Geology Reference
In-Depth Information
Figure 9.2.5. Tammy P. Taylor from the Chemical Division of Los Alamos National Laboratory, using a spatula
and scoop to scrape a mineral off of rock and soil and into a plastic vial, while using caution to minimize
contamination from these substrates. The sample was identified by X-ray diffraction as orthorhombic sulfur-8. It
was collected from the Southern Ute Indian Reservation near Durango, Colorado, where an underground coal fire
is thought to have been ignited by a forest fire started by lightning. Photo by Glenn B. Stracher, 2001.
minerals from contaminants may still be necessary, and it is absolutely essential for wet chemical analysis.
On one occasion, I was sent several beautiful samples from coal fires in East Kalimantan, Indonesia.
Numerous coal fires in Indonesia started when fire was used to clear forested areas for rubber, oil palm
plantations, pulpwood, and farming (Whitehouse and Mulyana, 2004). The specimens I received were never
separated from the soil they nucleated on. By the time they reached my lab, the minerals from the coal-fire
gas were completely pulverized and mixed with the soil, rendering separation and identification impossible.
Another useful method for collecting minerals formed from coal-fire gas is to
”
onto a substrate placed partially over a vent or fissure. Unglazed ceramic tiles were successfully used in East
Kalimantan for this purpose (Figure 9.2.6A), and minerals appeared within 2 weeks on the sides of the tiles
“
”
“
force
the gas to
condense
Figure 9.2.6. Collecting coal-fire minerals from unglazed ceramic tiles emplaced over coal-fire gas vents: (A) East
Kalimantan, Indonesia and (B) Centralia, Pennsylvania. The minerals on the bottom of the Indonesian tile (not
visible in the photo) that were identified by X-ray diffraction are gypsum and sulfur. The tile in Centralia was
removed multiple times from the vent and tossed on the ground by visitors to the fire, rendering the collection
procedure unsuccessful. Photos by (A) Asep Mulyana, 2002 and (B) Janet L. Stracher, 2003.
