Activity 8.1 in a geology course typically involves analyzing a cross section, or a vertical cutaway view, of a geologic area. The goal of this activity is to understand the sequence of geologic events that have occurred in a specific area by interpreting the various rock layers and structures present in the cross section.
To begin, geologists will first study the rock layers present in the cross section and determine their relative ages. This can be done by applying the principles of relative dating, which involve comparing the characteristics of the rock layers to determine their relative ages. For example, younger rock layers will typically be found on top of older rock layers, as the weight of the younger layers pushes down on the older layers. Additionally, sedimentary rocks, which are formed from sediment that has been deposited by wind or water, will typically be found on top of metamorphic or igneous rocks, which are formed through the transformation or solidification of preexisting rock.
Once the relative ages of the rock layers have been determined, geologists can then use this information to infer the sequence of geologic events that occurred in the area. For example, if a rock layer is composed of sedimentary rocks, it may indicate that the area was once underwater and that the sedimentary rocks were formed from sediment deposited by water. Similarly, if a rock layer is composed of metamorphic rocks, it may indicate that the area was subjected to high temperatures and pressures, such as those found deep within the Earth's crust.
By examining the different rock layers and structures present in a geologic cross section, geologists can reconstruct the sequence of events that occurred in a specific area over time. This information is critical for understanding the geology of an area and can be used to inform a variety of applications, such as resource exploration and land use planning.
geologic cross section worksheet answers
Place a sheet of paper along the cross-section line and mark points of intersection of geologic structures. This means you complete all work in a word processing document e. Transcribed Image Text: ACTIVITY 8. These geologic structures are important when studying geohazards such as earthquakes, tsunamis, and landslides; as movement along fault planes can trigger large scale natural disasters and affect people and structures near the fault movement and many times, hundreds of miles away. Some of the structures found on the map are: Dipping beds, Fault, Syncline, and Intrusive igneous rock.
Geology Lab: Geologic Faults and Cross
Vertical displacement along a fault plane is referred to as dip-slip movement, the resulting faults are called dip-slip faults. In previous lessons, we talked about the Geologic Time Scale and how scientists use it to piece together the history of the earth. In the map area below, the fault cuts across the syncline, and the intrusive rock cuts across the fault. If the side opposite the fault has moved to the left, the fault is a left-lateral strike-slip fault. Draw a line of section across the map area of interest, making it very near perpendicular to the strike of the rock units. Faults are common geologic features in many areas. Show the dips of the Devonian shale along the line of the cross section.
9+ determining sequence of events in geologic cross
Many times, these section lines will already by provided. Answer to ACTIVITY 8. Reverse faults that have a fault plane that dips less than 45 degrees are referred to as thrust fault. The map symbols, age of the rock units, the application of the geologic principles such as superposition and cross-cutting relationships help geologists "see" the relationships that exist below the surface. The geologic cross section below, illustrates a series of rock layers as they might appear in a roadcut or quarry wall.
Activity 8 1 sequence of events in geologic cross... Free Essays
View Notes - Geologic Maps, Cross-Sections and Faults ws from GEOL 102 at University of Wisconsin, River Falls. These judges hold their position for life or until they are impeached by Congress. Selected Answer: vesting Response Feedback: correct Question 2 0. A strike-slip fault is described as having either right-lateral or left-lateral displacement, depending on the relative motion of the blocks on either side of the fault. Reverse and thrust faults are the result of compressional deformation; large scale examples of both are found in mountain ranges that formed at convergent plate margins such as the Appalachian, Ouachita, and parts of the Rocky Mountains.
