ANCILLARY BENEFITS OF DRILLINGIn addition to the main focus of the proposed ODP leg discussed above, there will be important other benefits derived from the recovered sediment sequences.
2. The linking of seismic stratigraphy and the chronostratigraphy provided by the recovered sections will complement and extend the seismic stratigraphy developed by Mayer et al. (1985, 1986) and Bloomer et al. (1995). This will permit the development of a broad regional view of equatorial deposition currently constrained only by the extent and quality of seismic data coverage.
3. We should be able to map the latitudinal position of the change over through time between dust sourced from the Americas and that sourced from Asia. This, together with the pattern of dust flux and grain size variations, is likely to be a valuable independent check on models of Paleogene atmospheric circulation (Rea, 1994).
4. Although we have selected sites to minimize encounters with chert layers, it is unlikely that we will avoid them altogether. The recovery and logging of sections containing chert and comparisons to equivalent intervals without chert at other sites will be an important step toward a better understanding of the pervasive occurrence of these cherts in the early and middle part of the Eocene. Coring and logging data, together with material recovered in this drilling transect, will provide important information on the timing and geochemical nature of these cherts.
5. Because the equatorial Pacific is the major region of carbonate burial and an important region of biogenic silica burial in the abyssal Pacific Ocean, the transect will be important to develop the Paleogene mass balance of biogenic sediment components. Important new data will also be gathered to understand the shallow Eocene CCD and whether production or dissolution was most important in shaping the change in the Eocene CCD with time. The data will also be used to study to what extent the Eocene silica cycle was different than modern conditions.
6. Because each site is planned to terminate in the uppermost basaltic basement, we will sample the basal hydrothermal-rich sediments. Study of these sediments will give important data about the strength of hydrothermal input to global mass balances.
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