ICELAND Its about the size of Virginia Iceland

ICELAND (It’s about the size of Virginia)

Iceland is literally being pulled apart at a rate of about 1 inch per year. (Molten rock continually erupts from fissures and volcanoes to fill the gap. )

In addition, Iceland is sitting on top of a major HOT SPOT

Iceland Hot Spot Track

th 9 Since the century about 150 eruptions have been documented. (Most have come from fissures, not volcanic mountains. )

Iceland is the only place on earth where both a mantle plume and a mid-ocean ridge can be studied on land.

v. Volcanoes here usually develop at the centers of large swarms of fissures.

v. Volcanoes here usually develop at the centers of large swarms of fissures. v. Iceland’s volcanoes tend to erupt explosively because their magma is not very fluid.

Iceland was settled in the century AD. Since then…. th 9 There have been two or three eruptions per century with a VEI of 4 to 5. These eruptions have greatly affected Iceland’s population and its culture.

Laki Fissure Zone Eruptions of 1783– 1784 § § § Began June 8, 1783 Continued for 8 months Fissure zone 27 kilometers long 130 -140 individual vents (spatter cones) Dust and gases dispersed over most of Europe through February 1784

Chain of volcanic spatter cones above the Laki fissure

Laki 1783 continued…… § § Groundwater mixed with basalt magma brought on phreatomagmatic explosions Enormous clouds of hydrofluoric acid and sulfur-dioxide were released Basalt lava ejected exceeded 14 km 3 Lava fountains reached heights of 4, 600 ft, convective gas columns reached 10 miles

Laki 1783 continued…… § In 8 months it produced enough lava flow to bury all of Manhattan 800 feet deep! § Largest atmospheric pollution event in past 250 years.

Consequences to Iceland… 1. Over 50% of livestock died

Consequences to Iceland… 1. Over 50% of livestock died 2. 25% of population died from poisoning and famine

FLUORINE POISONING (Underground magma chamber had been rich in fluorine) 2, 700 square miles of pasture and farm land was heavily salted with fluorine. Grazing animals that ingested the ash developed fatal hemorrhages or severe bone and teeth deformations. Most died. With no sheep for meat, cattle for milk, or fish from poisoned rivers the livelihoods of whole communities collapsed.

Air pollution from Laki… Almost 120 million tones of sulfur dioxide was emitted, three times annual European output in 2006. Caused thick haze over Europe for about 1½ years

Consequences to world… 1783 hottest year on record in Europe. Fog was so thick that in summer 1783 most boats had to stay in harbors. Estimated 20, 000+ deaths in Europe from poisoned air. Winter 1784 most severe. England had 28 days of consecutive frost. Ice in frozen waters of Baltic and North Atlantic prevented fishing fleets from leaving port.

Consequences to world… Fall 1783 crops were affected world-wide. Mean temperatures remained below normal throughout 1784 and 1785. In Europe the winter of 1783 -1784 was coldest in 250 years (approx. 4 deg F below average every day). Crops in 1784 were greatly reduced. Affects on rainfall may have been to blame for famine in Egypt, killing one-sixth of its population. Some experts believe a famine in Japan in 1784 had the same root cause.

Consequences to USA… Baltimore harbor was sealed by ice from Jan. 2 to March 25 1784. There were ice jams in Virginia’s James River at Richmond. Ice flows were common in the mouth of the Mississippi at New Orleans.

ENGLAND 1783 -1784 Burial Records Autumn 1783: 40% higher mortality rate (=11, 500 “excess” deaths) Jan/Feb 1784: 30% higher mortality rate (= 8, 200 “excess” deaths) Read from pg. 289 of ERTSUTW

NO ONE WILL EVER KNOW HOW MANY DEATHS ARE ATTRIBUTABLE TO THE ERUPTION OF LAKI. ESTIMATES RANGE FROM THOUSANDS TO MILLIONS!

Letter from Mozart to his father on Feb. 10, 1784…. “……. I have just one more question to ask, and this is, whether you are now having in Salzburg such unbearably cold weather as we are having here (in Vienna)? ”

The Laki eruption illustrates that low energy, large volume, long duration basaltic eruptions can have climatic impacts greater than large volume explosive silica-rich eruptions. The sulfur contents of basaltic magmas are 10 -100 times higher than silica-rich magmas (Palais and Sigurdsson, 1989). (Think Hawaii!!!)