Avalon terrane in eastern coastal Maine: Seismic refraction-wide-angle reflection data

Journal Article · Sat Sep 01 04:00:00 EDT 1990 · Geology; (USA)

DOI:https://doi.org/10.1130/0091-7613(1990)018<0878:ATIECM>2.3.CO;2· OSTI ID:6212689

Luetgert, J ^[1]; Mann, C E ^[2]

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1. Geological Survey, Menlo Park, CA (USA)
2. Stanford Univ., CA (USA)

A 145-km-long seismic refraction line recorded parallel to the eastern coastline of Maine within the Avalon terrane provides information about the crustal velocity structure within the Avalon block and its relation to other Appalachian terranes. A crustal velocity model for the upper 8 km, determined by using two-dimensional ray tracing, accounts for all first arrivals on the traveltime curves for each of the shots recorded and shows that, except for a thin surficial layer of velocity 5.0-5.3 km/s, upper crustal granites and country rocks have velocities in the range 6.0-6.3 km/s and gabbros have a 6.5 km/s velocity. To determine the lower crustal structure, deep reflections were analyzed by applying normal moveout corrections routinely used in reflection data processing. Major reflective boundaries at approximately 3-4, 7, and 10-11 s two-way traveltime are easily distinguished, and are similar to those observed in a near-vertical seismic reflections survey crossing the refraction profile at its southwestern end. The deepest reflections correspond to the crust-mantle boundary at a depth of 34-35 km.

• OSTI ID: 6212689
• Journal Information: Geology; (USA), Journal Name: Geology; (USA) Vol. 18:9; ISSN GLGYB; ISSN 0091-7613
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
BOUNDARY CONDITIONS
CONTINENTAL CRUST
EARTH CRUST
EARTH MANTLE
FEDERAL REGION I
GABBROS
GEOLOGIC STRUCTURES
GEOPHYSICAL SURVEYS
GRANITES
IGNEOUS ROCKS
MAINE
NORTH AMERICA
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
PLUTONIC ROCKS
REFLECTIVITY
REFRACTIVITY
ROCKS
SEISMIC SURVEYS
SEISMIC WAVES
SURFACE PROPERTIES
SURVEYS
TWO-DIMENSIONAL CALCULATIONS
USA
WAVE PROPAGATION