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[Illustration: uncaptioned]
NORRIS GEYSER BASIN
The Norris Geyser Basin was named for Philetus W. Norris who served as
Yellowstone’s second superintendent from 1877 until 1882. Although he
did not discover it, his explorations and reports were largely
responsible for calling attention to that area.
Norris is considered to be the hottest and most active geyser basin in
Yellowstone. Here geysers and hot springs exhibit greater change in
activity over a short span of time than elsewhere in the park. It is not
unusual for a new hot spring to come into existence literally overnight.
The new feature may last for just a few days or perhaps a month or so;
upon occasion some have endured for many years.
Because of constant change in the thermal features, the ground here is
unstable and hazardous in many locations. Therefore, you are required to
stay on designated trails and boardwalks at all times. This not only
protects you from possible serious burns but also helps preserve the
features as well. Remember also not to throw any objects into thermal
features. Debris of any kind in a hot spring or geyser could clog the
vent and destroy the feature. Because many scalding hot pools and
run-off channels are near trails and boardwalks, pets are not permitted
on the trails.
The fact that thermal features change may come as a surprise, but
remember that geysers, hot springs and other thermal phenomena are
subject to natural stresses just like plant and animal communities. Of
course the changes in thermal activity result from a different set of
factors than those affecting plants and animals. Can you guess what they
might be?
Shifts in the earth’s crust (earthquakes) result in movements along
cracks and fissures in the ground. These tremors usually cause changes
in the underground “plumbing systems” of thermal features, thus altering
activity patterns. Look for signs of recent activity variations as you
walk along the trails, or ask a naturalist if there have been some
recent changes.
As you explore, look closely at the often intricate formations around
the edges of a few hot pools, geysers and in some thermal runoff
channels. You will notice a mineral called sinter or geyserite (a form
of silicon dioxide, SiO₂) being deposited like tiny spines. These rather
prickly formations result when geyserite is deposited from slightly acid
water, a characteristic of most thermal water in the Norris area. This
is in contrast to the bead-like structures that result when geyserite
forms from slightly alkaline water found in thermal features in the Old
Faithful area.
Notice too the variety of colors staining the basins. The refraction
(breaking up) of light, mineral deposits and living organisms, algae and
bacteria, all add their hues. The assortment of colors reflects
variations in water temperature and chemistry.
As you enjoy your walk remember that Norris is a great natural preserve
where nature is constantly at work designing and redesigning one of its
most unusual displays. We are only visitors here and must not spoil it
in any way. It also serves as a great natural research laboratory where
scientists from all over the world learn more about geothermal energy.
Help us preserve this unique area so that the next generation and those
who follow can come and enjoy it in the same grandeur you did.
The Norris Geyser Basin is made up of two or more less separate areas
called Porcelain Basin and Back Basin. Both basins are served by trails
which begin at the Norris Museum and are shown on this map. The
following briefly describes a few features in each.