Construction of the composite and spliced section from Holes 1130A and 1130B followed the methods outlined in "Composite Depths" in the "Explanatory Notes" chapter. Table T3 (also in ASCII format) relates mbsf to meters composite depth (mcd) for each core and section at Holes 1130A and 1130B and provides offset values for the conversion of mbsf to mcd. The composite section indicates that a nearly complete record of the Pleistocene-upper Miocene sedimentary section was recovered at Site 1130.
The primary lithologic parameters used to create the composite section were NGR emissions data collected by the MST on whole-round cores and a ratio of the 700- to 400-nm color reflectance data measured on split cores (Fig. F12). The 700- and 400-nm color reflectance data were also used individually but proved not to be as effective as the 700:400 ratio. Gamma-ray attenuation (GRA) bulk density and P-wave velocity data collected by the MST were disturbed by voids within the cores and were, therefore, not used for correlation purposes. Magnetic susceptibility was also not used for correlation because of a low signal-to-noise ratio. For specifics regarding data collection procedures and parameters, see "Physical Properties".
Biostratigraphic data aided in correlation by providing additional datums that were compared between holes (Table T4; see "Biostratigraphy"). Planktonic foraminifers were particularly useful in constraining correlative intervals of the recovered section. Because most biostratigraphic samples were taken from core catchers, the stratigraphic error associated with a particular datum is generally on the order of 10 m (the distance between core catchers in consecutive cores). The position of the last appearance datum (LAD) of G. tosaensis ties the base of Core 182-1130A-15H to the top of Core 182-1130B-16H and implies an age of ~0.65 Ma (or older) for this interval. Overlap of the G. truncatulinoides first appearance datum ties the top of Core 182-1130A-25X and the bottom of Core 182-1130B-24X and constrains the age of this interval to ~2 Ma (or younger). The LAD of Z. nepenthes overlaps and ties the base of Core 182-1130A-29X to the top of Core 182-1130B-30X and implies an age of ~4.2 Ma for this stratigraphic interval (Table T4).
The primary difficulties encountered in the correlation of Holes 1130A and 1130B were dissimilarities in the data records between the holes, which resulted partly from core distortion and partly from actual, though minor, lithologic variations between holes. Color reflectance data correlate poorly using small-scale (<1 m) features, most likely because of the relative homogeneity of the sediments on these scales (uniform packstones over much of the section; see "Lithostratigraphy"). Larger scale (>1 m) distinctive events are infrequent in the single-band color reflectance data. At several places, the data are interrupted by an erroneous shift to much higher values that do not correspond to any lithologic variation but, rather, are a result of an error in the output of the color reflectance scanner. To circumvent these problems, a ratio of the 700:400 nm color reflectance data was used with great success. The ratio data exhibit less noise and reveal more distinctive events that were more easily correlated between holes than simply using a single color reflectance band. Core overlap between holes averaged ~2-3 m where recovery was high and allowed for a statistical evaluation of ties used to create the composite section.
The upper 139 mcd (132 mbsf) are late Pleistocene in age, based upon biostratigraphic data (Fig. F13). The data record in this stratigraphic range is divided into one lithostratigraphic unit and two physical properties units. Physical properties Unit (PP Unit) 1 (above 47 mcd) was difficult to correlate, as data exhibit low-amplitude oscillations over long wavelengths with few clearly distinctive events. Below PP Unit 1, data (color reflectance ratio) exhibit higher amplitude oscillations with more distinctive characteristics that are more easily recognized between holes. At ~180 mcd, the data clearly change to higher frequency but lower amplitude oscillations that correlate well between holes. This characteristic signal is maintained to 252 mcd, the Pleistocene/Pliocene boundary. The upper Pliocene section is characterized by a 20-m-thick, uniform packstone in 1130B, which is interrupted by a nannofossil ooze in Hole 1130A. This packstone exhibits very low reflectance values (30%-40%) in the 700- and 400-nm ranges, but a high 700:400 nm ratio (1.75-2.5). The characteristics of this lower Pliocene bed are correlative between holes and easily distinguished from the overlying Pleistocene strata and underlying lower Pliocene strata. Below this unique bed, beginning at ~275 mcd, the data change character again to low-amplitude oscillations with very few easily correlated distinctive events (lithostratigraphic Unit II; upper Miocene-lower Pliocene). These relatively uniform data are maintained to the base of Core 182-1130B-35X (327.70 mbsf; 342.29 mcd), the last core analyzed by the MST.
The composite section indicates the existence of several unrecovered intervals in the record (Fig. F12). Low recovery in Core 182-1130A-3H and no recovery in Core 182-1130B-3H produced a gap in the record at 22-24 mbsf. The record below this is apparently continuous to ~188 mcd (Table T5, also in ASCII format). Below 188 mcd there are a number of gaps in the record resulting from the loss of overlap between cores in adjacent holes and requiring cores to be appended to the splice rather than tied. The mcd scale expansion relative to the mbsf scale is ~6%.
An
initial age model was produced using the biostratigraphic
datums (Table T4).
The 700:400 nm reflectance data were tuned to a composite
seawater 
18O
curve (Raymo et al., 1989; Shackleton et al., 1990;
Shackleton et al., 1995) using the initial age model as a
constraint. Results of the tuning were positive, with good
agreement with paleomagnetic and biostratigraphic data to
~0.7 Ma, and indicate that the variability apparent in color
reflectance data are probably of Milankovitch-scale cycli-city
in the Pleistocene section (Fig. F14).
