Physical Geology 2003











Norumbega Fault System:

Maine's Transform Fault Boundary

The Norumbega Fault System runs through mid-coastal Maine (starting just south of Penobscot Bay) and cuts south through Massachusetts. This fault system was created from a mid-crustal zone of transpression that occured during the middle of the Devonian. It has since "evolved" to an upper crustal zone of strike-slip faulting which occured during the late Carboniferous and early Permian periods. Norumbega is also the Paleo-Indian name for the State of Maine.

Exposed rock formations along the NFS located in Palermo, Maine.


The Origin of the Norumbega Fault System (NFS)


Just by looking over the landscapes of Maine, one can tell of the geologic significance that takes place here. The end of the visible Appalachian Mountains, an incredible number of lakes and rivers, and a rocky coast that equals half of the entire eastern coast line of the United States.The Norumbega Fault zone occurred due to continental drift and accretion. During the late Paleozoic period the Gondwanan plate (a piece of the African continent) collided with the North American plate. The place at which these two plates converged (the Gondwanan and the Laurasian plates) created the fault line the now runs through Maine, New Hampshire, Massachusetts, and is believed to end in Connecticut. A similar, more well-known, fault system in the United States comparable to the Norumbega is the San Andreas Fault zone. The San Andreas Fault bounds the North American plate with the Pacific coninental plate.




Geologic Layout of Maine:

Maine is a very diverse in terms of it's geology and rock base. Here is a link that displays this diversity ....... surficial map



Focused Location Along NFS:

Palermo, Maine

Palermo, Maine is a small rural community about 30 minutes east of Augusta (the state capital). Palermo is the centered focus of the NFS in Maine due to its excellent stratographic exposure. The NFS has two primary rock types exposed at this location, which make it easy to see the divided fault line. On the western side of the rock lies the low-grade metamorphic rock phyllite is present, and across the fault on the eastern side is the high-grade metamorphic rock gneiss.

There is not enough knowledge of the Norumbega Fault System (NFS) to know exactly everything involved. The following is what is considered a "well-known" theory, and is based on the information provided by the students and faculty at Unity College via web page posted below.

The NFS is a large fault zone that extends down through southern/southeastern Maine, and looks to have geologic impacts through New England. The most well established theory of how the NFS was initially created is the belief that it was the collision grounds of the North American sub-continent tectonic plate and the Avalon sub-continent plate over 44 million years ago.

The different rock types represented in the fault show the stratographic present in each of the plates that collided. Phyllite is present in the Avalon side of the fault. The NFS is also known to be a thrust fault (due to horizontal compression). This is shown by the hanging wall rock being the gneiss -- having reached a higher temperature; and the footwall being the phyllite -- being stable at lower temperatures.



The geologic impacts of the NFS are great in certain aspects. It has helped verify the existence of plate tectonics by giving visual references to sub-continent adhesion. In it's relationship to humans, the NFS poses little harm to it's surrounding environment. This fault has been dormant to seismic activity for millions of years.

Literature Cited
MARPLE, Ronald T.,
Possible Southwestward continuation of the Norumbega Fault System Beneath the Southern New England Fold-Thrust Belt
Dr. Allan Ludman
G.S.A. Special Paper 331: The Norumbega Fault Zone
The significance of the Norumbega fault zone in southwestern Maine:
clues from the geochemistry of granitic rocks
The Norumbega Fault Zone in Palermo
Unity college geo students
USM Lab Takes Global Tools to the World
University of Southern Maine

Callahan, Caitlin N. and Markley, Michelle. “Tectonic significance of igneous foliation and lineation in the Mount Waldo Pluton, Waldo County, Maine” Abstracts with Programs – Geological Society of America (November 2001, Vol. 33, Issue 6, pp.332) November 2001.

Ludman, Allan, and David P. West eds. Norumbega fault system of the northern Appalachians. Geological Society of America, 1999.

Bradley, Dwight, et al. “Late Silurian to Middle Devonian migration of the Acadian deformation front across Maine.” Abstracts with Programs – Geological Society of America. February 1998. 30:1, pp.7.



Author: Brian J. Bucher
Creation/revision date: 07 April 2003

earlham college geo students webpages

This website is part of a Geology 211 class project on Processes in Physical Geology.

Earlham · Geosciences Department · Geociences 211: Physical Geology

Copyright © 20031 Earlham College. Revised 25 February 2003. Send corrections or comments to brian bucher