Department or Program

Geology

Abstract

Mercury and PCB contaminants continue to leach out of the bedrock and till beneath the former chlor-alkali facility despite remedial efforts to prevent the escape of toxins in the 1990s. This study defines how contaminants could be escaping the site through bedrock structures. Bedrock geology mapping in Berlin, NH was conducted as part of a USGS/NHDES State Map program to define bedrock units and structural features within the northern half of the Berlin 7.5’ Quadrangle. In addition, the identification of groundwater transmissible features in the area continued previous efforts to define the escape of contaminants via groundwater flow from the chlor-alkali facility. Previous USGS reports recorded bedrock units and features from the riverbank adjacent to the site and identified fracture domains based on local field data.The updated regional bedrock data allowed us to better identify and contextualize brittle and ductile structures recorded at the chlor-alkali facility. The research also produced an expanded dataset of groundwater transmissible features measured in the field, including Mesozoic joint fractures, silicified zones, cylindrical folds and chlorite schist xenoliths. Lastly, a LiDAR hillshade analysis of fractures across the entire quadrangle was conducted. LiDAR hillshade raster imagery on ArcGIS was not available during previous studies, and this analysis provided a valuable way to confirm fracture domains at a regional scale. Measurements of brittle and ductile features surrounding the chlor-alkali facility indicated the presence of a syncline structure running from the chlor-alkali facility towards the Androscoggin River. This structure could facilitate groundwater flow from the site to the river. Fractures were found to primarily exist in three main domains: NE-SW, NW-SE and E-W. Fractures striking NE-SW appeared to dominate the domain surrounding the chlor-alkali facility.

Level of Access

Open Access

First Advisor

Eusden, Jr., Dykstra

Date of Graduation

5-2021

Degree Name

Bachelor of Arts

Number of Pages

120

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