volcano.si.edu...The last historical eruption of Eyjafjallajökull prior to an eruption in 2010 produced intermediate-to-silicic tephra from the central caldera during December 1821 to January 1823...Image:Halldor Kolbeins near Reykjavik
The Mid-Atlantic Ridge was central in the breakup of Pangaea that began some 180 million years ago... Now massive tectonic actions; bordering several continents... VIEW.
Today's volcanic spew forms scab (incrustation) to heal rifting (spread) of fissure zone running through Iceland... As situated on the tectonic plate boundaries... Image: [Enlarge] NASA NAV-TEQ
(More geological history of the 40,000-km-long bathymetry of valleys & ridges (below)
And a lovely view of the Þingvellir area, in this video (below) taken 8 months ago... You can see the faults and fissures of the area which make evident the rifting of the earth's crust...
Pierre on Vimeo.
On travel (in U.S.) today... Will post more later-on...
Today's Links...
Ridge System Theory Dates:
-1850: Inferred by Matthew Fontaine Maury.
-1872: Charles Wyville Thomson led expedition of HMS Challenger while seeking future location for transatlantic telegraph cable
-1925: Confirmed by Sonar; 40,000-km-long bathymetry of valleys & ridges
-1950’s: Mapping Bruce Heezen
and Marie Tharp crew found seismologically active central valley being and the epicentre of many earthquakes
