A Lithology zones B R F C A VA 0 I 1H 1H Pleist. 2H 2H Radiolarians 3H 3H 4H 4H 5H II ? 5H 6H Unzoned 50 6H 7H

7H 8H

8H 9H

9H 10H RP13

10H 11H AAbundant,bundant, well-well- ppreservedreserved radiolariansradiolarians RP12 11H 12H III 100 12H 13H RP11 13H 14H middle Eocene RP10 14H 15H

15H 16H IV RP9 Depth CSF-A (m) 16H 17X 150 17H 18X RP8 18X 19H 20H 19X Unzon. 21H uRP7

20X early Eocene 22H 21X 23X Va Unzon. 24X lRP7 22X 25X RP6 23X 200 26X 24X 25X 27X Paleocene 26X 28X 27X 29X Unzoned unzoned

28X Maast. 30X Vb B P M G 250 31X 32X Radiolarian 32X preservation

Recovery Lithology Recovered Nannofossil ooze Calcareous chalk Clay Not recovered Core overlap Nannofossil chalk Biosiliceous ooze

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Figure F3. Radiolarian zones, radiolarian abundance and preservation, and siliceous microfossil abundance in smear slides, Hole U1404A.

Radiolarian Biosilica in U1404A U1404B U1404C U1404A Core Core Core Radiolarian CaCO3 (wt %) abundance smear slides

recovery recovery recovery Image Lithology Lith. unit zones 0255075 B R F C A B R F C A VA 0 1H 1H I Pleist. 2H 2H Radiolarians Diatoms 3H Washed IIa 3H 2H 4H 4H 3H

5H Unzoned

5H Undetermined 6H 4H 6H 50 7H 7H 8H 8H 9H RN2 9H 10H 10H AAbundant,bundant, wwell-ell- 11H 11H ppreservedreserved radiolariansradiolarians 100 12H 12H

13H 13H early Miocene RN1 14H 14H

15H 15H 16H 16H RP22 17H 150 17H 18H 18H 19H RP21 19H Depth CSF-A (m) 20H 20H 21H 21H

22H Oligocene 22H 200 23H 23H 24H 24H 25H 25H III Barren 26H 26H 27H l. Eocene 27H 28H 250 29H RP16 30H 31H 32H IV RP15 33X

34X middle Eocene 35X RP14 300 36X BPMG Radiolarian Recovery Lithology preservation Recovered Nannofossil ooze Calcareous chalk Not recovered Clay Core overlap Nannofossil chalk Biosiliceous ooze

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Figure F4. Radiolarian zones, radiolarian abundance and preservation, and siliceous microfossil abundance in smear slides, Hole U1405A.

Radiolarian Biosilica in U1405A U1405B U1405C U1405A CaCO Core Core Core Radiolarian 3 (wt%) abundance smear slides recovery recovery recovery Image Lithology Lith. unit zones 0204060 B R F C A B R F C A VA 0 1H 1H 1H Ia 2H 2H Radiolarians 2H Ib Diatoms Pleist. 3H 3H 3H Barren 4H wash 4H 5H 5H 5H RN4 6H 50 6H 6H RN3 7H 7H 7H

8H 8H 8H

9H 9H 9H IIa 10H 10H 10H Not examined

11H 11H 11H 100 RN2 12H 12H 12H early Miocene 13H 13H 13H AAbundant,bundant, wwell-ell- ppreservedreserved radiolariansradiolarians 14H 14H 14H Not exam. 15H 15H 15H

16H 16H 16H 150 RN1 17H 17H 17H

18H 18H 18H Not Depth CSF-A (m) 19H 19H 19H IIb exam. 20H 20H 20H

21H 21H 21H 22H 200 22H 22H RP22 23H 23H 23H

24H 24H 24H

25H 25H 26H 27X

250 late Oligocene 28X

29X Not examined 30X

31X

32X 300 33X Barren

BPMG Recovery Lithology Radiolarian Recovered preservation Nannofossil ooze Calcareous chalk Not recovered Biosiliceous ooze Core overlap Nannofossil chalk Clay

Proc. IODP | Volume 342 10 C.J. Hollis Data report: siliceous microfossil abundance

Figure F5. Radiolarian zones, radiolarian abundance and preservation, and siliceous microfossil abundance in smear slides, Hole U1406A.

Radiolarian Biosilica in U1406A U1406A U1406B U1406C Core Core Core Radiolarian CaCO3 (wt %) abundance smear slides

recovery recovery recovery Image Lithology Lith. unit zones 02550755 B R F C A B R F C A VA 0 1H 1H 1H I 2H 2H Barren 3H 3H 3H

Plio-Pleist. RN3 4H 4H 4H 5H 5H RN2 5H 6H 6H 50 6H 7H 7H 7H RN1 8H 8H 8H

9H 9H early Miocene 9H II 10H 10H RP22 AAbundant,bundant, wwell-ell- 10H ppreservedreserved radiolariansradiolarians 11H 11H 100 11H 12H 12H 12H RP21b 13H 13H 13H 14H 14H 14H 15H 15H RP21a 15H 16H 16H 16H 150 17H 17H Oligocene 17H 18H 18H 18H

Depth CSF-A (m) 19H 19H 20X 20H 20H 21X 21H 21H 23X 22X 22H 200 24X 23X 23H 24X Barren 25X Radiolarians 24H 25X III 26X Diatoms 26X 26X 27X 27X 27X 28X 28X 28X 29X 29X 29X RP11− 250 30X mid to late Eocene RP12 30X 31X RP7 32X IV RP6c 33X 34X Paleocene BPMG Radiolarian preservation Recovery Lithology Recovered Foraminiferal ooze Clay Not recovered Core overlap Nannofossil ooze Nannofossil chalk Claystone

Proc. IODP | Volume 342 11 C.J. Hollis Data report: siliceous microfossil abundance

Figure F6. Radiolarian zones, radiolarian abundance and preservation, and siliceous microfossil abundance in smear slides, Hole U1407A. U1407A U1407B U1407B U1407C Radiolarian Biosilica in

Core Core Core Radiolarian CaCO3 (wt%) abundance smear slides recovery recovery recovery Image Lithology Lith. unit zones 0 255075100 B R F C A B R F C A VA 0 1H 1H 1H I wash 2H 2H II 3H Pleist. Radiolarians 3H 3H Diatoms 4H 4H wash 5H 5H 5H 6H 6H early Oligo.

50 6H III Barren 7H 7H 7H 8H 8H 8H 9H 9H 9H 10H 10H mid-Eocene 10H 11H 11H IV 11H RP11 100 12H 13H Wash Wash

14H early Eocene 13X unzoned 16X 14X 17X 13X 15X RP7 18X 14X 16X Va AAbundant,bundant, well-well- 150 19X 15X RP6b ppreservedreserved radiolariansradiolarians 17X 20X 16X 18X Paleocene RP6a Depth CSF-A (m) 21X 17X 19X 22X 18X 20X 23X 19X 21X Maast.

20X Camp. 200 24X 22X 21X 25X 23X Sant. 22X 24X 26X 25X

Vb Coniac. 23X 27X 26X 24X

28X 27X Tur. 25X Barren 29X 28X 250 26X 30X 29X 27X 31X 28X 32X

33X

VI Albian Cenom. 34X 300 35X

BPMG Radiolarian preservation Recovery Lithology Recovered Foraminiferal ooze Nannofossil chalk Clay Not recovered Core overlap Nannofossil ooze Radiolarian-rich Claystone

Proc. IODP | Volume 342 12 C.J. Hollis Data report: siliceous microfossil abundance

Figure F7. Radiolarian zones, radiolarian abundance and preservation, and siliceous microfossil abundance in smear slides, Hole U1408A.

Radiolarian Biosilica in U1408B U1408C U1408A U1408A Radiolarian CaCO smear slides Core Core Core 3 (wt%) abundance recovery 0 20 40 60 80100 B R F C A recovery recovery Image Lithology Lith. unit zones B R F C A VA 0 1H 1H 1H I 2H

2H Pleist. 3H II Radiolarians 3H 3H Diatoms disturbed 4H Mio. 4H 5H 5H Oligo. 5H 6H 6H 6H 50 7H 7H disturbed 7H 8H 8H 8H 9H 9H

9H Barren 10H 10H 10H 11H 11H 11H 12H 100 12H 12H 13H 13H 13H 14H 14H III 14H 15H 15H 15H 16H 16H Depth CSF-A (m) 17H 16H 17H Unzoned AAbundant,bundant, well-well- 18H middle Eocene RP13 150 17H 18H preservedpreserved radiolariansradiolarians 19X 18H 19H 20X 20X 19H 21X 21X disturbed 20H 22X 22X disturbed 21X 23X 22X 24X 200 Unzoned 23X 25X 24X 26X

25X early Eocene 26X IV 240 RP7

27X Paleoc.

BPMG Radiolarian preservation Recovery Lithology Recovered Foraminiferal ooze Clay Not recovered Core overlap Nannofossil ooze Nannofossil chalk Claystone

Proc. IODP | Volume 342 13 C.J. Hollis Data report: siliceous microfossil abundance

Figure F8. Radiolarian zones, radiolarian abundance and preservation, and siliceous microfossil abundance in smear slides, Hole U1409A.

Radiolarian Biosilica in

U1409A U1409B U1409C U1409A Radiolarian CaCO Core Core Core 3 (wt%) abundance smear slides recovery recovery recovery Image B R F C A Lithology Lith. unit zones 0 25 5075 100 B R F C A VA 0 1H1H 1H1H 2H2H I 2H2H Unzoned 2H2H Plio.- 3H3H Pleist. 3H3H 3H3H 4H4H II 4H4H Radiolarians 4H4H early Oligo. Diatoms 5H5H 5H5H 5H5H 6H6H 6H6H 50 6H6H 7H7H 7H7H 7H7H 8H8H 8H8H Barren III 8H8H 9H9H 9H9H middle Eocene Pleist. 9H9H 10H10H 10H10H 10H10H 11H11H 11H11H 100 11H11H 12H12H 12H12H 12H12H RP11 13H13H 13H13H IVa Depth CSF-A (m) RP9 13H13H 14H14H 14H14H

15X15X 15X15X 17X17X 16X16X RP8 17X17X

18X18X 16X16X early Eocene 18X18X IVb 19X19X 17X17X 19X19X 150 20X20X RP7 20X20X 18X18X 21X21X 21X21X 19X19X RP6c

22X22X IVc

23X23X Barren

24X24X middle to late Paleocene 200 BPMG Radiolarian preservation Recovery Primary lithology Lithology prefix

Recovered Foraminiferal ooze Clay Nannofossil Silty Not recovered Core overlap Nannofossil Clayey Radiolarian

Nannofossil Foraminiferal Diatomaceous

Proc. IODP | Volume 342 14 C.J. Hollis Data report: siliceous microfossil abundance

Figure F9. Radiolarian zones, radiolarian abundance and preservation, and siliceous microfossil abundance in smear slides, Hole U14010A.

Radiolarian Biosilica in U1410A U1410B U1410A U1410C Radiolarian CaCO3 (wt%) abundance smear slides Core Core Core recovery recovery recovery Image zones 0 20406080100 B R F C A B R F C A VA Lithology Lith. unit 0 1H 1H 1H 2H 2H 2H I 3H 3H 3H 4H Plio.-Pleist. Radiolarians Diatoms 4H 4H 5H 5H 5H 6H

II Miocene 50 6H 6H 7H 7H 7H Oligo. 8H 8H 8H 9H 9H 9H 10H 10H 10H 11H 12H 11H 100 11H 13H 12H 12H

14H 13H Barren 13H 15H 14H 14H 16H 15H 15H III Depth CSF-A (m) 17H 16H 16H 150 18H 17X middle Eocene 17X 19X 18X 18X 20X 19X 19X 21X 20X 20X 22X 21X 21X 23X 200 22X 22X 24X 23X 23X 25X RP11 24X RP10 24X 26X 25X IVa RP09 AAbundant,bundant, well-well- 25X 27X ppreservedreserved radiolariansradiolarians 26X 26X 28X RP08 early Eocene

250 27X IVb 28X Undet. Radiolarian preservation Recovery Principal lithology Lithology prefix Recovered Foraminiferal ooze Clay Nannofossil Silty Not recovered

Core overlap Nannofossil ooze Claystone Foraminiferal Clayey

Nannofossil chalk

Proc. IODP | Volume 342 15 C.J. Hollis Data report: siliceous microfossil abundance

Figure F10. Radiolarian occurrence in relation to linear sedimentation rate curves, Holes U1403–U1410. J- Anomaly Ridge sites are underlined. Green bands = intervals of abundant siliceous microfossils.

Abundant, U1410A well preserved

100 Abundant, poorly preserved

150

U1407A

Sedimentation rate

Depth CSF-A (m) 200 (cm/ky) U1409A U1408A 0.2 U1403A

250 0.5 1 U1406A 2 5 U1405A U1404A

300 Plio-Pleist. late Miocene mid Mio. early Miocene Oligocene late Eoc. middle Eocene early Eocene Paleocene L. Cretaceous

2 1 Radiolarian RN7-RN17 RN6RN5 RN4 RP22 RP21 RP20 RP16 RP14 RP9 RP8 RP7bRP7a RP6 RP1-RP4 A. tylotus zone RN RP19 RP18 RP12 RP1 0 5 10152025303540455055606570 75 Ma

Table T1. Siliceous microfossil abundance. This table is available in CSV format.

Table T2. Radiolarian abundance and preservation. This table is available in CSV format.

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