. Bulletins of American paleontology. 38 Bulletin 361 Bob Allen Core - - â â Coral Data .^, ^ , â â¢â ^ 1 n 1_ â i . r . â â * Core Data « . â ⢠â 1 r â 1 â 1 1 1 1 1 Bob Allen Bank Q. "(5 o I- 1860 1880 1900 1920 1940 1960 1980 2000 Year South Russell Bank Core - Core Data ^ , ,... â¢â¢...â¢.:â â â â ^ Coral Data ⢠â¢It L- I 1 â 1 â 1 ⢠{â¢III . 1 1860 1880 1900 1920 1940 1960 1980 2000 Year Text-figure 5.âComparison of the distribution of stable lead with dated cores (6A and 19C) and a dated coral. the bairen site is g/cin\ The
. Bulletins of American paleontology. 38 Bulletin 361 Bob Allen Core - - â â Coral Data .^, ^ , â â¢â ^ 1 n 1_ â i . r . â â * Core Data « . â ⢠â 1 r â 1 â 1 1 1 1 1 Bob Allen Bank Q. "(5 o I- 1860 1880 1900 1920 1940 1960 1980 2000 Year South Russell Bank Core - Core Data ^ , ,... â¢â¢...â¢.:â â â â ^ Coral Data ⢠â¢It L- I 1 â 1 â 1 ⢠{â¢III . 1 1860 1880 1900 1920 1940 1960 1980 2000 Year Text-figure 5.âComparison of the distribution of stable lead with dated cores (6A and 19C) and a dated coral. the bairen site is g/cin\ The core taken in the grass bed contains a high percentage of plant material, which decreases the overall density of the sediment. A similar comparison can be seen in the Pass Keys Coresâ17D and 17G (Text-tig. 7). Sedimentary Dynamics As mentioned above, the source of excess -'°Pb is a result of the severed decay chain by the gaseous ---Rn. As a result -'opb can reach a site of deposition via atmospheric fallout or a combination of atmospheric fallout and particle transport in which lead is added along the route of transport. The atmospheric flux along the northeastern coast of the United States has been measured as ± dpm/cm- (Turekian et al., 1983). This would produce a steady state inventory of excess -'"Pb of 32 ± 6 dpm/cm-. Similar inventories determined in lowland soil profiles in the eastern Unit- ed States average 26 ± 4 dpm/cm,. Baskaran et al. (1993) measured the atmospheric flux at Galveston and College Station, Texas, as varying between and dpm/ cm-/yr, with a mean of dpm/cm7 yr. Their data also demonstrated the flux differences in between continental and marine sources, with the ma- rine sources producing a smaller flux than the conti- nental source. In south Florida a flux of dpm/cin-/ Core 6C - Barren Site ⢠^ ^^^k^^ Pnrf* ^ Sif*» Core 6A-Grass Site 0 50 100 150 200 250 Y
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