Travel Reference
In-Depth Information
GLOSSARY
NOTE: Terms in
boldface
are defined in this glossary. Consult the index for terms not covered here that
may be defined in the text.
algae.
Aquatic non-vascular plants or plant-like organisms, now included in the Eukarya group.
alum.
Potassium aluminum sulfate, a chemical used in medicine to contract blood vessels or tissues.
Archaea.
One of the three main groups of organism, distinct from
Eukarya
and
Bacteria.
Archaea are
single-celled, and their cells lack nuclei. Their membranes differ from all other organisms.
arsenic sulfide.
One of the poisonous compounds of the grayish-white element arsenic.
bacteria.
Single-celled microorganisms varying in shape, metabolism, and ability to move.
basalt.
A type of volcanic rock or
lava
that is relatively low in
silica,
allowing it, when molten, to low
easily; it is high in iron, which turns it black.
butte.
A medium-sized, isolated, flat-topped, and steep-sided hill in an arid region.
calcium carbonate.
The chemical compound found in shells and some bones; used as a gastric antacid.
caldera.
A large circular or elliptical crater or depression formed by the collapse of a large land area after
the emptying of a
magma
chamber in a massive volcanic explosion.
carbon dioxide.
An odorless, colorless gas; an excessive amount replacing oxygen in the air can suffocate
animals.
cirque.
A steep-sided natural amphitheater gouged out by glacial ice on the side of a mountain.
cone-type geyser.
A
geyser
that erupts in a steady column of hot water from a narrow vent. The water
cools, precipitates
hydrous silicon dioxide,
and forms a cone. Compare with
fountain-type geyser.
Continental Divide.
A highland of North America, separating water that eventually flows into the Pacific
Ocean from that which flows into the Gulf of Mexico.
crinoid.
A type of ancient ocean plant with a cup-shaped body and a slender stem, related to today's star-
fish and sea urchins and helpful in dating fossils. Also called a sea lily.
dike.
A thin tabular sheet of igneous rock that cuts across preexisting rocks, squeezing into those rocks
when molten, then cooling and solidifying below ground. Compare with
sill.
dome.
In geology, an uplifted area, circular in outline. Also called resurgent dome.
drainage divide.
The boundary between two areas that contribute water to a stream or lake.
Eukarya.
Single- or multi-celled organisms whose cells contain a distinct membrane-bound nucleus.
exchange of function.
Underground connection among
geysers
or
hot springs
so that the activity of one
affects the behavior of the other. Examples are found at Fountain Paint Pot and Upper Geyser Basin.
exclosure.
An area fenced off by botanists to exclude all large browsing animals and then compare the
enclosed area with its surroundings.
explosion crater.
A feature found in volcanic terrains. A sudden pressure drop causes hot water to flash
into steam and blast a hole in Earth's surface.
extremophile.
A living being that can live and reproduce in extreme environments, such as very acidic
and very hot ones.
fault.
A fracture in rock where the two sides have moved past each other.
fissure.
A crack in rock along which there is a distinct separation.
