<figure><img src="image_36.png" /><figcaption>Figure F28. Data characterizing chemical anomalies associated with the T60 regional seismic marker, Site U1505.</figcaption></figure>

Wireline logging was conducted in Hole U1505C using the triple combo tool string, which included the HNGS, HLDS, DSI, and MSS. This logging string collected good data from 341.2 m (139.1 m above the bottom of Hole U1505C), which allows the definition of six logging units that mostly correlate with the lithostratigraphic units and core physical property data. Logging Unit 1 extends from the seafloor to the base of the drill pipe at 78 m. NGR is highly attenuated inside the drill pipe. Logging Unit 2 (base of the drill pipe to 96 m) exhibits NGR values that are ~50% lower than the underlying logging Unit 3. In Unit 3 (96–136 m), NGR increases with depth. Logging Unit 4 (136–220 m) exhibits relatively constant $V_p$ and $V_s$. In logging Unit 5 (200–296 m), resistivity increases with depth, whereas most of the other physical properties are relatively constant. Logging Unit 6 (296–341.2 m) has higher magnetic susceptibility values than logging Unit 5.

Four downhole temperature measurements were conducted in Hole U1505C using the APCT-3. The temperature values range from 4.7°C at 36.7 m to 11.7°C at 122.8 m, giving a geothermal gradient of 84.6°C/km. A heat flow of 94.0 mW/m² was obtained from the linear fit between temperature and thermal resistance. The geothermal gradient and heat flow at Site U1505 are comparable to the relatively high values observed in a number of ODP and IODP sites in this part of the SCS.

## Preliminary scientific assessment

In this section, we assess the achievements of Expedition 367/368 in the SCS toward meeting the four specific objectives as stated in the *Scientific Prospectus* (Sun et al., 2016b). Expedition 367 followed the original drilling plan and cored into acoustic basement at Ridges A and B and progressed without significant delays. However, based on Expedition 367 results, Expedition 368 followed a

modified drilling plan that included a second drill site on Ridge A. Drilling plans for Expedition 368 were further modified due to serious drilling equipment failures at deep-water Site U1503 on Ridge C (see Site U1503). This failure limited the drilling capability of the *JOIDES Resolution* to a maximum 3400 m drill string deployment from 25 May 2017 to the end of the expedition on 11 June. Only a couple of alternate drill sites could be addressed with this limit on drill string length. Two of these, both on the OMH, were implemented (Sites U1504 and U1505). Furthermore, expedition time spent from 14 to 25 May installing casing to 990 m for primary Site U1503 was de facto time wasted for the expedition because the site could not be completed, but it left an important drill site ready for coring in the future. The overall effects of this operational constraint are that it directed efforts more toward Objective 4 (Site U1505) than originally planned and that the tectonic high-priority Site U1503 was lost for Expedition 367/368.

1. *To determine the nature of the basement in critical crustal units across the COT of the SCS rifted margin to discriminate between different competing models of breakup at magma-poor rifted margins. Specifically, to determine whether the subcontinental lithospheric mantle was exhumed during plate rupture.*

This objective was partly achieved with the potential for a higher degree of completion during postexpedition research. However, eventually Site U1503 needs to be completed, and further efforts need to be made to understand the deep nature of Ridge A.

Site U1499 at Ridge A provided important clues to the timing of tectonism but failed to provide direct evidence for its deeper crustal composition. Site U1502, originally an alternate site to Site U1499, was therefore pursued because the nature of Ridge A was considered a very high priority and the most likely place to recover either deep crust or exhumed mantle. To give this site priority was a signif-
icant decision and deviation from the drilling plan in the *Scientific Prospectus* and potentially affected our ability to address an important site on Ridge C (Site U1503).

Site U1499 on Ridge A successfully penetrated into the acoustic basement, which comprises synrift and/or postrift deposits of Oligocene or possibly older age. The clasts found in these partly coarse sediments do not contain lithologies that suggest a source of lowermost crust to exhumed mantle origin. Therefore, the nature of the deeper crust at Site U1499 remains unconstrained by direct sampling. Site U1502, also on Ridge A, recovered ~180 m of submarine basalts of possible late Eocene to Oligocene age overlain by late Eocene/Oligocene to Miocene deep-water sediments. Onboard preliminary ICP-AES element analyses indicate they are tholeiitic basalt and are comparable to samples from the ocean crust in the SCS collected during Expedition 349 and from Site U1500 at Ridge B. However, unlike the fresh basalts of Site U1500, the Site U1502 basalts show strong fracturing and alteration by high temperature hydrothermal activity, including mineralization (e.g., massive pyrite). This difference may suggest that the deeper crust comprises plutonic bodies but does not further constrain the nature of the deep crust.

Combining the findings at Site U1502 with the recovery at Site U1499 (Expedition 367; Ridge A) of potentially rift-related syn-tectonic or prerift sediments suggests that Ridge A is a complex structure comprising both rift-related sediments and syntectonic igneous material. The specific question of whether upper/lower crust or subcontinental lithospheric mantle is present at depth, however, remains unanswered by coring data. Detailed examination of the recovered basalts and of the gravel unit may help constrain the specific nature of the deeper crust. Future dedicated geophysical surveying and one or two more deep drill holes will be required to firmly advance our understanding of Ridge A.

The nature of the acoustic basement below Ridge B was successfully determined at Site U1500. This site recovered 150 m of fresh, submarine basalts of Oligocene age in a location where seismic imaging shows a layered structure below the acoustic basement, extending to ~2.5 km depth. The presence of a kilometer-thick carapace of basaltic lavas in the upper crust is therefore concluded. However, this carapace does not prove this ~6 km thick crust to be entirely igneous, and its lower part conceivably could contain stretched continental lithosphere.

The nature of the crust at the OMH was well addressed at Site U1501. This site drilled ~45 m into the prerift? acoustic basement beneath the Cenozoic sedimentary section and recovered lithified, coarse-grained sedimentary rocks of presumed Mesozoic age. This finding verified our predrilling interpretation of the OMH as comprising upper continental crustal material. The basement of the easternmost extension of the OMH was also sampled at Site U1504. In this location, greenschist facies metamorphic rock was found, suggesting that only a moderate amount (~5 km) of upper crust was removed prior to deposition of the thin, mainly postbreakup sediments that overlie the basement. The timing of the removal of the uppermost crust is constrained to be at least before the late Eocene. Postexpedition work on age determination and thermobarometry may constrain an exhumation history and its possible relation to the Cenozoic rifting of the SCS.

Our inability to pursue deep drilling at Site U1503 obviously prevents us from characterizing the nature of the crust at Ridge C based on in situ drilling data. Combining seismic interpretation and the observations from Ridge B (Site U1500), however, constrains this to be primarily if not entirely of igneous origin.

## 2. To determine the time lag between plate rupture and asthenospheric upwelling that allowed decompression melting to generate igneous oceanic crust.

This objective was achieved. The simple answer to Objective 2 is that there was no substantial time lag between (final) plate rupture and asthenospheric upwelling supporting the generation of igneous material with a basaltic, MORB-type composition. Submarine MORB-type basalts of early Oligocene age were recovered at Site U1500 on Ridge B, and based on geophysical evidence, Ridge C can be interpreted to be at least partly igneous. Seafloor magnetic anomalies C10r to C11n (29–30 Ma; approximately mid-Oligocene) encompass these two ridges and provide independent evidence of the age of the basalts from Site U1500 (Oligocene). Submarine basalts of similar or possibly slightly older age (early Oligocene to late Eocene) were found on Ridge A (Site U1502). These observations rule out any significant time-lag between final plate rupture and the onset of magmatism. Postexpedition work on mantle melting history may detail the thickness of residual subcontinental lithosphere of lithospheric thinning during breakup. Excellent material for this type of work, and for age determination, is available from Site U1500, but modeling efforts will lack the constraints from Ridge C (Site U1503) representing a more advanced stage of spreading. Because of the highly altered nature of Site U1502 basalts, geochemical studies will unfortunately be challenging but very important because these rocks likely represent a stage in margin development where continental lithosphere had a stronger impact on magmatism (contamination and by lithospheric thickness). Expedition 367/368 findings also rule out that the margin in this location was overprinted by late-stage magmatism as recently proposed.

Although the failure to pursue Site U1503 did not seriously affect our ability to constrain a possible time lag between plate rupture and onset of magmatism, it left us without a well-defined reference frame for assessing mantle composition and mantle melting conditions during steady-state accretion of igneous crust. Recoupation of Site U1503 is therefore highly recommended to provide a benchmark against which the earlier breakup magmatism can be compared. Similarly, more and fresh basaltic material from Ridge A would greatly benefit the study of the SCS margin in terms of age determination of the earliest basaltic magmatism and its detailed geochemical elemental and isotopic composition evolution over time.

## 3. To constrain the rate of extension and vertical crustal movements.

This objective was partly achieved, but postexpedition work is needed to further develop our findings. Important stratigraphic control on the synrift sediments related to breakup was achieved at Sites U1499, U1501, U1502, and U1505. The findings of highly syntectonic deposits of Oligocene (and possibly older) age overlain by a very low sedimentation rate sequence of late Oligocene to early Miocene age at Ridge A (Site U1499) is strong evidence for an early Oligocene plate rupture that was completed by the latest Oligocene. This was further confirmed at Site U1501, located on the OMH. This site recovered the entire sequence of synrift sediments down to (presumed) Mesozoic basement. The sequence shows development from deltaic to shallow marine with terrigenous sedimentation (Eocene) through deepening water, yet still predominantly clastic detrital sediments (approximately early Oligocene), to deep-water marine calcareous sediments (approximately late Oligocene to Miocene). Biostratigraphic constraints on the Eocene deposits are lack-
ing below the uppermost late Eocene sediments. A very similar evolution was documented at Site U1505 for the early Oligocene to Miocene interval. Site U1504, also at the OMH and slightly shallower than at Sites U1501 and U1505, penetrated a 120 m thick postrift sedimentary sequence above crystalline basement. Deep-water conditions were established by lowermost early Miocene time. The presence of a carbonate reef debris deposit (very shallow marine water) with an approximate age of late Eocene suggests that the ~3 km subsidence experienced by these sediments was initiated post-late Eocene. Site U1502, also located on Ridge A, shows (minor) deep-water deposits of early Oligocene to perhaps late Eocene age followed exclusively by deep-water deposits of Oligocene to Miocene age. Deep-water conditions therefore developed earlier (pre-Oligocene) on Ridge A than on the OMH (approximately late Oligocene).

The inability to pursue coring at Site U1503 unfortunately prevented Expedition 368 from extending subsidence studies seaward of Ridge B (Site U1500), where the late Oligocene sediment package overlying the basalts is much better developed than at Site U1500 on Ridge B. However, the most serious lack of data needed for constraining rate of extension is the lack of biostratigraphic control in the deeper part of the Eocene section at Site U1501 and the older part of synrift or prerift deposits at Site U1499. Shallow water sediments of Eocene age similar to those at Site U1501 were found at Site U1435 (IODP Expedition 349), and, although the sediment is similarly barren of microfossils, detrital zircon is present. If also present in the Site U1501 samples, age determination on a population of these might provide maximum ages. The amount of crustal extension will be determined through a detailed tectonic interpretation of the regional seismic data (courtesy of the CNOOC) that the entire Expedition 367/368 program is based on.

4. *To improve the understanding of the Cenozoic regional tectonic and environmental development of the Southeast Asia margin and SCS by combining Expedition 367/368 results with existing ODP/IODP sediment records and regional seismic data.*

This objective was achieved, but intensive multidisciplinary postexpedition work is needed to maximize our findings. An important achievement in this regard was the recovery of a nearly continuous sequence of the prerift, synrift, and postrift sediments since the Eocene and older sediments at Site U1501. This sequence provides the sedimentary records of the SCS evolving from land to deep sea for the first time and will greatly help us to understand the sedimentary processes associated with tectonic events and paleoenvironmental development at the SCS northern margin. Together with the deep-water sediment packages from Sites U1499, U1500, U1502, and U1505, Expedition 367/368 findings provide the possible tectonic links between the SCS and the western Pacific in the aspects of the SCS formation history.

Based on the coring/drilling results of Expedition 367/368, new time-depth constraints on some of the major seismic stratigraphic unconformities are available. These unconformities were mapped regionally throughout the basin by integrating microfossil ages, petrophysics, and borehole logging data with the existing seismic reflection data. Among these seismic unconformities, the T60 unconformity is the most prominent. It is easily recognized basin-wide and is present at Sites U1500, U1501, U1502, U1503 (not sampled), and U1505. Though not resolved by seismic data, its stratigraphic position is also present at Site U1499 in an extremely

condensed section. Exploring its nature (e.g., timing and duration, processes, and mechanisms) is very important for understanding the regional geological evolution, but this objective will need further postexpedition work.

The postrift sediments cored during Expedition 367/368 will contribute to our understanding of the late Cenozoic tectonic and environmental history of the SCS. An early to middle Miocene succession of red claystone was found at Sites U1499, U1500, and U1502, all located deeper than 3500 mbls. The red claystone deposits near the acoustic basement (e.g., basalt or altered basalt or gravel) extending over all of these sites indicates that the SCS basin was deep and the sedimentation rate was extremely low at that time. These conditions may correlate with a basin-wide event related to deep circulation of oxygenated water from the western Pacific prior to the closure of the Luzon Strait.

A late Miocene succession of hemipelagic and turbidite deposits was observed at deeper Sites U1499, U1500, and U1502 and likely recorded the processes that delivered sediment from the shallow shelf or slope of the northern SCS to the deeper parts of the basin. A high sedimentation rate at the deep-water sites during the late Miocene and a nearly 10 Ma hiatus from the middle Miocene to Pleistocene observed at Site U1504 on the OMH indicate strong erosion from source areas in the upper slope and shelf region and efficient transport into the deep basin during late Miocene time.

In addition to the Oligocene to Plio-Pleistocene APC/XCB record (~100 percent) at Site U1505, the Plio-Pleistocene sequence was recovered by double APC, high-recovery holes at Site U1505 to establish a complete record for high-resolution paleoceanographic and paleoclimatic studies. The hemipelagic deposits, rich in calcareous microfossils, at this site above the modern CCD of the SCS should enable us to reconstruct the east Asian monsoonal climate and paleoceanographic changes in the SCS at orbital and millennial timescales.

Postexpedition research using samples from Expedition 367/368 together with seismic stratigraphic correlations will continue to improve the contributions to Objective 4. This research should be channeled into four general avenues:

1. To reconstruct the early stage history of the SCS, including paleoenvironmental changes from land to deep sea and new data (e.g., detrital zircon geochronology) to constrain the sedimentary provenance,

2. To explore the paleoceanographic conditions favorable for early to middle Miocene pelagic red clay and late Miocene turbidite deposition through geochemical and geophysical techniques,

3. To correlate the chronostratigraphic records between all ODP (Leg 184) and IODP drill sites from Expedition 349 and Expedition 367/368 sites in the SCS, and

4. To conduct high-resolution paleoceanographic study of Plio-Pleistocene- and Pleistocene-related monsoonal climate changes and deep-water exchange between the SCS and the Pacific.

## Integration of drilling results with seismic data

The large regional set of high-quality seismic data provided by the CNOOC formed an essential basis for the planning, scheduling, and implementation of Expedition 367/368. The continued availability of these data to the scientific party will be pivotal for postexpedition research on most of the scientific objectives discussed above.
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# Expedition 367/368 methods<fnref n="1" />

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Zhen Sun, Zhimin Jian, Joann M. Stock, Hans Christian Larsen, Adam Klaus, Carlos A. Alvarez Zarikian, Jacopo Boaga, Stephen A. Bowden, Anne Briais, Yifeng Chen, Deniz Cukur, Kelsie A. Dadd, Weiwei Ding, Michael J. Dorais, Eric C. Ferré, Fabricio Ferreira, Akira Furusawa, Aaron J. Gewecke, Jessica L. Hinojosa, Tobias W. Höfig, Kan-Hsi Hsiung, Baoqi Huang, Enqing Huang, Xiao-Long Huang, Shijun Jiang, Haiyan Jin, Benjamin G. Johnson, Robert M. Kurzawski, Chao Lei, Baohua Li, Li Li, Yanping Li, Jian Lin, Chang Liu, Chuanlian Liu, Zhifei Liu, Antonio Luna, Claudia Lupi, Anders J. McCarthy, Geoffroy Mohn, Lachit Singh Ningthoujam, Michael Nirrengarten, Nobuaki Osono, David W. Peate, Patricia Persaud, Ning Qiu, Caroline M. Robinson, Sara Satolli, Isabel Sauermilch, Julie C. Schindlbeck, Steven M. Skinner, Susanne M. Straub, Xiang Su, Liyan Tian, Froukje M. van der Zwan, Shiming Wan, Huaichun Wu, Rong Xiang, Rajeev Yadav, Lang Yi, Cuimei Zhang, Jinchang Zhang, Yang Zhang, Ning Zhao, Guangfa Zhong, and Lifeng Zhong<fnref n="2" />

**Keywords:** International Ocean Discovery Program, IODP, JOIDES Resolution, Expedition 367, Expedition 368, Site U1499, Site U1500, Site U1501, Site U1502, Site U1503, Site U1504, Site U1505, northern South China Sea, rifted margin, continent-ocean transition zone, hyperextension, continental breakup, lithosphere thinning, outer margin high, embryonic ocean

## Introduction

This introduction provides an overview of operations, depth conventions, core handling, curatorial procedures, and analyses performed on the R/V JOIDES Resolution during International Ocean Discovery Program (IODP) Expeditions 367 and 368. These two expeditions were implemented as a single science program; the methods used were intended to be the same for both expeditions. Any differences are clearly noted in this chapter. The information applies only to shipboard work described in the Expedition reports section of the Expedition 367/368 *Proceedings of the International Ocean Discovery Program* volume. Methods used by investigators for shore-based analyses of Expedition 367 and 368 data will be described in separate individual publications.

## Site locations

GPS coordinates (WGS84 datum) from precruise site surveys were used to position the vessel at the Expedition 367 and 368 sites. A SyQwest Bathy 2010 CHIRP subbottom profiler was used to monitor seafloor depth on the approach to each site to confirm the depth profiles from precruise surveys. Once the vessel was positioned at a site, the thrusters were lowered and a positioning beacon was dropped to the seafloor. Dynamic positioning control of the vessel uses navigational input from the GPS system and triangulation to the seafloor beacon (Figure F1) weighted by the estimated positional accuracy. The final hole position was the mean position calculated from the GPS data collected over a significant portion of the time during which the hole was occupied.

## Contents

1 Introduction

5 Lithostratigraphy

11 Igneous and metamorphic petrology

22 Structural geology

26 Biostratigraphy

39 Paleomagnetism

48 Geochemistry

52 Physical properties

57 Downhole measurements

62 Correlation to seismic data

63 References

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<footnote n="1">¹ Sun, Z., Jian, Z., Stock, J.M., Larsen, H.C., Klaus, A., Alvarez Zarikian, C.A., Boaga, J., Bowden, S.A., Briais, A., Chen, Y., Cukur, D., Dadd, K.A., Ding, W., Dorais, M.J., Ferré, E.C., Ferreira, F., Furusawa, A., Gewecke, A.J., Hinojosa, J.L., Höfig, T.W., Hsiung, K.-H., Huang, B., Huang, E., Huang, X.-L., Jiang, S., Jin, H., Johnson, B.G., Kurzawski, R.M., Lei, C., Li, B., Li, L., Li, Y., Lin, J., Liu, C., Liu, C., Liu, Z., Luna, A., Lupi, C., McCarthy, A.J., Mohn, G., Ningthoujam, L.S., Nirrengarten, M., Osono, N., Peate, D.W., Persaud, P., Qui, N., Robinson, C.M., Satolli, S., Sauermilch, I., Schindlbeck, J.C., Skinner, S.M., Straub, S.M., Su, X., Tian, L., van der Zwan, F.M., Wan, S., Wu, H., Xiang, R., Yadav, R., Yi, L., Zhang, C., Zhang, J., Zhang, Y., Zhao, N., Zhong, G., and Zhong, L., 2018. Expedition 367/368 methods. *In Sun, Z., Jian, Z., Stock, J.M., Larsen, H.C., Klaus, A., Alvarez Zarikian, C.A., and the Expedition 367/368 Scientists, 2018. *South China Sea Rifted Margin*. Proceedings of the International Ocean Discovery Program, 367/368: College Station, TX (International Ocean Discovery Program). https://doi.org/10.14379/iodp.proc.367368.102.2018</footnote>

<footnote n="2">² **Expedition 367/368 Scientists' addresses.**</footnote>

<footnote>MS 367368-102: Published 28 September 2018</footnote>

<footnote>This work is distributed under the **Creative Commons Attribution 4.0 International** (CC BY 4.0) license.</footnote>

<footnote>CC BY</footnote>
<figure><img src="image_39.png" /><figcaption>Figure F2. Coring systems used during Expeditions 367 and 368. A. APC system. ID = inside diameter. (Continued on next page.)</figcaption></figure>

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## Drilling operations

The advanced piston corer (APC), half-length APC (HLAPC), extended core barrel (XCB), and rotary core barrel (RCB) systems were available during Expeditions 367 and 368. Because sampling and logging the lowermost sediments and basement were our highest priority objectives, we used the HLAPC during Expedition 368 but not during Expedition 367.

The APC and HLAPC systems cut soft-sediment cores with minimal coring disturbance relative to other IODP coring systems. After the APC/HLAPC core barrel is lowered through the drill pipe and lands above the bit, the drill pipe is pressured up until the two shear pins that hold the inner barrel attached to the outer barrel fail. The inner barrel then advances into the formation and cuts the core (Figure F2A). The driller can detect a successful cut, or “full stroke,” by observing the pressure gauge on the rig floor because the excess pressure accumulated prior to the stroke drops rapidly. Cores collected with the APC system are denoted by the letter “H,” and those collected with the HLAPC system are denoted by the letter “F.”

APC refusal is conventionally defined in one of two ways: (1) the piston fails to achieve a complete stroke (as determined from the pump pressure and recovery reading) because the formation is too hard or (2) excessive force (>60,000 lb) is required to pull the core barrel out of the formation. When a full stroke could not be achieved, one or more additional attempts were typically made, and with each attempt the bit was advanced by the length of the core barrel. Note that these attempts resulted in a nominal recovery of ~100% based on the assumption that the barrel penetrated the formation by the length of core recovered. If an APC core does not achieve a full stroke, the next core can be taken after advancing to a depth determined by the recovery of the previous core (advance by recovery) or to a depth of a full APC core (typically 9.7 m). When a full or partial stroke was achieved but excessive force could not retrieve the barrel, the core barrel could be “drilled over,” meaning that after the inner core barrel was successfully shot into the formation, the drill bit was advanced to total depth to free the APC barrel.

The standard APC system uses a 9.5 m long core barrel, whereas the HLAPC system uses a 4.7 m long core barrel. In most instances, the HLAPC system was deployed after the standard APC consis-

tently had <50% recovery. During use of the HLAPC system, the same criteria were applied in terms of refusal as for the APC system. Use of the HLAPC system allowed for significantly greater APC sampling depths to be attained than would have otherwise been possible.

The XCB system is typically used when the APC/HLAPC system has insufficient recovery. Cores collected with the XCB system are denoted by the letter “X.” In our case, however, the XCB system was not able to recover the unconsolidated sands encountered at depths where the APC/HLAPC system could not be used. The XCB system was used to advance the hole when HLAPC refusal occurred before the target depth was reached or when drilling conditions required it. The XCB system has a small cutting shoe that extends below the large rotary APC/XCB bit (Figure F2B). The smaller bit can cut a semi-indurated core with less torque and fluid circulation than the main bit, potentially improving recovery. The XCB cutting shoe typically extends ~30.5 cm ahead of the main bit in soft sediments but is allowed to retract into the main bit when hard formations are encountered. Shorter XCB cutting shoes can also be used. The XCB system could not recover the poorly consolidated and loose sand lithologies penetrated during Expedition 367.

The bottom-hole assembly (BHA) used for APC and XCB coring is typically composed of an 11⅞ inch (~29.05 cm) drill bit, a bit sub, a seal bore drill collar, a landing saver sub, a modified top sub, a
<figure><img src="image_41.png" /><figcaption>Figure F2 (continued). B. XCB system. C. RCB system. OD = outside diameter.</figcaption></figure>

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modified head sub, five 8¼ inch control length drill collars, a tapered drill collar, two stands of 5½ inch transition drill pipe, and a crossover sub to the drill pipe that extends to the surface.

The RCB system is a rotary system designed to recover firm to hard sediments and igneous basement. The BHA, including the bit and outer core barrel, is rotated with the drill string while bearings allow the inner core barrel to remain stationary (Figure F2C).

A typical RCB BHA includes a 9⅞ inch drill bit, a bit sub, an outer core barrel, a modified top sub, a modified head sub, a variable number of 8¼ inch control length drill collars, a tapered drill collar, two stands of 5½ inch drill pipe, and a crossover sub to the drill pipe that extends to the surface. Cores collected with the RCB system are denoted by the letter “R.”

Nonmagnetic core barrels were used for all APC, HLAPC, and RCB deployments. APC cores were oriented with the Icefield MI-5 core orientation tool when coring conditions allowed. Formation temperature measurements were taken with the advanced piston corer temperature tool (APCT-3; see **Downhole measurements**). Information on recovered cores, drilled intervals, downhole tool deployments, and related information are provided in the Operations, Paleomagnetism, and Downhole measurements sections of each site chapter.

## IODP depth conventions

The primary depth scales used are based on the length of the drill string deployed (e.g., drilling depth below rig floor [DRF] and

drilling depth below seafloor [DSF]), the length of core recovered (e.g., core depth below seafloor [CSF] and core composite depth below seafloor [CCSF]), and the length of logging wireline deployed (e.g., wireline log depth below rig floor [WRF] and wireline log depth below seafloor [WSF]) (see IODP Depth Scales Terminology at http://www.iodp.org/policies-and-guidelines/142-iodp-depth-scales-terminology-april-2011/file). In cases where multiple logging passes are made, wireline log depths are mapped to one reference pass, creating the wireline log matched depth below seafloor (WMSF) scale. All units are in meters. The relationship between scales is defined either by protocol, such as the rules for computation of CSF depth from DSF depth, or by user-defined correlations, such as core-to-log correlation. The distinction in nomenclature should keep the reader aware that a nominal depth value in different depth scales usually does not refer to the exact same stratigraphic interval.

Depths of cored intervals are measured from the drill floor based on the length of drill pipe deployed beneath the rig floor (DRF scale; Figure F1). The depth of the cored interval is referenced to the seafloor (DSF scale) by subtracting the seafloor depth of the hole from the DRF depth of the interval. Standard depths of cores in meters below seafloor (CSF-A scale) are determined based on the assumption that (1) the top depth of a recovered core corresponds to the top depth of its cored interval (at the DSF scale) and (2) the recovered material is a contiguous section even if core segments are separated by voids when recovered. Standard depths of samples and associated measurements (CSF-A scale) are calculated by adding
the offset of the sample or measurement from the top of its section and the lengths of all higher sections in the core to the top depth of the core.

If a core has <100% recovery, for curation purposes all cored material is assumed to originate from the top of the drilled interval as a continuous section. In addition, voids in the core are closed by pushing core segments together, if possible, during core handling. Therefore, the true depth interval within the cored interval is unknown. This result should be considered a sampling uncertainty in age-depth analysis or in correlation of core data with downhole logging data.

When core recovery is >100% (the length of the recovered core exceeds that of the cored interval), the CSF depth of a sample or measurement taken from the bottom of a core will be deeper than that of a sample or measurement taken from the top of the subsequent core (i.e., the data associated with the two core intervals overlap at the CSF-A scale). This overlap can happen when a soft to semisoft sediment core recovered from a few hundred meters below the seafloor expands upon recovery (typically by a few percent to as much as 15%). Therefore, a stratigraphic interval may not have the same nominal depth on the DSF and CSF scales in the same hole.

During Expeditions 367 and 368, all core depths below seafloor were initially calculated according to the CSF-A depth scale. Unless otherwise noted, all depths presented are calculated on the CSF-A scale and reported simply in meters (m).

## Curatorial procedures and sample depth calculations

Numbering of sites, holes, cores, and samples follows standard IODP procedure. A full curatorial identifier for a sample consists of the following information: expedition, site, hole, core number, core type, section number, section half, piece number (hard rocks only), and interval in centimeters measured from the top of the core section. For example, a sample identification of "367-U1499A-5H-2W, 31-33 cm" indicates a 2 cm sample removed from the interval between 31 and 33 cm below the top of Section 2 (working half) of Core 5 ("H" designates that this core was taken with the APC system) of Hole A at Site U1499 during Expedition 367 (Figure F1). The "U" preceding the hole number indicates the hole was drilled by the US platform, the *JOIDES Resolution*. The drilling system used to obtain a core is designated in the sample identifiers as follows: H = APC, F = HLAPC, R = RCB, and X = XCB. Integers are used to denote the "core" type of drilled intervals (e.g., a drilled interval between Cores 2H and 4H would be denoted by Core 31).

## Core handling and analysis

### Sediment

When the core barrel reached the rig floor, the core catcher from the bottom of the core barrel was removed and a sample was extracted for paleontological (PAL) analysis. Next, the sediment core was extracted from the core barrel in its plastic liner. The liner was carried from the rig floor to the core processing area on the catwalk outside the core laboratory, where it was split into ~1.5 m sections. Blue (uphole direction) and clear (downhole direction) liner caps were glued with acetone onto the cut liner sections.

Once the core was cut into sections, whole-round samples were taken for interstitial water chemical analyses. When a whole-round sample was removed, a yellow cap was used to denote the missing interval. Syringe samples were taken for headspace gas analyses according to the IODP hydrocarbon safety monitoring protocol.

Core sections were placed in a core rack in the laboratory. When the core sections reached equilibrium with laboratory temperature (typically after 2 h), they were run through the Whole-Round Multisensor Logger (WRMSL) for P-wave velocity on the P-wave logger (PWL), magnetic susceptibility, and gamma ray attenuation (GRA) bulk density (see Physical properties). The core sections were also run through the Natural Gamma Radiation Logger (NGRL), and thermal conductivity measurements were taken once per core when the material was suitable.

The core sections were then split lengthwise from bottom to top into working and archive halves. Investigators should note that older material can be transported upward on the split face of each section during splitting.

The working half of each core was described by the sedimentologists and structural geologists. Discrete samples were then taken for moisture and density (MAD) and paleomagnetic (PMAG) analyses and for remaining shipboard analyses such as X-ray diffraction (XRD) and carbonate (CARB). Samples were not collected when the lithology was a high-priority interval for expedition or post-expedition research (e.g., ash layers, etc.), there was unsuitable core material, or the core was severely deformed. During the expeditions, no samples were taken for personal postexpedition research (except for ephemeral pore water samples and five reconnaissance samples for lipids necessary to determine the appropriate sample volume/number to prepare for sensible postexpedition sampling).

The archive half of each core was scanned on the Section Half Imaging Logger (SHIL) and measured for point magnetic susceptibility (MSP), and reflectance spectroscopy and colorimetry (RSC) were measured on the Section Half Multisensor Logger (SHMSL). Labeled foam pieces were used to denote missing whole-round (WR) intervals in the SHIL images. The archive-half sections were then described visually and by means of smear slides for sedimentology. Finally, the magnetization of archive-half sections and working-half discrete pieces was measured with the cryogenic magnetometer and spinner magnetometer.

### Hard rock

Pieces were extracted from the core liner on the catwalk or directly from the core barrel on the rig floor. The pieces were pushed to the bottom of 1.5 m liner sections, and the total rock length was measured. The length was entered into the database using the SampleMaster application as "created length." This number was used to calculate recovery. The liner sections were then transferred to the core splitting room.

Oriented pieces of core were marked on the bottom with a wax pencil to preserve orientation. Adjacent but broken pieces that could be fit together along fractures were curated as single pieces. The petrologists and structural geologists confirmed piece matches and marked the split line on the pieces, which defined how the pieces were to be cut into two equal halves. The aim was to maximize the expression of dipping structures on the cut face of the core while maintaining representative features in both archive and working halves. A plastic spacer was secured with acetone to the split core liner between individual pieces or reconstructed contiguous groups of subpieces. These spacers can represent substantial intervals of no recovery. The length of each section of core, including spacers, was entered into the database as "curated length," which commonly differs by several centimeters from the length measured on the catwalk. Finally, the depth of each piece in the database was recalculated based on the curated length.
Core pieces were imaged around the full 360° circumference and then placed in a core rack in the laboratory. When the core sections reached equilibrium with laboratory temperature (typically after 2 h), the whole-round core sections were run through the WRMSL (GRA and magnetic susceptibility only) and NGRL (see **Physical properties**).

Each piece of core was split with a diamond-impregnated saw into an archive half and a working half, with the positions of plastic spacers between pieces maintained in both halves. Pieces were numbered sequentially from the top of each section, beginning with 1. Separate subpieces within a single piece were assigned the same number but lettered consecutively (e.g., 1A, 1B, etc.). Pieces were labeled only on the outer cylindrical surfaces of the core. If it was evident that an individual piece had not rotated around a horizontal axis during drilling, an arrow pointing to the top of the section was added to the label. The piece's oriented character was recorded in the database using the SampleMaster application.

The working half of each core was first described by the petrologists and structural geologists. Samples were then taken for thin section preparation and shipboard paleomagnetic and physical properties analyses. The archive half of each core was scanned on the SHIL and measured for MSP and RSC on the SHMSL. Thermal conductivity measurements were made on selected archive-half samples (see **Physical properties**). After the archive halves were fully described, samples were taken for shipboard analyses (thin sections, inductively coupled plasma spectroscopy [ICP], XRD, MAD, etc). Finally, the magnetizations of archive-half sections, archive-half pieces, and discrete samples taken from the working half were measured with the cryogenic magnetometer and spinner magnetometer.

When all steps were completed, cores were wrapped, sealed in plastic tubes, and transferred to cold storage space aboard the ship. At the end of the expedition, the cores were sent to the IODP Gulf Coast Repository (Texas A&M University, College Station, Texas [USA]), where samples for postexpedition research were taken.

## Drilling and handling core disturbance

Cores may be significantly disturbed and contain extraneous material as a result of the coring and core handling process (Jutzeler et al., 2014). In formations with loose sand layers, sand from intervals higher in the hole may be washed down by drilling circulation, accumulate at the bottom of the hole, and be sampled with the next core. The uppermost 10–50 cm of each core must therefore be examined critically during description for potential “fall-in.” Common coring-induced deformation includes the concave-downward appearance of originally horizontal bedding. Piston action can result in fluidization (“flow-in”) at the bottom of APC cores. Retrieval from depth to the surface can result in elastic rebound. Gas that is in solution at depth may become free and drive apart core segments within the liner. When gas content is high, pressure must be relieved for safety reasons before the cores are cut into segments. Holes are drilled into the liner, which forces some sediment as well as gas out of the liner. These disturbances are described in each site chapter and graphically indicated on the visual core descriptions (VCDs).

## Authorship of chapters

The separate sections of the methods and site chapters were written by the following scientists (authors are listed in alphabetical order; see **Expedition 367/368 participants** for affiliation information):

### **Expedition 367 (Sites U1499 and U1500)**

* Background and objectives: J.M. Stock and Z. Sun

* Operations: A. Klaus and S. Midgley

* Lithostratigraphy: J.L. Hinojosa, K.-H. Hsiung, B.G. Johnson, Z. Liu, C. Robinson, C. Su, and N. Zhao

* Igneous and metamorphic petrology: T.W. Höfig, X.-L. Huang, A. Luna, A.J. McCarthy, and L. Zhong

* Structural geology: M.F.R. Nirrengarten and C. Zhang

* Biostratigraphy: A. Furusawa, B. Huang, C. Lupi, X. Su, and R. Xiang

* Paleomagnetism: S.M. Skinner, L. Yi, and Y. Zhang

* Geochemistry: Y. Chen, M.J. Dorais, and L. Li

* Physical properties: J. Boaga, A. Briais, C. Lei, I. Sauermilch, R. Yadav, and J. Zhang

* Downhole measurements: J. Boaga, A. Briais, C. Lei, I. Sauermilch, R. Yadav, and J. Zhang

* Core-log-seismic integration: J. Boaga, A. Briais, C. Lei, I. Sauermilch, R. Yadav, and J. Zhang

### **Expedition 368 (Sites U1501–U1505)**

* Background and objectives: Z. Jian and H.-C. Larsen

* Operations: C.A. Alvarez Zarikian and K. Grigar

* Lithostratigraphy: K.A. Dadd, C. Liu, J.C. Schindlbeck, S.M. Straub, S. Wan, and G. Zhong

* Igneous and metamorphic petrology: D.W. Peate, S.M. Straub, and F.M. Van der Zwan

* Structural geology: W. Ding, R.M. Kurzawski, and G.T.F. Mohn

* Biostratigraphy: F. Ferreira, A.J. Gewecke, S. Jiang, H. Jin, B. Li, C. Liu, and P.-S. Yu

* Paleomagnetism: E.C. Ferré, S. Satolli, and H. Wu

* Geochemistry: S.A. Bowden, Y. Li, and L. Tian

* Physical properties: D. Cukur, E. Huang, J. Lin, L.S. Ningthoujam, N. Osono, P. Persaud, and N. Qiu

* Downhole measurements: D. Cukur, J. Lin, P. Persaud, and N. Qiu

* Core-log-seismic integration: J. Lin and H.-C. Larsen

## Lithostratigraphy

The lithologies of sediment and sedimentary rocks recovered during Expeditions 367 and 368 were determined using visual (macroscopic) core description, smear slides, and thin sections. Integration of data from digital core images, color reflectance spectrophotometry, magnetic susceptibility, XRD, and geochemistry provided complementary information. The methods employed during the expeditions were adapted from those used during IODP Expedition 349 (Li et al., 2015), along with those from other IODP expeditions (e.g., Expedition 339 Scientists, 2013). We used the DESClogik application to record and upload descriptive data into the Laboratory Information Management System (LIMS) database (see the DESClogik user guide at http://iodp.tamu.edu/labs/documentation). Spreadsheet templates were set up in DESClogik and customized for Expeditions 367 and 368 before the first core was brought on deck. The templates were used to record macroscopic core descriptions and microscopic data from smear slides and thin sections. The location of all smear slide and thin section samples taken from the core were recorded in the SampleMaster application, and descriptive data uploaded to the LIMS database were used to produce VCD standard graphic reports.
## Core preparation

Standard methods for splitting core were performed either by pulling a wire lengthwise through the center of the core or by cutting the core with a rock saw. Each piece of core was split into archive and working halves, with the archive half used for visual description. When splitting the cores with a wire, we sometimes gently scraped across the cut surface of the core section using a stainless steel or glass scraper to prepare the surface for unobscured description and digital imaging, especially in the upper, poorly consolidated intervals. Most cores were imaged after they had dried; however, some cores were imaged still damp from the water used during cutting if this enhanced the features. If these cores had partially dried before they were imaged, we applied a light spray of deionized water to dampen the surface.

## Visual core description

VCDs include a simplified graphical representation of each site on a core-by-core basis (Figure F3). The principal function of the graphic VCD is to present the physical observations of the core in a columnar format. Site, hole, core, and depth in meters CSF-A are given at the top of each VCD, with the depth and core section numbers plotted along the left margin. Next to the depth and section columns, we plotted the lithostratigraphic unit and the biostratigraphic age (see *Biostratigraphy*). The lithostratigraphic units were assigned by grouping intervals based on their lithologic similarities (see *Definition of lithostratigraphic units*). Further definition of the lithostratigraphic units and their boundaries is described in each site chapter. Additional columns correspond to either core images, physical properties (e.g., natural gamma radiation [NGR]), entries made in DESClogik, or shipboard sample locations. Data taken from DESClogik entries include core summary, principal lithology, sedimentary structures, bioturbation intensity, and drilling disturbances. The VCDs also include descriptive and lithostratigraphic information from the metamorphic and igneous rocks recovered at each site. Each VCD column is described in more detail below.

### Core summary

The core summary provides a brief overview of major and minor lithologies present in the core, as well as notable features (e.g., sedimentary structures). The summary is presented at the top of the VCDs and includes sediment color determined qualitatively using Munsell soil color charts. Because sediment color may evolve during drying and subsequent oxidization, color was described shortly after the cores were split and imaged or measured by the SHIL and SHMSL. Deionized water was applied to the cut surface of lithified sedimentary rocks before determining color.

### Core images

High-resolution color images were produced by scanning the flat surface of the archive-half sections with the SHIL. The cores were scanned as soon as possible after splitting and scraping to avoid color changes caused by sediment oxidation and drying. In some cases involving lithified rock, we photographed the cores both wet and dry and selected the image that best represented the lithology.

The SHIL uses three pairs of advanced illumination, high-current-focused, LED line lights to illuminate large cracks and blocks in the core surface and sidewalls. Each LED pair has a color temperature of 6500 K and emits 90,000 lx at 76.2 mm. A line-scan camera images 10 lines/mm to create a high-resolution TIFF file. The camera height is adjusted so that each pixel images a 0.1 mm² section of

the core. However, actual core width per pixel varies because of differences in section-half surface height. High- and low-resolution JPEG files are subsequently created from the high-resolution TIFF file. Two different image types were uploaded to the LIMS database: one that includes a grayscale and ruler and one that is cropped to exclude the grayscale and ruler.

### Graphic lithology

The graphic lithology column illustrates an interval-by-interval record of the primary lithologies contained within each core. The column was constructed by pairing the principal lithology name assigned to each interval in DESClogik with a predetermined set of lithology patterns (Figure F4). The column plots to scale all intervals that are at least 2 cm thick. Principal lithology names were not assigned to intervals thinner than 2 cm unless they were of special significance (e.g., ash layers).

### Reflectance

Reflectance of visible light from the archive halves of sediment cores was measured using an Ocean Optics USB4000 spectrophotometer mounted on the automated SHMSL. Freshly split cores were covered with clear plastic wrap and placed on the SHMSL, and measurements were taken at 1, 2, or 2.5 cm spacing to provide a high-resolution stratigraphic record of color variation for visible wavelengths. Each measurement was recorded in 2 nm wide spectral bands from 400 to 900 nm. Reflectance parameters L\*, a\*, and b\* were recorded (Balsam et al., 1997, 1998).

The SHMSL takes measurements in empty intervals and over intervals where the core surface is well below the level of the core liner, but it cannot recognize relatively small cracks, disturbed areas of core, or plastic section dividers. Thus, SHMSL data may contain spurious measurements that must be edited out of the data set by the user. When significant fragmentation and/or brecciation from drilling disturbances was evident, the SHMSL spacing was adjusted manually to avoid taking measurements in the wide spaces caused by drilling fractures. Additional detailed information about measurement and interpretation of reflectance data can be found in Balsam et al. (1997, 1998) and Balsam and Damuth (2000).

### Natural gamma radiation

NGR occurs primarily by decay of $^{238}$U, $^{232}$Th, and $^{40}$K isotopes. This radiation is measured using the NGRL (see *Physical properties*). Data generated from this instrument were used to augment geologic interpretations.

### Magnetic susceptibility

We measured magnetic susceptibility with a Bartington Instruments MS2E point sensor (high-resolution surface-scanning sensor) on the SHMSL. Because the SHMSL demands direct contact between the point magnetic susceptibility sensor and the split core, measurements were made on the archive halves of split cores that were covered with clear plastic wrap. Measurements were taken at 1.0, 2.0, or 2.5 cm spacing. Measurement resolution was 1.0 SI, and each measurement integrated a volume of 10.5 mm × 3.8 mm × 4 mm, where 10.5 mm is the length perpendicular to the core axis, 3.8 mm is the width along the core axis, and 4 mm is the depth into the core.

### Sedimentary structures

The location and type of stratification and sedimentary structures visible on the surface of the split cores are shown in the sedimentary structures column of the VCDs. Symbols in this column
<figure><img src="image_43.png" /><figcaption>Figure F3. Example graphic visual description form (VCD), Expeditions 367 and 368. cps = counts per second.</figcaption></figure>

indicate the location, scale, and frequency of stratification and other sedimentary features, such as sole marks, cross-lamination, and fining-upward intervals (Figure F5).

For Expeditions 367 and 368, the following terminology (based on Stow, 2005) was used to describe the scale of stratification:

Thin lamination = <0.3 cm thick.

Medium lamination = 0.3–0.6 cm thick.

Thick lamination = 0.6–1 cm thick.

Very thin bed = 1–3 cm thick.

Thin bed = 3–10 cm thick.

Medium bed = 10–30 cm thick.

Thick bed = 30–100 cm thick.

Very thick bed = >100 cm thick.

## Bioturbation intensity

Five levels of bioturbation are recognized using a scheme like that of Droser and Bottjer (1986). These levels are illustrated with a numeric scale in the bioturbation intensity column. Any identifiable trace fossils (ichnofossils) are identified in the general interval comment field in DESClogik and in the core summary.

1 = No bioturbation.

2 = Slight bioturbation (<10%–30%).

3 = Moderate bioturbation (30%–60%).

4 = Heavy bioturbation (60%–90%).

5 = Complete bioturbation (>90%).

## Drilling disturbance

Drilling-related sediment disturbance is recorded in the disturbance type and intensity columns. The disturbance intensity, where
<figure><img src="image_44.png" /><figcaption>Figure F5. Symbols and nomenclature used for visual core description, Expeditions 367 and 368.</figcaption></figure>

<figure><img src="image_45.png" /></figure>

present, is ranked on a five-point scale: slight, slight to moderate, moderate, moderate to high, and high. The type of drilling disturbance is classified using the symbols shown in Figure F5. Each symbol corresponds to the following terms:

* Soupy: intervals are water-saturated and have lost all aspects of original bedding.

* Fall-in: characteristically occurs at the top of individual cores when out-of-place material from the shallower cored interval has fallen downhole onto the cored surface.

* Up-arching: bedding planes are slightly to moderately deformed but still subhorizontal and continuous across the core surface. The edges of the bedding planes typically show a concave downward shape caused by shear along the wall of the core liner.

* Flow-in: occurs in unconsolidated, sandy, or gravelly sediment, leaving a soupy texture at the base of the core. It typically occurs during APC drilling, following a partial stroke of the piston core.

* Biscuit: sediments of intermediate stiffness show vertical variations in the degree of disturbance. Softer intervals are washed and/or soupy, whereas firmer intervals are relatively undisburdened.

* Fractured: common in consolidated and lithified sediments. The core pieces are broken in places and may have been partly displaced or moved, but the correct stratigraphic sequence is maintained.

* Fragmented: complete fracturing of the core into large (>2 cm thick) pieces, where the stratigraphic order of the pieces is retained but their orientation is lost.

* Drilling breccia: core is crushed and broken into many small and angular pieces, with original orientation and stratigraphic position lost.

## Samples

The shipboard samples column records the position of samples used for microscopic descriptions (i.e., smear slides and thin sections), biochronological determinations, and shipboard analyses of chemical and physical properties.

# Classification of principal lithology

## Types of sediment

The sediment recovered during Expeditions 367 and 368 was described and classified by measuring the relative proportions of biosiliceous, calcareous, and siliciclastic material (Figure F6). This
Figure F6. Siliciclastic-calcareous-biosiliceous ternary diagram used for sediment name classification of different compositions.

<figure><img src="image_46.png" /></figure>

classification scheme was adapted from Integrated Ocean Drilling Program Expedition 339 (Expedition 339 Scientists, 2013), Expedition 349 (Li et al., 2015) and Stow (2005). Biosiliceous sediment is restricted to only include siliceous skeletal remains of microorganisms (e.g., radiolarians and diatoms), whereas calcareous sediment includes a wide range of grain types, such as the skeletal remains of microfauna (e.g., foraminifers) and microflora (e.g., nannofossils), macrofossil shell fragments, and fine-grained detrital carbonate. Siliciclastic sediment includes mineral and rock fragments eroded from igneous, sedimentary, and metamorphic rocks. In rare cases, sediment recovered during Expeditions 367 and 368 included grains that were directly derived from a volcanic eruption, mainly in the form of vitric material (e.g., ash and lapilli), so a separate classification scheme was applied to their description.

Naming conventions for Expeditions 367 and 368 follow the general guidelines of the Ocean Drilling Program (ODP) sediment classification scheme (Mazzullo et al., 1988), except that during Expeditions 367 and 368 a separate “mixed sediment” category was not distinguished and detrital biogenic sediment with evidence of being reworked and transported by sedimentary processes was described using the terminology for siliciclastic rocks with a prefix that describes the main biogenic component. For example, the term “foraminifer sand” defines sediment composed of >50% foraminifer tests that are >63 µm in size. A principal lithology name is assigned to each interval, and when the sediment comprises a mixture of different sediment types, modifying prefixes and suffixes are added to the principal name.

We followed the naming scheme of Shepard (1954) for the classification of siliciclastic sediment and sedimentary rock that reflects the relative proportion of sediments of different grain size (Figure F7). Sediment grain size divisions for siliciclastic and redeposited biogenic components are based on Wentworth (1922), with categories based on the relative proportions of gravel and sand-, silt-, and clay-sized particles (Figure F8). Distinguishing between some of these categories can be difficult at the macroscopic level, especially

Figure F7. Lithologic classification for textural names, Expeditions 367 and 368. A. Shepard ternary classification diagram (Shepard, 1954). B. Biogenic classification. N = nannofossil.

<figure><img src="image_47.png" /><figcaption>Figure F8. Udden-Wentworth grain-size classification of siliciclastic sediment (Wentworth, 1922), Expeditions 367 and 368.</figcaption></figure>

<table><thead><tr><th>Millimeters (mm)</th><th>Micrometers (µm)</th><th>Phi (φ)</th><th>Wentworth size class</th></tr></thead><tbody><tr><td>4096</td><td></td><td>-12.0</td><td>Boulder</td></tr><tr><td>256</td><td>—</td><td>-8.0</td><td>Cobble</td></tr><tr><td>64</td><td>—</td><td>-6.0</td><td>Pebble</td></tr><tr><td>4</td><td>—</td><td>-2.0</td><td>Granule</td></tr><tr><td>2.00</td><td>—</td><td>-1.0</td><td>Very coarse sand</td></tr><tr><td>1.00</td><td>—</td><td>0.0</td><td>Coarse sand</td></tr><tr><td>1/2</td><td>0.50</td><td>1.0</td><td>Medium sand</td></tr><tr><td>1/4</td><td>0.25</td><td>2.0</td><td>Fine sand</td></tr><tr><td>1/8</td><td>0.125</td><td>3.0</td><td>Very fine sand</td></tr><tr><td>1/16</td><td>0.0625</td><td>4.0</td><td>Coarse silt</td></tr><tr><td>1/32</td><td>0.031</td><td>5.0</td><td>Medium silt</td></tr><tr><td>1/64</td><td>0.0156</td><td>6.0</td><td>Fine silt</td></tr><tr><td>1/128</td><td>0.0078</td><td>7.0</td><td>Very fine silt</td></tr><tr><td>1/256</td><td>0.0039</td><td>8.0</td><td>Clay</td></tr><tr><td>0.00006</td><td></td><td>14.0</td><td>Clay</td></tr></tbody></table>
considering the relative abundance of the fine-grained fraction (e.g., silty clay versus clayey silt); therefore, smear slides and thin sections were used in classifying fine-grained sediment abundances.

The proportions of biogenic material, both siliceous and calcareous sediment, were first macroscopically determined by observing changes in color. We used Munsell soil color charts to assign a color to different intervals within a core. Sediments that contained significant amounts of calcareous material typically had a lighter color value. Biogenic material was also determined by observing physical property changes in NGR, magnetic susceptibility, and reflectance values. Low magnetic susceptibility and high color reflectance values were two defining patterns associated with significant amounts of calcareous material. We then used smear slides and thin sections to identify and estimate the relative abundance of the different microfossils, such as nannofossils, foraminifers, and radiolarians, within unique lithologic intervals. However, smear slide observations tend to overestimate the relative proportions of calcareous microorganisms with respect to the clay-sized fraction of siliciclastic material, so we used the shipboard calcium carbonate data as a quality control. Sediment with >40 wt% calcium carbonate was classified using a calcareous principal lithology.

The lithologic names assigned to a given interval of sediment consist of a principal name and in some cases a modifying prefix and/or suffix. The assigned names are based on abundance and composition of grains determined from visual description of the core and from smear slide/thin section observations. For sediment that contains >90% of one component (either the siliciclastic or biogenic component), only the principal name was used. For sediment that contains >90% biogenic components and is not clearly reworked, the name applied indicates the most common type of biogenic grain. For example, sediment composed of >90% calcareous nannofossils was named nannofossil ooze, and sediment composed of subequal amounts of foraminifers and nannofossils was named calcareous ooze.

For sediment with >90% siliciclastic grains, the principal name is based on the textural characteristics of siliciclastic sediment particles (Figure F7). For sediment that contains a significant mixture of siliciclastic and biogenic components (between 10% and 90% of both siliciclastic and biogenic components), the principal name is determined by the more abundant component. If the siliciclastic component is more abundant, the principal name is based on the textural characteristics of siliciclastic fraction. If the biogenic component is more abundant, the principal name is based on the predominant microfossil group.

If a microfossil group composes 10%–50% of the sediment and this group is not included as part of the principal name, modifiers are used instead. When a microfossil group (e.g., diatom, nannofossil, or foraminifer) comprises 20%–50% of the sediment, a major modifier consisting of the component name hyphenated with the suffix “-rich” (e.g., nannofossil-rich clay) is used. When the calcareous or biosiliceous material comprises a mixture of different microfossil grain types, the major modifier “calcareous-rich” or “biosiliceous-rich” is used instead.

If the principal component forms 80%–90% of the sediment, the principal name is followed by a minor modifier (e.g., “with nannofossils”), with the minor modifier based on the most abundant component that forms 10%–20% of the sediment. If the minor component is biogenic, the modifier describes the most limited group of grains that exceeds the 10% abundance threshold. If the minor component is siliciclastic, the minor modifier is based on the texture of the siliciclastic fraction.

If the primary lithology for an interval of core has a major modifier, that major modifier is indicated in the Graphic lithology column of the VCDs using a modified version of the lithologic pattern for the primary lithology (Figure F3). The modified lithologic patterns are shown in Figure F4. The minor modifiers of sediment lithologies are not included in the graphic lithology column. Although size-texture qualifiers were used to describe siliciclastic sediment (using prefixes such as clayey or sandy), size-texture qualifiers were not typically used in the principal name for biogenic sediment.

## Lithification

The degree of lithification was determined by observing the amount of deformation the sediment can accommodate and the level of sediment consolidation. Sediment was considered lithified when the sediment could not be deformed easily with a finger, toothpick, or metal scraper. Lithification was ranked using a qualitative scale with the terms slightly consolidated, moderately consolidated, well consolidated, and lithified.

Depending on the principal lithology, different lithification terms were used. For example, the name “ooze” was applied to unlithified biogenic sediment predominantly composed of calcareous or siliceous microorganisms (e.g., nannofossil ooze). The term “ooze” indicates that the sediment can be deformed by a finger. Chalk is the lithified variant of calcareous ooze that is fine grained and more compact although it can be scratched by a fingernail. Lithified sediment composed of siliceous microfossils (diatoms and radiolarians) is called “radiolarite/diatomite.” Well-lithified calcareous sediment that contains evidence of shallow water deposition (e.g., skeletal macrofossils such as coral) was called “limestone” with supporting prefixes such as “bioclast-rich,” “clast-supported,” and “dolomitic.”

For unlithified siliciclastic sediment, no lithification term was added, and the sediment was named for the dominant grain size (i.e., gravel, sand, silt, or clay). For more lithified siliciclastic material, the suffix “-stone” was appended to the dominant size classification (e.g., claystone), except for sediment of gravel size where the terms “conglomerate” or “breccia” were used for well-rounded and angular clasts, respectively. The principal names “conglomerate” and “breccia” were modified using the terms “matrix-supported” and “clast-supported,” depending on the matrix to clast ratio.

When the mineralogical, chemical, or structural compositions of the sediments or sedimentary rocks have been altered or changed from their original form, the prefix “meta” is used in conjunction with principal lithology (e.g., metasandstone). These rocks are described under the Metamorphic tab in DESClogik. In many cases, however, no clear distinction of boundary between well-lithified sediments and metasedimentary rock exists. Furthermore, extensive alteration by veins, fractures, and other structural features requires special treatment, particularly when a sedimentary rock is crosscut by a mesh network of veins. For this reason, the name “breccia” is applied in several different ways (see **Igneous and metamorphic petrology**).

## Ash layers (volcaniclastic sediment)

The classification of volcanic sediments followed here differs from the standard ODP and IODP classification (Mazzullo et al., 1988) in that we adopted a descriptive (nongenetic) terminology like that employed during ODP Leg 197 and Integrated Ocean Drilling Program Expedition 324 (Shipboard Scientific Party, 2002; Expedition 324 Scientists, 2010). Unless an unequivocally pyroclastic
origin for volcanogenic particles could be determined, we simply described these deposits as we did for siliciclastic sediment (i.e., sand, silt, etc.).

Where evidence for a pyroclastic origin is compelling and the sediment has >50% vitric and other primary volcanic material, we adopted the classification scheme of Fisher and Schmincke (1984). In these instances, we used the grain size terms “volcanic block or bomb” (>64 mm), “lapilli” (2–64 mm), and “ash” (<2 mm) for uncon- solidated sediment and “volcanic breccia” (>64 mm), “lapillistone” (2–64 mm), and “tuff” (<2 mm) for lithified material. When the vol- canic particles compose between 25% and 50% of the sediment frac- tion, the modifier “tuffaceous” was used as the prefix for the siliciclastic sediment (e.g., tuffaceous sandstone). The term “hyalo- clastite” is used for vitroclastic (i.e., glassy) materials produced by the interaction of water and hot magma or lava.

## Smear slide and thin section observation

Two or more smear slide samples of the main lithologies were typically collected from the archive half of each core. Additional samples were collected from areas of interest (e.g., laminations, ash layers, and nodules). A small amount of sediment was taken with a wooden toothpick and put on a 2.5 cm x 7.5 cm glass slide. The sed- iment sample was homogenized with a drop of deionized water and evenly spread across the slide to create a very thin (about <50 µm) uniform layer of sediment grains for quantification. The dispersed sample was dried on a hot plate. A drop of Norland optical adhesive was added as a mounting medium to a coverslip, which was care- fully placed on the dried sample to prevent air bubbles from being trapped in the adhesive. The smear slide was then cured in an ultra- violet light box.

Thin sections were prepared by cutting 3–5 cm³ billets of lith- ified sediment from the working half of the core. In some cases, the cut billet was impregnated with a clear epoxy to further consolidate the grains. They were then mounted on 2.5 cm x 4.5 cm glass slides and ground down to a thickness of ~30 µm.

Smear slides and thin sections were examined with a transmit- ted-light petrographic microscope equipped with a standard eye- piece micrometer. The texture of siliciclastic grains (relative abundance of sand-, silt-, and clay-sized grains) and the proportions and presence of biogenic and mineral components observed in thin sections or smear slides were recorded in DESClogik. Biogenic and mineral components were identified using IODP Technical Notes 1 and 2 (Marsaglia et al., 2013, 2015) for smear slides, and their per- centage abundances were visually estimated using Rothwell (1989). The mineralogy of clay-sized grains could not be determined from smear slides. Note that smear slide analyses tend to underestimate the amount of sand-sized and larger grains because these grains are difficult to incorporate onto the slide.

Relative abundances of identified components such as mineral grains, microfossils, and biogenic fragments were assigned on a semiquantitative basis using the following abbreviations:

Tr = trace (<1% in field of view [FOV]).

R = rare (1%–5% in FOV).

C = common (>5%–25% in FOV).

A = abundant (>25%–75% in FOV).

D = dominant (>75% in FOV).

## X-ray diffraction analysis

Samples for XRD analyses were selected from the working half, generally at the same depth as sampling for solid-phase geochemis-

try and smear slide analyses. Approximately one 5 cm³ sample was taken of a representative lithology per core. Samples analyzed for bulk mineralogy were freeze-dried and homogenized by grinding in the metal ball mill. Prepared samples were top-mounted onto a sample holder and analyzed using a Bruker D-4 Endeavor diffrac- tometer mounted with a Vantec-1 detector using nickel-filtered CuKα radiation. Settings for the standard locked coupled scan were as follows:

Voltage = 37 kV.

Current = 40 mA.

Goniometer scan = 4°–70°.

Step size = 0.0166°.

Scan speed = 1 s/step.

Divergence slit = 0.3 mm.

Diffractograms of bulk samples were evaluated with the aid of the Jade6 or EVA software package, which allowed for mineral iden- tification and basic peak characterization (e.g., baseline removal and characteristic peak intensity). Files were created that contained d-spacing values, diffraction angles, and peak intensities with and without the background removed. These files were scanned by the Jade6 or EVA software to find d-spacing values characteristic of a limited range of minerals. Peak areas were further quantitatively es- timated by the TOPAS software. Shipboard evaluation yielded semiquantitative results of the presence and relative abundances of the most common mineralogical components by applying correc- tion factors (Cook et al., 1975) to the measured intensity of the char- acteristic reflections of minerals.

## Definition of lithostratigraphic units

Sediments and sedimentary rocks were described at two levels: (1) the descriptive interval (a single descriptive line in DESClogik) and (2) the lithostratigraphic unit. Lithostratigraphic units are de- fined as assemblages of multiple descriptive intervals containing similar principal lithologies that are typically tens to hundreds of meters thick (e.g., Tamura et al., 2015). Lithostratigraphic units should be clearly distinguishable from each other by several charac- teristics, such as composition, bed thickness, grain-size class, and internal homogeneity. Following IODP tradition, they are num- bered sequentially as Unit I, Unit II, and so on from the top of the core to the bottom. Subunits were defined within units that showed distinct changes in minor lithology types or bed forms but main- tained continuity in the principal lithology. For instance, a unit pri- marily composed of clay and interbedded silt would be divided into two subunits if the interbedded lithology changed to sand and silt in the lower half of the unit's interval. Note that this distinction was interpreted differently during Expeditions 367 and 368, so a greater number of subunits were defined during Expedition 367 than during Expedition 368.

## Igneous and metamorphic petrology

Expedition 367 and 368 core description procedures for igneous and metamorphic rocks are based on those from IODP Expeditions 349 and 351 (Li et al., 2015; Arculus et al., 2015) and ODP Legs 209 and 210 (Shipboard Scientific Party, 2004a, 2004b).

## Core description workflow

Prior to splitting the core into working and archive halves, each core was subjected to nondestructive physical property measure- ments (see Physical properties) and imaged using the SHIL (see
**Lithostratigraphy)** on a wet outside surface at four different angles (0°, 90°, 180°, and 270°) that were combined to form a 360° whole-round image. The coherent hard rock sections and/or hard rock pieces were then split by a diamond-impregnated saw along lines drawn by a petrologist and/or a structural geologist in order to preserve significant compositional and structural features in both the archive and working halves. Afterward, fragmented pieces of hard rock that fit together were assigned a joint number and labeled with a letter in consecutive order downsection (e.g., 1A, 1B, 1C). Plastic spacers separate pieces with different numbers. An arrow added to the labels of single pieces that showed no evidence of rotation indicates the orientation by pointing to the top of the section. Scanning of the cut, dry archive-half surfaces by the SHIL produced high-resolution color images. Then the archive halves were analyzed for color reflectance and magnetic susceptibility at 1–2.5 cm increments by deploying the SHMSL (see Lithostratigraphy). Shipboard samples were taken from working halves for carrying out destructive physical properties and paleomagnetic measurements, as well as thin section, XRD, and inductively coupled plasma-atomic emission spectroscopy (ICP-AES) analysis. Because of the presence of hyaloclastic lava-sediment mixtures and sedimentary veins, working halves of igneous rock cores were also sampled for paleontological and sedimentary studies.

Initial macroscopic examination of each core section focused on petrologic and alteration features, followed by characterization of structures (see Structural geology). Subsequently, the texture and composition of any veins were recorded. Apart from thin sections, all descriptions were made on the archive half of each core. The DESClogik software was used to record the macroscopic and microscopic observations of primary (igneous) and secondary (alteration/metamorphic) characteristics, forming the basis of all descriptions. The use of a hand lens and binocular microscope aided the estimation of mineral modes and sizes.

## Macroscopic visual core description

VCDs present and summarize macroscopic features observed in the cores. Expedition 349 VCDs were used as the basis for macroscopic descriptions for this study so they would remain as closely comparable as possible. The slightly modified VCDs display the following entries (from left to right) in terms of igneous, alteration, and metamorphic features for each core section (Figure F9; see Figure F10 for VCD legend):

* CSF-A depth scale (meters below seafloor);

* Core length scale from 0 to 150 cm;

* Number and orientation of hard rock pieces;

* Interval of shipboard samples;

* Scanned digital image of the archive half;

* Graphic representation of lithology;

* Symbol “G” (for igneous rocks, next to the graphic lithology), which indicates the presence of volcanic glass either in the glassy rind of chilled margins or in hyaloclastite, if encountered; thin horizontal lines in the graphic lithology constrain the section interval containing the volcanic glass and mark the location of chilled margins/contacts;

* Igneous or metamorphic lithologic unit number;

* Vein texture, type, and connectivity;

* Line chart displaying vesicularity percentage;

* Stacked line chart displaying percent phenocryst abundance for plagioclase (PLAG; red line), olivine (OL; green line), and clino-pyroxene (CPX; blue line), if present;

* Chart displaying variation in crystal size of modal groundmass (in millimeters);

* Column with variable patterns depicting alteration intensity;

* Overall grain size of the corresponding lithology and deformation intensity for metamorphic rocks, for which vesicularity, percent phenocryst abundance, groundmass grain size, and alteration intensity are not applicable;

* Plot showing whole-round magnetic susceptibility measurements (and point source for Site U1500);

* Diagram displaying color reflectance, with total reflectance (L*), red (a*), and blue (b*) (Site U1500) or individual red-green-blue color space (RGB) values (Sites U1502 and U1504); and

* Description summary of each igneous/metamorphic lithologic unit identified in the corresponding section (see below for details).

The section unit summary (presented on the right side of the VCD) for each igneous lithologic unit contains the following details:

* Expedition, site, hole, core, core type (archive or working half), section number, and interval;

* Igneous lithologic unit/subunit number(s) and representative piece (Site U1500);

* Lithology and volcanic description (e.g., massive flow);

* Color of the bulk rock determined on dry rock surfaces using standard Munsell soil color charts (Munsell Color Company, Inc., 2000);

* Texture (microstructure) based on total percentage of phenocrysts and microphenocrysts by volume;

* Percent phenocryst abundance and type based on minerals identifiable by the unaided eye, hand lens, or binocular microscope;

* Groundmass texture or mineralogy;

* Percent vesicle abundance;

* Upper and lower unit contact relations and boundaries based on physical changes observed in retrieved core material (e.g., presence of chilled margins, changes in vesicularity, and alteration), including information regarding their position within the section; the term “not recovered” was entered where no direct contact was recovered (Expedition 349 Scientists, 2015);

* Alteration intensity and vein mineralogy; and

* Comment, if applicable.

The section unit summary (presented on the right side of the VCD) for each metamorphic lithologic unit contains the following details:

* Expedition, site, hole, core, core type (archive or working half), section number, and interval;

* Metamorphic lithologic unit/subunit number(s);

* Lithology;

* Color of the bulk rock determined on dry rock surfaces using standard Munsell soil color charts (Munsell Color Company, Inc., 2000);

* Deformation intensity;

* Texture based on appearance, grain size distribution and presence of foliations, lineations, or shears;

* Mineralogy;

* Metamorphic condition, applying the metamorphic facies;

* Clast description, if applicable; and

* Comment, if applicable.
<figure><img src="image_48.png" /><figcaption>Figure F9. Example VCDs for igneous rocks from (A) Expedition 367 and (B) Expedition 368 and (C) metamorphic rocks from Expedition 368.</figcaption></figure>

<figure><img src="image_49.png" /></figure>

<figure><img src="image_50.png" /></figure>

## Igneous and metamorphic lithologic units and lithostratigraphic units

A hard rock lithologic unit is defined by rock type or the similarity of phenocryst/mineral assemblages within each rock type.

Boundaries are defined by major changes in rock type, in phenocryst/mineral assemblages, or in the presence of a significant thickness of intervening sedimentary rocks. All igneous and metamorphic lithologic units are given consecutive downhole Ara-
<figure><img src="image_51.png" /><figcaption>Figure F10. Symbols and nomenclature used in igneous VCDs, Expeditions 367 and 368.</figcaption></figure>

bic numerals (e.g., igneous or metamorphic lithologic Units 1, 2, 3, etc.).

To aid description of igneous and metamorphic units, it is often convenient to divide them into subunits that are named igneous or metamorphic lithologic Subunits 1a, 1b, 1c, and so on. For igneous sequences, lithologic subunits are typically used in cases where a given lithologic unit changed deposition type (e.g., massive flows changed to pillow lavas or basaltic breccia and brecciated basalt changed to massive flows). For metamorphic rocks, lithologic subunits are used when different lithologies occur intercalated with the main rock type that defines the lithologic unit, (e.g., appearance of calc-silicate schists and marble within a unit of chlorite-epidote schists). Closely intercalated intervals may be grouped as subunits to avoid repetitive entry at the small-scale level. Because of the diversity of basement rock types encountered during Expeditions 367 and 368 (fresh basalt lavas, highly altered basalt lavas, and metamorphic schists), different criteria had to be developed by the shipboard scientists to define lithologic subunits at each site. These criteria are described in detail in the relevant site chapters.

Lithostratigraphic units (as used in Lithostratigraphy) are defined for (1) igneous rocks in which successions of consecutive cooling or depositional units with similar volcanic characteristics could be identified based on modal compositions and matrix fabric and (2) metamorphic rocks in which successions of similar metamorphic conditions and fabric could be determined. For Expeditions 367 and 368, the lithostratigraphic units are equivalent to the igneous and metamorphic lithologic units described above. These successions are given consecutive downhole Roman numerals (e.g., lithostratigraphic Units III, IV, and V) that follow directly from the overlying sedimentary units (lithostratigraphic Units I and II, in this example).

## Magmatic rock classification

Igneous rocks were classified on the basis of abundance, grain size, and texture of their primary minerals based on the International Union of Geological Sciences (IUGS) system (Le Maitre et al.,

2005). This approach also applies to igneous clasts found in sedimentary lithostratigraphic units.

### Grain size classification

The classification of Neuendorf et al. (2005) was used for grain size division:

* Coarse-grained (crystal diameters = 5 to ≤30 mm),

* Medium-grained (crystal diameters = 1 to <5 mm), and

* Fine-grained (crystal diameters = 0.2 to <1 mm).

### Grain size distribution

Terms used to describe the grain size distribution are bimodal (two dominant mineral sizes), equigranular (principal minerals are in the same size range), inequigranular (principal minerals have different grain sizes), and seriate (continuous range in grain size).

### Texture

Textures (microstructures) were described macroscopically for all igneous rock core sections and microscopically for a subset of intervals having thin sections.

Textural descriptors applied to volcanic rocks are aphyric, holocrystalline, hypocrystalline (comprising both crystals [major component] and glass), hypohyaline (comprising both crystals [minor component] and glass), holohyaline (vitric; only glass), poikilitic (larger crystals enclose smaller grains), ophiitic (pyroxene encloses plagioclase laths), subophitic (pyroxene partially encloses plagioclase laths), porphyritic, phaneritic, aphanitic, trachytic, flow banding, perlite (rounded hydration fractures in glass), glomeroporphyritic (clusters of phenocrysts), “chilled” margin (a glassy or micro to cryptocrystalline margin), and layered.

### Mineral shape and habit

Descriptions of mineral habits were based on Leg 209 (Shipboard Scientific Party, 2004a). The terms euhedral, subhedral, anhedral, and interstitial were used to describe the shapes of crystals interpreted to preserve their igneous morphology. The aspect ratio
of the grains was used to describe the euhedral to subhedral habit of a crystal. The aspect ratio is the ratio of the short to the long dimension of the crystal:

* Equant: aspect ratio = less than 1:2,

* Subequant: aspect ratio = 1:2 to 1:3,

* Tabular: aspect ratio = 1:3 to 1:5, and

* Elongate: aspect ratio = more than 1:5.

The description of habits for plagioclase and clinopyroxene groundmass crystals was adapted from ODP Legs 148 and 206 (Shipboard Scientific Party, 1993, 2003):

* Cryptocrystalline aggregates of fibrous crystals (fibrous),

* Comb-shaped or sheaf-like plumose crystals (fibrous),

* Granular-acicular subhedral to anhedral crystals, and

* Prismatic-stubby euhedral to subhedral crystals.

## Primary lithology names of volcanic (extrusive and hypabyssal) rocks

Units and subunits were classified on the basis of groundmass texture and primary modal composition. The combined color and texture of the groundmass and the major phenocryst(s) found in hand specimens were used to give a principal lithology name to a given igneous lithologic unit. Three rock categories were defined according to Expedition 351 (Arculus et al., 2015):

* Basalt: a black to dark gray rock with a microcrystalline to cryptocrystalline groundmass that contains plagioclase and pyroxene and/or olivine,

* Andesite: a dark to light gray rock with a microcrystalline groundmass that contains pyroxenes and/or feldspar and/or amphibole but is typically devoid of olivine and quartz, and

* Rhyolite/dacite: a light gray to pale white rock with glassy to cryptocrystalline groundmass that is usually plagioclase to potassium feldspar phyric and sometimes contains quartz ± biotite.

A prefix was applied as a modifier to the primary lithology names to indicate the abundance of phenocrysts:

* Aphyric (<1% phenocrysts),

* Sparsely phytic (1%–5% phenocrysts),

* Moderately phytic (>5%–10% phenocrysts), and

* Highly phytic (>10% phenocrysts).

Moreover, the most abundant phenocryst phase was used as a mineralogical modifier for the primary lithology name of porphyritic rocks, whereas aphyric rocks were not assigned any mineralogical modifier. If present in a given sample, multiple phenocryst minerals were used as modifiers appearing in the order of increasing abundance. For example, in plagioclase-olivine phytic basalt, olivine is the more abundant phenocryst mineral.

Other volcanic rock types distinguished are fragmented rocks made up of either (1) lithic clasts associated with basaltic lava flows (basaltic breccias are defined as matrix-supported breccias with basalt clasts, whereas brecciated basalts are clast supported) or (2) hyaloclastites defined as glass-rich volcanic rocks formed by lava-water/sediment interaction where the lava is shattered into small angular glassy fragments that may be suspended in any sediment present. Breccias not related to flows are described in the Sedimentary tab in DESClogik (see DESC_WKB in Supplementary material). Large (>2 cm) volcanic clasts in sediments and sedimentary rocks were classified in the Volcanic tab in DESClogik.

## Groundmass

For the textural description of the groundmass of volcanic rocks, we used terms and definitions modified from Expedition 349 (Li et al., 2015). The groundmass of extrusive lithologies was defined as the finer grained matrix enclosing phenocrysts.

For grain size descriptions of the groundmass, we used the following terms:

G = glassy.

cx = cryptocrystalline (<0.1 mm).

µx = microcrystalline (0.1–0.2 mm).

fg = fine grained (>0.2–1 mm).

The following nomenclature was applied to describe the groundmass, predominantly at the microscopic level (MacKenzie et al., 1982; Neuendorf et al., 2005):

* Aphanitic (crystalline but individual grains not discernable with a hand lens),

* Equigranular (similar crystal sizes),

* Glomeroporphyritic (containing clusters of phenocrysts),

* Felty (tightly irregularly interwoven feldspar microlites),

* Holohyaline (100% glass),

* Holocrystalline (100% crystals),

* Hypohyaline (glass is a major component, and crystals are a minor component),

* Inequigranular (different crystal sizes),

* Intergranular (plagioclase crystals surrounded by interstitial granular pyroxene, olivine, and/or oxide minerals),

* Intertedral (plagioclase laths surrounded by interstitial glass or cryptocrystalline material),

* Interstitial (glass, crypto-, or microcrystalline material between coarser grained crystals),

* Ophitic (total inclusion of plagioclase in clinopyroxene),

* Porphyritic (increasing presence of phenocrysts),

* Seriate (continuous range in grain size),

* Spherulitic (fan-like arrangement of divergent microlites),

* Subophitic (partial inclusion of plagioclase in clinopyroxene), and

* Vitrophyric (phenocrysts in a glassy groundmass).

Flow textures are defined below.

Glass groundmass was recorded in terms of the percentage of fresh material:

* Fresh glass (amber in transmitted plane-polarized light and isotropic in transmitted cross-polarized light [XPL]),

* Dark glass (darkness is caused by abundant crystallites; interstitial volcanic glass of basaltic composition is termed tachylite),

* Glass with spherulites (spheroid aggregates of acicular crystals forming a nucleus), and

* Altered glass (partially or completely altered to clay minerals).

## Vesicularity

Vesicularity is characterized by the abundance of vesicles:

Nonvesicular = <1% vesicles.

Sparsely vesicular = 1%–5% vesicles.

Moderately vesicular = >5%–20% vesicles.

Highly vesicular = >20% vesicles.

The description of the size, shape, and roundness of vesicles is based on the classification charts from Integrated Ocean Drilling Program Expedition 330 and Expedition 349 (Expedition 330 Scientific
<figure><img src="image_52.png" /><figcaption>Figure F11. Comparison chart for describing vesicle sphericity and roundness in volcanic rocks, Expeditions 367 and 368. After Expedition 330 Scientists (2012) and Li et al. (2015), modified from Wentworth (1922).</figcaption></figure>

tists, 2012; Li et al., 2015), modified from Wentworth (1922) (Figure F11). An estimate of the percentage abundance of vesicles is included in the VCDs (Figure F9).

## Lava flow types

The suffix of the principal lithology name indicates the nature of the volcanic body. We applied the classification scheme used for Expedition 349 (Li et al., 2015), which includes the following types:

* Pillow lava flows: 0.1–1 m in thickness and defined by curved chilled margins, spherulitic textures, glassy margins and/or hyaloclastites, and microcrystalline to cryptocrystalline groundmass grain size, as well as decreasing crystal abundances and sizes (phenocrysts, groundmass) toward the glassy rims.

* Lobate lava flows: 1–2 m thick and formed by the same inflationary process as pillow lavas. In contrast to pillow lavas, they have massive, coarser grained, and sparsely vesicular flow interiors, often with pipe vesicle domains. Vesicle zoning occurs in the upper zones of the inflation unit as a series of vesicle bands, whereas the lower zones contain sparse, poorly defined vesicle banding and/or teardrop-shaped vesicles at the basal chilled zone.

* Sheet lava flows and massive lava flows: defined as more texturally uniform, sparsely vesicular, and characterized by a gradual increase in grain size toward the center of the flow, with sheet lava flows being <3 m thick and massive lava flows being >3 m thick.

For purposes of clarity, pillow lava flows and lobate lava flows are considered to be the same subunit when they occurred together. When pillow lava and lobate lava flows occurred in succession of each other, the igneous lithologic subunit was called a “pillow lava flow.” However, if a lobate lava flow had no pillow lava flow components and occurred as a separate flow either within or between massive and sheet flows, the igneous lithologic subunit was considered a “lobate lava flow” and given its own designation. Individual lobate and pillow lava flows were still recorded in DESClogik, but the lithologic subunit was not affected.

## Contact types

Margins and contacts of flows were described by observing the features of the chilled sections that indicate a possible hiatus between two flows/pillows. A chilled contact, with or without glass, was recognized by observing the terminal end of the margin for sediment that was not entrenched into the rock but rather baked or cooked onto the rock, indicating a baked or chilled contact with the rock. A chilled margin was recognized through identification of a sudden change in groundmass over a very short distance. Unlike a chilled contact, sediment at the terminal end of the lobe or pillow was not required to determine its nomenclature. Several sections were described as having a chilled contact (typically with glass) in direct contact with sediments with an adjacent (or grading into) chilled margin (typically without glass) where the groundmass was determined to be cryptocrystalline and graded into a microcrystalline texture further up- or downhole. Glassy margins, chilled margins, and contact boundaries were inserted individually for the top and bottom of each section where they could be determined to discriminate individual flows and allow for a greater level of precision in the descriptions.

The following contact types were defined:

* Baked contact: contact with sediments that were baked by proximity of lava.

* Bottom (or top) chilled contact: chilled contact with sediments, with or without glass, in direct contact with sediments.

* Bottom (or top) chilled margin: chilled contact without sediments, without glass, determined by cryptocrystalline groundmass, typically found quenched adjacent to the chilled contact.

* Chilled contact: a contact that cannot be determined to be top or bottom of a flow that has sediment attached, such as a “roller.”

* Chilled margin: a chilled contact without sediment or obvious glass that cannot be determined to be top or bottom of a flow.

* Glassy margin: a margin between two pillows that has no sediment and the pillows have fused together. There is no clear indication of the boundary between the pillows as originally deposited.

## Alteration

### Alteration minerals

Alteration minerals were recorded in DESClogik in the macroscopic template under separate tabs for alteration, veins, and halos. Primary minerals are rock-forming minerals present prior to alteration (e.g., igneous minerals), whereas secondary minerals are related to alteration (e.g., metasomatism and hydrothermal circulation). Secondary minerals found replacing primary minerals and composing vesicle fillings and veins were classified as dominant, second order, and third order.

Identified alteration minerals or mineral mixtures include carbonate (calcite, dolomite, or siderite), chlorite, clay minerals (green clay), epidote (clinozoisite), secondary feldspar (albite), iddingsite, iron hydroxides, iron oxide, mica (sericite), neptunite, silica (jasper, quartz, opal, or hydrated quartz), spinel (magnetite), sulfides (chalcopyrite, covellite, pyrite, or sphalerite), zeolites, or unknown when the mineral could not be identified.

### Alteration intensity

Low-temperature and low-pressure (i.e., seafloor) mineralization, veins, and background alteration were defined as alteration. Alteration description includes primary mineralogy, groundmass, phenocryst alteration, and infilling of vesicles and halos. Textures used to define groundmass alteration are patchy, corona, pseudomorphic, and recrystallized.
Levels of background alteration were recorded as follows:

Fresh = <2 vol.%

Slight = 2–10 vol.%

Moderate = >10–50 vol.%

High = >50–95 vol.%

Complete = >95 vol.%

## Veins and halos

We used the term “vein” to refer to any later crosscutting feature formed by sediment injection or precipitation from hydrothermal fluids and reserved the word “dike” to describe any later crosscutting feature that formed by introduction of magma. The term “halo” refers to alteration zones around veins or minerals identified by discoloration through change of the primary mineral assemblage. The density (i.e., the percentage of veins within a piece or an interval estimated visually), mineralogy, width, color, vein type (banded, composite, en echelon, haloed, intravenous, and uniform), connectivity (isolated, single, branched, and network), texture (cross-fiber, slipfiber, massive, polycrystalline, and vuggy), and contacts with host rocks (diffuse, irregular, and sharp) were described, modified from the criteria from Leg 209 (Shipboard Scientific Party, 2004a) (Figures F11, F12). The length, width, and orientation of representative veins in a section were measured.

## Metamorphic petrology

### Primary metamorphic lithology names

The nomenclature for metamorphic rocks applied here follows the recommendations of the IUGS Subcommission on the Systematics of Metamorphic Rocks (Schmid et al., 2004). A simple but comprehensive terminology for common metamorphic rocks follows their division into three major groups on the basis of their structure (as seen in hand specimen), giving the rock its principal lithology name: schist, gneiss, or granofels. The terms essentially reflect the degree of fissility or schistosity (i.e., a preferred orientation of tabular to elongate mineral grains or grain aggregates produced by metamorphic processes) shown by the rock. If the schistosity in a metamorphic rock is well developed, the rock has a schistose texture and is termed “schist.” If it is poorly developed, the rock has a gneissose texture and is termed “gneiss,” and if schistosity is effectively absent, the rock has a granofelsic texture and is termed “granofels.” Identified characteristic rock-forming minerals were added as a prefix. One exception to this general terminology was introduced for the specific case of mylonitic metabreccias (i.e., rocks showing an overprinted inherited fabric consisting of clasts within a matrix). To emphasize that the clasts are clearly prekinematic with respect to the mylonitic foliation, they were termed “granofels clasts.”

Other standard rock names used to describe metamorphic rocks as a function of mineralogy and texture are as follows:

* Marble: dominated by carbonates (>50% calcite ± Ca-bearing silicate, such as epidote and wollastonite). If the carbonates consist of dolomite, the prefix “dolomite” was added.

* Calc-silicate schist: schistose rock consisting of silicates and carbonates (<50% calcite ± Ca-bearing silicate, such as epidote and wollastonite).

### Metamorphic textures

For metamorphic rocks, textural descriptions such as ductile (pervasive, weak, strong, or mylonitic) and brittle deformation (cataclasite or fractures) were used, as well as porphyroblasts, neo-

<figure><img src="image_53.png" /><figcaption>Figure F12. Textures used to describe veins, Expeditions 367 and 368. From Li et al. (2015), modified from Expedition 324 Scientists (2010).</figcaption></figure>

blasts, and porphyroclasts. Reaction textures were categorized, including prograde and retrograde metamorphism, coronas, symplectites, and intergrowths.

For deformed rocks, characteristics include (1) fault breccia, defined as any rock composed of angular broken rock fragments held together by mineral cement or a fine-grained matrix; (2) cataclasite, defined as a rock whose mineral grains or aggregates are fractured, rotated, bent, and granulated without accompanying recrystallization; and (3) mylonites, defined as a rock from a shear zone where the dominant deformation mechanism is ductile as solid-state flow and whose mineral grain sizes are often reduced in size by dynamic recrystallization.

## Microscopic (thin section) description

The characterization of thin sections was used to complement and refine macroscopic core observations for igneous and metamorphic rocks (Figure F13). All thin section observations were entered into the LIMS database through a special DESClogik thin section template (see DESC\_WKB in **Supplementary material**). Thin section descriptions include both primary (igneous) rock-forming minerals (including phenocrysts, groundmass, etc.) and secondary (alteration/metamorphism) mineral phases (in veins, vesicles, groundmass, etc.). Their mineralogy, abundance (modal volume percentages), sizes, shapes, habits, textural relationships, inclusions, alteration color, intensity and style, veins (type and number), and vesicles (type and fillings) were determined, enabling verification of macroscopic observations. The percentages of the original, primary mineral phases, groundmass, and vesicles (Original [%] = Present [%] + Replaced [%]) anP when entering mineral abundances in DESClogik. Moreover, the presence of inclusions, overgrowths, zonations, and accessory minerals were documented.

### Extrusive and hypabyssal thin section descriptions in the LIMS database

Thin section descriptions include the following terms:

* Sample domain: if there is more than one domain on the slide, each domain is described separately. For example, a slide that shows a large sedimentary vein (25% of the slide) in a basaltic matrix (75% of the slide) is described as two slides (samples): the first sample domain as “vein” and the second one as “host rock”. Other possible domains include clast, glass, halo, lithology, and xenolith.

* Lithology prefix: lithology prefix for the described sample domain.

* Principal lithology: refers only to the lithology of the described sample domain, which includes basalt, brecciated basalt, breccia, and hyaloclastite.
<table><caption>Figure F13. Example of a thin section report for igneous rocks, Expeditions 367 and 368.</caption><tr><td>THIN SECTION LABEL ID:</td><td>367-U1500B-70R-2-W 120/124-TSB-TS_30</td><td>Thin section no.: 30</td></tr><tr><td>Observer:</td><td>A. Luna</td><td>Piece no.:</td></tr><tr><td>Thin section summary:</td><td colspan="2">Highly plagioclase phyllitic basalt with remnant olivine that has been mostly destroyed. Plagioclase and CPX are in near pristine condition. Vessicles are filled with calcite, and a green amorphous mineral that is being replaced by a zeolite. A vein bisects the slide from corner to corner and is filled with mostly calcite although there are two types of clay, one a sediment, the other is insitu weathering.</td></tr></table>

<figure><img src="image_54.png" /></figure>

Plane-polarized: 40780541

<figure><img src="image_55.png" /></figure>

Cross-polarized: 40780561

## Igneous Petrology

**Lithology:** highly plagioclase phyllitic basalt

**Groundmass grain size (avg.):** microcrystalline

**Texture:** porphyritic

**Grain size distribution:** bimodal

<table><thead><tr><th>Phenocrysts</th><th>Original (%)</th><th>Present (%)</th><th>Replaced (%)</th><th>Size min. (mm)</th><th>Size max. (mm)</th><th>Shape</th><th>Habit</th><th>Comments</th></tr></thead><tbody><tr><td>Plagioclase</td><td>20</td><td>18</td><td>2</td><td>0.5</td><td>3.25</td><td>euhedral</td><td>elongate</td><td></td></tr><tr><td>Olivine</td><td>2</td><td>1</td><td>1</td><td>0.25</td><td>0.25</td><td>euhedral</td><td>euhedral</td><td></td></tr></tbody><thead><tr><th>Groundmass</th><th>Original (%)</th><th>Present (%)</th><th>Replaced (%)</th><th>Size min. (mm)</th><th>Size max. (mm)</th><th>Shape</th><th>Habit</th><th>Comments</th></tr></thead><tbody><tr><td>Plagioclase</td><td>34</td><td>29</td><td>5</td><td>0.01</td><td>0.5</td><td>euhedral</td><td>elongate</td><td></td></tr><tr><td>Clinopyroxene</td><td>30</td><td>25</td><td>5</td><td>0.01</td><td>0.1</td><td>anhedral</td><td>elongate</td><td></td></tr><tr><td>Fe-Ti oxide</td><td>1</td><td>1</td><td>0</td><td>0.01</td><td>0.01</td><td>interstitial</td><td>subequant</td><td></td></tr><tr><td>Glass</td><td>0</td><td>0</td><td>0</td><td>N/A</td><td>N/A</td><td>N/A</td><td>N/A</td><td></td></tr></tbody></table>

## Alteration

**Alteration intensity:** slight

**Total alteration (%):**

**Recrystallization extent:** weak

<table><thead><tr><th>Alteration mineral</th><th>Percent</th><th>Comments</th></tr></thead><tbody><tr><td>Calcium carbonate</td><td>1</td><td></td></tr><tr><td>Chlorite</td><td>2</td><td>chlorite appears to be infilling areas that are not vesicles but are voids possibly due to dissolution</td></tr><tr><td>Clay, other</td><td>5</td><td>clay mineral located within the vein crossing the slide</td></tr><tr><td>Zeolite</td><td>15</td><td>zeolites appear to be replacing green chlorite within the vesicles and forming acicular radiating laths</td></tr><tr><td>Other</td><td></td><td>olivine crystals have been replaced by iddingsite</td></tr></tbody></table>

**Vesicle abundance (%):** 10

**Vesicle shape:** rounded

**Vesicle distribution:** moderate

**Vesicle min. size (mm):** 0.1

**Vesicle max. size (mm):** 1.2

**Vesicle mode size (mm):** 0.75

<table><thead><tr><th>Vesicle fill composition</th><th>Percent</th></tr></thead><tbody><tr><td>Total vesicle fill</td><td>95</td></tr><tr><td>Calcium carbonate</td><td>25</td></tr><tr><td>Zeolite</td><td>75</td></tr></tbody></table>

## Veins and Halos

**Vein type:** composite vein

**Vein boundary:** diffuse boundary or contact

**Avg. thickness (cm):** 2

**Vein texture:** polycrystalline

<table><thead><tr><th>Vein fill composition</th><th>Percentage</th></tr></thead><tbody><tr><td>Calcium carbonate</td><td>50</td></tr><tr><td>Fe oxide</td><td>15</td></tr></tbody></table>

**Vein comments:** filled with clays from sediment as well as a diagenic clay, calcite and iron oxide
* Average groundmass grain size modal name: grain sizes follow Neuendorf et al. (2005) using the divisions glass, cryptocrystalline, microcrystalline, fine-, medium-, and coarse-grained (as defined in **Primary lithology names of volcanic (extrusive and hypabyssal) rocks**).

* Maximum grain size modal name: analogous to "average groundmass grain size modal name."

* Grain size distribution: bimodal, equigranular, granular, inequigranular, poikilitic, and seriate (see **Texture**).

* Texture: aphanitic, aphyric, granular, glomeroporphyritic, holocrystalline, holohyaline, hypocrystalline, hypohyaline, intergranular, intersertal, interstitial, ophitic, porphyritic, seriate, spherulitic, subophitic, trachytic, and vitrophyric (see definitions above).

* Mineral phenocryst shape: the dominant (>50% of crystals) shape of the olivine (ol), plagioclase (plag), clinopyroxene (cpx), orthopyroxene (opx), and spinel (sp) crystals in euhedral, subhedral, and anhedral shapes.

* Mineral phenocryst habit: the dominant (>50% of crystals) habit of ol, plag, cpx, opx, and sp crystals in elongate, equant, subequant, and tabular habits (see definitions below).

* Plag phenocryst zoning type: continuous, discontinuous, oscillatory, and patchy zonation of the plagioclase crystals.

* Plag phenocryst zoning extent: none, scarce, abundant, and very abundant.

* Cpx and opx phenocryst exsolution: blebs and lamellae.

* Vesicle shape: see Figure F11.

* Mineral groundmass shape: for ol, plag, cpx, opx, sp, Fe-Ti oxides and sulfides—euhedral, subhedral, and anhedral.

* Mineral groundmass habit: for ol, plag, cpx, opx, sp, Fe-Ti oxides and sulfides—elongate, equant, subequant, and tabular.

Additional features such as dissolution/resorption textures, sieve textures, and inclusions are noted in the comments section.

Domains in DESClogik define different lithologies or textural domains inside a single lithologic unit (see **Igneous and metamorphic lithologic units and lithostratigraphic units**) within a thin section, including a diverse population of clasts, xenoliths, alteration, mingled magma, vesicular banding, and so on. Thus, thin sections encompassing a single lithologic unit might have multiple domains defined as Domain 1, Domain 2, and so on.

## Metamorphic thin section description

Thin section descriptions include stable mineral parageneses, grain sizes, texture, minerals overprinting events (e.g., coronas, overgrowths, and pseudomorphs), secondary mineral assemblages, and estimation of the metamorphic facies. Such information is provided in the thin section summary in DESClogik.

Thin section descriptions include the following terms:

* Sample domain: if there is more than one domain on the slide, each domain is described separately. For example, a slide that shows a large granofels clast (25% of the slide) in an epidote-chlorite schist (75% of the slide) is described as two slides (samples): the first sample domain as "clast" and the second one as "groundmass."

* Lithology prefix: lithology prefix for the described sample domain that includes epidote-chlorite, calc-silicate, and epidote.

* Principal lithology: refers only to the lithology of the described sample domain, which includes schist and granofels.

* Average grain size modal name: grain sizes follow Neuendorf et al. (2005) using the divisions cryptocrystalline, microcrystalline, fine grained, medium grained, and coarse grained.

* Maximum grain size class: maximum grain size encountered in the thin section, which includes fine grained, medium grained, and coarse grained.

* Grain size distribution: bimodal, equigranular, granular, inequigranular.

* Texture: isotropic and foliated.

## Chemical analysis

During Expedition 368, a handheld portable X-ray fluorescence spectrometer (pXRF) (Olympus Delta) was used to conduct rapid in situ chemical analysis of solid rock samples (surfaces of the archive core sections and thin section billets). Previous IODP expeditions (e.g., Reagan et al., 2015; Ryan et al., 2017) demonstrated the utility of the pXRF to provide quick chemical characterization of igneous rocks encountered in the core. Such data are invaluable in initial assessments of broad chemical variations and the nature of the igneous rocks and, in conjunction with petrographic observations, in determining unit boundaries. These compositional data also help to target sample selection for postexpedition research.

The Olympus Delta pXRF is a self-contained, energy-dispersive XRF survey instrument. The instrument setup includes several modes (e.g., Geochem and Soils) that apply different correction protocols depending on sample type and geometry. During Expedition 368, we only applied the Geochem mode, which uses two sequential beams of different energy to determine a wide range of elements. The Olympus Delta pXRF cannot determine elements lighter than Mg (such as Na). For quantitative analyses, it is important to have the sample surface parallel to and in direct contact with the face of the instrument analyzer. To ensure a consistent geometry, two different holders were used, depending on the type of sample. Long core pieces (>5 cm) were analyzed directly in the core liner using a specially made, shielded XRF holder that holds the pXRF pointed vertically downward and resting in direct contact with the flat core surface. For smaller rock pieces (<5 cm) and calibration standard powders, the pXRF was pointed vertically upward and supported in a stand, and a special shielded chamber was attached to the front of the instrument. This allowed samples to be placed directly on the face of the analyzer. Analyses were made directly on the archive half of the core. Each measurement took 60 s, and three measurements were implemented on each sample point and averaged for an individual analysis (following the protocol in Reagan et al., 2015). A basaltic powder standard reference material (BHVO-2) was analyzed approximately every 12 samples to monitor data quality and instrument performance. Raw data were exported regularly and saved to the shipboard file directory for easy access. All data processing was done using Microsoft Excel spreadsheets.

To assess how well the correction protocols of the Geochem analysis mode recovered accurate concentration data in igneous rocks, calibration curves were produced on powder mounts of a suite of international standard reference materials (JP-1, BIR-1, BE-N, BCR-2, JB-2, AGV-1, and JA-2). These standards were chosen to cover the range of compositions that were initially anticipated for Expedition 368 (basalts, andesites, and peridotites). The accepted values for these standards were taken from the GEOREM database (http://georem.mpch-mainz.gwdg.de). These calibration standards were analyzed at the start (11 May 2017) and end (7 June 2017) of the analysis period (Table T1). Drift over this time period is limited (Figure F14), so the data from both calibration runs were combined to calculate a single calibration curve for each element.

<caption>Table T1. Major element oxides and minor elements in reference solids, Expedition 367/368. Download table in CSV format.</caption>
Figure F14. Comparison plots of measured pXRF data on a suite of reference materials (JP-1, BIR-1, BE-N, BCR-2, JB-2, AGV-1, and JA-2) compared to accepted values (preferred values from GEOREM database; http://georem.mpch-mainz.gwdg.de). Calibration reference materials were analyzed at the start (11 May 2017; open circles) and end (7 June 2017; solid circles) of the analysis period. Drift over this time period is limited relative to the method precision, so a single calibration curve was calculated from these data for each element (solid black line). Calibration curves were then used to apply a secondary correction to the raw data (see text for details). Dashed line = 1:1 trend. (Continued on next page.)

<figure><img src="image_56.png" /></figure>

These calibrations were used to correct the raw concentration data output from the pXRF to improve the accuracy relative to the accepted values for the mafic igneous rock standards. Although these secondary calibrations were made on powders of standard materials and expedition data were measured on solid core material, previous studies have shown that this difference in method does not introduce

any significant bias within the precision of the pXRF data (e.g., Ryan et al., 2017). Calibration data for 21 elements (Si, Ti, Al, Fe, Mn, Mg, Ca, K, P, V, Cr, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Mo, and Pb) are shown in Figure F14. For the remaining 13 elements measured by the pXRF (S, Co, As, Se, Ag, Cd, Sn, Sb, W, Hg, Bi, Th, and U), concentrations in the suite of standards were mostly below the instru-
<figure><img src="image_57.png" /><figcaption>Figure F14 (continued).</figcaption></figure>

ment detection limits, so these elements were not considered further and are not reported in data tables. Although S is below detection limits in the calibration standards, it is semiquantifiable in rocks containing sulfide minerals, so raw S concentration data are reported when detected in samples. The correlation curves in Figure F14 are of varying quality, but most give high correlation coefficient values ($R^2$ > 0.95). In a few cases, the high $R^2$ values are influenced by one standard with a significantly higher (Mg, Cr, Ni, Nb, and Mo) or lower (Al) concentration. Several elements, such as Fe and Ca, show excellent correlations but with slopes that are significantly different to 1, and for these particular elements, making the secondary calibration correction is critical to get accurate data. Although V is above the instrument detection limits in most samples, a secondary calibration could not be applied because the calibration curve is extremely poor, and V results are presented as raw data only for information.

Results for the 42 replicate analyses of the data quality standard reference material (BHVO-2) are given in Table T1. Two of the 42 analyses had anomalously low values ($SiO_2$ and $Al_2O_3$), perhaps indicating that the powder mount was not properly centered over the analysis window, and are thus excluded from the data analysis. Re-

producibility over the course of analytical work during Expedition 368 was better than ±3% (relative standard deviation) for many elements (Si, Ti, Al, Fe, Mn, Ca, K, Ni, Cu, Zn, Sr, Y, and Zr) and better than ±10% for the remaining elements (Mg, P, Cr, Rb, Nb, and Mo), except for V (11%) and Pb (which is close to the instrument detection limit in BHVO-2). In terms of accuracy, the corrected concentrations of Si, Fe, Mn, Ca, Zn, Sr, Zr, and Nb are within 3% of the accepted values for BHVO-2 and Ti, Mg, K, Cu, and Y are within 5% of the accepted values.

To complement and considerably extend the chemical analysis made by the shipboard pXRF data set, a third-generation, energy-dispersive Avaatech XRF core scanner was used postexpedition. Onshore in situ XRF measurements were implemented for major (beyond the atomic number of Mg) and selected trace elements on Site U1500 and U1502 volcanic rock sections at the JRSO XRF Core Scanning Facility at the Gulf Coast Repository at Texas A&M University. A high standard resolution of 2 cm was applied (partially down to 0.1 cm), whereas a lower resolution had to be chosen in sections with cracks, rubble, and plastic spacers. Three runs with irradiated sample dimensions of 1.2 cm cross-core and 1 cm down-core were performed on each core section along its centerline under
<figure><img src="image_58.png" /><figcaption>Figure F17. Vein description scheme used during Expeditions 367 and 368, modified after Expedition 324 Scientists (2010).</figcaption></figure>

<figure><img src="image_59.png" /></figure>

* Veins: fractures filled with secondary minerals. Veins were described in both the Structure and Veins/halos tabs in DESC-logik.

* Fault rocks: brittlely deformed rocks such as fault breccia and fault gouge. For sake of simplicity in this volume, the term “fault breccia” is defined as a clast-supported fault rock with angular clasts, and the term “fault gouge” is defined as a matrix-supported fault rock with rounded clasts.

* Hydrothermal breccia: fluid-assisted deformation leading to the fragmentation and brecciation of the rocks.

* Shear zones: zones affected by ductile crystal-plastic deformation and surrounded by less deformed rocks.

* Sedimentary bedding: layering of sediments and sedimentary rocks.

* Folds: folded sedimentary or basement rock layers.

* Igneous contacts: material contacts of extrusive or intrusive igneous rocks.

* Magmatic fabrics: magmatic foliations defined by the preferred orientations of primary minerals with no evidence of crystal-plastic deformation.

## Structural observation and description

Structural features were described from the top to the bottom of each section of the core. For fractures, we examined and measured the following parameters:

* Location: where a fracture occurs in a core, measured in centimeters from the top of the section.

* Morphology and structure: morphological shape of a fracture (e.g., straight, curved, banded, irregular, composite, isolated, single or branched).

* Displacement: lateral offset and/or opening of a fracture measured in centimeters; a closed fracture with no lateral offset is recorded as 0 cm of displacement.

* Orientation: dip angle, strike, and dip direction of a fracture measured in degrees; where applicable, reorientation of a fracture to geographic coordinates (i.e., relative to true north) was done to determine the real dip direction (see **Orientation measurements and correction**).

* Frequency: occurrence frequency of fractures per section.

* Types: type of deformation of a fracture (e.g., normal, reverse, dextral, sinistral displacement, or a combination of the above).

For veins, we examined and measured several parameters:

* Location: where a vein occurs in a core, measured in centimeters from the top of the section.

* Morphology: main morphological characteristics of a vein such as shape, connectivity, texture, structure, and particular vein geometries (Figure F17).

* Orientation: dip angle and dipping direction of a vein.

* Frequency: occurrence frequency of veins per section.

* Mineral infill and alteration: these features are recorded as described by petrologists.

For fault rocks, hydrothermal breccias, and shear zones, we examined and measured the following parameters:

* Location: interval where a shear zone occurs in a core, measured in centimeters from the top of the section.

* Nature: type of fault rock, hydrothermal breccia, or shear zone, including fault gouge, fault breccia, cataclasite and mylonite.

* Morphology: morphological shape of the deformed zone and of the clasts.
* Orientation: dip angle and dip direction of the preferred orientation of the clasts, where applicable.

* Deformation intensity: characterization of the deformation intensity including foliation development.

* Frequency: occurrence frequency of shear zones per section.

* Mineral and alteration: matrix and clasts described by petrologists.

For sedimentary bedding, we described the following parameters:

* Location: where a nonsubhorizontal bedding occurs in a core (dip > 5°), measured in centimeters from the top of the section.

* Type of contacts: type of sedimentary contact boundary.

* Orientation: dip angle, strike, and dip direction of sedimentary bedding.

For folds, we described the following parameters:

* Location: where a fold contact occurs in a core, measured in centimeters from the top of the section.

* Type: type of fold.

* Frequency: occurrence frequency of fold axis per section.

For igneous contacts, we described the following parameters:

* Location: where an igneous contact occurs in a core, measured in centimeters from the top of the section.

* Type of contacts: type of igneous contact boundary.

* Orientation: dip angle and dip direction of an igneous contact.

* Frequency: occurrence frequency of igneous contacts per section.

* Mineral infill and alteration: as described by petrologists.

For magmatic fabrics, we measured the following parameters:

* Location: where a magmatic fabric feature occurs in a core, measured in centimeters from the top of the section.

* Morphology: morphological shape of a magmatic fabric feature.

* Orientation: dip angle, strike and dip direction of a magmatic fabric feature.

* Frequency: occurrence frequency of magmatic fabrics per section. The occurrence frequency of a structure per section is normalized on a 10 cm section.

## Orientation measurements and correction

### Orientation measurements

We used a plastic goniometer for orientation measurements. For sealed structures, we wrapped a transparent plastic protractor template around the core to determine the true dip (Figure F18). Orientations of planar and linear features in a core section were determined relative to the core reference frame (Figure F19). The vertical axis of the core reference frame is aligned with the upcore direction of the core section, whereas the double line marked on the core liner is defined as 180° in the cross-sectional plane perpendicular to the core vertical axis.

To determine the orientation of a planar structural element (shaded plane in Figure F19), two apparent dips of the element were measured in the core reference frame. The first apparent dip measures the intersection angle between the planar structural element and the split face of the core ($β_1$ in Figure F19); it is determined by measuring the dip direction and angle of the planar structural element in the core reference frame. A planar structural element could have a trend of 90° or 270° and a plunge angle ranging from 0° to 90°. The second apparent dip measures the intersection angle between

<figure><img src="image_60.png" /><figcaption>Figure F19. Core reference frame and coordinates used in orientation data calculation, Expeditions 367 and 368. ($α_1, β_1$) and ($α_2, β_2$) = azimuths and apparent dips of traces of the plane on two sections, $V_1$ and $V_2$ = unit vectors parallel to traces of the plane on two sections, $V_n$ = unit vector normal to plane.</figcaption></figure>

<figure><img src="image_61.png" /></figure>

the central line of the planar structural element and the split face of the core ($β_2$ in Figure F19). In most cases, this was a plane either parallel or perpendicular to the core axis. In the former case, the apparent dip would trend 0° or 180° with a plunge angle ranging from 0° to 90°; in the latter case, the trend would range from 0° to 360° with a plunge angle of 0°.

A linear feature observed in the surface of a split core is often associated with a planar structural element (e.g., a fault plane) in the core; the orientation of the planar structural element is determined by measuring either the rake (or pitch) of the associated plane or the
trend and plunge of the planar element in the core reference frame. All measured data were manually typed into the log sheet together with the measured depths in the core section and descriptive information (Figure F15).

## Plane orientation calculation

For a planar structural element (e.g., a bedding or fault plane), two apparent dips on two different surfaces (e.g., one being the split core surface, which is east-west vertical, and the other being a horizontal or north-south vertical surface) were measured in the core reference frame. The two apparent dips are the azimuth (measured clockwise from north, looking down) and plunge. An x, y, z coordinate system was defined in such a way that the positive x-, y-, and z-directions coincide with north, east, and vertical downward, respectively. If the azimuths and plunges of the two apparent dips are given as ($α_1, β_1$) and ($α_2, β_2$), respectively, as in Figure F19, the unit vectors representing these two lines, $v_1$ and $v_2$, are given by the following expression:

$$v_1 = \begin{pmatrix} l_1 \\ m_1 \\ n_1 \end{pmatrix} = \begin{pmatrix} \cos \alpha_1 \cos \beta_1 \\ \sin \alpha_1 \cos \beta_1 \\ \sin \beta_1 \end{pmatrix} \quad \text{and}$$

$$v_2 = \begin{pmatrix} l_2 \\ m_2 \\ n_2 \end{pmatrix} = \begin{pmatrix} \cos \alpha_2 \cos \beta_2 \\ \sin \alpha_2 \sin \beta_2 \\ \sin \beta_2 \end{pmatrix}.$$

For any plane, the direction of the normal to the plane can be found by taking the cross product of two (nonparallel) vectors that lie within the plane. Using the above equations for $v_1$ and $v_2$, therefore, the unit vector normal to plane $v_n$ (Figure F20) is defined as follows:

$$v_n = \begin{pmatrix} l_n \\ m_n \\ n_n \end{pmatrix} = \frac{v_1 \times v_2}{|v_1 \times v_2|}, \text{ where}$$

$$v_1 \times v_2 = \begin{pmatrix} m_1 m_2 \\ n_1 n_2 \\ |n_1 n_2| \\ l_1 l_2 \\ |l_1 l_2| \\ m_1 m_2 \end{pmatrix} = \begin{pmatrix} m_1 n_2 - m_2 n_1 \\ n_1 l_2 - n_2 l_1 \\ l_1 m_2 - l_2 m_1 \end{pmatrix}.$$

The azimuth $α_n$ and plunge $β_n$ of the vector $v_n$ are given by

$$α_n = \tan^{-1}\left(\frac{m_n}{l_n}\right) \text{ and}$$

$$β_n = \sin^{-1} n_n.$$

Figure F20. Dip direction ($α_d$), right-hand rule strike ($α_s$), and dip ($β$) of a plane deduced from its normal azimuth ($α_n$) and dip ($β_n$), Expeditions 367 and 368. $V_n$ = unit vector normal to plane. A. $β_n < 0°$. B. $β_n ≥ 0°$.

<figure><img src="image_62.png" /></figure>

<figure><img src="image_63.png" /></figure>

The dip direction $α_d$ and dip angle $β$ of this plane are $α_d = α_n$ and $β = 90° + β_n$, respectively, when $β_n < 0°$ and $α_d = α_n ± 180°$ and $β = 90° - β_n$, respectively, when $β_n ≥ 0°$. The strike of this plane, $α_s$, according to the right-hand rule is then given by $α_s = α_d - 90°$ (Figure F20).

## Azimuth correction based on paleomagnetic data

Provided that a core is vertical, its magnetization is primary, the core was magnetized in the Northern Hemisphere, and its bedding is horizontal, its paleomagnetic declination $α_p$ indicates the magnetic north direction when its inclination $β_p ≥ 0°$ (Figure F21); in contrast, the angle $α_p$ indicates the magnetic south direction when $β_p < 0°$. The dip direction and strike of a planar structural element in the geographic reference frame, $α_d^*$ and $α_s^*$, are therefore $α_d^* = α_p - α_d$ and $α_s^* = α_p - α_s$ when $β_p ≥ 0°$ or $α_d^* = 180° + α_p - α_d$ and $α_s^* = 180° + α_p - α_s$ when $β_p < 0°$.

If a core section was complete and continuous, one paleomagnetism sample per section (1.5 m) was deemed sufficient to determine the paleomagnetic orientation of the core section. If the core was discontinuous, one paleomagnetism sample for each subsection of the core that was continuous and structurally important was required. Paleomagnetism samples were taken as cubic or cylindrical samples close to a planar structural element of interest (usually within 5 cm) and from a coherent core interval that included the structural element of interest. In general, we avoided core fragments that were so small that potential spinning during drilling might cause significant deviation from the core axis (e.g., fragments of brecciated segments). This procedure was carefully followed, but for different reasons at each site we failed to reorient our structural measurements with respect to the paleomagnetic data.
<figure><img src="image_64.png" /><figcaption>Figure F21. Azimuth correction based on paleomagnetic data, Expeditions 367 and 368. αₚ = paleomagnetic declination, α₉ and α₅ = dip direction and right-hand rule strike of a plane. A. βₚ ≥ 0°. B. βₚ < 0°.</figcaption></figure>

Azimuth correction based on FMS log

If an FMS log is available for the section of the drill hole that
contains the core, there may be distinctive features that can be cor-
related from the FMS log to the core, such as bedding, fractures,
folds, veins, stratification, and bioturbation. In this case, the core
can be oriented with respect to geographic north. However, this ori-
entation has to be done after the FMS log is obtained after all the
cores in the hole have been collected.

Thin section description

Following ODP Leg 210 (the most recent expedition to sample
basement rocks similar to those of the current expeditions), thin
sections of sedimentary, igneous, and metamorphic rocks recov-
ered were examined to

* Document each type of macroscopic deformation structure in a systematic and quantitative way,

* Characterize the microstructure of the rocks,

* Provide information on the kinematics of ductile and brittle de-
  formation,

* Assess the role of fluids in contributing to deformation, and

* Document major structural zones and downhole variations.

For the description of microstructures, we applied the terminol-
ogy of Passchier and Trouw (2005). Shipboard thin sections were
oriented, except when they were made from small pieces whose ori-
entation with respect to the rest of the core was unknown. Orienta-
tion was in the core reference frame and was marked on each thin
section by an arrow pointing upward and a short tick pointing west
from the base of the arrow. Marking two directions is necessary to
achieve complete orientation of thin sections, which are cut parallel
to the split surface of the core.

Biostratigraphy

During Expeditions 367 and 368, calcareous nannofossils, planktonic and benthic foraminifers, diatoms, and ostracods were studied in core catcher samples. Samples from core sections were examined when a more refined age determination was necessary and when time permitted. Biostratigraphic events, mainly the first appearance datum (FAD or base) and last appearance datum (LAD or top) of the age-diagnostic species are tied to the geomagnetic polarity timescale (GPTS) of Gradstein et al. (2012) (Figure F22).

Calcareous nannofossils

Calcareous nannofossil zonation was based on the schemes of
Okada and Bukry (1980) and Martini (1971). Calibrated ages for
bioevents are from Gradstein et al. (2012) and given in Table T2.
The timescale of Gradstein et al. (2012) assigns the Pleisto-
cene/Pliocene boundary between the Gelasian and Piacenzian
stages (2.59 Ma), the Pliocene/Miocene boundary between the Zan-
clean and Messinian stages (5.33 Ma), the late/middle Miocene
boundary between the Tortonian and Serravalian stages (11.63 Ma),
the middle/early Miocene boundary between the Langhian and
Burdigalian stages (15.97 Ma), the Miocene/Oligocene boundary
between the Aquitanian and Chattian stages (23.03 Ma), and the
Oligocene/Eocene boundary between the Rupelian and Priabonian
stages (33.89 Ma). For calcareous nannofossil biostratigraphy, the
Pleistocene/Pliocene boundary now falls within Zone NN16 (Mar-
tini, 1971) between the LADs of *Discoaster surculus* (2.49 Ma) and
*Discoaster tamalis* (2.8 Ma). The Pliocene/Miocene boundary falls
within Zone NN12 between the LAD of *Triquetrorhabdulus rugo-
sus* (5.28 Ma) and the FAD of *Ceratolithus larrymayeri* (5.34 Ma);
however, *C. larrymayeri* was not noted in our samples, so we used
the FAD of *Ceratolithus acutus* (5.35 Ma) as an alternative event.
The late/middle Miocene boundary is placed within Zone NN7 be-
tween the LAD of common *Discoaster kugleri* (11.58 Ma) and the
FAD of common *D. kugleri* (11.90 Ma). The middle/early Miocene
boundary falls within Zone NN4 between the LADs of *Heli-
cosphaera ampliaperta* (14.91 Ma) and *Sphenolithus belemnos*
(17.95 Ma). The Miocene/Oligocene boundary is placed within
Zone NN1 between the FAD of *Discoaster druggii* (22.82 Ma) and
the LAD of *Reticulofenestra bisecta* (>10 µm; 23.13 Ma). The Oligo-
cene/Eocene boundary is placed within Zone NP21 between the
LADs of *Coccolithus formosus* (32.92 Ma) and *Discoaster saipanen-
sis* (34.44 Ma). In this study, the subdivision of these geologic time
boundaries was mostly based on recognition of these nannofossil
bioevents.

Several species of the genus *Gephyrocapsa*, which are com-
monly used as Pleistocene biostratigraphic markers, often show a
great range of variation in sizes and other morphological features,
causing problems in identification (e.g., Samtleben, 1980; Su, 1996;
Bollmann, 1997). Size-defined morphological groups of this genus
(Young, 1998; Maiorano and Marino, 2004; Lourens et al., 2004;
Raffi et al., 2006) were used as event markers during shipboard
study, including *Gephyrocapsa* sp. 3, *Gephyrocapsa* spp. medium I
(≥4 µm), large *Gephyrocapsa* spp. (≥5.5 µm), *Gephyrocapsa* spp. me-
dium II (≥4 µm; bmG event), and small *Gephyrocapsa* spp. (<3.5
µm).

Several *Reticulofenestra* species with different coccolith and
central opening sizes have been used as Neogene and Quaternary
biostratigraphic markers; however, these parameters show consid-
erable variations within and between “species,” making species dif-
ferentiation difficult (e.g., Su, 1996; Young, 1998). In this study, we
followed the definition of *Reticulofenestra pseudoumbilicus* by
<figure><img src="image_65.png" /><figcaption>Figure F22. Calcareous nannofossil, diatom, and planktonic foraminiferal events and scaled ages (Gradstein et al., 2012), Expeditions 367 and 368. B = base, Ba = base acme, Bc = base common, T = top, Ta = top acme, Tc = top common, Tr = top regular, X = crossover in abundance. This figure is available in an **oversized format**.</figcaption></figure>

Young (1998) as having a coccolith length >7 µm (similar to the size of its holotype), especially for specimens from its uppermost range in the early Pliocene. We distinguished *Reticulofenestra asanoi* from the similarly sized *Pseudoemiliania lacunosa* by the absence of slits on the shield (Su, 1996). In addition, we further distinguished three *Reticulofenestra* morphotypes including *Reticulofenestra ampla* (5~7 µm, with central opening), *R. bisecta* (5~10 µm, with a solid central plug), and *R. bisecta* (>10 µm, with a solid central plug) following Young et al. (2014).

The LAD of *Sphenolithus* spp. (3.54 Ma) in Pliocene Zone NN16 was based on the LADs of *Sphenolithus abies* and *Sphenolithus neobies* according to Raffi et al. (2006). Species concepts for other taxa mainly follow those of Perch-Nielsen (1985) and Bown (1998).

## Methods

Calcareous nannofossil samples were prepared using standard smear slide techniques. For samples from sandy sediments, sus-

<figure><img src="image_66.png" /></figure>

pended aliquots of the raw sample were analyzed. Samples were examined with a Zeiss microscope under XPL and plane-transmitted or phase contrast light at 1000× to 2000× magnification. A Hitachi TM3000 tabletop scanning electron microscope (SEM) was used to confirm the presence of small forms such as *Emiliania huxleyi*, an important marker for the latest Pleistocene–Holocene. Preservation of nannofossils was defined as follows:

VG = very good (no evidence of dissolution and/or overgrowth).

G = good (slight dissolution and/or overgrowth; specimens are identifiable to the species level).

M = moderate (some etching and/or overgrowth; most specimens are identifiable to the species level).

P = poor (severely etched or overgrowth; most specimens cannot be identified at the species and/or generic level).
<table><caption>Table T2. Calcareous nannofossil events and scaled ages (GTS2012; Gradstein et al., 2012), Expeditions 367 and 368. T = top/last appearance datum, B = base/first appearance datum. Bold text indicates age-diagnostic datum. (Continued on next page.) **Download table in CSV format.**</caption><thead><tr><th rowspan="2">GTS2012 chrono-stratigraphy</th><th colspan="2">Standard tropical-subtropical biozone (biochron)</th><th rowspan="2">Biohorizon (datum)</th><th rowspan="2">GTS2012 age (Ma)</th></tr><tr><th>CN zones (Okada and Bukry, 1980)</th><th>NN zones (Martini, 1971)</th></tr></thead><tbody><tr><td>0.126 Ma</td><td></td><td></td><td></td><td></td></tr><tr><td rowspan="2">Ionian (middle Pleistocene)</td><td>CN15/CN14b</td><td>NN21/NN20</td><td>B Emiliania huxleyi</td><td>0.29</td></tr><tr><td>CN14b/CN14a</td><td>NN20/NN19</td><td>T Pseudoemiliania lacunosa</td><td>0.44</td></tr><tr><td>0.781 Ma</td><td></td><td></td><td>T Gephyrocapsa sp. 3</td><td>0.61</td></tr><tr><td rowspan="5">Calabrian</td><td>CN14a</td><td rowspan="5">NN19</td><td>T Reticulofenestra asanoi (common)</td><td>0.91</td></tr><tr><td></td><td>T small Gephyrocapsa spp. dominance</td><td>1.02</td></tr><tr><td></td><td>B Gephyrocapsa sp. 3</td><td>1.02</td></tr><tr><td>CN14a/CN13b</td><td>B medium (&gt;4 µm) Gephyrocapsa spp. reentrance (reenG event)</td><td>1.04</td></tr><tr><td>CN13b</td><td>B Reticulofenestra asanoi (common)</td><td>1.14</td></tr><tr><td rowspan="5">1.806 Ma</td><td>CN13b/CN13a</td><td></td><td>T large (&gt;5.5 µm) Gephyrocapsa spp.</td><td>1.24</td></tr><tr><td>CN13a</td><td></td><td>B small Gephyrocapsa spp. dominance</td><td>1.24</td></tr><tr><td>CN13a/CN12d</td><td>NN19/NN18</td><td>T Helicosphaera sellii</td><td>(1.26)</td></tr><tr><td>CN12d</td><td>NN18</td><td>T Calcidiscus macintyrei</td><td>1.60</td></tr><tr><td>CN12d/CN12c</td><td>NN18/NN17</td><td>B large (&gt;5.5 µm) Gephyrocapsa spp.</td><td>1.62</td></tr><tr><td>CN12c/CN12b</td><td>NN17/NN16</td><td>B medium (&gt;4 µm) Gephyrocapsa spp. (=bmG event)</td><td>1.73</td></tr><tr><td rowspan="3">Gelasian</td><td>CN12b</td><td></td><td></td><td></td></tr><tr><td>CN12b/CN12a</td><td rowspan="2">NN16</td><td>T Discoaster brouweri</td><td>1.93</td></tr><tr><td>CN12a</td><td>T Discoaster triradiatus</td><td>1.95</td></tr><tr><td>2.588 Ma</td><td></td><td></td><td>B acme Discoaster triradiatus</td><td>2.22</td></tr><tr><td rowspan="2">Piacenzian</td><td>CN12b/CN12d</td><td>NN18</td><td>T Discoaster pentaradiatus</td><td>2.39</td></tr><tr><td>CN12b</td><td>NN17/NN16</td><td>T Discoaster surculus</td><td>2.49</td></tr><tr><td>3.600 Ma</td><td></td><td></td><td></td><td></td></tr><tr><td rowspan="6">Zanclean</td><td>CN12a/CN11b</td><td>NN16/NN15</td><td>T Reticulofenestra pseudoumbilicus</td><td>3.70</td></tr><tr><td>CN11b</td><td>NN15/NN14</td><td>T Amaurolithus tricorniculatus</td><td>(3.92)</td></tr><tr><td>CN11b/CN11a</td><td>NN14/NN13</td><td>B common Discoaster asymmetricus</td><td>4.13</td></tr><tr><td>CN11a/CN10c</td><td rowspan="2">NN13</td><td>T Amaurolithus primus</td><td>4.50</td></tr><tr><td></td><td>B Reticulofenestra pseudoumbilica, Discoaster ovata (subbottom)</td><td>4.91</td></tr><tr><td></td><td></td><td>T Ceratolithus acutus</td><td>5.04</td></tr><tr><td>CN10c/CN10b</td><td>NN13/NN12</td><td>B Ceratolithus rugosus</td><td>5.12</td></tr><tr><td>5.333 Ma</td><td>CN10b</td><td>NN12</td><td>T Triquetrorhabdulus rugosus</td><td>5.28</td></tr><tr><td rowspan="5">7.246 Ma</td><td>CN10b/CN10a</td><td></td><td>B Ceratolithus acutus</td><td>5.35</td></tr><tr><td>CN10a/CN9d</td><td>NN12/NN11</td><td>T Discoaster quinqueramus</td><td>5.59</td></tr><tr><td>CN9d/CN9c</td><td rowspan="2">NN11</td><td>T Nicklithus amplificus</td><td>5.94</td></tr><tr><td>CN9c/CN9b</td><td>B Nicklithus amplificus</td><td>6.91</td></tr><tr><td>CN9b</td><td></td><td></td><td></td><td></td></tr><tr><td rowspan="15">Tortonian</td><td>CN9b/CN9a</td><td></td><td>B Amaurolithus primus, Amaurolithus spp.</td><td>7.42</td></tr><tr><td>CN9a</td><td></td><td>T Discoaster loeblichii</td><td>7.53</td></tr><tr><td></td><td></td><td>B common Discoaster surculus</td><td>7.79</td></tr><tr><td></td><td></td><td>B Discoaster quinqueramus</td><td>(8.12)</td></tr><tr><td>CN9a/CN8</td><td>NN11/NN10</td><td>B Discoaster berggrenii</td><td>8.29</td></tr><tr><td>CN8</td><td>NN10</td><td>T Minylitha convallis</td><td>8.68</td></tr><tr><td></td><td></td><td>B Discoaster loeblichii</td><td>8.77</td></tr><tr><td></td><td></td><td>B paracme Reticulofenestra pseudoumbilicus</td><td>8.79</td></tr><tr><td></td><td></td><td>T Discoaster bollii</td><td>9.21</td></tr><tr><td></td><td></td><td>B common Discoaster pentaradiatus</td><td>9.37</td></tr><tr><td>CN8/CN7</td><td>NN10/NN9</td><td>T Discoaster hamatus</td><td>9.53</td></tr><tr><td>CN7</td><td>NN9</td><td>T Catinaster calyculus</td><td>9.67</td></tr><tr><td></td><td></td><td>T Catinaster coalitus</td><td>9.69</td></tr><tr><td></td><td></td><td>B Minylitha convallis</td><td>9.75</td></tr><tr><td></td><td></td><td>B Discoaster bellus</td><td>10.40</td></tr><tr><td></td><td></td><td>B Discoaster neohamatus</td><td>10.52</td></tr><tr><td>CN7/CN6</td><td>NN9/NN8</td><td>B Discoaster hamatus</td><td>10.55</td></tr><tr><td>CN6</td><td>NN8</td><td>B common Helicosphaera stalis</td><td>10.71</td></tr><tr><td></td><td></td><td>T common Helicosphaera walbersdorfensis</td><td>10.74</td></tr><tr><td></td><td></td><td>B Discoaster brouweri</td><td>10.76</td></tr><tr><td></td><td></td><td>B Catinaster calyculus</td><td>10.79</td></tr><tr><td>CN6/CN5b</td><td>NN8/NN7</td><td>B Catinaster coalitus</td><td>10.89</td></tr><tr><td>CN5b</td><td>NN7</td><td>T Coccolithus miopelagicus</td><td>10.97</td></tr><tr><td></td><td></td><td>T Calcidiscus premacintyrei</td><td>11.21</td></tr><tr><td></td><td></td><td>T common Discoaster kugleri</td><td>11.58</td></tr></tbody></table>
<table><caption>Table T2 (continued).</caption><thead><tr><th rowspan="2">GTS2012 chrono-<br>stratigraphy</th><th colspan="2">Standard tropical-subtropical biozone<br>(biochron)</th><th rowspan="2">Biohorizon (datum)</th><th rowspan="2">GTS2012<br>age (Ma)</th></tr><tr><th>CN zones<br>(Okada and Bukry,<br>1980)</th><th>NN zones<br>(Martini, 1971)</th></tr></thead><tbody><tr><td rowspan="2">11.608 Ma</td><td>CN5b</td><td>NN7</td><td>T Cyclicargolithus floridanus</td><td>11.85</td></tr><tr><td>CN5b/CN5a</td><td>NN7/NN6</td><td><b>B common Discoaster kugleri</b><br>T Coronocyclus nitescens<br>T regular Calcidiscus premacintyrei<br>B common Calcidiscus macintyrei<br>B Reticulofenestra pseudombilicus<br>B Triquetrorhabdulus rugosus<br>T common Cyclicargolithus floridanus<br>B Calcidiscus macintyrei</td><td><b>11.90</b><br>12.12<br>12.38<br>12.46<br>12.83<br>13.27<br>13.28<br>13.36</td></tr><tr><td rowspan="2">Serravallian</td><td>CN5a</td><td>NN6</td><td>T Sphenolithus heteromorphus</td><td><b>13.53</b></td></tr><tr><td>CN5a/CN4</td><td>NN6/NN5</td><td></td><td></td></tr><tr><td>13.82 Ma</td><td>CN4</td><td>NN5</td><td>T Helicosphaera ampliaperta</td><td><b>14.91</b></td></tr><tr><td rowspan="2">Langhian</td><td>CN4/CN3</td><td>NN5/NN4</td><td>T abundant Discoaster deflandrei group<br>B Discoaster signus</td><td>15.80<br>15.85</td></tr><tr><td>CN3</td><td>NN4</td><td></td><td></td></tr><tr><td rowspan="2">15.97 Ma</td><td>CN3/CN2</td><td>NN4/NN3</td><td>B Sphenolithus heteromorphus</td><td>17.71</td></tr><tr><td>CN2/CN1c</td><td>NN3/NN2</td><td><b>T Sphenolithus belemnos</b><br><b>T Triquetrorhabdulus carinatus</b><br>B Sphenolithus belemnos<br>B Helicosphaera ampliaperta</td><td><b>17.95</b><br><b>18.28</b><br>19.03<br>20.43</td></tr><tr><td rowspan="2">Burdigalian</td><td>CN1c</td><td>NN2</td><td>B common Helicosphaera carteri<br>B Orthorhabdus serratus<br>B Sphenolithus belemnos<br><b>B Discoaster druggi (sensu stricto)</b><br>T Sphenolithus capricornutus</td><td>22.03<br>22.42<br>22.76</td></tr><tr><td>CN1c/CN1a-b</td><td>NN2/NN1</td><td></td><td><b>22.82</b><br>22.97</td></tr><tr><td rowspan="2">(20.44 Ma)</td><td>CN1a-CN1b</td><td>NN1</td><td></td><td></td></tr><tr><td>CN1a-CN1b</td><td>NN1</td><td>T Sphenolithus delphix</td><td>23.11</td></tr><tr><td rowspan="2">Aquitanian</td><td>CN1a-CN1b</td><td>NN1</td><td><b>T Reticulofenestra bisecta (&gt;10 µm)</b><br>B Sphenolithus delphix<br>T Zygrhablithus bijugatus<br>T Sphenolithus ciperoensis<br>T Cyclicargolithus abisectus (common)<br>T Chiasmolithus altus<br>B Triquetrorhabdulus carinatus (common)</td><td><b>23.13</b><br>23.21<br>23.76<br>24.43<br>24.67<br>25.44<br>26.57</td></tr><tr><td>CN1a-CN1b</td><td>NN1</td><td><b>T Sphenolithus distentus</b><br>T Sphenolithus predistentus</td><td><b>26.84</b><br>26.93</td></tr><tr><td rowspan="2">23.03 Ma</td><td>CN1a-CN1b</td><td>NN1</td><td></td><td></td></tr><tr><td>CN1a-b/CP19b</td><td>NN1/NP25</td><td>T Sphenolithus pseudoradians<br><b>B Sphenolithus ciperoensis</b><br>B Sphenolithus distentus</td><td><b>28.73</b><br><b>29.62</b><br>30.00</td></tr><tr><td rowspan="2">Chattian</td><td>CP19b</td><td>NP25</td><td><b>T Reticulofenestra umbilicus (low-mid lat.)</b><br><b>T Coccolithus formosus</b><br>T Clausicoccus subdistichus (top of acme)</td><td><b>32.02</b><br><b>32.92</b><br>33.43</td></tr><tr><td>CP19b/CP19a</td><td>NP25/NP24</td><td></td><td></td></tr><tr><td rowspan="2">(28.09)</td><td>CP19a</td><td>NP24</td><td></td><td></td></tr><tr><td>CP19a/CP18</td><td>NP24/NP23</td><td>T Sphenolithus pseudoradians</td><td>28.73</td></tr><tr><td rowspan="5">Rupelian</td><td>CP18/CP17</td><td>NP23</td><td><b>B Sphenolithus ciperoensis</b><br>B Sphenolithus distentus</td><td><b>29.62</b><br>30.00</td></tr><tr><td>CP17/CP16c</td><td>NP23/NP22</td><td><b>T Reticulofenestra umbilicus (low-mid lat.)</b></td><td><b>32.02</b></td></tr><tr><td>CP16c/CP16b</td><td>NP22/NP21</td><td><b>T Coccolithus formosus</b></td><td><b>32.92</b></td></tr><tr><td>CP16b/CP16a</td><td>NP21</td><td>T Clausicoccus subdistichus (top of acme)</td><td>33.43</td></tr><tr><td>CP16a</td><td>NP21/NP20-NP19</td><td></td><td></td></tr><tr><td rowspan="2">Priabonian</td><td>CP16a/CP15</td><td>NP20-NN19</td><td><b>T Discoaster saipanensis</b><br>T Discoaster barbadiensis<br>T Reticulofenestra reticulata</td><td><b>34.44</b><br>34.76<br>35.40</td></tr><tr><td>CP15</td><td>NP20-NP19/NP18<br>NP18/NP17</td><td><b>B Isthmolithus recurvus</b><br><b>B Chiasmolithus oamaruensis (common)</b></td><td><b>36.97</b><br><b>37.32</b></td></tr><tr><td rowspan="2">(37.75)</td><td>CP15/CP14b</td><td>NP17</td><td>T Chiasmolithus grandis<br>B Chiasmolithus oamaruensis (rare)<br>B Reticulofenestra bisecta (&gt;10 µm)</td><td>37.98<br>38.09<br>38.25</td></tr><tr><td>CP14b</td><td>NP17/NP16</td><td><b>T Chiasmolithus solitus</b></td><td><b>40.40</b></td></tr><tr><td>Bartonian</td><td>CP14b/CP14a</td><td>NP17/NP16</td><td></td><td></td></tr></tbody></table>

The relative abundance of calcareous nannofossils within the sediment was visually estimated at 1000× magnification by referring to the particle abundance charts in Rothwell (1989) and reported using the following abundance categories:

D = dominant (>90% of sediment particles).

A = abundant (>50%–90% of sediment particles).

C = common (>10%–50% of sediment particles).

F = few (1%–10% of sediment particles).

R = rare (<1% of sediment particles).

B = barren (no nannofossils present in 100 FOV).
The relative abundance of individual calcareous nannofossil species or taxa groups was estimated at 1000× magnification and defined as follows:

D = dominant (>50%, or 100 specimens/FOV).

A = abundant (10%–50%, or 10–100 specimens/FOV).

C = common (1%–10%, or 1–10 specimens/FOV).

F = few (0.1%–1%, or 1 specimen/1–10 FOV).

R = rare (<0.1%, or <1 specimen/10 FOV).

## Foraminifers

### Planktonic foraminifers

The planktonic foraminiferal zonation schemes of Blow (1969, 1979) and Berggren et al. (1995) as modified by Wade et al. (2011) were used in this study. Calibrated ages for bioevents are from Gradstein et al. (2012) (Table T3). We also adopted the use of the LAD (0.12 Ma; Thompson et al., 1979) and FAD (1.16 Ma; Li et al., 2005) of *Globigerinoides ruber* (pink) as biostratigraphic indicators. The FAD of *G. ruber* (pink) acme (0.40 Ma; Li et al., 2005) was also adopted. The age for the LAD of *Globorotalia mutlicamerata* (2.18 Ma) was adjusted based on regional stratigraphic work (Li et al., 2005).

Taxonomic concepts for Neogene and Paleogene taxa mainly follow those of Kennett and Srinivasan (1983) and Bolli and Saunders (1985).

Planktonic foraminifer species distribution and range charts are presented in each site chapter.

### Benthic foraminifers

Taxonomic assignments for benthic foraminifers follow Loeblich and Tappan (1988), Kaminski and Gradstein (2005), and Holbourn et al. (2013). Paleodepth estimates were based on selected benthic foraminiferal taxa noted and described by van Morkhoven et al. (1986) using the following categories:

Neritic = <200 m.

Bathyal = 200–2000 m.

Upper bathyal = 200–600 m.

Middle bathyal = 600–1000 m.

Lower bathyal = 1000–2000 m.

Abyssal = >2000 m.

Upper abyssal = 2000–3000 m.

Lower abyssal = >3000 m.

Benthic foraminiferal assemblage composition and paleodepth estimates were based on counts of at least 100 specimens from the >150 µm size fractions, where possible.

## Preparation and examination techniques

Sample preparation for foraminifer identification uses the same techniques for both planktonic and benthic foraminifers. Core catcher samples (and additional core samples as needed) were soaked in distilled water and washed over a 63 µm mesh sieve. Consolidated or lithified samples were cut in pieces and crushed to pea size, to which a hydrogen peroxide solution was added. This mixture was heated in the oven below 50°C for several hours and then sieved as above. Some samples were rewashed by additional disaggregation with the hydrogen peroxide solution. All samples were dried in a low temperature oven at ~50°C. The dried samples were sieved over a 150 µm sieve, retaining the <150 µm size fraction in a separate vial. To avoid contamination of foraminifers between samples, the sieves were thoroughly cleaned between samples, placed

into a sonicator for at least 15 min, and then carefully checked. Species identifications for planktonic and benthic foraminifers were generally made on the >150 µm size fractions. The 63–150 µm size fraction was observed for distinctive taxa.

In addition, mudline (or hole top) samples were taken from selected sites and analyzed for planktonic and benthic foraminifers and ostracods. Mudline samples were collected by emptying the sediment/water material from the top core liner of a hole into a bucket and then washing it with tap water over a 63 µm sieve. Sample staining using Rose Bengal (1 g/L) was performed to confirm the presence of living foraminifers and ostracods in the mudline sample. For this, a portion of the sample was incubated for 12 h with Rose Bengal stain before being washed through a 63 µm sieve. All samples were then dried at ~50°C and subsequently examined under a binocular light microscope. Selected microfossil specimens were also examined and imaged using the shipboard SEM.

The total abundance of planktonic foraminifers was reported using the following categories:

A = abundant (>30% planktonic foraminifer specimens in total residue).

C = common (10%–30% planktonic foraminifer specimens in total residue).

R = rare (1%–10% planktonic foraminifer specimens in total residue).

P = present (<1% planktonic foraminifer specimens in total residue).

B = barren (no planktonic foraminifer specimens in total residue).

Individual planktonic foraminifers were recorded in qualitative terms based on an assessment of forms observed in a random sample of ~400 specimens from the >150 µm size fraction. Relative abundances were reported using the following categories:

D = dominant (>30% of the assemblage).

A = abundant (>10%–30%).

F = few (>5%–10%).

R = rare (1%–5%).

P = present (<1%).

Preservation of planktonic foraminifer assemblages was recorded using the following categories:

VG = very good (no evidence of breakage or dissolution).

G = good (>80% of specimens unbroken with only minor evidence of diagenetic alteration).

M = moderate (30%–80% of the specimens unbroken).

P = poor (strongly recrystallized or dominated by fragments and broken or corroded specimens).

## Ostracods

Ostracods were studied at selected sites when time was available. Sample preparation for ostracod examination and illustration followed the same techniques as for foraminifers. Ostracod taxonomic assignments follow Yang et al. (1990), Zhao et al. (2000), Zhao (2005), Hu and Tao (2008), and Alvarez Zarikian (2015).

Abundance of ostracods was noted using the following definitions:

C = common (>20 specimens per sample).

X = present (<20 specimens per sample).

B = barren.
<table><caption>Table T3. Planktonic foraminiferal events and scaled ages (GTS2012; Gradstein et al., 2012), Expeditions 367 and 368. T = top/last appearance datum, B = base/first appearance datum. Bold text indicates age-diagnostic datum. (Continued on next two pages.) **Download table in CSV format.**</caption><thead><tr><th rowspan="2">GTS2012<br>chronostratigraphy</th><th colspan="2">Standard tropical-subtropical biozone<br>(biochron)</th><th rowspan="2">Biohorizon (datum)</th><th rowspan="2">GTS2012<br>age (Ma)</th><th rowspan="2">Error (My)</th></tr><tr><th>Indo-Pacific<br>(Blow, 1969, 1979;<br>Berggren et al.,<br>1995)</th><th>Indo-Pacific<br>(Berggren et al.,<br>1995;<br>Wade et al., 2011)</th></tr></thead><tbody><tr><td>Tarantian<br>(late Pleistocene)<br>0.126 Ma</td><td rowspan="10">N22</td><td rowspan="2">PT1b</td><td>T Globorotalia flexuosa</td><td>0.07</td><td></td></tr><tr><td></td><td>T Globigerinoides ruber pink</td><td>0.12</td><td></td></tr><tr><td rowspan="4">Ionian<br>(middle Pleistocene)<br>0.781 Ma</td><td rowspan="4">PT1b/PT1a</td><td>B Globigerinella calida</td><td>0.22</td><td></td></tr><tr><td>Bc Globigerinoides ruber pink</td><td>0.40</td><td></td></tr><tr><td>B Globorotalia flexuosa</td><td>0.40</td><td></td></tr><tr><td>B Globorotalia hirsuta</td><td>0.45</td><td></td></tr><tr><td rowspan="7">1.806 Ma<br>Gelasian<br>(early Pleistocene)</td><td rowspan="5">PT1a</td><td>T Globorotalia tosaensis</td><td>0.61</td><td></td></tr><tr><td>B Globorotalia hessi</td><td>0.75</td><td></td></tr><tr><td>B Globigerinoides ruber pink</td><td>1.16</td><td></td></tr><tr><td>T Globigerinoides obliquus</td><td>1.3</td><td>±0.1</td></tr><tr><td>T Neogloboquadrina acostaensis</td><td>1.58</td><td>±0.03</td></tr><tr><td></td><td>T Globoturborotalita apertura</td><td>1.64</td><td>±0.03</td></tr><tr><td rowspan="5">2.588 Ma</td><td rowspan="5">N22/N21<br>N21<br>N21/N19-N20</td><td rowspan="5">PT1a/PL6</td><td>T Globigerinoides fistulosus</td><td>1.88</td><td>±0.03</td></tr><tr><td>T Globigerinoides extremus</td><td>1.98</td><td>±0.03</td></tr><tr><td>B Pulleniatina finalis</td><td>2.04</td><td>±0.03</td></tr><tr><td>T Globorotalia multicamerata</td><td>2.18</td><td></td></tr><tr><td>T Globorotalia pertenuis</td><td>2.30</td><td></td></tr><tr><td rowspan="2">Piacenzian<br>(late Pliocene)</td><td rowspan="2">PL6/PL5</td><td>T Globoturborotalita woodi</td><td>2.30</td><td>±0.02</td></tr><tr><td>T Globorotalia pseudomiocenica</td><td>2.39</td><td></td></tr><tr><td rowspan="3">3.600 Ma<br>Zanclean<br>(early Pliocene)</td><td rowspan="3">PL5/PL4<br>PL4<br>PL4/PL3</td><td>T Globoturborotalita decoraperta</td><td>2.75</td><td>±0.03</td></tr><tr><td>B Globigerinoides fistulosus</td><td>3.33</td><td></td></tr><tr><td>B Globorotalia tosaensis</td><td>3.35</td><td></td></tr><tr><td rowspan="3">5.333 Ma</td><td rowspan="3">N19-N20/N18<br>N18/N17b</td><td>T Dentoglobigerina altspira</td><td>3.47</td><td>±0.03</td></tr><tr><td>B Globorotalia pertenuis</td><td>3.52</td><td></td></tr><tr><td>T Sphaeroidinellopsis seminulina</td><td>3.59</td><td></td></tr><tr><td rowspan="5">Messinian<br>(late Miocene)</td><td rowspan="3">PL3</td><td>T Pulleniatina primalis</td><td>3.66</td><td></td></tr><tr><td>T Globorotalia plesiotumida</td><td>3.77</td><td>±0.02</td></tr><tr><td>T Globorotalia margaritae</td><td>3.85</td><td>±0.03</td></tr><tr><td rowspan="2">N17b/N17a</td><td>T Pulleniatina spectabilis</td><td>4.21</td><td></td></tr><tr><td>B Globorotalia crassaformis sensu lato</td><td>4.31</td><td>±0.04</td></tr><tr><td rowspan="5">Tortonian<br>(late Miocene)</td><td rowspan="5">N17a/N16<br>N16<br>N16/N15<br>N15/N14</td><td>T Globoturborotalita nepenthes</td><td>4.37</td><td>±0.01</td></tr><tr><td>B Goblorotalia exilis</td><td>4.45</td><td>±0.04</td></tr><tr><td>T Sphaeroidinellopsis kochi</td><td>4.53</td><td>±0.17</td></tr><tr><td>T Globorotalia cibaoensis</td><td>4.60</td><td></td></tr><tr><td>T Globigerinoides seiglei</td><td>4.72</td><td></td></tr><tr><td rowspan="10">Tortonian<br>(late Miocene)</td><td rowspan="2">N19/N18<br>N18/N17b</td><td>B Sphaeroidinella dehiscens sensu lato</td><td>5.53</td><td>±0.04</td></tr><tr><td>B Globorotalia tumida</td><td>5.57</td><td></td></tr><tr><td rowspan="5">M14/M13b</td><td>B Turborotalita humilis</td><td>5.81</td><td>±0.17</td></tr><tr><td>T Globoquadrina dehiscens</td><td>5.92</td><td></td></tr><tr><td>B Globorotalia margaritae</td><td>6.08</td><td>±0.03</td></tr><tr><td>T Globorotalia lenguaensis</td><td>6.14</td><td></td></tr><tr><td>B Globigerinoides conglobatus</td><td>6.20</td><td>±0.41</td></tr><tr><td rowspan="5">M13b</td><td>B Pulleniatina primalis</td><td>6.60</td><td></td></tr><tr><td>B Globorotalia miotumida (economiozea)</td><td>7.89</td><td></td></tr><tr><td>B Neogloboquadrina humerosa</td><td>8.56</td><td></td></tr><tr><td>T Paragloborotalia mayeri/siakensis</td><td>8.58</td><td>±0.03</td></tr><tr><td>B Neogloboquadrina acostaensis</td><td>8.93</td><td>±0.03</td></tr><tr><td rowspan="5">M13a</td><td>B Globigerinoides extremus</td><td>9.44</td><td>±0.05</td></tr><tr><td>B Globorotalia cibaoensis</td><td>9.69</td><td>±0.26</td></tr><tr><td>B Neogloboquadrina acostaensis</td><td>9.83</td><td>±0.06</td></tr><tr><td>T Globorotalia challengeri</td><td>9.99</td><td></td></tr><tr><td>T Paragloborotalia mayeri/siakensis</td><td>10.46</td><td>±0.02</td></tr><tr><td rowspan="5">M12/M11</td><td>B Globorotalia limbata</td><td>10.64</td><td>±0.26</td></tr><tr><td>T Cassigerinella chipolensis</td><td>10.89</td><td></td></tr><tr><td>B Globoturborotalita apertura</td><td>11.18</td><td>±0.13</td></tr><tr><td>B Globorotalia challengeri</td><td>11.22</td><td></td></tr><tr><td>B regular Globigerinoides obliquus</td><td>11.25</td><td></td></tr><tr><td rowspan="2">11.608 Ma</td><td rowspan="2"></td><td>B Globoturborotalita decoraperta</td><td>11.49</td><td>±0.04</td></tr><tr><td>T Globigerinoides subquadratus</td><td>11.54</td><td></td></tr></tbody></table>
<table><caption>Table T3 (continued). (Continued on next page.)</caption><thead><tr><th rowspan="2">GTS2012<br>chnostratigraphy</th><th colspan="2">Standard tropical-subtropical biozone<br>(biochron)</th><th rowspan="2">Biohorizon (datum)</th><th rowspan="2">GTS2012<br>age (Ma)</th><th rowspan="2">Error (My)</th></tr><tr><th>Indo-Pacific<br>(Blow, 1969, 1979;<br>Berggren et al.,<br>1995)</th><th>Indo-Pacific<br>(Berggren et al.,<br>1995;<br>Wade et al., 2011)</th></tr></thead><tbody><tr><td rowspan="6">Serravallian<br>(middle Miocene)</td><td>N14/N13</td><td>M11/M10</td><td><b>B Globoturborotalita nepenthes</b></td><td><b>11.63</b></td><td>±0.02</td></tr><tr><td>N13/N12</td><td>M10/M9b</td><td><b>T Fohsella fohsi, Fohsella plexus</b></td><td><b>11.79</b></td><td>±0.15</td></tr><tr><td></td><td></td><td>T Clavatorella bermudezi</td><td>12.00</td><td></td></tr><tr><td></td><td></td><td>B Globorotalia lenguanensis</td><td>12.84</td><td>±0.05</td></tr><tr><td></td><td></td><td>B Sphaeroidinellopsis subdehiscens</td><td>13.02</td><td></td></tr><tr><td></td><td>M9b/M9a<br>M9a</td><td><b>B Fohsella robusta</b></td><td><b>13.13</b></td><td>±0.02</td></tr><tr><td></td><td>N12/N11</td><td>M9a/M8</td><td>T Cassigerinella martinezpicoi</td><td>13.27</td><td></td></tr><tr><td></td><td>N11</td><td>M8</td><td><b>B Fohsella fohsi</b></td><td><b>13.41</b></td><td>±0.04</td></tr><tr><td></td><td>N11/N10</td><td>M8/M7</td><td><b>B Fohsella praefohsi</b></td><td><b>13.77</b></td><td></td></tr><tr><td></td><td></td><td></td><td>T Fohsella peripheroronda</td><td>13.80</td><td></td></tr><tr><td rowspan="6">Langhian<br>(middle Miocene)</td><td>N10</td><td>M7</td><td>T regular Clavatorella bermudezi</td><td>13.82</td><td></td></tr><tr><td></td><td></td><td>T Globorotalia archeomenardii</td><td>13.87</td><td></td></tr><tr><td>N10/N9</td><td>M7/M6</td><td><b>B Fohsella peripheroacuta</b></td><td><b>14.24</b></td><td></td></tr><tr><td></td><td></td><td>B Globorotalia praemenardii</td><td>14.38</td><td></td></tr><tr><td></td><td></td><td>T Praeorbulina sicana</td><td>14.53</td><td></td></tr><tr><td></td><td>N9</td><td>M6</td><td>T Globigeriantella insueta</td><td>14.66</td><td></td></tr><tr><td></td><td></td><td></td><td>T Praeorbulina glomerosa sensu stricto</td><td>14.78</td><td></td></tr><tr><td></td><td></td><td></td><td>T Praeorbulina circularis</td><td>14.89</td><td></td></tr><tr><td rowspan="6">15.97 Ma</td><td>N9/N8</td><td>M6/M5b</td><td><b>B Orbulina suturalis</b></td><td><b>15.10</b></td><td></td></tr><tr><td></td><td></td><td>B Clavatorella bermudezi</td><td>15.73</td><td></td></tr><tr><td></td><td></td><td>B Praeorbulina circularis</td><td>15.96</td><td></td></tr><tr><td>N8</td><td>M5b</td><td>B Globigerinoides diminutus</td><td>16.06</td><td></td></tr><tr><td></td><td></td><td>B Globorotalia archeomenardii</td><td>16.26</td><td></td></tr><tr><td></td><td>M5b/M5a<br>M5a</td><td><b>B Praeorbulina glomerosa sensu stricto</b></td><td><b>16.27</b></td><td></td></tr><tr><td rowspan="6">Burdigalian<br>(early Miocene)</td><td>N8/N7</td><td>M5a/M4b<br>M4b</td><td>B Praeorbulina curva</td><td>16.28</td><td></td></tr><tr><td></td><td></td><td><b>B Praeorbulina sicana</b></td><td><b>16.38</b></td><td></td></tr><tr><td></td><td></td><td>T Globorotalia incognita</td><td>16.39</td><td></td></tr><tr><td>N7</td><td>M4b/M4a<br>M4a</td><td><b>B Fohsella birnageae</b></td><td><b>16.69</b></td><td></td></tr><tr><td></td><td></td><td>B Globorotalia miozea</td><td>16.70</td><td></td></tr><tr><td></td><td></td><td>B Globorotalia zealandica</td><td>17.26</td><td></td></tr><tr><td></td><td></td><td>T Globorotalia semivera</td><td>17.26</td><td></td></tr><tr><td></td><td>N7/N6</td><td>M4a/M3</td><td><b>T Catapsydrax dissimilis</b></td><td><b>17.54</b></td><td></td></tr><tr><td></td><td></td><td>M3</td><td>B Globigeriantella insueta sensu stricto</td><td>17.59</td><td></td></tr><tr><td></td><td></td><td></td><td>B Globorotalia praescitula</td><td>18.26</td><td></td></tr><tr><td></td><td></td><td></td><td>T Globiquadrina binaiensis</td><td>19.09</td><td></td></tr><tr><td></td><td>N6-N5</td><td>M3/M2</td><td><b>B Globigerinatella sp.</b></td><td><b>19.30</b></td><td></td></tr><tr><td></td><td></td><td></td><td>B Globigerinoides altiaperturus</td><td>20.03</td><td></td></tr><tr><td rowspan="6">(20.44 Ma)</td><td></td><td></td><td>T Tenuitella munda</td><td>20.78</td><td></td></tr><tr><td></td><td></td><td>B Globorotalia incognita</td><td>20.93</td><td></td></tr><tr><td></td><td></td><td>T Globoturborotalita angulisuturalis</td><td>20.94</td><td></td></tr><tr><td>N5/N4b</td><td>M2/M1b</td><td><b>T Paragloborotalia kugleri</b></td><td><b>21.12</b></td><td></td></tr><tr><td></td><td></td><td>T Paragloborotalia pseudokugleri</td><td>21.31</td><td></td></tr><tr><td></td><td>N4b</td><td>M1b</td><td>B Globoquadrina dehiscens f. spinosa</td><td>21.44</td><td></td></tr><tr><td rowspan="4">Aquitanian<br>(early Miocene)</td><td></td><td></td><td>T Dentoglobigerina globularis</td><td>21.98</td><td></td></tr><tr><td>N4b/N4a</td><td>M1b/M1a</td><td><b>B Globoquadrina dehiscens</b></td><td><b>22.44</b></td><td></td></tr><tr><td></td><td></td><td>T Globigerina ciperoensis</td><td>22.90</td><td></td></tr><tr><td>N4a</td><td>M1a</td><td>B Globigerinoides trilobus sensu lato</td><td>22.96</td><td></td></tr><tr><td></td><td>N4a/P22</td><td>M1a/O7</td><td><b>B Paragloborotalia kugleri</b></td><td><b>22.96</b></td><td></td></tr><tr><td rowspan="4">Chattian<br>(late Oligocene)</td><td></td><td></td><td>T Globigerina euapertura</td><td>23.03</td><td></td></tr><tr><td>P22 (N3)</td><td>O7</td><td>T Tenuitella gemma</td><td>23.50</td><td></td></tr><tr><td></td><td></td><td>B common Globigerinoides primordius</td><td>23.50</td><td></td></tr><tr><td></td><td>O7/O6<br>O6</td><td><b>B Paragloborotalia pseudokugleri</b></td><td><b>25.21</b></td><td></td></tr><tr><td></td><td>P22/P21</td><td>O6/O5</td><td>B Globigerinoides primordius</td><td>26.12</td><td></td></tr><tr><td></td><td></td><td></td><td><b>T Paragloborotalia opima sensu stricto</b></td><td><b>26.93</b></td><td></td></tr><tr><td rowspan="4">Rupelian<br>(early Oligocene)</td><td>P21 (N2)</td><td>O5/O4</td><td></td><td>28.09</td><td></td></tr><tr><td>P21/P20</td><td>O4/O3</td><td><b>T common Chiloguembelina cubensis</b></td><td><b>29.18</b></td><td></td></tr><tr><td></td><td></td><td><b>B Globigerina angulisuturalis</b></td><td>29.50</td><td></td></tr><tr><td>P20</td><td>O3</td><td>B Tenuitellinata juvenilis</td><td>29.84</td><td></td></tr><tr><td></td><td>P20/P19</td><td>O3/O2</td><td><b>T Turborotalia ampliapertura</b></td><td><b>30.28</b></td><td></td></tr></tbody></table>
<table><caption>Table T3 (continued).</caption><thead><tr><th rowspan="2">GTS2012<br>chronostratigraphy</th><th colspan="2">Standard tropical-subtropical biozone<br>(biochron)</th><th rowspan="2">Biohorizon (datum)</th><th rowspan="2">GTS2012<br>age (Ma)</th><th rowspan="2">Error (My)</th></tr><tr><th>Indo-Pacific<br>(Blow, 1969, 1979;<br>Berggren et al.,<br>1995)</th><th>Indo-Pacific<br>(Berggren et al.,<br>1995;<br>Wade et al., 2011)</th></tr></thead><tbody><tr><td rowspan="3">Rupelian<br>(early Oligocene)</td><td>P19</td><td>O2</td><td>B Paragloborotalia opima</td><td>30.72</td><td></td></tr><tr><td><strong>P19/P18</strong></td><td><strong>O2/O1</strong></td><td><strong>T Pseudohastigerina naguewichiensis</strong></td><td><strong>32.10</strong></td><td></td></tr><tr><td></td><td>O1</td><td>B Cassigerinella chipolensis</td><td>33.89</td><td></td></tr><tr><td rowspan="6">Priabonian<br>(late Eocene)</td><td rowspan="3">P18</td><td></td><td><strong>O1/E16</strong></td><td><strong>T Hantkenina spp.</strong></td><td><strong>33.89</strong></td><td></td></tr><tr><td>P18/P17</td><td rowspan="2">E16</td><td>T common Pseudohastigerina micra</td><td>33.89</td><td></td></tr><tr><td>P17/P16</td><td>T Turborotalia cerroazulensis</td><td>34.03</td><td></td></tr><tr><td></td><td></td><td>T Cribrohantkenina inflata</td><td>34.22</td><td></td></tr><tr><td rowspan="3">P16</td><td><strong>E16/E15</strong></td><td><strong>T Globigerinatheka index</strong></td><td><strong>34.61</strong></td><td></td></tr><tr><td rowspan="2">E15</td><td>T Turborotalia pomeroli</td><td>35.66</td><td></td></tr><tr><td>B Turborotalia cunialensis</td><td>35.71</td><td></td></tr><tr><td></td><td><strong>P16/P15</strong></td><td></td><td>B Cribrohantkenina inflata</td><td>35.87</td><td></td></tr><tr><td></td><td></td><td><strong>E15/E14</strong></td><td><strong>T Globigerinatheka semiinvoluta</strong></td><td><strong>36.18</strong></td><td></td></tr><tr><td>(37.75 Ma)</td><td>P15</td><td>E14</td><td>T Acarinina spp.</td><td>37.75</td><td></td></tr><tr><td>Bartonian</td><td></td><td></td><td></td><td></td><td></td></tr></tbody></table>

Ostracod preservation was estimated using the following definitions:

VG = very good (valves translucent; no evidence of overgrowth, dissolution, or abrasion).

G = good (valves semitranslucent; little evidence of overgrowth, dissolution, or abrasion).

M = moderate (common but minor calcite overgrowth, dissolution, or abrasion).

P = poor (substantial overgrowth, dissolution, or fragmentation of the valves).

## Diatoms

### Diatom zonal scheme and taxonomy

The taxonomy for diatoms studied during Expeditions 367 and 368 is taken largely from Burckle (1972), Akiba (1986), Akiba and Yanagisawa (1986), Baldauf and Iwai (1995), Barron (1981, 1985, 2005), and Barron et al. (2004). The diatom datum sequence follows Lazarus et al. (2014) with adjustments based on updates (J.A. Barron, pers. comm., 2017) and calibration to the GPTS of Gradstein et al. (2012) (Table T4). The diatom zonal scheme used follows the biostratigraphic study by Scherer et al. (2007). A taxonomic list of relevant diatom species is given in Table T5.

### Methods

Strewn slides were prepared for samples examined from Expedition 368 by placing a small amount of raw sediment onto a slide and allowing the water to evaporate by heating on a hot plate for ~5 min. About 1–2 drops of optical adhesive were applied to the dry slide, which was then covered with a 22 mm × 40 mm glass coverslip. The adhesive was solidified by placing the slide under ultraviolet light for ~10 min. Strewn slides were scanned at a maximum magnification of 1250× for stratigraphic markers and other common taxa.

Abundance estimates of the diatom assemblage are qualitative estimates of the concentration of diatoms in individual sediment samples as defined by the following categories:

D = dominant (>90% of sediment particles).

A = abundant (>50%–90% of sediment particles).

C = common (>10%–50% of sediment particles).

F = few (1%–10% of sediment particles).

R = rare (<1% of sediments particles).

B = barren (none present).

Abundance of individual diatom species was recorded using the following categories:

D = dominant (>50 valves per counted transect).

A = abundant (>20–50 valves per counted transect).

C = common (>10–20 valves per counted transect).

F = few (>1–10 valves per counted transect).

R = rare (≤1 valve per counted transect).

Preservation of the diatom assemblage was recorded using the following categories:

G = good (majority of specimens complete with minor dissolution and/or breakage and no significant enlargement of the areolae or dissolution of the frustules rim detected; the sample generally has a high diatoms per gram concentration).

M = moderate (minor but common areolae enlargement and dissolution of the frustule rim with a considerable amount of breakage of specimens).

P = poor (strong dissolution or breakage, some specimens unidentifiable, strong dissolution of the frustule rim and areolae enlargement; the sample generally has lower diatoms per gram concentration).

## Other microfossils

The presence of other microfossils such as pteropods, fish teeth, sponge spicules, corals, radiolarians, and other bioclasts found in the >150 µm size fractions was noted.
<table><caption>Table T4. Diatom events and scaled ages (Gradstein et al., 2012), Expedition 368. T = top/last appearance datum, B = base/first appearance datum. (Continued on next four pages.) Download table in CSV format.</caption><thead><tr><th>Diatom zonation<br>(Scherer et al., 2007)</th><th></th><th>Diatom bioevent</th><th>GTS2012<br>age (Ma)</th><th>Age reference</th></tr></thead><tbody><tr><td rowspan="10">Fragilariopsis doliolus</td><td rowspan="10">Fragilariopsis reinholdii</td><td>T Nitzschia aequatorialis</td><td>0.14</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td>T Fragilariopsis reinholdii</td><td>0.62</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>T Fragilariopsis fossilis</td><td>0.70</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>T Thalassiosira plicata</td><td>0.80</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>T Thalassiosira symbolophora</td><td>0.90</td><td>Lazarus et al., 2014; Schrader, 1974</td></tr><tr><td>T Rhizosolenia matuyamai</td><td>1.05</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Rhizosolenia matuyamai</td><td>1.18</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>T Rhizosolenia praebergonii var. robusta</td><td>1.72</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Azpeitia barronii</td><td>1.80</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Nitzschia punctata</td><td>1.80</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td>T Rhizosolenia praebergonii</td><td>1.90</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Actinopytichus bipunctatus</td><td>1.90</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td>B Asterolampra brookei</td><td>2.00</td><td>Lazarus et al., 2014; Schrader, 1974</td></tr><tr><td>B Nitzschia interruptestiata</td><td>2.00</td><td>Lazarus et al., 2014; Koizumi and Tanimura, 1985</td></tr><tr><td>B Fragilariopsis doliolus</td><td>2.01</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Nitzschia braarudii</td><td>2.02</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td>B Nitzschia dietrichii</td><td>2.20</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td rowspan="10">Rhizosolenia praebergonii</td><td rowspan="10">Rhizosolenia praebergonii</td><td>T Thalassiosira convexa</td><td>2.43</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>T Thalassiosira convexa var. aspinosa</td><td>2.43</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Rhizosolenia praebergonii var. robusta</td><td>2.50</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>T Triceratium acutangulum</td><td>2.60</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td>T Nitzschia jouseae</td><td>2.79</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Bacteriastrum hyalinum</td><td>2.90</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td>B Rhizosolenia praebergonii</td><td>3.17</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Thalassiosira plicata</td><td>3.30</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Thalassiosira symbolophora</td><td>3.30</td><td>Lazarus et al., 2014; Schrader, 1974</td></tr><tr><td>T Actinocyclus ellipticus f. lanceolata</td><td>3.40</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Cymatotheca weissflogii</td><td>3.40</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td>B Roperia tesselata</td><td>3.60</td><td>Lazarus et al., 2014; Schrader, 1974</td></tr><tr><td>T Azpeitia vetustissima</td><td>3.80</td><td>Lazarus et al., 2014; Schrader, 1974</td></tr><tr><td>T Roperia praetesselata</td><td>3.80</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td>B Azpeitia africana</td><td>3.80</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td rowspan="10">Nitzschia jouseae</td><td rowspan="10">Nitzschia jouseae</td><td>B Thalassiosira convexa var. aspinosa</td><td>3.83</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Asteromphalus elegans</td><td>4.20</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>T Fragilariopsis cylindrica</td><td>4.30</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Nitzschia seriata</td><td>4.30</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td>T Actinocyclus ellipticus f. elongatus</td><td>4.50</td><td>Lazarus et al., 2014; Schrader, 1974</td></tr><tr><td>B Nitzschia panduriformis</td><td>4.70</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td>B Coscinodiscus centralis</td><td>4.80</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td>B Asteromphalus flabellatus</td><td>4.90</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td>B Nitzschia jouseae</td><td>5.12</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Nitzschia aequatorialis</td><td>5.20</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td>B Asteromphalus pettersonii</td><td>5.40</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td>B Shionodiscus oestrupii</td><td>5.59</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Cyclotella striata</td><td>5.60</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td rowspan="10">Thalassiosira convexa</td><td rowspan="10">Thalassiosira convexa</td><td>T Thalassiosira miocenica</td><td>5.95</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>T Asterolampra acutiloba</td><td>6.00</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Roperia praetesselata</td><td>6.10</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td>T Fragilariopsis miocenica</td><td>6.17</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>T Nitzschia miocenica var. elongata</td><td>6.18</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Thalassiothrix frauenfeldii</td><td>6.20</td><td>Lazarus et al., 2014; Schrader, 1974</td></tr><tr><td>T Thalassiosira praeconvexa</td><td>6.29</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>T Bogorovia lancettula</td><td>6.30</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>T Azpeitia komurae</td><td>6.50</td><td>Lazarus et al., 2014; Yanagisawa and Akiba, 1998</td></tr><tr><td>T Bogorovia praepaleacea</td><td>6.62</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td rowspan="10">Nitzschia miocenica</td><td rowspan="10">Nitzschia miocenica</td><td>B Nitzschia bicapitata</td><td>6.70</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td>B Nitzschia dietrichii</td><td>6.70</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td>B Nitzschia inflatula</td><td>6.70</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td>B Planktoniella sol</td><td>6.70</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td>B Thalassiosira symmetrica</td><td>6.70</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td>B Thalassiosira miocenica</td><td>6.74</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>T Cavitus jouseana</td><td>6.75</td><td>Lazarus et al., 2014; Barron et al., 2004</td></tr><tr><td>B Thalassiosira convexa</td><td>6.77</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Thalassiosira nodulolineata</td><td>6.80</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td>B Asteromphalus arachne</td><td>6.90</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td>B Azpeitia komurae</td><td>6.90</td><td>Lazarus et al., 2014; Yanagisawa and Akiba, 1998</td></tr><tr><td>B Nitzschia miocenica var. elongata</td><td>6.90</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Thalassiosira praeconvexa</td><td>6.91</td><td>Lazarus et al., 2014; Barron, 2003</td></tr></tbody></table>
<table><caption>Table T4 (continued). (Continued on next page.)</caption><thead><tr><th>Diatom zonation<br>(Scherer et al., 2007)</th><th></th><th>Diatom bioevent</th><th>GTS2012<br>age (Ma)</th><th>Age reference</th></tr></thead><tbody><tr><td rowspan="3">Nitzschia miocenica</td><td rowspan="3">A</td><td>B Asterolampra heptactis</td><td>7.00</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td>B Thalassionema bacillaris</td><td>7.00</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td>T Nitzschia porteri</td><td>7.24</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td rowspan="10">Nitzschia porteri</td><td rowspan="5">B</td><td>B Fragilariopsis miocenica</td><td>7.39</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Nitzschia interrupta</td><td>7.40</td><td>Lazarus et al., 2014; Schrader, 1974</td></tr><tr><td>B Actinocyclus ellipticus f. elongatus</td><td>7.50</td><td>Lazarus et al., 2014; Schrader, 1974</td></tr><tr><td>B Fragilariopsis cylindrica</td><td>7.65</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>T Rossiella paleacea</td><td>7.70</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td rowspan="4">A</td><td>B Fragilariopsis reinholdii</td><td>7.71</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>T Actinocyclus ellipticus var. javanica</td><td>7.85</td><td>Lazarus et al., 2014; Barron, 1985</td></tr><tr><td>T Thalassiosira burckliana</td><td>8.00</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Alveus marinus</td><td>8.02</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td rowspan="16">Thalassiosira yabei</td><td rowspan="5">A</td><td>B Synedra indica</td><td>8.20</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td>T Thalassiosira yabei</td><td>8.32</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>T Rossiella elongata</td><td>8.40</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>T Pseudopyxilla americana</td><td>8.70</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td>T Triceratium condecorum</td><td>8.70</td><td>Lazarus et al., 2014; Barron, 1976</td></tr><tr><td rowspan="4">B</td><td>B Asteromphalus robustus</td><td>8.72</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td>T Coscinodiscus loeblichii</td><td>8.89</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>T Coscinodiscus yabei var. ellipticus</td><td>8.90</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Rhizosolenia bergonii</td><td>8.90</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td rowspan="10">A</td><td>B Coscinodiscus yabei var. ellipticus</td><td>9.01</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Fragilariopsis fossilis</td><td>9.01</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>T Azpeitia endoi</td><td>9.11</td><td>Lazarus et al., 2014; Barron, 1976</td></tr><tr><td>B Thalassiosira burckliana</td><td>9.11</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Thalassiosira eccentrica</td><td>9.11</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>T Denticulopsis dimorpha</td><td>9.30</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>T Azpeitia aeginensis</td><td>9.51</td><td>Lazarus et al., 2014; Fenner, 1985</td></tr><tr><td>T Coscinodiscus vetustissimus var. javanica</td><td>9.51</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Coscinodiscus loeblichii</td><td>9.64</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Coscinodiscus vetustissimus var. javanica</td><td>9.70</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td rowspan="10">Actinocyclus moronensis</td><td rowspan="5">B</td><td>T Actinocyclus moronensis</td><td>9.87</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Hemidiscus simplicissimus</td><td>9.90</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td>B Denticulopsis dimorpha</td><td>10.00</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Asterolampra acutiloba</td><td>10.10</td><td>Lazarus et al., 2014; Koizumi and Tanimura, 1985</td></tr><tr><td>B Actinocyclus ellipticus f. lanceolata</td><td>10.46</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td rowspan="5">A</td><td>T Azpeitia apiculata</td><td>10.71</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Bogorovia praepaleacea</td><td>11.13</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>T Coscinodiscus gigas var. diorama</td><td>11.27</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Rossiella elongata</td><td>11.27</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>T Actinocyclus ellipticus var. spiralis</td><td>11.34</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td rowspan="5">B</td><td>T Crucidenticula punctata</td><td>11.44</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>T Craspedodiscus coscinodiscus</td><td>11.48</td><td>Lazarus et al., 2014; Barron, 2005</td></tr><tr><td>B Hemidiscus cuneiformis</td><td>11.64</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>T Macrora stella (Azpeitia)</td><td>11.74</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td>B Thalassiosira brunii</td><td>12.26</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td rowspan="10">Coscinodiscus gigas var. diorama</td><td rowspan="5">B</td><td>B Nitzschia porteri</td><td>12.29</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>T Crucidenticula nicobarica</td><td>12.36</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>T2 Annellus californicus</td><td>12.54</td><td>Lazarus et al., 2014; Barron, 2005</td></tr><tr><td>B Asteromphalus imbricatus</td><td>12.54</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td>B Bogorovia lancettula</td><td>12.63</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td rowspan="5">A</td><td>T Azpeitia salisburyana</td><td>12.91</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>T Coscinodiscus lewisianus</td><td>12.94</td><td>Lazarus et al., 2014; Shackleton et al., 1995</td></tr><tr><td>T Azpeitia vetustissima var. voluta</td><td>13.02</td><td>Lazarus et al., 2014; Baldauf and Barron, 1982</td></tr><tr><td>T Thalassiosira perispinosa</td><td>13.02</td><td>Lazarus et al., 2014; Tanimura, 1996</td></tr><tr><td>B Coscinodiscus gigas var. diorama</td><td>13.02</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td rowspan="5">A</td><td>T Thalassiosira tappanae</td><td>13.20</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Azpeitia nodulifera</td><td>13.25</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Pseudotriceratium wallichii</td><td>13.32</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Coscinodiscus gigas</td><td>13.40</td><td>Lazarus et al., 2014; Cervato and Burckle, 2003</td></tr><tr><td>B Crucidenticula punctata</td><td>13.40</td><td>Lazarus et al., 2014; Barron, 1985</td></tr><tr><td rowspan="10">Coscinodiscus lewisianus</td><td rowspan="5">A</td><td>B Thalassiosira yabei</td><td>13.50</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>T Cestodiscus pulchellus var. maculata</td><td>13.89</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Azpeitia apiculata</td><td>13.89</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>B Actinocyclus ellipticus var. javanica</td><td>13.98</td><td>Lazarus et al., 2014; Barron, 1985</td></tr><tr><td>B Actinocyclus moronensis</td><td>13.98</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td rowspan="5">B</td><td>B Azpeitia aeginensis</td><td>13.98</td><td>Lazarus et al., 2014; Fenner, 1985</td></tr><tr><td>B Actinocyclus ellipticus</td><td>14.02</td><td>Lazarus et al., 2014; Barron, 2003</td></tr><tr><td>T Cestodiscus peplum</td><td>14.03</td><td>Lazarus et al., 2014; Barron, 2003</td></tr></tbody></table>