Connecticut

Summary

The Connecticut Geological and Natural History Survey partners with USGS STATEMAP, Earth MRI, and NGGDPP programs to advance modern geologic mapping and data preservation. The current Earth MRI airborne survey is refining Connecticut’s geologic framework, STATEMAP projects are producing updated digital maps, and NGGDPP efforts are preserving historic maps and creating an interactive web map for mines and quarries. These initiatives provide critical data that support hazard mitigation, infrastructure planning, and public access to geoscience information.

STATEMAP (2016-2024):

  • Bedrock Mapping.
    • Modern bedrock map of the Mesozoic Hartford Basin 1:100k scale.
    • Digitized 6 previously mapped 7.5′ quadrangles.
    • Digitized the State-wide Bedrock Geological Map of Connecticut.

EARTH MRI

  • Connecticut Valley Airborne Geophysical Survey.
    • Currently flying aeromagnetic and radiometric survey covering significant portions of CT, MA, and parts of RI, VT, and NH. The results of this survey will provide valuable data to allow for targeted on the ground mapping in the future.

NGGDPP (Data Preservation)

  • Connecticut Mines and Quarries Interactive Map:
    Through the National Geological and Geophysical Data Preservation Program (NGGDPP), the Connecticut Geological and Natural History Survey has created a new interactive web map of more than 1,000 bedrock mining sites. This tool preserves historic mining information, integrates modern data, and makes Connecticut’s mining legacy discoverable and accessible for economic development, land-use planning, hazard mitigation, and cultural preservation.

    • Synthesizes archival records, mine plans, scientific reports, landscape analyses, and field inspections.
    • Covers 1,000+ bedrock mining sites across the state.
    • Ensures long-term preservation of mining information while making it publicly accessible.
  • Applications:
    • Supports economic development and industry by identifying resource sites.
    • Informs land-use planning for both conservation and development.
    • Aids in pollution prevention and hazard assessment.
    • Preserves cultural and historic data tied to Connecticut’s long mining tradition.
  • National Relevance:
    • Contributes to the USGS National Critical Minerals Assessment and aligns with both Earth MRI and NGGDPP objectives.
  • Mining Legacy & Modern Uses:
    Historic Commodities (colonial era–20th century): copper, silver, lead, cobalt, tungsten, iron/pig iron, garnet, rare-earth-element pegmatites, uranium, barite, feldspar, mica, graphite, and possibly gold
  • Cultural Legacy:
    • Copper coins and munitions during the Revolutionary War.
    • Brownstone quarries fueling the architectural boom of the 1800s.
    • Granite and marble used in government buildings and national monuments.
  • Modern Commodities: basalt/diabase (traprock), granite, granitic gneiss, marble, sand & gravel, and clay.
  • Modern Uses: crushed rock for construction, building stone, pharmaceuticals, industrial processes, brick manufacture, landscaping, and jewelry.

Impact for Connecticut:

  • Preserves and modernizes centuries of mining records.
  • Provides a publicly accessible, interactive tool for resource management and planning.
  • Strengthens Connecticut’s contributions to national critical mineral assessments.
  • Demonstrates the enduring value of NGGDPP in linking history, economy, and modern science.