Icelandic rocks could have steered Vikings

BBC ^ | November 1, 2011 | Jennifer Carpenter

[decimon]

Vikings used rocks from Iceland to navigate the high seas, suggests a new study.

In Norse legends, sunstones are said to have guided seafarers to North America.

Now an international team of scientists report in the journal the Proceedings of the Royal Society A that the Icelandic spars behave like mythical sunstones and polarise light.

By holding the stones aloft, voyaging Vikings could have used them to find the sun in the sky.

The Vikings were skilled navigators and travelled thousand of kilometres between Northern Europe and North America.

But without a magnetic compass, which was not invented until the 13th Century, they must have relied on other navigational aids.

[decimon]

Sunstones are found in Norway, Canada and Russia; once polished they are used in jewellery

[decimon]

Ping

Not new but maybe confirming.

[muawiyah]

At the same time SOME PEOPLE can detect polarized light without the assistance of lenses or sunstones (as they are called). Try: http://www.polarization.com/haidinger/haidinger.html

[Graewoulf]

I read the article, but did not find what an” Icelandic Spar” was. Do you know?

[DManA]

When I was in 6th grade (early 60s) I did a report on the Vikings. It included a bit about how they navigated with sun stones.

[ApplegateRanch]

Iceland spar is a clear, crystalized form of calcite. It is best know for its property of double refraction.

[Ciexyz]

I did research on this topic and it's quite interesting that the Vikings could navigate even on cloudy days with no sun to guide them, with the aid of a sunstone.

[ApplegateRanch]

It is fascinating, especially since they first had to find Iceland; then find the crystals; then.... *<];-’)

[Graewoulf]

Thanks! Another great, and useful compound filled to the brim with CO2! (CaO+CO2).

[SunkenCiv]

GGG managers are SunkenCiv, StayAt HomeMother & Ernest_at_the_Beach	join list or digest view topics view or post blog bookmark post a topic subscribe
Thanks decimon. By the same token, fieldstones help navigate fields. To all -- please ping me to other topics which are appropriate for the GGG list.

[Bernard Marx]

The term "sunstone" is a bit confusing to those like me who work with minerals. It generally refers to a type of gem-quality labradorite or andesine feldspar found in Oregon, India and Tanzania mainly. Optical calcite is very different stuff. In the referenced article the name refers to any mineral used by the Vikings to locate the sun for navigation purposes.

It's long been believed that the mineral iolite (cordierite) was used for Viking navigation. A friend who comes from strong Nordic roots and is an accomplished gemologist/mineralogist put together this nice explanation on her website: Viking Sunstone

[decimon]

Thanks.

[ApplegateRanch]

Thanks. It’s been over 40 years since I took my introductory mineralogy classes; and never kept it up.

I always think of “sunstones” as those artificial glass teardrop things filled with bronze or copper fillings.

[Bernard Marx]

"Sunstones," at least the type from Oregon, can be strikingly beautiful. They feature a type of labradorite feldspar that contains copper in varying amounts. The best occur in saturate reds, greens or a combination of the two colors. Many show an optical effect called "schiller," an almost metallic sheen caused by nearly invisible aligned particles in the stones. The ones from India and Tanzania feature bright spangles, sometimes multicolored, resulting from light bouncing off crystal inclusions in the stones.

Go here for images of various sunstones: Sunstone Images

[ApplegateRanch]

Thanks for the link!

[Bernard Marx]

My pleasure!

[TheOldLady]

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[ApplegateRanch]

Lakeview, Oregon: Sunstone (Feldspar) Gem Mines

The arid south-central portion of Oregon is a classic volcanic region. There the relatively young rock consists of dark basalts, andesites, rhyolites, ash and cinders. Millions of years ago a magma chamber several miles below the surface supported the correct geochemical conditions for the growth of labradorite, a calcium-rich plagioclase feldspar. ... http://www.mtlilygems.com/mineinfo/plshinfo.html

The Yellowstone hot pocket?

[Bernard Marx]

The Yellowstone hot pocket?

I'm not sure. If you look at a map of Idaho you an see a long volcanic scar across the southern part of the state called the Snake River Plain. It's a huge jumble of basaltic lava flows and the location of the other-worldly Craters of the Moon National Monument. Current theory suggests it's the result of the American plate moving westward over the Yellowstone Hot Spot (which remains stationary.) It's a process that seems to be continuing.

Oregon and the West Coast in general have seen plenty of volcanic action and it's going to continue. I have a hunch the sunstone region is more likely the result of volcanism related to subduction of the Pacific Plate under the American plate. Subducted rock forms magma chambers resulting in active volcanoes like the Three Sisters at Bend, Mt. St. Helen's, etc., extending south to Lassen and Shasta in California and all the way to the tip of Chile.

We're lucky to live in a time when those Ring of Fire volcanoes are relatively inactive. Think of what it would have been like if we'd been around when the Columbia Plateau Flood Basalts were forming! Columbia Plateau

[ApplegateRanch]

Nope; wouldn’t be the Hot Spot. McDermitt Caldera is the one I was thinking of, but that is over 100 miles east of Lakeview; about 175 miles ESE of the sunstone fields in that link. That entire region is volcanic, one way or another.

And, no; I would not have wanted to be anywhere even half way near any flood flows. We had andesite flows in the Medford area, most notably visible as Upper & Lower Table Rock.

We used to drive across central & south eastern Oregon a lot. The state/counties have pits where they dig, screen, & stockpile red lava gravel, mainly for ‘sanding’ the roads in winter. Those deserted pits also make decent ‘pit stops’, during some of which we picked up a life time supply of bath-grade grey pumice stones.

Loved our visit to Craters of the Moon.