1. Refer to Figure 11.1 below (Fig. 15.12 in the original source), and answer th
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Question
1. Refer to Figure 11.1 below (Fig. 15.12 in the original source), and answer the questions given. Please note that on the second page of this figure (the full-page map), the north direction for the map is given incorrectly. To view the map properly, lay the page in landscape orientation, so that you can read the text (e.g., Shoemaker Hill, Ringer Hill, Packhorse, Sylvan Lane, etc). From this orientation, the north direction points upwards; the south downwards; the east to your right; and the west to your left.
What is the name of the oldest unit? In terms of geography and elevation, where is this unit exposed?
How old is the Loyalhanna Formation? (Give the geologic period.)
What kind of contact exists between the Qal unit and underlying rocks?
In the west-central part of the map, at the eastern crest of Glade Mountain (just west of the white patch on the map), is a contact between two geological units. Identify the two units.
Note: The red lines on the map (and the red lines on Figure 11.2 in this Assignment Manual) are called structure contours. They are like topographic contours, but instead of giving the elevation above sea level of the land surface, they give the elevation above sea level of a specified geological surface.
When the elevation of a structure contour is less than that of nearby topographic contours, the geologic surface is buried beneath the ground. When the elevation of a structure contour is greater than the topographic contours, that surface is above ground—in other words, it has been eroded. Where the elevation of a structure contour is identical to that of a topographic contour, the geologic surface should crop out (Figure 15.13 [11.2]). (Busch, 1990, pp. 166-167)
Figure 11.1. Geologic map for a portion of Somerset County, southwestern Pennsylvania, showing structure on the Upper Kittanning coal seam. Shown on this page is a stratigraphic column for the area.
Figure 11.1 continued.
Figure 11.2. Profile and map view of a coal bed.
FIGURE 15.12 Geologic map (opposite) for a portion of Somerset County, southwestern Pennsylvania, showing structure on the Upper Kittanning coal seam. North is toward left margin of page. Shown on this page is a stratigraphic column for the area. (From Pennsylvania Geological Survey Bulletin C56A, Geology and Mineral Resources of Southern Somerset County, by Norman K. Flint.) DESCRIPTION Stream and swamp Shale, sandstone, limestone, coal, clay Map Scale 2 miles 3000 6000 9000 12,000 feet Shale, sandstone nonmarine limestone, minor coal and 0 0.5 3 kilometers Red, green, and gray shale and Shale, sandstone marine limestone minor coal and clay Sandy limestone Shale, sandstone, coal, clay Gray shale and platy sandstone thin shale and coal beds Red shale and sandstoneExplanation / Answer
1. The oldest unit in this region is the Catskill formation. It is exposed in the South West of this region and is located at an elevation of 3900 feet (maximum)
2. The Loyalhonna formation is of Mississippian Period (Early Carboniferous)
3. There is an unconformity betwwen thw qal unit and the underlying rocks.
4. The contact is between Mauch Chunk formation and Pocono formation
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