Whitman Geology-345 Mineralogy
Fall 2002 Field Trip
The Crater of Mt. St. Helens
September 20-22

Group photo taken in the crater (by Jeanne Fromm): back seven (L-R): Erik Donaldson, Nolan Brewer, Shauna Nyborg,
Mike Kalk, Cooper Brossy, Willie Scott (CVO), and Brennan Jordan; middle five: Emily Owens, Ashley Meganck,
Michelle Heimgartner, Katie Wagner, and Jenn New; front pair: Spruce Schoenemann and Toby Meierbachtol.
 

Route taken into the crater of Mt. St. Helens; note that the DEM from which
this image was developed is based on the late 1980 topography so the
dome is quite small
 

Northeast ridge of Mt. St. Helens, note drainage development since 1980 eruptions
 

View of the incised Goat Rocks fan below the mouth of the crater on the north
 

Striae caused by the sliding of the debris avalanche over the Goat Rocks fan
 

The group takes a break before entering the breach into the crater; the dome is in the background
 

The group approaches the dome in the crater of Mt. St. Helens
 

A glacier has formed between the dome and the crater wall, the dirty snout looms in the center
of the photo; this is the youngest glacier in North America
and perhaps the only glacier in the lower 48 states that is advancing!
 

The dome of Mt. St. Helens
 

Looking north out crater; the white cliffs are deeply weathered rhyolite cut by basalt dikes
which fed the overlying lavas of the Castle Creek eruptive period ~2000 years ago;
also note Mt. Ranier in the distance
 

Willie Scott (CVO) leads a discussion of geothermal springs at Mt. St. Helens
 

Brennan Jordan gets a feel for the contrast between two streams at their confluence; the stream on the
right is born of glacial melt water, the stream on the left emerges from a field of thermal springs and is uncomfortable to the touch!
 

Peering over the edge of Loowit Falls toward Spirit Lake
 

A large breadcrust bomb (lens cap for scale) formed by the continued expansion of the
interior after a rigid crust had formed
 

Radial polygonal jointing, a small-scale equivalent to columnar jointing; this jointing indicates that
this block was still hot when in rolled off of the lava dome
 

On the return trip to Walla Walla we took a side trip to Paradise on the south slopes of Mt. Ranier;
this photo shows Ranier and Little Tahoma (right) on the drive from White Pass to Paradise