TABLE CAPTIONS

Table T1. Acquisition and processing parameters for seismic site survey data.

Table T2. Summary of operations.

Table T3. Parameters used for paleotopographic reconstructions and sea level estimates.

FIGURE CAPTIONS

Figure F1. Map showing the location of DSDP Site 209 (solid square), ODP Leg 133 sites (solid circles), and ODP Leg 194 sites (open circles) off northeastern Australia. The box at the lower right indicates the location of Figure F2.

Figure F2. Map showing locations of Leg 194 sites (open circles) and two Leg 133 sites (solid circles). Thin solid lines = location of multichannel seismic lines from the Australian Geological Survey Organization (Survey 75). Heavier lines = location of multichannel seismic lines from the Leg 194 site survey (MAR data). Shaded areas = estimated extent of the northern MP2 and the southern MP2/MP3 platforms. Dashed line = boundary of the Great Barrier Reef Marine Park.

Figure F3. Topography of acoustic basement in the area covered by Leg 194 site survey. Topography is given in two-way traveltime and is not depth corrected. Basement cannot be mapped below the internal MP2 platform in the north or below the entire MP2/MP3 platform in the south, because scattering and attenuation on the platform top hinders penetration of the seismic signal. Fine lines are spaced every 20 ms, which equals ~20 m. MP = Marion Plateau.

Figure F4. Water-loaded tectonic subsidence (i.e., with the isostatic sediment load removed) for ODP Leg 133 Sites 812, 814, 811/825, 815, and 823, assuming constant eustatic sea level (shown on left) and using eustatic sea level variations of Haq et al. (1987) (shown on right). The latter is not shown for Site 823, as the errors in water depth (vertical error bars) are much larger than eustatic sea level variations. Shading around error bars indicates the area in which the true subsidence curve should occur. Comparisons between constant and varying eustatic sea levels allow evaluation of the potential effect of eustatic variations on tectonic subsidence models. For instance, the first model (left) for Site 814 shows a gently subsiding platform until about 5 Ma, whereas the second model (right), including eustasy, shows a tectonic subsidence pulse between 14 and 12 Ma. Therefore, the latter may be entirely due to the input of an ill-constrained eustatic sea level curve.

Figure F5. Stratigraphic summary of previously cored sites located near Leg 194 sites. All sites were cored during Leg 133 except for Site 209, which was cored during DSDP Leg 21.

Figure F6.Seafloor photographs from Leg 194 sites. Phototrigger at upper right of each photograph is 10 cm in diameter. A.Seafloor photograph at Site 1194 at 374 mbsl shows decimeter-range sediment ripples and cemented pieces. The cut section of a dredged cemented piece reveals a burrow heavily encrusted by sponges suggesting early cementation occurring on the seafloor. B.Dredged submarine crust from Site 1196. The photo shows the underside of a 2- to 3-cm-thick reddened crust colonized by bryozoans and serpulids. C. Seafloor photographs at Site 1196 at 304 mbsl, showing patchy distribution of the hardground crust on the drowned MP3 platform top. D. Seafloor photograph at Site 1193 at 348 mbsl. Abundant decimeter-scale ripples document strong bottom currents.

Figure F7. Seismic overview displaying characteristics of seismic megasequences along the northern transect with seismic lines MAR13, MAR20, and MAR15 linking Sites 1193, 1194, 1192, and 1195 and a correlation between ODP Leg 194 sites (see Fig. F2 for location of profiles). MS = megasequence.

Figure F8. Seismic overview displaying characteristics of seismic megasequences along the southern transect with seismic line MAR07 linking Sites 1198, 1196, 1999, and 1197. Site 1199 is ~5 km northeast of line MAR07 and was projected perpendicularly onto line MAR07 (see Fig. F2 for location of profiles). Bas. = basement, MS = megasequence.

Figure F9. Stratigraphic correlation summary for Leg 194. A. Correlation between Sites 1193, 1194, 1192, and 1195, which represents the northern depth transect from the MP2 platform to the distal periplatform/hemipelagic setting. B. Correlation between Sites 1198, 1196, 1199, and 1197, which represents the southern depth transect extending across the MP2/MP3 platform from the northwest, across the platform top, to the southeast. C. Seven data panels are presented for each site and an explanation is provided describing the data and symbols used. Data sets include depth downhole in mbsf, core number, core recovery, lithostratigraphic units with age derived from biostratigraphy and magnetostratigraphy, a graphic display of the lithologies, mineralogy based upon XRD analysis, natural gamma ray profiles from downhole logging and core-based physical properties measurements, and the megasequences defined from seismic reflection data. MS = megasequence, wd = water depth.

Figure F10. Correlation between seismic two-way traveltime (ms) and depth for all Leg 194 sites. These data were obtained by check-shot surveys (solid circles), virtual check shots (open circles), and integration of sonic log and shipboard velocity data in between. Virtual check shots are obvious links between high-amplitude reflection on the seismic data and unique petrophysical horizons in the cores (e.g., basement and hardgrounds).

Figure F11. Sedimentation rates at Leg 194 sites. Sites 1195 and 1192 trends are very similar and represent distal, drift-dominated deposition at rates of ~30 m/m.y. during the Miocene and 15 m/m.y. during the Pliocene-Pleistocene. The decrease in depositional rates at ~5 Ma probably reflects the decrease in nearby carbonate shedding. Carbonate platform Site 1193 shows a dramatic increase in depositional rates from 15 m/m.y. to 150 m/m.y. in the late early Miocene, probably heralding the approaching carbonate platform. Sedimentation rates in the overlying platform, which started to accumulate at Site 1193 at the beginning of the middle Miocene (~16 Ma) are nor directly defined. However, neritic upper-slope deposition (>100 m paleowater depth) at the adjacent slope Site 1194 evolved into a neritic ramp (>60 m paleowater depth) at ~12.8 Ma, suggesting a major sea level fall that would have exposed Site 1193 and ended MP2 phase carbonate buildup there. The presumed lowstand ramp deposition at Site 1194 ended at 11.5-12 Ma (hiatus at 117 mbsf). The time involved in the sea level fall is not constrained, the uncorrected magnitude relative to the present strata was ~115 m. At Site 1196 (and Site 1199, not shown), platform growth rates of at least 80 m/m.y. are documented for an ~ 140 m thick middle Miocene interval, but subsequent growth could not be constrained in time. Adjacent slope Site 1197 shows increased depositional rates in the late middle Miocene, which is interrupted near the middle late Miocene boundary (11.1-? Ma; hiatus at 175 mbsf), a time of inferred sea level rise at Site 1194. Subsequent late Miocene (and early Pliocene?) platform shedding is only roughly constrained in time at Site 1197 (5-11 Ma). However, the other slope site adjacent to the platform Site 1196, Site 1198, documents increased platform shedding (~50 m/m.y.) during the middle late Miocene, a time of apparent nondeposition at Sites 1193 and 1194. Deposition at Site 1198 ended at ~7.8 Ma (hiatus at 200 mbsf), which probably marks the end of the MP# phase of carbonate buildup at Site 1196. This starvation, lasting several million years, probably also occurred at Site 1197 (hiatus at 59 mbsf). The shaded area in the top left corner of the diagram highlights the records of the hemipelagic seismic Megasequence D, which fills in the topography created by the Miocene carbonate buildup. The oldest Megasequence D records (7.2-7.8 Ma) were recovered at Sites 1192, 1194, and 1195. This time coincides with the starvation of periplatform deposition at Site 1198 and could mark the onset of widespread drowning of the carbonate factory. The thickest record of Megasequence D (200 m), accumulated since ~3.6 Ma, was recovered at the drift focus Site 1198.MP = Marion Plateau.

Figure F12. Seismic correlation between Leg 194 sites (see Figure F2 for location profiles). A. Northern transect along seismic lines MAR13, MAR20, and MAR15 linking Sites 1193, 1194, 1192, and 1195. B. Southern transect along seismic line MAR07 linking Sites 1198, 1196, 1199, and 1197. Site 1199 is ~5 km off line MAR07 and was projected perpendicularly onto line MAR07. Roman numbers in left columns are lithologic unit boundaries. They do not correlate from site to site, as unit definition was based upon shipboard sedimentologic description of the drilled cores. Right columns indicate epoch boundaries defined with the shipboard age models. Numbers on the seismic section next to the sites indicate the age of seismic sequence boundaries, derived from time-depth conversion and shipboard age models. MS = megasequence.

Figure F13. A. Scheme to calculate the middle Miocene eustatic fall from Sites 1193 and 1194. Seismic line MAR13 displaying sediment geometries between Sites 1193 and 1194. Seismic megasequences are indicated at right. The onlapping unit below the Megasequence B/C boundary was deposited during the Zones N12-N14 lowstand, exposing the MP2 platform top. B, C. Reconstructing the needed Zones N12-N14 sea level fall assuming local isostasy, paleowater depths, and physical properties data. For explanation see "Sea Level Variability and Magnitude Recorded by Sediment Sequences on the Marion Plateau." MS = megasequence, SL = sea level.

Figure F14. Schematic diagrams reconstructing the depositional history of the area of the northern drilling transect (Sites 1192, 1193, 1194, and 1195) based on recovered lithologies (see "Platform Evolution" for a description of the evolutionary sequence of depositional events). A. Paleogene to early Miocene. B. Late early Miocene. C, D. Middle Miocene. E. Late middle Miocene. F. Late Miocene. G. Latest Miocene to Pleistocene. MS = megasequence.

Figure F15. Schematic diagrams reconstructing the depositional history of the area of the southern drilling transect (Sites 1196, 1197, 1198, and 1199) based on recovered lithologies (see "Platform Evolution" for a description of the evolutionary sequence of depositional events). A. Paleogene to early Miocene. B. Middle Miocene. C. Late middle Miocene. MS = megasequence. MSB = megasequence boundary.

Figure F16. Multichannel seismic reflection profile (MAR13) showing the location of Site 1194 and the basement reflection (dashed line). Shown are examples of thin sections of altered olivine basalts that comprise the basement in this region. A. Thin section view showing the products of alteration (zeolites-natrolite) infilling an amygdaloid under cross-polarized light. B. Thin section view showing the infilling of veins with plagioclase under cross-polarized light. C. General thin section view under cross-polarized light showing olivine phenocrysts and plagioclase lathes. D. Magnetic inclination data from the basement sequence.

Figure F17. Multichannel seismic reflection profile (MAR07) showing the location of Site 1197 and the basement reflection (dashed line). Shown are examples of thin sections of altered olivine basalts that comprise the basement in this region. A. Thin section view under cross-polarized light showing pyroxene phenocrysts. B. Thin section view under cross-polarized light showing olivine phenocrysts and plagioclase lathes. C. Magnetic inclination data from recovered basalts.

Figure F18. Multichannel seismic reflection profile (MAR13) showing the location of Site 1193 and the basement reflection (dashed lines). Shown are examples of thin sections of altered olivine basalts that comprise the basement in this region. A. Thin section view showing the products of alteration (zeolites-natrolite) infilling an amygdaloid under cross-polarized light. B. Thin section view under normal light showing the "ghost" residuals of plagioclase lathes and pyroxenes. C. Thin section view under cross-polarized light showing the "ghost" residuals of plagioclase lathes and pyroxenes. D. Magnetic inclination data from recovered basalts.

Figure F19. Multichannel seismic reflection profile (MAR07) showing the location of Site 1198 and the basement reflection (dashed line). Shown are examples of thin sections of altered olivine basalts that comprise the basement in this region. A. Thin section view under cross-polarized light showing the groundmass, olivine phenocrysts and plagioclase lathes. B. View of altered plagioclase phenocrysts under cross-polarized light showing olivine phenocrysts, and plagioclase lathes. C. Thin section view showing the products of alteration (quartz) infilling an amygdaloid under cross-polarized light. D. Magnetic inclination of recovered basalts.

Figure F20. Multichannel seismic line MAR07 at Site 1198. Strontium (solid circles) and sulfate (open circles) concentrations are plotted on the location of Site 1198 vs. depth (in two-way traveltime). Note the near-seawater values of strontium and sulfate in Megasequence C, indicating circulation of seawater, possibly through a hydraulic connection with the MP2/MP3 platform.

Figure F21. Multichannel seismic line MAR13 at Site 1193. Strontium (solid circles) and sulfate (open circles) concentrations are plotted on the location of Site 1193 vs. depth (in two-way traveltime). Note the near-seawater values of strontium and sulfate above and below the MP2 platform, indicating circulation of seawater within the MP2 platform.

Table of Contents