The composite section for Site 1125 yielded overlapping records for the upper ~238 meters composite depth (mcd) using data from Holes 1125A and 1125B. Two high-resolution data sets proved most useful for correlation at this site: magnetic susceptibility (MS) measured on whole cores on the MST, and spectral reflectance at 550 nm (the center wavelength of the range measured), measured on split cores. At other sites it was possible to concentrate on one parameter and use alternatives for checking correlations. However, in the case of Site 1125 both reflectance and MS had such low variability that it was only possible to complete the splice by frequent alternation between parameters. In some cases the "signal" from one parameter (e.g., reflectance) was not reproduced at the corresponding level in the adjacent hole, despite excellent correlation with the alternative parameter (e.g., MS). Data were edited to remove information collected over voids as identified by very low gamma-ray attenuation porosity evaluator (GRAPE) density values; the final composite section is illustrated in Figure F13.
Downhole core offsets in the composite section follow a model of 15% stretch between the mbsf and mcd depth scales (Fig. F14). It is not known why the offset increases at a rate of 15% rather than the more typical 10%. Table T7 (also in ASCII format) contains the offsets between the mbsf and mcd scales that result from composite section construction.
The continuous spliced record, based on MS and reflectance data (reflectance percentage) (Fig. F15), extends to 238 mcd. Wherever possible, splice tie points (Table T8, also in ASCII format) were picked at well-defined maxima or minima where the overlap in data from Holes 1125A and 1125B are strongly correlated. Typically, parameter values differed by less than 10% at tie levels. In all cases, ties were selected so that the spliced record was as free from noise (high-frequency variability) as possible.