Calcareous nannofossil biostratigraphy of ODP Hole 108-667A and DSDP Site 85-574

Detailed quantitative analyses of selected calcareous nannofossil species were used to determine the placement of zonal boundaries. In Hole 667A in the equatorial Atlantic Ocean, Zones CP19 through CN5 were recognized, whereas at Site 574 in the equatorial Pacific Ocean, only the CN4/CN5 boundary could be determined. Boundaries were identified by sharp rises and declines in abundance at the beginnings and ends, respectively, of index fossil ranges. The sharp rise in abundance at the beginning of the range of Triquetrorhabdulus rugosus provided a good datum level in both regions; the same is true for the sharp decline in abundance at the end of the range of Cyclicargolithus floridanus. The last occurrence of Helicosphaera ampliaperta was used to mark the CN3/CN4 boundary in Hole 667A, while at Site 574, H. ampliaperta was absent. The abundance pattern of Triquetrorhabdulus carinatus obtained from Hole 667A makes it impossible to observe a distinct disappearance level. Age/depth plots reveal uniform sedimentation rates at both sites during early Miocene times. At Site 667 in the Atlantic the mean sedimentation rate was 14.90 m/m.y., and at Site 574 in the Pacific it was 16.17 m/m.y. during this same period. One new nannofossil species, Triquetrorhabdulus rioensis, is described; and one species, Triquetrorhabdulus serratus, is recombined.

Global database of surface ocean particulate organic carbon export fluxes diagnosed from the 234Th technique

Through the processes of the biological pump, carbon is exported to the deep ocean in the form of dissolved and particulate organic matter. There are several ways by which downward export fluxes can be estimated. The great attraction of the 234Th technique is that its fundamental operation allows a downward flux rate to be determined from a single water column profile of thorium coupled to an estimate of POC/234Th ratio in sinking matter. We present a database of 723 estimates of organic carbon export from the surface ocean derived from the 234Th technique. Data were collected from tables in papers published between 1985 and 2013 only. We also present sampling dates, publication dates and sampling areas. Most of the open ocean Longhurst provinces are represented by several measurements. However, the Western Pacific, the Atlantic Arctic, South Pacific and the South Indian Ocean are not well represented. There is a variety of integration depths ranging from surface to 220m. Globally the fluxes ranged from -22 to 125 mmol of C/m**2/d. We believe that this database is important for providing new global estimate of the magnitude of the biological carbon pump.