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ILÍMAUSSAQ - A brief introduction
On the rocky
edge of this barren gray mountaintop it’s hard to hide from
arctic sun. Late afternoon on this mid-July day an eerie light, dim and evenly cast, seeps into
everything. I grab a
makeshift tarpaulin and escape under it to inspect our latest find,
in darkness.
Here, under this
extra-large black barbeque grill cover, it’s as dark as night should
be—just a thin rim of light along the bottom betrays external
reality. A few minutes wait, eyes adjust to darkness, and our portable
ultraviolet lamp is switched on.
Instantly the cold
gray rocks at my feet explode in brilliant color: Ilímaussaq’s
fluorescent minerals.
I’ve traveled 3,000
miles from home in sunny Florida to be here—Greenland—in search of these special rocks.
When struck with
invisible ultraviolet radiation (UV), they emit light—colored light;
‘fluorescing’ in response to the unseen UV. Viewed in the dark, they
are suddenly beautiful: a range of brilliant reds, pinks, oranges,
greens, and blues; soft pastel mixtures in spots and streaks; an
endless variety of striking, luminous patterns.
Now, spread out
before us inside my makeshift dark room, they glow vividly. I’m on
the last of a 10-day mineral collecting trip to Ilímaussaq and this
final catch is among our best.
GREENLAND & ILÍMAUSSAQ
 Home to only
56,000 people, and much ice and snow, Greenland—earth's largest
island—is also home to the Ilímaussaq alkaline complex.
An unusual type of igneous intrusion,
the 1.2 billion year old complex covers roughly 150 square
kilometers near the southwest coast of Greenland.
Click on this photo for a better view
At its
surface the Ilímaussaq complex is split in two by the deep blue
waters of Tunulliarfik fjord. Below, exploratory drilling has yet to
find its bottom.
Named for a
prominent neighboring mountain, geologists have been attracted to
the Ilímaussaq complex since the 19th century, when early
visitors first noticed its unusual formations.
Little grows here—the
landscape stark; the peculiar alkaline rock crumbly, friable.
Within the complex the ground is colored in gray and rust hues. For
most of the year Ilímaussaq is also exceedingly cold and
snow-covered. It presents an alien environment.
In the 1950s,
scientists from Denmark pioneered a detailed exploration and study
of this intrusion of igneous rock. Joined by colleagues from Russia,
Germany, and the UK, a vast body of
scientific literature was
published in succeeding years.
Ilímaussaq’s
unusual chemistry—these are among the most sodium-rich igneous rocks
known—also includes large stores of the metals zirconium, niobium,
uranium, thorium, and beryllium. In fact, nearly half the periodic
table can be found in the 200-plus mineral species reported from
Ilímaussaq—easily the most diversely mineralized in Greenland.
Ilímaussaq’s fluorescent mineral treasures are considerably
less-well known, however..
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