11. Data Report: High-Resolution Site Survey

Home , Tamu Massif

Bralower, T.J., Premoli Silva, I., Malone, M.J., et al., 2002 F1. Bathymetric map of Shatsky Proceedings of the Ocean Drilling Program, Initial Reports Volume 198 Rise, p. 7.

Shatsky Rise, NW Pacific 44° Seismic reflection data collected during N cruise TN037 of the Thomas Thompson 5

ODP Leg 198 drill site

Location of South High, Central High, 5 ° North High and Thompson Trough 42 survey areas shown in Figures F2, F3, F4, and F5 5 5 Contour interval is 500 m; contour labels are in km 0 500 Papanin Ridge Thompson km 40° Trough

L4 North High 5

1207 4 38°

Central High 5 5 5 4 L7

36 ° 1208 L12 5 6 5 6 h nc Japan re il T M1 r ) M Ku 124 34° ( ns 1 6 L13 ese eatio h pan Lin c 0 ° 1 Ja netic 0 40 n M ag M1 e M 3) South High 13 Tr ( 5 6 M n Shatsky Rise a 1 p Hawaiian

a J 6 4 1209 M1

1) M M h 4 agnetic

(1 1 c M2

n 1 e 1 L

r 2 ) in T 8 e ° M 4 a

n tio

32 3 30° i (1 M M n 1 n

5 2 M s o 5 6

16 2 2 B M 1 4 1210 M 54) (1 9 ) M L17C 1 2 8 2 Izu- 2 5 1212 5 5 M M 5 (1 25 M M 29 9 1211 2 L17D M 20° 1 FZ 2 FZ 30° 6 M 1213 1214 6 140° 150° 160° 170° 11. DATA REPORT: HIGH-RESOLUTION 154°E 158° 162° 166° 170° SITE SURVEY SEISMIC REFLECTION DATA F2. South High survey area, p. 8.

32 1600 54 15 26 (22 Aug) 44 ° (25 Aug) 14A 33 40 N 2000 22 FOR EG RILLING 1200 (27 Aug) 30 ODP L 198 D 0400 2000 50 28 1209 26 0800 0000 (24 Aug)

1000 16 1600 2000 1600 1200 48 0000 (23 Aug) 1212 1600

1 (DSDP 47) 577 14C 49 1600 ON HATSKY ISE ORTHWEST ACIFIC 50 810 48 2000 S R , N P 26 1300

0400 14D 1200 44 1210

34 38 36 17A 1211 0800 14B 40 0000 28 36 32° (DSDP 305) (28 Aug) 1214 (25 Aug) 0000 0400 (DSDP 306) 4 Adam Klaus2,3 and William W. Sager3,4 17B 0800 32 1213 36

1200 40

44 44 48 17C 1600 48

31° 50 2000 50 46 52 0000 (29 Aug) 52 0400 17D 54

156°E 157° 158° 159° 0 50 100

F3. Central High survey area, p. 9.

ABSTRACT 52 56

48 54

48 1400 (17 Aug) In 1994, we conducted a marine geophysical and geological survey of 2000 46 44

Shatsky Rise in the northwest Pacific. The primary objective of this 37° 44 N 40

1800 36 cruise was to investigate the formation and evolution of the rise as well 1600 34 1000 54 11C as to collect site survey data required for ocean drilling. During this (18 Aug) 1000 0600 10 Site 11A 1208 1400 44

0400 1200 0200 (16 Aug) 1200 cruise, we collected >3200 km of seismic reflection data, which forms 9 42 0400 34 38 0400 0200

8 2200 8 1400 (15 Aug) 1000 0600 0600 the primary seismic data set on which Leg 198 drill sites are located. 36° 1000 1600 1800 52 0000 1400 20 Aug 34 46 0000 32 0000 21 Aug (14 Aug) 50 19 Aug 2000 34 12 This paper presents the seismic reflection data collected during this sur- 44 38 2200 42 44

11B 2000 0400 vey. 46 157°E 158° 159°

0 50 100

km INTRODUCTION

Ocean Drilling Program (ODP) Leg 198 returned to Shatsky Rise in 1Examples of how to reference the the northwest Pacific, revisiting the South High drilled during Deep Sea whole or part of this volume. Drilling Project (DSDP) Legs 6, 32, and 86, as well as ODP Leg 132 (Figs. 2Ocean Drilling Program, 1000 F1, F2; Fischer, Heezen, et al., 1971; Larson, Moberly, et al., 1975; Discovery Drive, College Station TX 77845-9547, USA. Heath, Burkle, et al., 1985; Storms, Natland, et al., 1991). In addition, [email protected] Leg 198 also occupied one site each on the Central and North Highs 3Department of Oceanography, Texas (Figs. F1, F3, F4). A high-resolution seismic reflection survey was carried A&M University, College Station TX out in 1994 to determine the origin and evolution of the rise and to ob- 77843-3146, USA. 4 tain site survey data required for ocean drilling. The purpose of this pa- Department of Geology and Geophysics, Texas A&M University, per is to present these seismic reflection data as a first step toward inte- College Station TX 77843-3115, USA.

Ms 198IR-111 A. KLAUS AND W.W. SAGER CHAPTER 11, DATA REPORT: HIGH-RESOLUTION SEISMIC REFLECTION DATA 2 grating the regional seismic reflection data set with the Leg 198 coring F4. North High survey area, p. 10. and logging data.

2000 (9 Aug)

44 5A 38 42 38°00' 40 38 N 36 6 2200 36 34 34 30 2100 2200 REGIONAL GEOLOGIC SETTING 32 32 2300 (10 Aug) 0000 0000 (11 Aug)

0200

5C 0400 (12 Aug) 0600 2200 32 0000

Site 1207 2000 Shatsky Rise is a large (450 km long, 1650 km wide) oceanic plateau 34 0200 36 38 1800 40 40 located in the northwestern Pacific 1600 km east of Japan (Fig. F1). 1600 37°30' 0400

Magnetic lineations (Fig. F1 inset) show that the Pacific Plate near 38 40 1400 40 34 38 7 (13 Aug) 40 0400 0600 Shatsky Rise was formed during the Jurassic and Early Cretaceous at two 1200

42 1000 spreading ridges that met at a triple junction (Larson and Chase, 1972; 0500 0800 40 5B

0600 Hilde et al., 1976; Handschumacher et al., 1988; Sager et al., 1988; 38 34 Nakanishi et al., 1989, 1999). The northeast-trending Japanese linea- 162°30'E 163°00' 020 tion set formed at the spreading ridge separating the Pacific from the km Izanagi plate to the northwest. The southeast-trending Hawaiian lineations formed at the ridge separating the Pacific from the Farallon plate to the northeast (Woods and Davies, 1982). Tectonic reconstructions indicate that this part of the Pacific Plate formed near the equator (e.g., Larson and Chase, 1972). The regional seafloor surrounding Shatsky Rise is deep (5.5–6.0 km) and sediment cover is thin, typically a few hundred meters (Houtz and Ludwig, 1979; Ludwig and Houtz, 1979). Sediments on the top of Shatsky Rise are much thicker, up to 1.2 km (Ewing et al., 1966; Zdoro- venin et al., 1972; Neprohnov et al., 1984; Karp and Prokudin, 1985; Khankishieva, 1989; Sliter and Brown, 1993; Klaus et al., 1995) and are composed of Cretaceous pelagic carbonates deposited above the calcite compensation depth when the rise was younger and nearer the equator (e.g., Sliter and Brown, 1993). Shatsky Rise is a thick igneous construct with a seismic velocity structure similar to oceanic crust, but thickened by several times under the highest parts (Den et al., 1969; Gettrust et al., 1980; Kogan, 1981). This suggests that the rise has a composition similar to oceanic crust and that dredges have recovered basalts from basement outcrops on the rise (Kashintsev and Suzymov, 1981; Sager et al., 1999). The huge size of the igneous pile, however, indicates that it was not formed by typical seafloor spreading. A relationship between Shatsky Rise and the Pacific-Izanagi-Farallon triple junction has long been suspected because the Japanese and Hawaiian magnetic lineations converge at the rise axis (Larson and Chase, 1972; Hilde et al., 1976). Magnetic bights occur in many places within the lower parts of the rise, implying that the triple junction was composed of spreading ridges (Fig. F1) (Nakanishi et al., 1999). Because its size implies a large amount of volcanism, several authors have sug- gested that the rise formed as the result of a mantle plume (Sager et al., 1988; Nakanishi et al., 1989; Sager and Han, 1993; Sager et al., 1999). A predominantly reversed magnetic polarity over the southwestern part of the South High suggests a short formation period and an extremely high magma eruption rate similar to those of flood basalts and postu- lated for plume heads (Sager and Han, 1993). There are few age dates for Shatsky Rise because basalts dredged from it are typically too altered for radiometric dating. Despite several attempts at drilling basement prior to Leg 198, no borehole has pene- trated basement to obtain fresher rocks. The oldest well-dated sediments recovered from drilling the rise, which are at DSDP Site 306 on the southwest side of the South High (Fig. F2), are Berriasian (earliest Cretaceous; 137–144 Ma [timescale of Gradstein et al., 1994]) and were A. KLAUS AND W.W. SAGER CHAPTER 11, DATA REPORT: HIGH-RESOLUTION SEISMIC REFLECTION DATA 3 recovered ~80 m above a reflector thought to represent basement (Lar- son, Moberly, et al., 1975). Late Jurassic magnetic lineations M21 (148 Ma) to M19 (145 Ma) bracket the South High, so this massif must have formed near the end of the Jurassic or beginning of the Cretaceous. The Central High, North High, and Papanin Ridge must be younger because the magnetic lineations indicate that the lithosphere beneath is younger than early Berriasian (Fig. F1 inset). Shatsky Rise gravity data indicate Airy-type isostatic compensation typical for features emplaced near spreading ridges (Watts et al., 1980; Sandwell and MacKenzie, 1989), suggesting an age for the rise near that of the underlying lithosphere. These observations imply that the age of the rise becomes younger to the northeast (Sager and Han, 1993). Volcanism occurred on Shatsky Rise after the main shield-building volcanic phases. Both the South and Central Highs have late-stage volcanic ridges on their top; the one on the South High rises ~1 km above the level at which shallow-water fossils were dredged. Assuming that this ridge formed below sea level (it shows no obvious subaerial ero- sion), the high subsided as normal lithosphere (Johnson and Carlson, 1992), and the fossils are autochthonous, the depth difference implies a time gap of ~8 to 9 m.y. In addition, basalts dredged from Toronto Ridge on top of the South High are trachytes and trachyandesites (Te- jada et al., 1995), which are typical of fractionated, late-stage eruptions (Macdonald and Abbott, 1970).

TECTONIC EVOLUTION

Sager et al. (1999) inferred that Shatsky Rise was formed by plume- related volcanism near a triple junction from about M21 to M1 (147 to 124 Ma). The three large highs and the normal lithosphere between them imply that volcanism was episodic, with separate pulses building each of the highs. The volume trend implies that the first eruption was extraordinarily large and that subsequent eruptions were of diminish- ing size. As indicated by the narrow time gap between the age of the underlying lithosphere and oldest sediments drilled at Site 306, Shatsky Rise ev- idently began forming near the Jurassic–Cretaceous boundary with rapid, massive eruptions that formed the South High (Sager and Han, 1993). This nearly coincided with an 800-km eastward jump of the Pacific-Izanagi-Farallon triple junction and a reorientation of the Pacific-Izanagi Ridge between M21 and M19 (148-145 Ma) (Sager et al., 1988). Whether this large jump was caused by the eruption of the South High is unclear, but morphology and anomaly positions imply that the volcanic edifice formed slightly off-ridge and affected the ridge positions (Sager et al., 1999). Ridge jumps also occurred at about the time of formation of the Central and North Highs (M16-MI5 and M14, 138 and 136 Ma, respectively), moving the triple junction farther northeast (Nakanishi et al., 1999). The shape of the rise implies that the plates were moving rapidly southwest relative to the mantle plume (~1400 km in the 22 m.y. between M20 and M1), so the ridge jumps may have occurred to keep the spreading ridges located atop or near the plume (Sager et al., 1999). A. KLAUS AND W.W. SAGER CHAPTER 11, DATA REPORT: HIGH-RESOLUTION SEISMIC REFLECTION DATA 4

DATA ACQUISITION AND PROCESSING F5. Thompson Trough survey area on Papanin Ridge, p. 11. In 1994, we conducted a geophysical and geological survey of Papanin Ridge 50

Shatsky Rise (cruise TN037 of Thomas G. Thompson). We collected seis- 48 48 mic reflection, swath bathymetric (Hydrosweep), and potential field 46

52 45 3 52 1500 (magnetic, gravity) data, as well as a number of dredges and cores. The 50 1600 50 54 45 52 bathymetric and magnetic data and their interpretations have been 48 50 Th ° om 40 00' ps 1300 48 on N Tro 1700 ug 52 published elsewhere (Nakanishi et al., 1999; Sager et al., 1999). In this h 48 50 52

50 1800 0100 paper, we present the results of seismic reflection data acquisition. 1200 52 45 42

A total of 3213 km of seismic reflection data were collected over 48 38 0000 2000 45 Shatsky Rise using a six-channel streamer and air gun sources (Figs. F1, (8 Aug) 1100 (7 Aug) 4 2100 48 2200 52 2300 F2, F3, F4, F5). The acquisition geometry, recording parameters, and 0100 (9 Aug) 52 50 processing sequence are summarized in Figure F6 and Table T1. The 6- 50 channel Teledyne streamer consisted of a 70-m tow leader, a 5-m

39°30' weighted section, a 25-m stretch section, six 25-m active sections, and 163°30'E 164°00' two additional spare active sections (Fig. F6). Two different air gun sources were used. A single generator-injector (45/105 in3) air gun was F6. Seismic data acquisition geom- used primarily when conducting long profiles between survey areas etry, sources, and receivers used on over the highs. This source could be towed at relatively high speeds (~7 Thomas Thompson cruise, p. 12. nmi/hr) and produced two-fold data. The second source, an array of 83.5 m 178 m 70 m GPS 37.2 m antenna 3 18 m four air guns (80, 108, 150, 200 in ), was used to conduct most of the sea level 9 m air gun 70 m streamer stretch 12 3456 detailed surveys over the South, Central, and North Highs. Profiles col- 25 m magnetometer lected with this array were run at ~5 nmi/hr, resulting in three-fold cov- erage. We recorded the seismic reflection data at 1 ms in SEGY format Air gun array configuration 80 in3 magnetometer

200 in3 on 4-mm (DAT) and 8-mm (Exabyte) tapes using “a2d” seismic acquisi- 150 in3 streamer tion software on a Sun workstation. Following the cruise, the data were 108 in3 completely processed through migration using the steps shown in Table GI-gun array configuration magnetometer

45/105 in3

T1. The entire seismic reflection data set collected over Shatsky Rise is streamer presented in Figures F7, F8, F9, F10, F11, F12, F13, and F14. T1. Field acquisition, recording, ACKNOWLEDGMENTS and processing parameters, p. 21.

We thank the captain, crew, and technical staff of the Thomas F7. Seismic lines 5A, 5C, and 11B, Thompson. Perry Crampton and Seth Mogk from Scripps Institution of p. 13. Oceanography (University of California, San Diego) provided seismic data acquisition services. A number of scientists (Masao Nakanishi of F8. Seismic lines 14A, 14C, 17A, the Ocean Research Institute, University of Tokyo, in particular), stu- and 17B, p. 14. dent watch standers, and Earthwatch volunteers contributed to the shipboard data collection. Michael Holzrichter provided invaluable ex- F9. Seismic lines 3 and 4, p. 15. pertise and attention to detail while processing seismic data. Mauricio Canon assisted with seismic figure preparation. Adam Klaus acknowl- edges the Ocean Drilling Program (ODP) for supporting his involve- F10. Seismic lines 5B, 6, and 7, ment throughout the project. We used GMT software (Wessel and p. 16. Smith, 1995) to produce the maps. This work funded by National Sci- ence Foundation (ODP) grant OCE93-14229. F11. Seismic line 9, p. 17.

F12. Seismic lines 10, 11A, and 11C, p. 18.

F13. Seismic lines 12, 13, 14B, and 14C, p. 19.

F14. Seismic lines 15, 16, 17C, and 17D, p. 20. A. KLAUS AND W.W. SAGER CHAPTER 11, DATA REPORT: HIGH-RESOLUTION SEISMIC REFLECTION DATA 5 REFERENCES

Den, N., Ludwig, W.J., Murauchi, S., Ewing, J.I., Hotta, H., Edgar, N.R., Yoshii, T., Asanuma, T., Hagiwara, K., Sato, T., and Ando, S., 1969. Seismic-refraction measurements in the northwest Pacific Basin. J. Geophys. Res., 74:1421–1434. Ewing, M., Saito, T., Ewing, J.I., and Burckle, L.M., 1966. Lower Cretaceous sediments from the Northwestern Pacific. Science, 152:751–755. Fischer, A.G., Heezen, B.C., et al., 1971. Init. Repts. DSDP, 6: Washington (U.S. Govt. Printing Office). Gettrust, J.F., Furukawa, K., and Kroenke, L.W., 1980. Crustal structure of the Shatsky Rise from seismic refraction measurements. J. Geophys. Res., 85:5411–5415. Gradstein, F.M., Agterberg, F.P., Ogg, J.G., Hardenbol, J., van Veen, P., Thierry, J., and Huang, Z., 1994. A Mesozoic time scale. J. Geophys. Res., 99:24051–24074. Handschumacher, D.W., Sager, W.W., Hilde, T.W.C., and Bracey, D.R., 1988. Pre- Cretaceous tectonic evolution of the Pacific Plate and extension of the geomag- netic polarity reversal time scale with implications for the origin of the Jurassic “Quiet Zone.” Tectonophysics, 155:365–380. Heath, G.R., Burckle, L.H., et al., 1985. Init. Repts. DSDP, 86: Washington (U.S. Govt. Printing Office). Hilde, T.W.C., Isezaki, N., and Wageman, J.M., 1976. Mesozoic sea-floor spreading in the North Pacific. In Woolard, G.P., Sutton, G.H., Manghnani, M.H., and Moberly, R. (Eds.), The Geophysics of the Pacific Ocean Basin and its Margins. Geophys. Monogr., Am. Geophys. Union, 19:205–226. Houtz, R.E., and Ludwig, W.J., 1979. Distribution of reverberant subbottom layers in the southwest Pacific Basin. J. Geophys. Res., 84:3497–3504. Johnson, H.P., and Carlson, R.L., 1992. Variation of sea floor depth with age: a test of models based on drilling results. Geophys. Res. Lett., 19:1971–1974. Karp, B.Y., and Prokudin, V.G., 1985. The structure of the sedimentary layer on the Shatsky Rise according to seismic data. Tikhookkean. Geol., 3:26–33. Kashintsev, G.L., and Suzymov, A.Y., 1981. Basalts of the Shatsky Rise. Dokl. Akad Nauk SSSR, 258:86-90. Khankishieva, L.M., 1989. The structure and seismostratigraphy of the sedimentary cover on the Shatsky Rise (Pacific Ocean). Okeanologiya, 29:178–183. Klaus, A., Khankishieva, L., Brown, G.R., Sager, W.W., Kim, J., Nakanishi, M., 1995. Preliminary seismic reflection results from Shatsky Rise, western Pacific Ocean. Eos, Trans. Am. Geophys. Union, 76:611. (Abstract). Kogan, L.L., 1981. Crustal structure of the Shatsky Rise of the northwestern Pacific, from deep seismic reflection profiling. Dokl. Akad. Nauk SSSR, 258:25–30. Larson, R.L., and Chase, C.G., 1972. Late Mesozoic evolution of the western Pacific Ocean. Geol. Soc. Am. Bull., 83:3627–3644. Larson, R.L., Moberly, R., et al., 1975. Init. Repts. DSDP, 32: Washington (U.S. Govt. Printing Office). Ludwig, W.J., and Houtz, R.E., 1979. Isopach Map of Sediments in the Pacific Ocean Basin and Marginal Sea Basins. AAPG Map Ser., 647. Macdonald, G.A., and Abbott, A.T., 1970. Volcanoes in the Sea: Honolulu (Univ. of Hawaii Press). Nakanishi, M., Tamaki, K., and Kobayashi, K., 1989. Mesozoic magnetic anomaly lineations and seafloor spreading history of the northwestern Pacific. J. Geophys. Res., 94:15,437–15,462. Nakanishi, M., Sager, W.W., and Klaus, A. 1999. Magnetic Lineations within Shatsky Rise, Northwest Pacific Ocean: Implications for Hot Spot-Triple Junction Interac- tion and Oceanic Plateau Formation. J. Geophys. Res., 104:7539–7556. Neprochnov, Y.P., Merklin, L.R., and Khankishiyeva, L.M., 1984. Distribution map of the sedimentary cover on the Shatsky Rise. Dokl. Akad. Nauk SSSR, 277:1204–1207. A. KLAUS AND W.W. SAGER CHAPTER 11, DATA REPORT: HIGH-RESOLUTION SEISMIC REFLECTION DATA 6

Sager, W.W., and Han, H.-C., 1993. Rapid formation of the Shatsky Rise oceanic plateau inferred from its magnetic anomaly. Nature, 364:610–613. Sager, W.W., Handschumacher, D.W., Hilde, T.W.C., and Bracey, D.R., 1988. Tectonic evolution of the northern Pacific Plate and Pacific-Farallon-Izanagi triple junction in the Late Jurassic and Early Cretaceous (M21-M10). Tectonophysics, 155:345–364. Sager, W.W., Kim, J., Klaus, A., Nakanishi, M., Khankishieva, L.M. 1999. Bathymetry of Shatsky Rise, Northwest Pacific Ocean: Implications for oceanic plateau devel- opment at a triple junction. J. Geophys. Res., 104:7557–7576. Sandwell, D.T., and MacKenzie, K.R., 1989. Geoid height versus topography for oceanic plateaus and swells. J. Geophys. Res., 94:7403–7418. Sliter, W.V., and Brown, G.R., 1993. Shatsky Rise: Seismic stratigraphy and sedimentary record of Pacific paleoceanography since the Early Cretaceous. Natland, J.H., Storms, M.A. (Eds.). Proc. ODP, Sci. Results, 132: College Station, TX (Ocean Drilling Program), 3-13. Storms, M.A., Natlund, J.H., et al., 1991. Proc. ODP, Init. Repts., 132. College Station, TX (Ocean Drilling Program). Tejada, M.L.G., Mahoney, J.J., Sager, W.W., and Shipboard Scientific Party, 1995. Iso- topic study of basement rocks from Shatsky Rise, northwestern Pacific Ocean. Eos, Trans. Am. Geophys. Union, 76:699. (Abstract). Watts, A.B., Bodine, J.H., and Ribe, N.M., 1980. Observations of flexure and the geological evolution of the Pacific Ocean Basin. Nature, 283:532–537. Wessel, P., and Smith, W.H.F., 1995. New version of the Generic Mapping Tools released. Eos, Trans. Am. Geophys. Union, 76:329. Woods, M.T., and Davies, G.F., 1982. Late Cretaceous genesis of the Kula Plate. Earth Planet Sci. Lett., 58:161–166. Zdorovenin, V.V., Shekhvatov, B.V., Kuzmin, V.A., Suzyumov, A.Y., Filatyev, V.P., and Sheina, L.P., 1972. Origin of the sedimentary cover of the Shatsky Rise. Dokl. Akad. Nauk SSSR, 202:243-245. A. KLAUS AND W.W. SAGER CHAPTER 11, DATA REPORT: HIGH-RESOLUTION SEISMIC REFLECTION DATA 7

Figure F1. Bathymetric map of Shatsky Rise showing the locations of seismic reflection profiles collected for this study (solid lines). Gray rectangles show the outline of study areas shown in Figures F2, p. 8, F3, p. 9, F4, p. 10, and F5, p. 11. Bathymetric map is from Sager et al. (1999). L4, L7, L12, and L13 show the locations of seismic profiles not shown in Figures F2, p. 8, F3, p. 9, F4, p. 10, and F5, p. 11. ODP Leg 198 drill sites (1207–1214) are shown in red. Inset: Location of Shatsky Rise in the northwest Pacific showing a simplified magnetic lineation interpretation of Nakanishi et al. (1999). Numbers in parentheses below “M” anomaly labels indicate age in Ma (based on the timescale of Gradstein et al., 1994).

Shatsky Rise, NW Pacific 44° Seismic reflection data collected during N cruise TN037 of the Thomas Thompson 5

ODP Leg 198 drill site

L4 North High 5

1207 4 38°

Central High 5 5 5 4 L7

36 ° 1208 L12 5 6 5 6 h Japan M1 M1 ° Kuril Trenc (124) 34 6 L13 e h Lineations ° c 0 Japanes 0 40 n M1 agnetic M1 South High e M Tr (133) 5 6 M1 n Shatsky Rise a p Hawaiia

J 4 1209 M16 Magnetic M10 (141) M2 n 1 1 2 Lineations

° Trench M

32 ° n M M1 3 30 (148) 2

16 5 M2 6 Boni M 1 4 M25 1210 (154) M L17C 1 2 Izu- 5 1212 5 5 M2 M29 (158) 5 M2 M2 9 1211 9 L17D M2 20° 1 FZ 2 FZ 30° 6 M 1213 1214 6 140° 150° 160° 170° 154°E 158° 162° 166° 170° A. KLAUS AND W.W. SAGER CHAPTER 11, DATA REPORT: HIGH-RESOLUTION SEISMIC REFLECTION DATA 8

Figure F2. The South High (TAMU massif of Sager et al., 1999) survey area showing the locations of seismic reflection profiles collected for this study and ODP Leg 198 drill sites (1209–1214). Numbers in boxes indicate seismic line numbers. Bold white lines show seismic profiles that are shown in Figure F8, p. 14. The remaining seismic profiles are shown in Figures F13, p. 19, and F14, p. 20. Bathymetric data are from Sager et al. (1999), and depth units are meters × 102. The location of the South High survey area is shown in Figure F1, p. 7.

32 1600 54 15 26 (22 Aug) 44 ° (25 Aug) 14A 33 40 2000 22 N 1200 (27 Aug) 30 0400 2000 50 28 1209 26 0800 0000 (24 Aug)

1000 16 1600 2000 1600 1200 48 0000 (23 Aug) 1212 1600

(DSDP 47) 577 14C 49 1600 50 810 48 2000 26 1300

0400 14D 1200 44 1210

34 38 36 17A 1211 0800 14B 40 0000 28 36 32° (DSDP 305) (28 Aug) 1214 (25 Aug) 0000 0400 (DSDP 306) 4

17B 0800 32

1213 36

1200 40

44 44 48 17C 1600 48

31° 50 2000 50 46 52 0000 (29 Aug) 52 0400 17D 54

156°E 157° 158° 159° 0 50 100

km A. KLAUS AND W.W. SAGER CHAPTER 11, DATA REPORT: HIGH-RESOLUTION SEISMIC REFLECTION DATA 9

Figure F3. The Central High (ORI massif of Sager et al., 1999) survey area showing the locations of seismic reflection profiles collected for this study and ODP Leg 198, Site 1208. Numbers in boxes indicate seismic line numbers. Bold white lines show seismic profiles that are shown in Figure F7, p. 13. The remaining seismic profiles are shown in Figures F11, p. 17, F12, p. 18, and F13, p. 19. Bathymetric data are from Sager et al. (1999), and depth units are meters × 102. The location of the survey area is shown in Figure F1, p. 7.

48 54

48 1400 (17 Aug) 2000 46 44

37° 44 N 40

1800 36 1600

34 1000 54 11C (18 Aug) 1000 0600 10 Site 11A 1208 1400 44

0400 1200 0200 (16 Aug) 1200 9 42 0400 34 38 0400 0200

8 2200 8 1400 (15 Aug) 1000 0600 0600 36° 1000 1600 1800 52 0000 1400 20 Aug 34 46 0000 32 0000 21 Aug (14 Aug) 50 19 Aug 2000 34 12 44 38 2200 42 44

11B 2000 0400 46 157°E 158° 159°

0 50 100

km A. KLAUS AND W.W. SAGER CHAPTER 11, DATA REPORT: HIGH-RESOLUTION SEISMIC REFLECTION DATA 10

Figure F4. The North High (Shirshov massif of Sager et al., 1999) survey area showing the locations of seismic reflection profiles collected for this study and ODP Leg 198, Site 1207. Numbers in boxes indicate seismic line numbers. Bold white lines show seismic profiles that are shown in Figure F7, p. 13. The remaining seismic profiles are shown in Figure F10, p. 16. Bathymetric data are from Sager et al. (1999), and depth units are meters × 102. The location of the survey area is shown in Figure F1, p. 7.

2000 (9 Aug)

44 5A 38 42 38°00' 40 38 N 36 6 2200 36 34 34 30 2100 2200 32 32 2300 (10 Aug) 0000 0000 (11 Aug)

0200

5C 0400 (12 Aug) 0600 2200 32 0000

Site 1207 2000 34 0200 36 38 1800 40 40

1600 37°30' 0400

38 40 1400 40 34 38 7 (13 Aug) 40 0400 0600 1200

42 1000 0500

0800 40 5B

0600 38 34

162°30'E 163°00'

020 km A. KLAUS AND W.W. SAGER CHAPTER 11, DATA REPORT: HIGH-RESOLUTION SEISMIC REFLECTION DATA 11

Figure F5. The Thompson Trough survey area on Papanin Ridge showing the locations of seismic reflection profiles collected for this study. Numbers in boxes indicate seismic line numbers. Seismic profiles are shown in Figure F9, p. 15. Bathymetric data is from Sager et al. (1999), and depth units are meters × 102. The location of the survey area is shown in Figure F1, p. 7.

Papanin Ridge 50

48 48

52 45 3 52 1500 50

1600 50 54 45 52 48 50 Thompson Trough ° 40 00' 1300 N 48 1700 52 48 50 52

50 1800 0100 1200 52 45 42

48 38 0000 2000 45 (8 Aug) 1100 (7 Aug)

4 2100 48 2200 52 2300 0100 (9 Aug) 52

50 50

39°30' 163°30'E 164°00' A. KLAUS AND W.W. SAGER CHAPTER 11, DATA REPORT: HIGH-RESOLUTION SEISMIC REFLECTION DATA 12

Figure F6. Seismic data acquisition geometry, sources, and receivers used on the Thomas Thompson cruise TN037 over Shatsky Rise. GI = generator injector, GPS = Global Positioning System.

83.5 m 178 m 70 m GPS 37.2 m antenna 18 m sea level 9 m air gun 70 m streamer stretch 12 3456 25 m

magnetometer

Air gun array configuration 80 in3 magnetometer

200 in3 150 in3 streamer 108 in3

GI-gun array configuration magnetometer

45/105 in3

streamer A. KLAUS AND W.W. SAGER CHAPTER 11, DATA REPORT: HIGH-RESOLUTION SEISMIC REFLECTION DATA 13 ocation lines 8 and 11B. 8 and lines wn in this figure (5B, N SE E E p. is available 19. This figure 1100 Continues from end of Continues line 8, part 1 (above) 0700 15 Aug 0800 F13, 0100 km 1200 010 0600 km 0700 km 0200 p. and 18, 1300 010 010 0500 F12, 0600 Site 1208 0300 the Central High showing the location of Site showing the location of High Site 1208. Central the E 1400 0400 p. 17, km 0500 10 Aug 0000 F11, 010 0400 11 Aug 1500 0300 km 0400 0100 010 0500 0200 1600 0300 0200 0100 0600 1700 1700 10 Aug 94 10 Aug mic lines collected; mic bold white lines show locations of seismic Cross line 5A Cross line 5B 0200 Site 1207 the locationseismic of lines 5Aand5C. Seismic lines notsho Site 1207 0300 0000 9 Aug 94 9 Aug 1800 0700 0100 er the North High showing the location of Site 1207. Bathymetric map displays the l displays map Bathymetric 1207. Site of location the er the showing High North 0400 2300 1900 0800 19 Aug 0000 2200 0500 18 Aug 2000 0900 2300 Line 5C 2100

0600 4 5 W (s) traveltime Two-way

Line 11B p. over collected 11B) and (8 lines Seismic Bottom: 16.

S 4 5 6 Two-way traveltime (s) traveltime Two-way 2100 1000 2000 F10, F10, Line 8, part 1 Line 8, part 2

2200

4 5 6 W Two-way traveltime (s) traveltime Two-way

1900

44 Aug) (14 line 8 1400 Line 5A 46 44 46 48 0400

4 5 6 NW

42 line 10 Two-way traveltime (s) traveltime Two-way 52

38 2300 1800 ° line 12 line 11 1800 Continues from end of line 8, partContinues 2(below)

0000 21 Aug 159 1400 (17 Aug) 34

1200

1600

1000

34 2000 2200 32

(18 Aug) 1600 1200 1000 44 40 2200

40 0000 19 Aug

0400

2000

0000 (11 Aug) (11 0000 34

0400 36 0600

line 5A

0800 2000

40 00'

38 ° 44 0200 48 line 11B 1000 40

2300

0000 (12 Aug) (12 0600 34 1400 34 38 line 6 32 163 52 36 0400 34 ° 14 Aug

Site 2200 1000 0400 0000 2000 1208 32 2200 20 Aug

0600

0200 line 7 Top: Seismic lines (5A and 5C) collected ov and collected (5A 5C) lines Top: Seismic

0400 0600 34 Central High Central 0000 40 38 (10 Aug) 0000 54 (13 Aug)

0200

0500 0200 (16 Aug) (16 0200 42 2200

1800 42 44

W 4 5 6

0600 0400 1000 15 Aug

2000 (9 Aug) 2000 (9 Aug) North High 1200 Site 2100 (s) traveltime Two-way line 9 1207 40 38 km 30 line 8 30' E 46 1600 ° oversized format. oversized line 5A 34

1400

162 Aug) (15 1400 36 34

0600 E 158 line 5C ° km 36 38 38 50 40 40 157 52 0 50 100 38 020 54 ° ° ° ° N 00' 30' 38 37 N 36 37 Bathymetric map displays the locations of all Central High seis High the locations of Central all displays map Bathymetric 6, and 7) are shown in Figure Figure in shown are 7) and 6, Figure F7. Figure of all North High seismic lines collected; bold white lines show white lines bold collected; lines seismic North High all of Seismic profiles not shown in this (10, 11C, and in this are Figures figure 11A, 12) shown not profiles Seismic in an an in A. KLAUS AND W.W. SAGER CHAPTER 11, DATA REPORT: HIGH-RESOLUTION SEISMIC REFLECTION DATA 14 d 1214 d S 36 1600

line 14C collected. Seismic collected. 30 0000 Aug) (25 °

28 2000 159 2000 1200

26 Continues from end Continues of line 17A (below)

1600 (22 Aug)

line 14A

0400

2000 46

0000 (24 Aug) 0800

0300

1300 0000 (23 Aug)

1600 Site 26 1209 26 1600 28

0400

(25 Aug) 2000 1200 Site 32 1210 32 ° 0000 (28 Aug) 36 0800 E 158 48 1000 48 line 17A 1600 40 50 44 52 810 577 54 0400

km 0200 (DSDP 305) Site 1211 p. 20.This figure is availablein an 1200 (27 Aug) 40 South High 4 (DSDP 47) Site 1212 0800 line 17B (DSDP 306) 44 Site 1214 010 1200 Site 1600 1213 1800 F14, ° 34 157 0100 2000 36 38 49 km 0000 (29 Aug) 50 44 40 48 48 1900 44 54 50 23Aug 50 52 0400 E 0 50 100 ° 0000 ° ° ° N 156 p. and 19, 32 31 33 km 22 Aug F13, 2000 010 2300 SW Site 1209 2100 0500 Cross line 14C 2200 S Continues from end of line 17B (below) Continues 2200 0400 2100 1300 2300 km 0300 2000 km 1200 010 0000 Cross line 14A 010 24 Aug 23 Aug (projected) Site 1209 Site 1211 (DSDP 305) 1900 0200 1100 0100 Site 1213 1800 0100 1000 0200 1700 0900 0000 0300 27 Aug 28 Aug 1600 0800 0400 2300 1500 0700 0500 2200 Seismic lines (14A, 14C, 17A, and 17B) collected over the South High showing the locations of Sites 1209, 1210, 1211, 1213, an 1213, 1211, 1210, 1209, Sites of locations the showing High South the over collected 17B) and 17A, 14C, (14A, lines Seismic Site 1214 (DSDP 306) 1400 0600 0600 Site 1210 2100 Continues from end of line 17A (above) Continues Continues from end of line 14A (above) Continues Line 17A Line 14A Line 17B Line 14C

5 7 W 4 5 3 3 4 5 4 6 N

3 4 5 N

Two-way traveltime (s) traveltime Two-way Two-way traveltime (s) traveltime Two-way Two-way traveltime (s) traveltime Two-way Two-way traveltime (s) traveltime Two-way (Site 1212 is not located on one of our seismic lines). Bathymetric map shows the locations of all the South High seismic lines seismic High South the all of locations the shows map Bathymetric lines). seismic our of one on located not is 1212 (Site in Figures shown 17D) are 16, 17C, and 14D, 15, (14B, this figure in displayed not lines Figure F8. Figure oversized format. oversized A. KLAUS AND W.W. SAGER CHAPTER 11, DATA REPORT: HIGH-RESOLUTION SEISMIC REFLECTION DATA 15 SE 1100 p. 11. NE F5, 0100 Aug 9 1200 seismic profile seismic km 0200 010 1300 0300 1400 0400 1500 NW C/C NE 0500 1600 0600 oversized format. oversized 1700 SW C/C NW 0700 1800 0800 Papanin Ridge. Location of the seismic Location of Ridge. is shown the line in Figure Papanin seismic 1900 0900 2000 SE C/C 1000 E 2100 1100 2200 1200 E C/C 2300 SW 1300 Aug 7 0000 Aug 8 Aug p. in an available is figure This heading. in ship’s = change 7. C/C 1400 F1, 0100 1500 0200 . Top: Seismic line 3 collected over the Thompson Trough on the the on Trough the Thompson over collected line 3 Seismic Top: . Line 4

6 SW 7 8 Two-way traveltime (s) traveltime Two-way km 010 Line 3

8 7 6 4 5 NE Two-way traveltime (s) traveltime Two-way Figure F9 Figure Bottom: Seismic line 4 collected during the transit from the Thompson Trough to the North High survey area. The location of the of High the North survey The location area. to from Trough the Thompson transit the during 4 collected line Seismic Bottom: shown in Figure is A. KLAUS AND W.W. SAGER CHAPTER 11, DATA REPORT: HIGH-RESOLUTION SEISMIC REFLECTION DATA 16 W 2100 2200 NE 0400 , p., and Middle 10. e is shown in Figure E C/C 2300 F4 Aug 13 Aug N 0500 km Aug 11 Aug 0000 010 Aug 12 Aug 0600 Line 6

4 5 6 S Two-way traveltime (s) traveltime Two-way 0700 2200 NE 0800 Aug 10 Aug 2100 0900 2000 NE SW C/C 1000 E 2300 Continues from end of line 7 (above) Continues 1900 1100 Aug 13 Aug 0000 Aug 14 Aug km 1800 010 1200 oversized format. oversized 0100 1700 1300 0200 1600 1400 0300 SW C/C 1500 NW 1500 0400 1400 1600 0500 1300 1700 0600 km 1200 010 1800 0700 1100 1900 SW Line 7

0800 9 8 7 6 Two-way traveltime (s) traveltime Two-way 1000 2000 km 010 . Top: Seismic 5B lines and 6 collected over the North High. The locations of seismic profiles are shown in Figure 0900 2100 Continues from end of line 7 (below) Continues Line 7 W 4 5 7 8 6

0800 p. in an available is figure This heading. in ship’s = change 7. C/C (s) traveltime Two-way Line 5B

6 4 5 SE Two-way traveltime (s) traveltime Two-way Figure F10 Figure bottom: Seismic line 7 collected during the transit from the North High to the Central High. The location profil the seismic of location The High to High. the North from Central 7 collectedtransit the the during line Seismic bottom: F1, A. KLAUS AND W.W. SAGER CHAPTER 11, DATA REPORT: HIGH-RESOLUTION SEISMIC REFLECTION DATA 17 S Aug 16 Aug Continues from end of line 9 (above) Continues 1100 1200 p. 9. C/Cchange = in ship’s F3, 1300 1400 1500 W 1600 Aug 16 Aug 0300 km 1700 010 cation of the seismic profile is shown in Figurethecationinshown seismic of profile is 0400 1800 E C/C N 0500 1900 S 0600 C/C 2000 W oversized format. oversized 0700 2100 0800 2200 km 0900 . Seismic line 9 over The . Seismic High. collected Central the lo 2300 010 Continues from end of line 9 (below) Continues E Line 9 Line 9

3 4 5

6 7 3 1000 6 8 4 5 7 N

Two-way traveltime (s) traveltime Two-way Two-way traveltime (s) traveltime Two-way Figure F11 Figure heading. This figure is available in an in an available figure is This heading. A. KLAUS AND W.W. SAGER CHAPTER 11, DATA REPORT: HIGH-RESOLUTION SEISMIC REFLECTION DATA 18 N Aug 19 1100 is shown 1200 1300 1400 1500 NE Aug 18 Aug 0900 1600 1000 1700 SW C/C 1100 1800 N oversized format.oversized 1200 1900 1300 2000 S C/C E 1400 N 2100 1400 km W Aug 17 Aug 1500 C/C 2200 S 010 , and over 11C of The 11A, the Central collected profile the seismic High. location 1500 1600 2300 1600 km Aug 19 Aug 1700 0000 Aug 20 Aug 010 1700 1800 S 0100 C/C S NW C/C E 1800 N C/C 1900 0200 W 1900 2000 0300 2000 2100 p. an in is available This figure heading. ship’s in = change 9. C/C 0400 km . Top, middle, and bottom: Seismic lines 10 lines Seismic bottom: and middle, . Top, F3, 2100 010 2200 0500 Line 10 Line 11C Line 10 Line 11A

SE 5 5 6 4 5 6 4 4 6 7 E 7 W

Two-way traveltime (s) traveltime Two-way Two-way traveltime (s) traveltime Two-way (s) traveltime Two-way Figure F12 Figure in Figure Figure in A. KLAUS AND W.W. SAGER CHAPTER 11, DATA REPORT: HIGH-RESOLUTION SEISMIC REFLECTION DATA 19 N NW km 010 ines are 2100 1100 2200 1200 2300 1300 Aug. 21 Aug. 0000 1400 Aug. 22 Aug. 0100 1500 0200 1600 S C/C NE 0300 1700 er the South High. The locations of seismic lines are shown 0400 1800 W oversized format.oversized 1900 0500 0500 2000 0600 0600 Line 13

4 5 6 7 8 SW Two-way traveltime (s) traveltime Two-way 2100 0700 NW Aug 21 Aug 2200 0100 0800 C/C E NE SE C/C 2300 SW 0200 0900 C/C 0000 ESW 0300 1000 Aug 25Aug 24 Aug NE 0100 SE C/C C/C 0400 1100 N S 0200 0500 1200 p. collected 7. andMiddle ov lines 14B 14C bottom: Seismic and F1, 0300 km 1300 0600 p. an in is available This figure heading. ship’s in = change 8. C/C km . Top: Seismic . 12 andlines 13 collected the Top: Seismic during the from totransit High. High the South of Central locations l The seismic km 010 F2, 0400 010 010 1400 0700 Line 12 Line 14B Line 14D 0500 3 4 6 4 3 5 6 4 5 6 7 8 S 5

W Two-way traveltime (s) traveltime Two-way Two-way traveltime (s) traveltime Two-way Two-way traveltime (s) traveltime Two-way Figure F13 Figure shown in Figure shown in Figure Figure in A. KLAUS AND W.W. SAGER CHAPTER 11, DATA REPORT: HIGH-RESOLUTION SEISMIC REFLECTION DATA 20 NE p. 8. 1600 F2, 1700 shown in Figures shown in 1800 1900 2000 2100 2200 2300 km oversized format. oversized SE S Aug 28 Aug 0000 010 Aug 27 Aug 1300 Aug 29 Aug 0900 Aug 25 Aug Line 17c

6 7 8 Two-way traveltime (s) traveltime Two-way NE 1400 1000 Aug 29 Aug km C/C SE N 010 0200 1500 1100 0300 1600 NW C/C 1200 N 0400 1700 1300 0500 1800 S C/C 1400 NW 0600 1900 1500 0700 2000 1600 NW 0800 C/C 2100 NE 1700 p. an in figure is available This heading. ship’s change in = 8. C/C 0900 F2, 2200 1800 . Top. and middle: Seismicand 15 lines collected 16 over the SouthThe High. locations of seismic lines are shownFigure in km km 1000 010 2300 010 1900 p. 7, and Line 17d Line 16 Line 15

7 3 5 3 4 5 6 6 6 4 SE SW

Two-way traveltime (s) traveltime Two-way Two-way traveltime (s) traveltime Two-way Two-way traveltime (s) traveltime Two-way Figure F14 Figure Bottom: Seismic lines 17C and 17D collected during the transit from the South High to Guam. The locations of seismic lines are lines seismic of The locations Guam. to High South the from the transit during andcollected 17D lines 17C Seismic Bottom: F1, A. KLAUS AND W.W. SAGER CHAPTER 11, DATA REPORT: HIGH-RESOLUTION SEISMIC REFLECTION DATA 21

Table T1. Acquisition and processing parameters for TN037 seismic reflection data collected for this study.

Field acquisition: Vessel: Thomas Thompson Cruise: TN037 Start date: 23 Jul 1994 End date: 4 Sep 1994 Source: 1. Air gun array: 200, 150, 108, and 80 in3 2. GI air gun: 45/105 in3 Pressure: 2000 psi Shot interval: Maximum: 37 m Minimum: 25 m Streamer: Active group length: 25 m Number of groups: 6 Recording: Acquisition hardware: Sun SPARC10 Acquisition software: “a2d” Data format: SEGY Data length: 6–7 s Delay: 2–3 s Shot interval: 10 s Sample interval: 1 ms Filters: Low: 15 hz (24 dB/oct) High: 3khz (24 dB/oct) Processing sequence: Pick water bottom time (WBT) Despike Bandpass filter 5–200 Hz Geometry definition, insert WBT in header Mute to water bottom Spherical divergence correction Resample (2 ms) Notch filter (60 Hz) Deconvolution Velocity analysis NMO correction Stack Pick and apply static correction Finite difference migration Time-varying filter: Seafloor to 0.25 s: 30–150 Hz 0.25 to 1.0 s: 20–150 Hz 1.0 s to end of record: 6–70 Hz Gain (500 ms AGC) Mute to water bottom

Notes: Data were processed at the Ocean Drilling Program, Texas A&M University. Processing software: SIOSEIS and PROMAX. Data were processed by Michael Holzrichter and Adam Klaus. NMO = normal moveout. AGC = automatic gain control.