Cross-sections
Carmen Martinez Cross-sections
In this unit we have studied what cross-sections are, what they are used for and how we can interpret them in order to find out the geological history of the area. This review sheet will help us to establish the necessary background knowledge to carry out a good interpretation of our cross-sections.
1. Complete the following text about the rocks deformations:
The .............................................................. stresses to which the crust is subjected produce three types of deformation in the rocks:
- .................................................. This is a reversible deformation. Rocks are deformed when they experience an abrupt shock, but later they recover their initial shape. The passage of .................................... produces this type of deformation in rocks.
- Ductile deformation. This is the folding of rocks, and is ...............................; it normally occurs when they are subjected to intense ......................................................... over millions of years.
- ................................................ This is the breaking of rocks. It occurs when they are subjected to compressive or tensile stresses .......................... of what they can that can be absorbed by elastic or plastic deformation.
2. The ductile deformations leads to the formation of folds, draw its six parts with their names pointed the structure:
AXIS, CREST, LIMB, TROUGH, AXIAL PLANE, NUCLEUS
3. Match the photo types of folds with their name and definition.
Anticline
Syncline
is a type of fold that is an arch-like shape and has its oldest beds at its core
Is a fold of rocks with younger rock layers closer to the center of the structure
4. Identify the different types of faults in the following pictures:
5. Complete the definition.
Index fossils are any ......................................... preserved in the rock record of the Earth that is characteristic of a particular span of ....................................... or .................................. A useful index fossil must be ..........................or easily recognizable, .........................., and have a wide geographic distribution and a .............................. through time.
environment
distinctive
abundant
short range
6. Match the photo with their era.
Mesozoic
Cenozoic
Palaeozoic
7. Complete the following photo with the principles of geology.
All the principles are here? or there is another one? Name the principle:
8. Interpret the following cross-section using the principles of geology as help:
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