The Clinton-Newbury Fault Zone

The Clinton-Newbury fault in Massachusetts, USA is actually a fault zone and consists of many faults along a linear trend.   It forms an arc that trends east-west to northeasterly at its northeast end near Newbury, Massachusetts along the Atlantic coast.   In Massachusetts the fault zone is approximately 97 miles long.   The fault zone curves southwestward to Clinton and Worcester, and then southward into the state of Connecticut.

Lake Quinsigamund (in the picture on the right) along the Worcester-Shrewsbury line is a long, narrow lake that occupies a zone of bedrock weakness on the Clinton-Newbury fault zone.

Bedrock north and west of the fault zone is that of the Merrimack terrane (Skehan, 2001).   These rocks are of Ordovician to Devonian age and are composed of metasedimentary rocks that contain metaigneous intrusives.

Bedrock south and east of the Clinton-Newbury fault zone is of the Nashoba terrane.   They consist of mafic, intermediate, and felsic volcanic, volcanogenic, and plutonic rocks.

Plate Tectonics

Plate tectonics theory suggests that eastern Massachusetts has undergone at least three plate collisions in the last 500 million years (Skehan, p. 6).   At plate boundaries, the denser plate, usually consisting of oceanic crust, sinks under the less dense continental crust in a trench at a subduction zone.

The most recent movements along the Clinton-Newbury fault zone probably occurred near the end of the Paleozoic era when a collision of continental blocks took place during the creation of the Pangean supercontinent.

Parallel with this fault zone to the south and east is the Bloody Bluff fault zone which also transects eastern Massachusetts from the Atlantic coast near Newbury into the state of Connecticut.    The Bloody Bluff fault zone separates Nashoba terrane from Avalon terrane.

Some Useful Links

The above discussion provides basic information and illustrations for the Clinton-Newbury fault zone.   To further explore this subject, excellent publications or the resources of the internet can be explored.   Following are some hyperlinks that may help with the evaluation and description of faults:

• Historical Perspective – Pangaea, Laurentia, and Gondwana (U.S. Geological Survey website):  Website that explains Plate Tectonics and the evolution of Supercontinents.

• Gondwana (MSN Encarta Encyclopedia website):  Website with associated graphics and links describing Gondwana (or Gondwanaland) and the role played by plate tectonics.

• What is a Fault? (Berkley Seismological Laboratory):  Website describing the various types of faults and providing a number of useful informational links.
• Faults (University of Leeds, School of Earth and Environment, UK):  Material describing faults and faulting with pictures and drawings.   Based on information presented in their first year course in structural geology.
• A Model of Three Faults (USGS Website):   Educational information about faults, faulting, and tectonics with many hyperlinks to descriptive information.
• Earthquake Watch - Current information based on earthquakes reported to the USGS in the last 24 hours and information about recent earthquakes.

• USGS maps, products, and publications - Online information resource on the U.S. Geological Survey website.