CZO: Susquehanna/Shale Hills Critical Zone Observatory

EAR-0725019

Duffy

THE SUSQUEHANNA/SHALE HILLS CRITICAL ZONE OBSERVATORY

Intellectual Merit: The surface of the earth comprises a weathering engine or mill that solubilizes and disaggregates rock to form regolith. Over the long term, the rates of weathering and erosion combine to control the evolution of landscapes and help to define the access, rates of motion, and time scales of water and energy within the Critical Zone (CZ). Despite the importance of these processes, we are generally unable to quantitatively predict the rates or mechanisms by which regolith forms or how it controls water flow. Understanding these rates is of particular importance due to the rapid rates of change of the CZ in response to anthropogenic and climate perturbation. Here we propose a Critical Zone Observatory dedicated to developing this understanding for one of the most common lithologies on earth.

Our Critical Zone Observatory site, the focus of National Science Foundation-supported research since the 1970s, provides long term datasets for hydrological response that will be augmented here by new geochemical, geomorphological, ecological, and soils datasets. The observatory is a small catchment in central Pennsylvania (hereafter termed the Susquehanna/Shale Hills Observatory or SSHO) on Rose Hill Shale. As a tectonically quiescent and relatively pristine watershed, Shale Hills presents the opportunity to investigate the rates and mechanisms of regolith formation on a simple but ubiquitous bedrock lithology. The regolith at the SSHO has experienced at least two potentially significant perturbations in the geologically recent past: a climatic perturbation from peri-glacial to modern conditions and a biologic perturbation from anthropogenic clearing of forests during colonial occupation. The magnitude of these perturbations and their influence on regolith generation afford an opportunity to assess the time scales of response of soil production to both long-term climate change and human activity.

Broader Impacts: To predict the creation, evolution, and structure of regolith as a function of the geochemical, hydrologic, biologic, and geomorphologic processes in our forested landscape, we have created an interdisciplinary team of 14 scientists from 8 universities, 1 federal agency, and 2 national laboratories. This team will coordinate not only the SSHO but also six satellite sites where we will initiate similar but less extensive investigations to explore the effect of climate and composition on shale weathering. Among these, Alabama A&M and University of Puerto Rico are minority-serving institutions that will facilitate the involvement of under-represented groups in Critical Zone science. Scientists and REU students from each satellite site (eighteen students over three years) will work closely with members of the Penn State team on a variety of activities ranging from geochemical analyses of soil and bedrock samples to measurement of soil moisture with onsite detectors. The observational data and model capabilities developed in the proposed effort will be made available through web-services for both time series data and geospatial data through the CZEN cyberinfrastructure initiative. Development of the SSHO on-line information system will be supported by ongoing NSF observatory and cyberinfrastructure grants. It is our vision that the SSHO will become an exemplar for Critical Zone observational and modeling science that will attract many additional investigators from the broader community to test ideas, techniques, and predictions.