Second Quarter: 2004 UO Summer Geology Field Camp with Becky Dorsey

    The Frying Pan: Introduction to mapping and Field Stratigraphy
The second project of the 2003 UO Summer Geology Field Camp will  give students an introduction to the basics of geological mapping, field stratigraphy and related essential skills of observation, description, and interpretation., with Becky Dorsey. The "Frying Pan" locality lies about 15 miles out of Dillon. An aerial view of the area is shown on the left

 
Frying Pan displays excellent bedrock exposures, lithologic diversity, and simple fold structures (see photo above).  The rocks make up a thick succesion of Triassic- to Cretaceous-age fluvial and marine sedimentary rocks that include conglomerate, sandstone, shale and limestone of the Dinwoody, Morrison and Kootenai Formations.  These sediments were deposited under varying tectonic and climatic conditions, and the Cretaceous part of the section accumulated near the western margin of a large interior seaway that flooded the continent during thrusting and mountain building in the Rocky Mountains.  The basal conglomerate member of the Kootenai Formation (see photo below) is a regionally widespread unit that records Cretaceous uplift and erosion in the mountainous fold-thrust belt to the west.

In the process of creating a geologic map, students will also: (1) determine the correct stratigraphic order of the map units; (2) describe map units and interpret their environments of deposition; (3) determine the geometry of structures that deform the section; and (4) measure, describe and intepret a portion of the stratigraphic section in some detail.  Detailed sections will be measured in different parts of the area, which will allow students to compare their results and develop a larger picture of the natural stratigraphic variations at Frying Pan.

The objective of this project is to teach students essential skills that are needed for all kinds of field mapping and field study, with an emphasis on sedimentary rocks and stratigraphy.  In the mapping work we will emphasize the importance of accurate field locations, correct placement of lithologic contacts on the map, accurate descriptions of map units, and synthesis of map-scale structures and stratigraphic patterns into an integrated whole picture of the area.  In the stratigraphy part, we will begin with primary observations of lithologies, sedimentary structures, and vertical transitions, and then we will work systematically toward interpretations of depositional processes and the different kinds of environments within which deposition occurred.  Ultimately, this work will allow us to develop a first-hand understanding of how these rocks record the regional evolution of the Rocky Mountains fold-thrust belt and related foreland basin during Mesozoic time.

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Page last updated 03 January 2004