Geochemical Tracers of Extraterrestrial Matter in Sediments

Every year, tens of thousands of tons of cosmic dust accumulate at the Earth’s surface, representing a continuation of the accretion process that started 4.57 billion years ago. The unique geochemical properties of these materials, compared to the Earth’s surface, render them excellent tracers of Solar System, atmospheric, oceanographic, and geologic processes. These processes can be recovered from the records preserved in marine and terrestrial sediments, including snow and ice. We review evidence from these natural archives to illuminate temporal and spatial variations in the flux and composition of extraterrestrial material to Earth, as well as the terrestrial processes that affect the distribution of extraterrestrial tracers in sediments.