Reply to Comment on “On the importance of opal, carbonate, and lithogenic clays in scavenging and fractionating 230Th, 231Pa and 10Be in the ocean”

Abstract

We extend our analysis of the Chase et al. data [Earth and Planetary Science Letters 204 (2002) 215–229] to those other than from the equatorial Pacific and the Southern Ocean. The analysis offers support to our previous conclusion that Kd(Th) for carbonate is on the order of ∼1.0×106 g/g, or about two orders of magnitude smaller than that for open-ocean lithogenics. There is a lowering of Kd(Th) of lithogenics at high-lithogenic sites attributable to factors including the sediment remobilization from ocean-margin deposits. But the lowered Kd(Th) of lithogenics is still about one order of magnitude greater than that of carbonate at those high-lithogenic sites. Using an independent method, we estimate that Kd,l(Th) is >(2.2±0.9)×108 g/g at stations adjacent to our EqPac sites, reinforcing our conclusion that the major scavenger for 230Th is lithogenic, not carbonate particles, even in the low-lithogenic open ocean.