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Magmatic fissures and their systems in Iceland: A tectonomagmatic model
Author(s) -
Tentler Tatiana,
Temperley Stephen
Publication year - 2007
Publication title -
tectonics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.465
H-Index - 134
eISSN - 1944-9194
pISSN - 0278-7407
DOI - 10.1029/2006tc002037
Subject(s) - geology , volcano , seismology , tectonics , fissure , echelon formation , rift , fault (geology) , subsidence , petrology , geomorphology , paleontology , structural basin
Volcanic systems in Iceland comprise a central volcano linked to magmatic fissures, whose subsurface architecture remains enigmatic. The surface dimensions and trends of active fissures show their spatial relation with fault systems. Structure of the Fremri‐Namur and Hengill volcanic systems was analyzed. The linear vent arrays marking recent fissures are tightly bound by vertical segmented faults, while normal faults accommodating extension are common on the flanks of the fissure swarm. Evidence of normal frictional slip on the fissure‐bounded faults suggests that failure occurred in response to subsidence with subsequent dilation. This is supported by inward tilting of strata adjacent to faults compatible with a downsag phase. We propose that magmatic fissures have vertical feeders with lateral offshoots extending along the rift zone. Their inflation/deflation during an eruptive cycle causes subsidence. Such magmatically generated faults can be subsequently modified by tectonic extension.