Geologic Structure and Maps


Read the materials below carefully. Questions are included with choices in parenthesis. Click on a response to check your answer.

FOLDS are usually the result of compressional forces in the earth's crust. Examine the illustration below.

cross section

A is an ANTICLINE or an upfold or arch. B is a SYNCLINE or downfold or trough. C is another (anticline, syncline). Layer E is (younger, older) than layer D. Layer E is (younger, older) than layer F. Figure 1 is a GEOLOGIC CROSS SECTION. It shows a slice through the earth. Figure 2 is part of the GEOLOGIC MAP from the cross section.

geologic map

A map shows a bird's eye view of the surface. A geologic map shows the surface rocks. This map is incomplete, because not all of the rock bodies are identified, and the symbols showing the geologic structure are missing. The lines between different kinds or layers of rock a called CONTACTS. Contacts appear on geologic maps, cross sections, and block diagrams. On a cross section, the surface of the earth is at the top line, while a map is entirely the surface. Examine the relationship between the geologic cross section and the map below, and think about what a block diagram of this area would look like.

geology illustration

The rest of the map needs to be completed. The rock that should be shown on the MAP in the area labeled above it as A is (shale, coal, conglomerate, limestone, sandstone). The rock in the map area B is (shale, coal, conglomerate, limestone, sandstone). The rock in the map area C is (shale, coal, conglomerate, limestone, sandstone). The rock in the map area I is (shale, coal, conglomerate, limestone, sandstone). The rock in the map area J is (shale, coal, conglomerate, limestone, sandstone). The rock in the map area K is (shale, coal, conglomerate, limestone, sandstone). The rock in the map area L is (shale, coal, conglomerate, limestone, sandstone). The rock in the map area M is (shale, coal, conglomerate, limestone, sandstone). The rock in the map area N is (shale, coal, conglomerate, limestone, sandstone). The rock in the map area O is (shale, coal, conglomerate, limestone, sandstone).
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