Dr. Charles R. Bacon of the United States Geological Survey
August 23, 2003
[Award Comments by K. Rodney Cranson]
It was a hundred and seventeen
years ago this month that the first organized geologic party
conducted field work at Crater Lake. Just a few hundred
meters east of here a boat was lowered onto the lake to
begin soundings. Their technology was basic - a heavy weight
and a spool of piano-like wire lowered into the water along
with ‘spotters’ stationed at strategic locations to fix the
The results of this first investigation,
however, were startling! A maximum dept of more than 600 meters (nearly
2,000 feet) was discovered - one of the deepest in the world. United States
Geological Survey geologist Clarence Dutton lead this first research party
aided by William Steel who conducted the lake survey. As word of this
work spread, interest in Crater Lake grew rapidly.
Some ten years later another USGS party began
field studies. This group led by geologist J.S. Diller and H.B. Patton used
technology available to analyze the rocks and piece together the geological
history of a volcano that stood where Crater Lake is now located. The
outcome of their work established that this mountain’s summit had collapsed
to form the basin that now holds Crater Lake. William Steel’s mountain
climbing club, The Mazamas, also played a roll during this period when they
gave their name to that mountain.
The first comprehensive formal report on
the geology o Crater Lake was published in 1902, the same year that
Congress created Crater Lake National Park. It was the seventh National
Park established, a fore-runner of nearly 400 areas that now make up the
National Park System.
While geological studies continued at
Crater Lake during the next four decades, the next major work began in
the late 1930s. Dr. Howel Williams, a prominent geologist at the
University of California, initiated field work based on much better
understandings of how volcanoes behave and improved technology. He spent
several summer seasons in the park and surrounding region. William’s
results, sponsored by the Carnegie Institute of Washington D.C., was
published in 1942 as The Geology of Crater Lake National Park, Oregon.
In this classic work, he clearly established the geological history and
fate of Mount Mazama. It has become the definitive geological study for
Crater Lake, which is recognized world wide as the classic example
illustrating how calderas form.
Since William’s time technology has
improved by several orders of magnitude, especially in the areas of
geochemistry and dating of rocks. Now it is possible to determine a
rock’s chemistry to parts per billion. Many new techniques for
determining when a volcanic rock formed have also been developed.
Moreover, the science of Volcanology had progressed dramatically since
This is the happy situation that greeted
Dr. Bacon as he entered the story in 1980. Building on the work of
William’s and numerous other geologists that preceded him, Charlie
brought these new ideas and techniques to bear. Through ten seasons of
detailed field work coupled with these advances in understanding the
nature of volcanoes, he added important details to geological history of
Mount Mazama and the creation of the Crater Lake Caldera.
A clear picture of the growth of Mazama
has been established with confined dates for many of the features seen in
the caldera walls. He has made a number of new interpretations that
provide much better understanding of both the construction of the
volcano and its collapse. Especially interesting is the period of time
just preceding he collapse when Red cloud Cliff, Llao Rock, Grouse Hill
and the Cleetwood Flows were active.
The really exciting finding, however, are
associated with Mazama’s climactic event that occurred some 7,700 years
ago. Here he has clearly described great detail of the massive eruption
sequence, dividing it into two separate phases. The initial phase
immediately followed the Cleetwood Flow and produced a plinian column
similar, but much larger, than that produced by Mount St. Helen in 1980.
Debris from this plume was carried across
the U.S. and likely around the world. As this column enlarged the vent,
pressure was reduced and part of it began to collapse. This hot
gas-charged material flowed down the north slope of Mazama to become the
Wine Glass Flow and marks the beginning of the second phase. Massive
amounts of pumice began boiling out of Mazama’s vent and flooding the
canyons flaking the volcano.
Today we see this material in Anne Creek
Canyon and along the Pinnacles road. Collapse followed quickly as
the magma chamber was partially emptied removing support for the upper
portion of the mountain. The Crater Lake caldera was born.
Charlie’s interest in Crater Lake has
continued for this past quarter century and recently he has offered a
detailed interpretation of the geology of the caldera floor.
For his dedication and work on the geology
of Crater Lake National Park, The Crater Lake Institute presents its
Centennial Award for Excellence in Scientific Research to Dr. Charles R.