Field Location: Unaweep Canyon (click on link to see
Geologic Feature: Uncompahgre Uplift.
Necessary Background Information: Tectonic origin of the Ancestral
Rocky Mountains and associated basins.
Geologic Problem: How did the Uncompahgre Uplift form, when did it
form, and how large was it originally?
Rock Units Exposed: Precambrian granite, Triassic Chinle Formation to
Cretaceous Dakota Sandstone.
Skills: Mineral identification and classification, contact
identification and classification, making descriptions in the field
(note-taking), developing a plan for a field study, reading topographic and
Other Questions to Consider: 1) Why is bedding in the sedimentary
rocks overlying the Uncompahgre parallel to the upper surface of the
Uncompahgre? 2) What is the composition of the large dikes that cut
through the Uncompahgre? 3) What is the likely origin of these
dikes? 4) Is the Uncompahgre older or younger than the sedimentary
rocks overlying it? 5) What happened to all of the rock that must have
been eroded from the top of the Uncompahgre since the time that it first
appeared? Is the mineralogy of the overlying and surrounding
sedimentary rock similar to that of the Uncompahgre?
Anticipated Outcomes: Students learn to identify basic rock-forming
minerals, distinguish between and name sedimentary and igneous rocks,
identify geologic contacts, develop a plan for conducting field study,
understand the tectonic setting of the Ancestral Rocky Mountains, Eagle
Basin, San Juan Basin and Paradox Basin, and develop hypotheses about the
origin, age and original size of the Uncompahgre Uplift.