The datums used to determine linear sedimentation rates (LSRs) (Fig. F6) for the Paleocene section of Hole 1068A are biostratigraphic zonal markers, with the exception of the last occurrence (LO) of F. tympaniformis and the FO of Cruciplacolithus primus (Table T6). The LO of F. tympaniformis was placed at Sample 173-1068A-8R-6, 99-100 cm (787.39 mbsf), based on LCO, because the few occurrences upsection are considered to be a result of reworking. The sedimentation rate over the barren interval is an estimate based on the datums directly above and below the interval. Note that there are also many smaller barren intervals throughout the Paleocene section of Hole 1068A (Table T2). These barren intervals may have an effect on the values of the sedimentation rates, depending on sample spacing.
The datums used for the Cretaceous section of Hole 1068A are biostratigraphic zonal markers. The sedimentation rate for this section should be seen as an approximation because there are few markers to use for a reliable determination.
Mass accumulation rates (MARs) were calculated for Hole 1068A (Fig. F7) using 22 physical properties measurements collected on the ship during Leg 173. Data used for MAR determination are listed in Table T7. Because of the scarcity of sample spacing, some measurements were averaged to obtain useful data for all sections. Mass accumulation rates vary between 0.35 g/cm2/k.y. and 0.95 g/cm2/k.y. in the Upper Cretaceous and lower to middle Paleocene to >1.5 g/cm2/k.y. in the upper Paleocene.
The datums used for determination of LSRs in Hole 1069A (Fig. F8) are biostratigraphic zonal markers, with the exceptions of the LO of F. tympaniformis and the FO of Sphenolithus primus (Table T8). The use of F. tympaniformis was based on the LCO noted in Sample 173-1069A-7R-5, 18-19 cm (782.98 mbsf). Many of the markers that were used to calculate the sedimentation rate for Hole 1068A could not be used here because of poor recovery or because these markers were not encountered. The sedimentation rate over the barren interval is an estimate that is based on the datums directly above and below the interval.
Datums used in the Cretaceous section of Hole 1069A are biostratigraphic markers with the exception of U. trifidus, which is used here to approximate the Subzone CC23b/Zone CC24 boundary. Because most of the stratigraphy is determined from turbidite-derived sediments, it is possible that last occurrences may be reworked uphole. This may affect the sedimentation rates of sections that are determined using last occurrences.
Mass accumulation rates were calculated for Hole 1069A (Fig. F9) using 16 physical properties measurements that were collected on the ship during Leg 173. Data used for MAR determination are listed in Table T9. As in Hole 1068A, some measurements were averaged to accommodate sparse measurement spacing. MARs in Hole 1069A are fairly low in the upper Campanian, varying from 0.6 g/cm2/k.y. in the lowest part of the hole (~75 Ma) to 0.15 g/cm2/k.y. around the Campanian/Maastrichtian boundary. This extremely low rate may indicate the presence of hiatuses in this part of the section. MARs are high again near the end of the Maastrichtian (~1.0 g/cm2/k.y.), peaking to 2.75 g/cm2/k.y. at the K/T boundary. However, this peak of mass accumulation may be a result of poor recovery just above the K/T boundary and/or sample spacing. MARs are low again in the lower Paleocene (averaging ~0.35 g/cm2/k.y.), increase to over 1.0 g/cm2/k.y. through the mid-Paleocene, and then drop off again in the upper Paleocene to an average of ~0.40 g/cm2/k.y.