Site 1130 (Fig. F30) intersects Cenozoic seismic Sequences 2, 3, 6A, and 7 (sequences defined in Feary and James, 1998, reprinted as Chap. 2), although hole instability restricted penetration of Sequence 7 sandstones to only the top 27 m. The high-resolution site-survey seismic data (Fig. F31), together with the regional seismic database, indicate that significant hiatuses should occur at sequence boundaries corresponding to the base of Sequence 2, the base of Sequence 3 (missing the basal part of Sequence 3 and all of Sequence 4), and the top of Sequence 7 (missing all but the youngest part of Sequence 6A).
A check-shot survey using the single-channel WST was undertaken at this site to establish the time-depth relationship within the Cenozoic succession and to correct the integrated sonic curve for drift and for the pipe interval. The parameters and procedures undertaken during the check-shot survey at Site 1130 are described in "Downhole Measurements". The eight time-depth tie points derived from the check-shot survey are presented in Figure F32. These points were plotted on a depth to two-way-traveltime graph (Fig. F33A) to (1) determine the relationship between depths encountered at Site 1130 and sequence boundaries and horizons located on seismic data and (2) compare the check-shot-corrected time-depth relationship with predictions based on stacking velocities. This plot shows that the actual time-depth relationship defined by the check-shot survey falls slightly below the envelope defined by the six stacking velocity curves for the immediate vicinity of Site 1130 (resulting from stacking velocities providing an underestimate of true traveltimes). These velocity underestimates correspond to depth errors of as great as 17 m between predicted and corrected depths to boundaries (Table T19).
The data collected at Site 1130, particularly lithostratigraphic and biostratigraphic information, provide an opportunity to interpret the site data within a more regional context and also allow a description of the characteristics of seismic sequences intersected at this site (see "Lithostratigraphy" and "Biostratigraphy"). The correlation of lithostratigraphic and biostratigraphic data with seismic stratigraphy (Fig. F34) was based on the regional moderate-resolution multichannel seismic data collected by the Japan National Oil Corporation (JNOC) in 1990 (Feary and James, 1998, reprinted as Chap. 2) and the high-resolution site-survey seismic data collected by the Australian Geological Survey Organisation (AGSO) in 1996 (Feary, 1997).
Comparison of the high-resolution site-survey seismic data at Site 1130 to regional seismic data indicates that the Sequence 2 interval intersected at Site 1130 should represent a relatively complete succession; however, the 259-m thickness represents a lower sedimentation rate and decreased resolution compared with the ~550-m thickness of Sequence 2, which forms the spectacular clinoforms at Sites 1127, 1129, and 1131. Seismic data show that the component of Sequence 2 intersected at Site 1130 should represent an expanded upper part and a relatively condensed middle part of this sequence, with the oldest parts either highly condensed or absent. The high-resolution site-survey seismic data indicate that there should be significant facies differences between the succession intersected at this site compared with Site 1132, with reflectors at Site 1130 being more evenly stratified and continuous compared with the mounded reflection geometry at Site 1132. Litho-stratigraphic analysis shows that these evenly stratified and continuous reflections correspond to strongly bioturbated bioclastic packstones interbedded with bioclastic wackestone and nannofossil ooze. The basal sequence boundary correlates to the transition from lithostratigraphic Unit I to Unit II, corresponding to a transition from slumped glauconitic bioclastic packstone and nannofossil bioclastic packstone of Subunit IC to the undeformed nannofossil foraminiferal chalk and ooze of Unit II. Biostratigraphic data show that the hiatus associated with this boundary represents ~1.7 m.y. missing, corresponding to the lower/upper Pliocene boundary. The prominent reflector intersected at ~0.8 s two-way traveltime (Fig. F31) correlates with a marked finer wackestone unit at 132 mbsf, which is interpreted as a flooding surface (see "Lithostratigraphy").
From a regional perspective, Sequence 3 is thickest (~240 m) beneath the modern shelf and thins downslope to a feather edge beneath the modern middle shelf (Feary and James, 1998, reprinted as Chap. 2). Site 1130 intersects Sequence 3 beneath the uppermost slope, where it is only 69 m thick. Sequence 3 correlates with lithostratigraphic Unit II, of late Miocene to early Pliocene age, which is dominated by calcareous nannofossil foraminiferal chalk and ooze. The lower one-third of this unit contains many omission surfaces and firmgrounds, as well as two prominent turbidite horizons. The sequence boundary at the base of Sequence 3 represents a very substantial hiatus, with the older (middle Miocene) parts of Sequence 3 and all of Sequence 4 (lower Miocene) completely missing. This hiatus corresponds to an interval of 14-15 m.y. (see "Biostratigraphy").
Sequence 6A is represented at Site 1130 by a 40-m-thick, poorly recovered upper Oligocene interval corresponding to lithostratigraphic Unit III. Because of limited recovery, it was only possible to conclude that Sequence 6A at this site consists of a nannofossil foraminiferal chalk/ooze interval containing preferentially silicified thin beds and lenses.
The basal interval intersected at Site 1130 consists of 27 m of poorly recovered and diverse lithologies corresponding to lithostratigraphic Unit IV. The calcareous sandstone, bioclastic glauconitic wackestone, bryozoan grainstone, and bivalve grainstone are assigned to seismic Sequence 7. The absence of either calcareous nannofossils or planktonic foraminifers within core catcher samples means that the only direct indications of age are based on a few foraminifer tests observed in thin sections in the calcareous sandstone. These indicate a middle-late Eocene age (see "Biostratigraphy"), although it is likely that postcruise studies will enable this age to be further refined. Hole instability, presumably caused by poorly cemented sandstone portions of this sequence, prevented penetration to the base of Sequence 7 and attainment of one of the major objectives at this site.