An Adduction Zone - A Precursor to a Subduction Zone

JACOBEEN, FRANK H., JR., Locust Grove, Virginia

("ADDUCT-to pull or draw toward the main axis", The American Heritage Dictionary.)
A precursor to a subduction zone is shown to be present along the east coast of the United States. This zone is named an ADDUCTION ZONE. It is shown that the so-called passive margin of the eastern North American continental plate is actively undergoing compression that is the initial phase of subduction. Evidence of this process and the theory for the development of this stage in the tectonic development of a subduction zone is presented.
An ADDUCTION ZONE is defined as a zone of depression in an oceanic plate, at or near the seaward edge of a sedimentary wedge, where the plate is initially pulled or drawn downward from its relatively horizontal attitude. If this process continues, it is concluded that a plane will develop along which a shearing movement ultimately occurs and a subduction zone is created.
 

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