Other
Scientific paper
Dec 1982
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1982e%26psl..61..257d&link_type=abstract
Earth and Planetary Science Letters, Volume 61, Issue 2, p. 257-271.
Other
24
Scientific paper
Particle mixing rates have been determined for 5 South Atlantic/Antarctic and 3 equatorial Pacific deep-sea cores using excess 210Pb and 32Si measurements. Radionuclide profiles from these siliceous, calcareous, and clay-rich sediments have been evaluated using a steady state vertical advection diffusion model. In Antarctic siliceous sediments 210Pb mixing coefficients (0.04-0.16 cm2/y) are in reasonable agreement with the 32Si mixing coefficient (0.2 or 0.4 cm2/y, depending on 32Si half-life). In an equatorial Pacific sediment core, however, the 210Pb mixing coefficient (0.22 cm2/y) is 3-7 times greater than the 32Si mixing coefficient (0.03 or 0.07 cm2/y). The difference in 210Pb and 32Si mixing rates in the Pacific sediments results from: (1) non-steady state mixing and differences in characteristic time and depth scales of the two radionuclides, (2) preferential mixing of fine-grained clay particles containing most of the 210Pb activity relative to coarser particles (large radiolaria) containing the 32Si activity, or (3) the supply of 222Rn from the bottom of manganese nodules which increases the measured excess 210Pb activity (relative to 226Ra) at depth and artificially increases the 210Pb mixing coefficient. Based on 32Si data and pore water silica profiles, dissolution of biogenic silica in the sediment column appears to have a minor effect on the 32Si profile in the mixed layer. Deep-sea particle mixing rates reported in this study and the literature do not correlate with sediment type, sediment accumulation rate, or surface productivity. Based on differences in mixing rate among three Antarctic cores collected within 50 km of each other, local variability in the intensity of deep-sea mixing appears to be as important as regional differences in sediment properties.
Present address: Department of Chemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, U.S.A.
Cochran Kirk J.
Demaster David J.
No associations
LandOfFree
Particle mixing rates in deep-sea sediments determined from excess 210Pb and 32Si profiles does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Particle mixing rates in deep-sea sediments determined from excess 210Pb and 32Si profiles, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Particle mixing rates in deep-sea sediments determined from excess 210Pb and 32Si profiles will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-928974