Field Work #1
Your first assignment is to study the Geology of the LaSalle, IL region including Starved Rock State Park. Below are the field notes you have taken over five specific stops. On the left is the work to be completed using these field notes. A "Stratigraphic Column" represents the vertical location of rock units in layers and their relative grain sizes. A stratigraphic column is a good, simplified way to illustrate the overall stratigraphy of an area. Your assignment is to create a stratigraphic column of the LaSalle, IL region!
Stratigraphy: 60 feet of rock, layering evident
Rocks: Dolomite on bottom, capped by 10 feet of shale shale
Structure: Galena Plat Dolomite
Notes: Formed in a shallow marine environment. There must be another rock structure below this one...
Stratigraphy: 60 feet of rock. Three rock types.
Rocks: Shale at the bottom (same shale seen at stop 1), 10 feet of conglomerate, and 40 feet of Sandstone at top
Structure: Vermilionville Sandstone
Notes: Rock is younger than stop 1's main formation. Same shale was seen at both stops.
Stratigraphy: 110 feet of rock. Two rock types.
Rocks: 100 feet of Sandstone, 10 feet of Galena Plat Dolomite
Structure: St. Peter's Sandstone
Notes: Formed in a Beach environment. The lowest rock formation.
Stratigraphy: 120 feet of rock. 4 rock types.
Rocks: Galena Plat Dolomite on the bottom. 50 feet of shale. Conglomerate and Vermilionville Sandstone at the top.
Structure: Mixture of different layers.
Notes: This is a good look at some of the rocks seen on previous stops.
Stratigraphy: 20 feet of rock. One type
Structure: LaSalle Limestone
Notes: We have moved to the stratigraphic highest location.