Speaker:  Professor Shanan Peters University of Wisconsin-Madison 

Title: "Unsteady growth of the continental sedimentary reservoir: implications for the Earth-life system"

Abstract: Much of the mass of most biogeochemically important elements, and nearly all of the information required to reconstruct the long-term evolution of Earth’s surface environment, resides in sedimentary rocks. Knowing the mass-age distribution and composition of sediments is, therefore, fundamental to our understanding of the evolving Earth-life system. Here we use information describing rock abundance and composition as a function of geologic age in the Macrostrat database to show that, as previously suggested, there are wide-ranging timescales of sediment cycling. Somewhat unexpectedly, the total mass of sediments sequestered in continental crust has experienced at least one, and possibly two, dramatic growth phases in response to climatic and/or tectonic forcing. Implications for long-term shifts in Earth’s surface conditions, notably atmospheric composition and sea level, are discussed.