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doi:10.2204/iodp.proc.302.202.2008

Stretching and squeezing of material

One of the advantages of using composite records is that they allow small-scale deformations and lateral heterogeneities in sediments from neighboring sites and holes to be recognized. The highest quality and most representative material available from the overlapping sections are then preferentially incorporated into the spliced record. However, in developing the composite depth scale and spliced record, a single tie is commonly used to align neighboring cores. This results in small-scale heterogeneities within depth equivalent cores remaining misaligned. The stretching and squeezing of material within any individual core to ultimately “tune” it to the composite record has traditionally been a separate step during ODP and IODP expeditions. Occasionally, this is done when the composite depth scale is converted to age or when it is integrated into an equivalent logging depth scale.

High-resolution studies of the ACEX material that falls within the uppermost 19 rmcd will need to account for these small offsets between coeval materials that cannot be accounted for by a single tie point. These adjustments to the rmcd scale only need to be made when integrating material that falls outside the spliced record (Table T2). The alignment of material from Holes M0003A and M0004C with the composite record from ACEX is shown in Figure F12, with the ties required to achieve optimal alignment through stretching and squeezing listed in Table T3. Between ~19 and 27 rmcd, only material from Hole M0004A is used in the revised composite splice, and no adjustments have been attempted for potentially overlapping material from Hole M0002A.

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