Site 1132 (Fig. F28) was predicted to intersect Cenozoic seismic Sequences 2, 3, 4, 6A, 6B, and 7 (sequences defined in Feary and James, 1998, reprinted as Chap. 2). However, as was the case with Site 1130, hole instability within Sequence 7 sandstones severely restricted penetration and caused coring to be terminated. The high-resolution site-survey seismic data (Fig. F29), together with the regional seismic database, indicated that significant hiatuses should occur at all sequence boundaries.
A check-shot survey was not planned at this site because there was an expectation that the time-depth conversion parameters derived from Site 1130 (only ~11.5 km to the south and intersecting a broadly similar succession) would be applicable at Site 1132. However, hole restriction or collapse (see "Operations") encountered during deployment of the FMS/sonic tool string would have prevented a check-shot survey in any case. Because the FMS/sonic tool string was only run over a short interval, it was not even possible to derive a useful integrated sonic curve as a guide to time-depth conversion. Accordingly, the time-depth relationship for sequence boundaries and horizons located on seismic data was estimated to correspond, as was the case at Site 1130, to a line tracking immediately below the envelope defined by the six stacking velocity curves for the immediate vicinity of Site 1132 (Fig. F30A). On this basis, estimates of depth errors of as great as 15 m between predicted and corrected depths to boundaries can be determined (Table T16), although these values must be viewed as only very approximate estimates.
The data collected at Site 1132, 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 final best-fit correlation of lithostratigraphic and biostratigraphic data with seismic stratigraphy (Fig. F31) was based both 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 on the high-resolution site-survey seismic data collected by the Australian Geological Survey Organisation (AGSO) in 1996 (Feary, 1997). This correlation shows that the predicted seismic stratigraphy (Fig. F29) is considerably different from the sequences actually intersected at Site 1132, and at present only some of this variance can be explained. Detailed postcruise work will be necessary to clarify and explain the difference between the sequences encountered at nearby Site 1130 and the stratigraphy at this site.
Comparison of the high-resolution site-survey seismic data at Site 1132 with regional seismic data indicates that the Sequence 2 interval intersected at Site 1132 should represent a quite different facies succession compared to the adjacent Site 1130. Seismic data shows that the component of Sequence 2 intersected at Site 1132 should contain a hiatus surface toward the base, corresponding to the possible top Pliocene boundary at 188 mbsf. Apart from this surface, Sequence 2 appears essentially complete. The uppermost part of Sequence 2 displays a dramatic mounded appearance, corresponding to the bryozoan mounds of lithostratigraphic Unit I (see "Lithostratigraphy"). This unit consists of bryozoan floatstone and rudstone alternating with bryozoan packstone and contains an abundant and diverse bryozoan fauna. The portion of Sequence 2 underlying the mounded zone and overlying the hiatus surface contains much more evenly stratified and continuous reflections, corresponding to the bioclastic packstones with variable bryozoan component of lithostratigraphic Unit II and Subunits IIIA and IIIB. Several firmgrounds are present in this interval, and the hiatus surface visible on seismic data correlates to a firmground at the top Subunit IIIC boundary at 188 mbsf. The lowermost component of Sequence 2, beneath the hiatus surface, corresponds to lithostratigraphic Subunit IIIC and most of Subunit IIID. Sediments in this upper? Pliocene or basal? Pleistocene interval (see "Biostratigraphy") consist of bioclastic packstone with bioclastic wackestone interbeds. Bryozoan bioclasts are not as abundant within this interval as they are in the overlying part of Sequence 2. The base of Sequence 2 (at 240 mbsf) corresponds to a dramatic decrease in gamma-ray values observed on the downhole logs (see "Downhole Measurements"). This surface also represents a hiatus of some 6.5 m.y. (Fig. F31).
Sequence 3 provides the greatest difficulty in correlating between Sites 1132 and 1130. Seismic data from the upper Miocene succession comprising Sequence 3 at Site 1130 appear to correlate to seismic data from the basal part of Sequence 3 at Site 1132. However, biostratigraphic information (see "Biostratigraphy") indicates that Sequence 3 is represented at Site 1132 by a thin interval (17 m) of upper Miocene sediment overlying a substantial thickness of middle Miocene sediment (168 m), indicating that a previously unrecognized major disconformity/erosional surface presumably exists between these two sites. Identification of the exact nature and location of this surface will require postcruise work. The thin upper Miocene component of Sequence 3 consists of foraminiferal ooze and chalk, in contrast to the overlying packstone-dominated lithologies of Sequence 2. The thick middle Mio-cene interval consists of very poorly recovered, variably silicified, and partially dolomitized bioclastic grainstone, with the silicification distinguishing this unit from underlying and overlying units.
Poor recovery of both the overlying middle Miocene Sequence 3 interval and the lower Miocene Sequence 4 interval resulted in a lack of lithostratigraphic expression of the ~5-m.y. hiatus at the base of Sequence 3 (indicated by biostratigraphic data). Regional correlation indicates that the thin interval (~16 m) of lower Miocene sediment at Site 1132 should be assigned to seismic Sequence 4. It appears that this occurrence of Sequence 4 may represent the feather edge of a thinning-seaward sequence present beneath the modern outer shelf. Lithostratigraphic data indicate that Sequence 4 consists of bioclastic grainstone and packstone.
A combination of regional biostratigraphic and seismic data indicate that the 76-m-thick lower Oligocene interval intersected at Site 1132 (lithostratigraphic Unit V) corresponds to seismic Sequence 6A, and the 38-m-thick upper Eocene interval (lithostratigraphic Unit VI) corresponds to seismic Sequence 6B. These sequences are considerably thicker at Site 1132 than predicted before drilling, and they will necessitate a postcruise reinterpretation of the seismic grid in this vicinity. Sequence 6 sediments were poorly recovered, but sufficient lithostrati-graphic information exists to categorize Sequence 6A as partially dolomitized bioclastic and foraminiferal packstone and grainstone overlying a mineralized and bored hardground that marks the top Sequence 6B boundary. Seismic data show that Sequence 6B at Site 1132 corresponds to a distinct mound; however, poor recovery of this interval precludes a detailed analysis of mound composition. Recovered core consists of a diverse range of lithologies, including echinoid wackestone, bioclastic packstone, bioclastic wackestone, and bioclastic grainstone, with bioclasts dominated by bryozoan, brachiopod, echinoid, and bivalve fragments. Abundant firmgrounds and hardgrounds are present through-out lithostratigraphic Unit VI, and it appears likely that this interval represents mound development on a shallow marine shelf (see "Lithostratigraphy").
The lack of recovery within the ~45-m-thick interval of seismic Sequence 7 intersected at Site 1132 is attributed to the loose, unconsolidated character of the sand inferred to constitute the succession underlying lithostratigraphic Unit VI. The unconsolidated nature of these sediments resulted in collapse around the drill bit, which caused the drill string to jam and required that the hole be abandoned. It is likely that pebbles of coarse sand- to granule-sized calcareous sandstone at the base of lithostratigraphic Unit VI either may have been derived from Sequence 7 or may actually represent the uppermost part of Sequence 7. If the latter is true, then the drilling difficulties encountered deeper in the hole would seem to indicate a variable distribution of calcareous cement surrounding siliciclastic grains within this unit.