IDENTIFYING STRATIGRAPHIC PROBLEMS IN NEW ENGLAND, A COLLABORATIVE PROJECT OF THE NEW ENGLAND STATES GEOLOGIC MAPPING COALITION (NESGMC)

Every map is a progress report. As well as adding data, new maps present a new understanding of geologic relationships. The state bedrock maps for New England were compiled by various authors between 1983 and 2011. They are therefore to some degree incompatible and outdated. While the concept of New England as a Paleozoic plate tectonic collision zone is well established, recent high-precision geochronology has led to more sophisticated regional models.

As a first step to improving the stratigraphic framework, the NESGMC engaged 21 geologists and graduate students representing the six states to contribute to a project “Identifying Stratigraphic Problems in New England.” Supported by the USGS NGMDB, the strategy was to review existing maps and literature for problems that cross state lines relevant to needs of the states. The group decided on four priority areas: Rowe-Hawley/Moretown, northern Connecticut Valley, Merrimack-Central Maine, and western Avalon lithotectonic belts. An ArcGIS Online web app designed for the project allowed participants in the four working groups to enter citations and associated location points. Participants entered information into data fields for each citation about the stratigraphic problem such as correlation, edge matching map units, uncertainty of age or stratigraphic sequence, nomenclature, or other. Stratigraphy-related issues of societal concern such as water quality or suitability for construction aggregate were also noted. This process allowed participants to work with map-based information independently and collaboratively.

All data from the web app, including formal, informal, and unpublished sources with lat/long coordinates, was downloaded into a large data file (csv), available online through the MGS Digital Maine repository. To accompany the data file, each working group presented a narrative summary of significant stratigraphic problems, local or regional, and proposed ways in which the problems might be addressed.

The project was not designed solve problems. Instead it points to the very places where discoveries and progress are waiting to happen. The hope is that it will guide future research, whether small or large, from local student projects to regional federally funded programs, to where the accuracy, quality, or usefulness of maps could be improved.