Accession Number : ADA204875

Title :   Multidisciplinary Geophysical Study of the Earth's Upper Structure.

Descriptive Note : Final rept. 1 Jun 85-31 Oct 88,

Corporate Author : BOSTON COLL CHESTNUT HILL MA

Personal Author(s) : Skehan, James W ; Devane, John F ; Kafka, Alan L

PDF Url : ADA204875

Report Date : 27 Dec 1988

Pagination or Media Count : 51

Abstract : Investigations were made of: 1) Geophysical properties of the shallow crust underlying the Appalachians of southern New England by means of dispersion of Rg waves and electromagnetic methods; and 2) Deeper geological structure by interpretation of multichannel seismic reflection lines in the onshore and offshore portions of New England. Major contributions include: (1) Southern New England has been subdivided into Rg wave dispersion regions and correlations with tectonostratigraphic divisions of the region were established. (2) Electromagnetic studies, and analysis of existing aeromagnetic maps, suggest that major fault zones in eastern MA constitute part of a series of stacked thrust faulted duplexes. (3) Analysis of multichannel seismic reflection lines collected by the USGS in the Gulf of Maine and on the Long Island Platform gave rise to revisions of previous interpretations of the large scale geology of the region. Revisions include our interpretation that the Fundy Fault of the Bay of Maine should be correlated with the Blue Hills fault south of Boston that is traced and/or extrapolated through Rhode Island as an easterly dipping thrust fault, the newly mapped Smithfield fault zone of Alleghanian or early Permian age; (4) Large scale overthrusting and underthrusting was produced throughout the region as a result of continent-island arc, island arc-island arc, and continent-continent collisions; and the resulting structures have been modified by those produced by rifting tectonics. (edc)

Descriptors :   *FAULTS(GEOLOGY), *STRUCTURAL GEOLOGY, DISPERSING, EARTH CRUST, ELECTROMAGNETIC PROPERTIES, ELECTROMAGNETISM, FUNDY BAY, MOUNTAINS, SEISMIC REFLECTION, MULTICHANNEL, RAYLEIGH WAVES, TECTONICS, STRATIGRAPHY, MAGNETIC PROPERTIES, GEOPHYSICS, ISLANDS, MAINE GULF, METHODOLOGY, NEW ENGLAND, OFFSHORE, REGIONS, RHODE ISLAND, SHALLOW DEPTH, SHORES, STACKING, TECTONICS, THRUST, SEISMIC WAVES

Subject Categories : Geology, Geochemistry and Mineralogy
      Seismology

Distribution Statement : APPROVED FOR PUBLIC RELEASE