Remediation of Abandoned Mine Lands

Friday, October 3, 2008 : 4:20 p.m.

Rocky Mountain Soils Derived from Intermediate to Mafic Volcanic Bedrock: A Potentially Significant CO2-Stabilization-Wedge Resource

Douglas B. Yager, USGS, Alison Burchell, Natural Capitalism Solutions, Rob Robinson, Bureau of Land Management, ret., Richard P. Dick, Ohio State University, Jack Hidinger, US EP and Stephanie Odell, US Bureau of Land Management

Soils represent a potentially large and important natural carbon reservoir. The Natural Terrestrial Sequestration potential (NTS) of soils is among the “CO2 stabilization wedges' or carbon management strategies needed to thwart doubling of atmospheric CO2.

To better understand NTS, we analyzed soil-cores from 16 Colorado, Rocky Mountain Cordillera sites. Northerly-facing, high-plains to alpine sites in non-wetland environments were selected, because such temperate soils may be less susceptible to baseline C-pool declines due to global warming than soils in warmer regions. All undisturbed soils sampled have 2 to 6 times greater total organic soil carbon (TOSC) than global TOSC averages (4 – 5 Wt. %). Forest soils derived from weathering of intermediate to mafic volcanic bedrock have the highest C (34.16 Wt %), C:N (43), microbial-biomass arylsulfatase (ave. 142, high 338).  Intermediate TOSC was identified in soils derived from Cretaceous shale (7.2 Wt. %) and Precambrian, felsic gneiss (6.2 Wt. %). Unreclaimed mine-sites have the lowest: C (0.01 to 0.78 Wt. %), C:N (2.4 to 6.5), and arylsulfatase (0 to 41).  However, reclaimed and undisturbed mined-lands soils derived from propylitically-altered andesite have high: C (13.5 – 25.6 Wt. %), C:N (27), arylysulfatase (338). In our previous studies, propylitic-rocks were found to have high Acid Neutralizing Capacity (ANC). Radiocarbon dates on charcoal collected from paleo-burn horizons (found in high C, N soils) indicates an old carbon pool (840-5,440 ±40 yrs B.P).

The data suggest volcanic-soils, including volcanic-hosted reclamation sites, represent a potentially significant C-sink. Future research will probe: ecosystem variability; NTS in pilot-projects that model natural “geomimicry” processes and use soil-amendments (e.g.: ANC-rock; biochar) to support soil-productivity, soil-moisture and CO2-sequestration (mine-reclamation, forest-health, watershed-protection); implications for disturbing soils that sequester C for millennia; the geo-environmental value of NTS as carbon markets mature and offer economic measures to areas targeted for resource extraction; and post-reclamation success.

Douglas B. Yager, USGS Douglas Yager, a Geologist with the US Geological Survey, Denver, Colorado studies the environmental impacts due to weathering of mineralized terrain and mined areas. His work has focused on acid neutralizing capacity of volcanic rocks, and recently on natural terrestrial carbon sequestration potential of soils derived from weathering of volcanic bedrocks. Douglas is also involved in GIS analysis and database design, applicable to geo-environmental and mineral resource investigations. Douglas completed: undergraduate studies in geology at Colorado State University , and GIS studies at the University of Denver.

Alison Burchell, Natural Capitalism Solutions Alison Burchell is a Geologic Consultant with US and international projects including: Federal mapping and geochemical surveys, coral reef and wetland assessment, mined-lands reclamation, volcanic hazards and renewable-energy site-assessment. Her undergraduate work was in Organic Chemistry with a minor in Environmental Sciences and Planning. Her graduate degree was in Volcanology and Isotope-Geochemistry under a joint Department of Interior/ US Geological Survey Fellowship at the University of Arizona. Currently, her research is focused on understanding and quantifying the mechanisms and kinetics of Natural Terrestrial Sequestration (NTS) and geologic variables that influence maximal NTS potential.


Remediation of Abandoned Mine Lands