Kinematic problem of oblique rift zones in Iceland

Conference · Tue Jan 01 00:00:00 EST 1985 · Geol. Soc. Am., Abstr. Programs; (United States)

OSTI ID:6462142

Jancin, M

Regional distribution of surficial isochrons on Iceland locally lacks the oceanic-ridge subparallel alignment that is characteristic of the adjoining North Atlantic sea floor. Strikes of Icelandic lava isochrons generally reflect dips imparted by continued lava accumulation, subsidence, and burial. The angle between trends of central volcano-related fissure swarms, dikes, and faults, and regionally-adjacent approximate isochrons, defines the Obliquity Angle (OA). The OA is measured from the isochron to the extensional structures, and may vary from 0/sup 0/ to 90/sup 0/; cw angles are (+), ccw (-). Three large-OA neovolcanic zones are present in Iceland: the WNW-trending zone is central Iceland; the ENE zone along Reykjanes peninsula; and, possibly, the WNW and largely submarine Tjornes Fracture Zone (TFZ). The TFZ shares characteristics of a highly-oblique rift zone and a transform-related shear zone. In north-central Iceland, OA's along 7-11 Ma isochrons vary continuously from +40/sup 0/ to 90/sup 0/ to -50/sup 0/, over 130 km from West to East. As subaerial isochrons on Iceland range up to 90/sup 0/ to spatially-associated extensional structures, isochron trends locally parallel presumed plate-flow lines (N8OW); offshore, isochrons are approximately normal to flow lines. However extension in central Iceland occurs within the long-lived, WNW-trending oblique rift zone, with little or no commensurate extension and volcanism parallel to structural strike to the South and North, constitutes a major kinematic problem.

• Research Organization: Georgia Southwestern College, Americus (USA)
• OSTI ID: 6462142
• Report Number(s): CONF-8510489-
• Journal Information: Geol. Soc. Am., Abstr. Programs; (United States), Vol. 17; Conference: 98. annual meeting of the Geological Society of America, Orlando, FL, USA, 28 Oct 1985
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
ICELAND
PLATE TECTONICS
RIFT ZONES
GEOMETRY
ORIENTATION
GEOLOGIC FAULTS
LAVA
OCEANIC CRUST
SUBDUCTION ZONES
VOLCANISM
VOLCANOES
DEVELOPING COUNTRIES
EARTH CRUST
EUROPE
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
ISLANDS
MATHEMATICS
TECTONICS
WESTERN EUROPE
580201* - Geophysics- Seismology & Tectonics- (1980-1989)