CT, MA aerial survey maps geology, pyrrhotite hazard

Pyrrhotite, found in bedrock under certain parts of Connecticut and Massachusetts, can cause long-term structural weakness in construction when used in cement, causing building foundations to crumble. The corrosive mineral pyrrhotite is a well-known hazard in Connecticut and an emerging hazard in central Massachusetts.

"Increasing knowledge of New England's geologic framework will help with national priorities, like earthquake and landslide hazards, water availability, and sourcing critical minerals -- as well as regional concerns, like mapping pyrrhotite to minimize its use in local infrastructure," said Jamey Jones, science coordinator for the USGS Earth Mapping Resources Initiative. "By working together on this survey, Connecticut and Massachusetts are helping with the work of the nation."

"I'm excited that this survey covers a large portion of southern New England. It will provide new insights into Connecticut's bedrock that wouldn't be possible without modern geophysical tools, and by coordinating with Massachusetts and Rhode Island, we can improve mapping along state borders. The results will help the Connecticut Geological Survey improve our understanding of geological hazards across the state," said Meghan Seremet, Connecticut state geologist.

"Better geologic maps will help us screen for the presence of pyrrhotite, ultimately protecting homeowner investments. We have a broad sense of where this corrosive mineral is, but not enough detail yet to assure that it doesn't end up in concrete that makes its way into people's home foundations," said Brian Yellen, director of the Massachusetts Geological Survey and professor at the University of Massachusetts-Amherst. "Some 35,000 houses have been identified in Connecticut with crumbling foundations, and there are similar numbers in central Massachusetts."

The survey is part of USGS' Earth MRI, a partnership with the geological surveys of Connecticut, Massachusetts and other states, educational institutions and industry to modernize knowledge of the U.S. geologic framework. Applications include mapping pyrrhotite and radon, assessing hazards such as earthquakes and landslides, and supporting efforts in mine waste remediation and resource recovery.

Instruments on the airplane will measure variations in the Earth's magnetic field and natural, low-level radiation created by different rock types up to several miles below the surface. For geologists working in New England, the rocks are often hidden by trees and plants, so these datasets are especially helpful. The information will help researchers develop geologic maps of resources and hazards in three dimensions.

Flights for the southern portion of the survey are based out of Robertson Airport in Plainville, CT. The aircraft, which Anjana Shah, USGS coordinator for the Connecticut River Valley Survey, toured for reporters Tuesday along with Seremet and Yellen, is equipped with an elongated "boom" that extends in front of the main cabin and houses sensors. These scientific instruments are completely passive with no emissions that pose a risk to humans, animals, or plant life. No photography or video data is collected.

Connecticut State Geologist Meghan Seremet, Massachusetts State Geologist Brian Yellen, and USGS coordinator for the Connecticut River Valley Earth MRI survey Anjana Shah in front of survey aircraft at Robertson Airport, Plainville, CT. Photo credit: Daegan Miller, UMass-Amherst.

Blue outline shows the complete area of the USGS Connecticut River Valley Survey.

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