Geology Home Page physical geology historical geology planetary gems
Roger Weller, geology instructor
by Selina Moore
The Origin of Tektites
Tektites are pieces of natural glass, ranging in sizes as small as
specks to larger blocks. Tektites are usually black but some (very few) have
been found in yellow or green.
Few are transparent
to translucent, but most are nearly opaque. Their hardness is 5-6 and most
Tektites are found in Australia, also known as Australites. Although there have
been many theories and arguments of the Origin of Tektites, the question still
remains; where did they come from?
One of the first theories was said that Tektites were obsidian that
had been launched from the Moon to the Earth due to lunar volcanism. However,
soon scientist learned craters in the moon are an impact from meteorites and
lava only exists in the core of the moon.
Now the Lunar theory suggests Tektites are pieces of rocks from the
moon that have been launched to the Earth due to the impact of meteorites. Once
the rocks entered the Earth’s atmosphere, they began a melting process which
gave the Tektites their distinct shape.
Some argue against the lunar theory because during the Apollo mission samples of the Moon’s soil were brought back and did not match the chemical composition of Tektites.
The Terrestrial Origin came about because the chemical composition of Tektites matches some of the rocks found in the Earth’s crust. Some scientists believe after a comet or asteroid struck the Earth molten blobs were splashed out of the Earth’s atmosphere and fell back down at high velocity. The argument against the Terrestrial Origin is that there has never been an appropriate impact crater to account for all of the Earth’s tektite fields.
One thing scientists can agree on is how Tektites obtained their
shape. The shape is explained by two heating events; the first created the
glass and the second is from the object entering the Earth’s atmosphere at such
a high velocity.
Other factors that come about when determining the origin of
Tektites is that most Tektites have been dated at 700,000 years which implies
they originated from one big event. However, there are still some Tektites that
are dated at 4 million years. Tektites also show evidence that they were not in
space for a long period of time. Another factor is that Tektites are found in
very concentrated patches instead of being spread out.
The earliest discovery of Tektites dates back to the late 1700’s, after all the years of study the true origin of Tektites is still unknown. The true origin may never be discovered, but to some part of the beauty of Tektites is because the mystery behind them.