Extracting the Silicate Mineral Fraction from Ancient Carbonate: Assessing the Geologic Record of Dust

摘要

The climatic influence of eolian dust (particles < 63 µm) is well recognized in the Cenozoic earth system, but less so for the pre-Cenozoic. In ancient carbonate rocks that formed isolated from fluvio-deltaic influx, the silicate mineral fraction can, in some cases, represent atmospheric dust. Here we present a methodology for sequential extraction of carbonate, organic matter, pyrite, and iron oxide from pre-Cenozoic carbonate strata to isolate the eolian fraction, and illustrate the application to stratigraphic sequences from a late Paleozoic carbonate buildup and ramp setting.