terragraphica
Azores Geology
Azores schematic geology. ©1999 V.H. Forjaz in: Atlas Básico dos Açores, 2004
This schematic shows a fan-shaped triangular microplate with its point of origin east of Santa Maria Island in the Azores-Gibraltar fault zone.
The "feather-pattern" of these long SE-NW trending fractures may be related to a left-handed rotation of the African tectonic plate. Fractures between the "fan blades" would tend to open progressively from E to W and thus allow for the emplacement of today's Azores Islands.
New oceanic crust is being added continuously by the Mid-Atlantic Ridge (MAR) spreading zone to the western end of the fan blades.
This schematic predates more recent suggestions of short sections of MAR being displaced over several hundred kilometers and observable on São Miguel Island among other places (see: Ron Redfern, 2000/2002, ORIGINS, The evolution of continents, oceans and life). An alternative explanation for short staggered "spreading sections" may be the existence of a conjugate set of northerly-trending feather fractures allowing for local extensional regimes.
JT 2007
Azores Geology
Azores schematic geology. ©1999 V.H. Forjaz in: Atlas Básico dos Açores, 2004
This schematic shows a fan-shaped triangular microplate with its point of origin east of Santa Maria Island in the Azores-Gibraltar fault zone.
The "feather-pattern" of these long SE-NW trending fractures may be related to a left-handed rotation of the African tectonic plate. Fractures between the "fan blades" would tend to open progressively from E to W and thus allow for the emplacement of today's Azores Islands.
New oceanic crust is being added continuously by the Mid-Atlantic Ridge (MAR) spreading zone to the western end of the fan blades.
This schematic predates more recent suggestions of short sections of MAR being displaced over several hundred kilometers and observable on São Miguel Island among other places (see: Ron Redfern, 2000/2002, ORIGINS, The evolution of continents, oceans and life). An alternative explanation for short staggered "spreading sections" may be the existence of a conjugate set of northerly-trending feather fractures allowing for local extensional regimes.
JT 2007