Other
Scientific paper
Apr 1993
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1993gecoa..57.1473s&link_type=abstract
Geochimica et Cosmochimica Acta, vol. 57, Issue 7, pp.1473-1488
Other
13
Scientific paper
Rates of bioturbation measured in deep-sea sediments commonly are tracer dependent; in particular, shorter lived radiotracers (such as 234 Th) often yield markedly higher diffusive mixing coefficients than their longer-lived counterparts (e.g., 210 Pb). At a single station in the 1240-m deep Santa Catalina Basin, we document a strong negative correlation between bioturbation rate and tracer half-life. Sediment profiles of 234 Th (half-life = 24 days) yield an average mixing coefficient (60 cm 2 y -1 ) two orders of magnitude greater than that for 210 Pb (half-life = 22 y, mean mixing COEFFICIENT = 0.4 cm 2 y -1 ). A similar negative relationship between mixing rate and tracer time scale is observed at thirteen other deep-sea sites in which multiple radiotracers have been used to assess diffusive mixing rates. This relationship holds across a variety of radiotracer types and time scales. We hypothesize that this negative relationship results from "age-dependent mixing," a process in which recently sedimented, food-rich particles are ingested and mixed at higher rates by deposit feeders than are older, food-poor particles. Results from an age-dependent mixing model demonstrate that this process indeed can yield the bioturbation-rate vs. tracer-time-scale correlations observed in deep-sea sediments. Field data on mixing rates of recently sedimented particles, as well the radiotracer activity of deep-sea deposit feeders, provide strong support for the age-dependent mixing model. The presence of age-dependent mixing in deep-sea sediments may have major implications for diagenetic modeling, requiring a match between the characteristic time scales of mixing tracers and modeled reactants.
Demaster David J.
Magaard Lorenz
Pope Robin H.
Smith Craig R.
No associations
LandOfFree
Age-dependent mixing of deep-sea sediments 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 Age-dependent mixing of deep-sea sediments, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Age-dependent mixing of deep-sea sediments will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1370880