Fulthorpe, C.S., Hoyanagi, K., Blum, P., and the Expedition 317 Scientists Proceedings of the Integrated Ocean Drilling Program, Volume 317 Expedition 317 summary1 Expedition 317 Scientists2 Chapter contents Abstract Abstract . 1 Integrated Ocean Drilling Program (IODP) Expedition 317 was de- voted to understanding the relative importance of global sea level Introduction . 2 (eustasy) versus local tectonic and sedimentary processes in con- Geologic setting . 3 trolling continental margin sedimentary cycles. The expedition Site survey data and interpretation . 4 recovered sediments from the Eocene to recent period, with a par- Scientific objectives . 6 ticular focus on the sequence stratigraphy of the late Miocene to Operational strategy . 8 recent, when global sea level change was dominated by gla- Traveltime/depth conversion . 9 cioeustasy. Drilling in the Canterbury Basin, on the eastern mar- Synopsis. 10 gin of the South Island of New Zealand, takes advantage of high Preliminary scientific assessment . 24 rates of Neogene sediment supply, which preserves a high-fre- Site summaries . 25 quency (0.1–0.5 m.y.) record of depositional cyclicity. Because of References . 39 its proximity to an uplifting mountain chain (the Southern Alps) Figures . 44 and strong ocean currents, the Canterbury Basin provides an op- Tables. 84 portunity to study the complex interactions between processes re- sponsible for the preserved sequence stratigraphic record. Cur- rents have locally built large, elongate sediment drifts within the prograding Neogene section. These elongate drifts were not drilled during Expedition 317, but currents are inferred to have strongly influenced deposition across the basin, including loca- tions lacking prominent mounded drifts. Upper Miocene to recent sedimentary sequences were cored in a transect of three sites on the continental shelf (landward to basin- ward, Sites U1353, U1354, and U1351) and one on the continen- tal slope (Site U1352). The transect provides a stratigraphic record of depositional cycles across the shallow-water environment most directly affected by relative sea level change. Lithologic boundar- ies provisionally correlative with seismic sequence boundaries were identified in cores from each site, providing insight into the origins of seismically resolvable sequences. This record will be used to estimate the timing and amplitude of global sea level change and to document the sedimentary processes that operate during sequence formation. Sites U1353 and U1354 provide sig- nificant double-cored, high-recovery sections through the Holo- cene, allowing for high-resolution study of recent glacial cycles in 1 Expedition 317 Scientists, 2011. Expedition 317 a continental shelf setting. summary. In Fulthorpe, C.S., Hoyanagi, K., Blum, Continental slope Site U1352 represents a complete section from P., and the Expedition 317 Scientists, Proc. IODP, modern slope terrigenous sediment to hard Eocene limestone, 317: Tokyo (Integrated Ocean Drilling Program Management International, Inc.). with all the associated lithologic, biostratigraphic, physical, geo- doi:10.2204/iodp.proc.317.101.2011 chemical, and microbiological transitions. This site also provides 2 Expedition 317 Scientists’ addresses. a record of ocean circulation and fronts during the last ~35 m.y. Proc. IODP | Volume 317 doi:10.2204/iodp.proc.317.101.2011 Expedition 317 Scientists Expedition 317 summary The early Oligocene (~30 Ma) Marshall Paraconfor- sessing anthropogenic influences. However, eustatic mity was the deepest drilling target of Expedition effects are complexly intertwined with processes of 317 and was hypothesized to represent intensified basin subsidence and sediment supply (e.g., Cloet- current erosion or nondeposition associated with the ingh et al., 1985; Karner, 1986; Posamentier et al., initiation of thermohaline circulation following the 1988; Christie-Blick et al., 1990; Reynolds et al., separation of Australia and Antarctica. 1991; Christie-Blick and Driscoll, 1995; Kominz et Expedition 317 set a number of scientific ocean drill- al., 1998; Kominz and Pekar, 2001). Controversy ing records: (1) deepest hole drilled in a single expe- arises from the application of the sequence strati- dition and second deepest hole in the history of sci- graphic model (Mitchum et al., 1977; Van Wagoner entific ocean drilling (Hole U1352C, 1927 m); (2) et al., 1988; Posamentier et al., 1988; Posamentier deepest hole and second deepest hole drilled by the and Vail, 1988; Vail et al., 1991) to sea level studies. R/V JOIDES Resolution on a continental shelf (Hole Sequence stratigraphy has highlighted the cyclical U1351B, 1030 m; Hole U1353B, 614 m); (3) shallow- nature of the continental margin stratigraphic record est water depth for a site drilled by the JOIDES Resolu- and led to the theory of eustatic sequence control as tion for scientific purposes (Site U1353, 84.7 m water well as the resultant eustatic cycle chart (Haq et al., depth); and (4) deepest sample taken during scien- 1987). This global sea level model remains conten- tific ocean drilling for microbiological studies (Site tious (e.g., Cloetingh et al., 1985; Carter, 1985; U1352, 1925 m). Karner, 1986; Christie-Blick et al., 1990; Christie- Blick, 1991; Carter et al., 1991; Karner et al., 1993; Expedition 317 supplements previous drilling of sed- Christie-Blick and Driscoll, 1995; Dewey and Pitman, imentary successions for sequence stratigraphic and 1998; Miall and Miall, 2001). sea level objectives, particularly drilling on the New Jersey margin (Ocean Drilling Program [ODP] Legs High rates of Neogene sediment supply preserved a 150, 150X, 174A, and 174AX and IODP Expedition high-frequency (0.1–0.5 m.y.) seismically resolvable 313) and in the Bahamas (ODP Leg 166), but in- record of depositional cyclicity in the offshore Can- cludes an expanded Pliocene section. Completion of terbury Basin (Fulthorpe and Carter, 1989; Browne at least one transect across a geographically and tec- and Naish, 2003; Lu and Fulthorpe, 2004). Explora- tonically distinct siliciclastic margin was the neces- tion wells indicate the presence of middle Miocene sary next step in deciphering continental margin to recent sedimentary sequences that are generally stratigraphy. Expedition 317 also complements ODP correlative in age with those drilled on the New Jer- Leg 181, the focus of which was drift development in sey margin by the Ocean Drilling Program (ODP). more distal parts of the Eastern New Zealand Oce- However, the Canterbury Basin differs in ways that anic Sedimentary System (ENZOSS). allow for expanded study of the complex processes of sequence formation in line with the global ap- proach to sea level change advocated by previous Introduction planning groups: Defining the relative importance of global sea level 1. The stratigraphy records the early development (eustasy) versus local tectonic, sedimentary, and of the Antarctic circumpolar circulation and re- oceanographic processes in controlling continental lated southern oceanographic fronts. Currents margin depositional cyclicity is a fundamental prob- strongly influenced deposition, modifying se- lem in sedimentary geology. A better understanding quence architecture and locally leading to the de- of how these processes interact to form preserved position of large sediment drifts that aggraded to stratigraphy would greatly enhance our ability to upper-slope depths within the prograding Neo- read the record, covering many tens of millions of gene section. years, of Earth history contained within the thick 2. Rifting is younger (Cretaceous) than the New Jer- sedimentary deposits beneath the world’s continen- sey margin (Jurassic), and from the earliest Mio- tal shelves. This problem was addressed during Inte- cene copious terrigenous sediment was supplied grated Ocean Drilling Program (IODP) Expedition from a rapidly uplifting nearby mountain range 317 by drilling the Canterbury Basin on the eastern (the Southern Alps). Regional tectonic and geo- margin of the South Island of New Zealand (Figs. F1, logic histories have been intensively studied, al- F2, F3). lowing evaluation of the influence of sediment The geologic record provides an opportunity to supply on sequence formation and of the tec- quantify the timing, rate, amplitude, mechanisms/ tonic evolution of the Alpine Fault plate bound- controls, and effects (stratigraphic response) of eu- ary. static change, which in turn provides a baseline for The Canterbury Basin is part of the Eastern New Zea- predicting future relative sea level changes and as- land Oceanic Sedimentary System (ENZOSS) (Carter Proc. IODP | Volume 317 2 Expedition 317 Scientists Expedition 317 summary et al., 1996). The distal (up to 4460 m water depth) section can be divided into three principal intervals, component of ENZOSS was targeted by ODP Leg 181, the Onekakara, Kekenodon, and Otakou groups which focused on drift development in the south- (Carter, 1988), during which contrasting large-scale west Pacific gateway, principally under the influence sedimentary processes operated (Fig. F4). of the evolving Antarctic Circumpolar Current and the Deep Western Boundary Current (Shipboard Sci- Cretaceous–Paleogene transgression and entific Party, 1999a). Expedition 317 complements Oligocene highstand Leg 181 drilling by focusing on the landward part of ENZOSS. The postrift transgressive phase (Onekakara Group) produced ramplike seismic geometries and termi- nated during the late Eocene, when flooding of the Geologic setting