Determination of mixing parameters from tracer distributions in deep-sea sediment cores

Computer optimization and approximate analytical procedures are developed for the determination of the depth of bioturbation mixing, d , and the mixing coefficient, D , for instantaneous tracer inputs. The methods have been applied to observations of microtektites, volcanic ash and pumice in sixteen deep-sea sediment cores. The values for d are well determined, generally with confidence intervals of a few centimeters or less and with an average value of d = 11 cm for the sixteen cores. The values for D are determined to first figure accuracy, at best, with values of around 10 cm 2 ka −1 or greater.