1. MSc. Paleontology and Stratigraphy
Relative Dating
Majed Turkistani
MSc. Paleontology and Stratigraphy
mturkistani.kau.edu.sa
Historical Geology Lab

2. Outlines Introduction. Definition. Examples. Lab assignment.
Review and resources.
Historical Geology Lab

3. Introduction My name is: Majed Turkistani.
Lecturer of Paleontology and Stratigraphy.
My office located in Bld. 27 Room 215.
Office hours usually from 10 to 11 AM everyday except Tuesday. My
Contact through .
My webpage: mturkistani.kau.edu.sa.
Historical Geology Lab

4. Historical geology
“Historical geology is a discipline that uses the principles and techniques of geology to reconstruct and understand the geological history of Earth.” (Levin, 2003).
It focuses on:
Geologic processes that change the Earth's surface and subsurface;
The use of stratigraphy, structural geology and paleontology to tell the sequence of these events.
The evolution of plants and animals during different time periods in the geological timescale.
From Palaeos.com
Historical Geology Lab

5. Relative Dating
It means to determine “which rock units are older and which are younger in a particular settings” (Gore, 2014).
Stratification is a scientific description of layered bed rocks (Sedimentary).
Usually they can be seen in large scale or small ones.
Strata is sediments accumulated through time in which each layer represents an event that took place in the past. The results of this accumulation is called sedimentary sequence.
Historical Geology Lab

6. Tuwaiq Mountians
Historical Geology Lab

7. Steno’s Laws
In 1669 Nicolas Steno applied four laws discussing stratigraphical position.
The concept of steno’s laws is “The older beds are on the bottom, and the younger beds are on the top” (Gore, 2014)
Historical Geology Lab

8. The principle of superposition
This is the first law in stratigraphy, and first applied by Steno in 1669.
It states “In sedimentary sequence, the older beds are on the bottom, and the younger on the top. With an exception that these not forced by folding or faulting”. (Gore, 2014)
Historical Geology Lab

9. Principle of original horizontality
This principle applies in case of folding or faulting in sedimentary sequence.
This means the layers have deposited horizontally then an external force fold/fault it.
In this case the grains/particles will deposited on the bottom horizontally because of the gravity.
A geologist must have an excellent background of primary sedimentary structures, such as graded bedding and ripple marks.
Historical Geology Lab

10. Principle of original lateral continuity
This principle states that sediments deposited on flat area, such as sea floor, and it extends in all directions.
In this case, the correlation, first used by William Smith, is the best approach to date the sedimentary sequence.
In a correlation, a geologist must match the sedimentary units with its similar units in other areas. Also, fossils with fossils that been found in sedimentary units.
Historical Geology Lab

11. Principle of cross cutting relationship
This principle was first developed by Nicolaus Steno in then later formulated by James Hutton 1795.
It stats that “the geologic feature which cuts another is the younger of the two features”.
Examples for a geologic feature that cuts another: fault and any plutonic intrusion (Dyke).
Historical Geology Lab

12. Law of inclusion
It states that the clasts in a rock are older than the rock itself.
Historical Geology Lab

13. Cross Cutting
There are two: Sill and Dyke. The sill is horizontally, and the dyke is vertically.
Historical Geology Lab

14. Faults There are two fault types: Normal and Reverse Faults.
Historical Geology Lab

15. Folds
There are several fold types, but the most common are anticline and syncline.
Historical Geology Lab

16. Unconformity
Historical Geology Lab

17. Unconformity
Historical Geology Lab

18. Unconformity
Historical Geology Lab

19. Unconformity
Historical Geology Lab

20. Unconformity
Historical Geology Lab

21. Lab assignment Go to my webpage: mturkistani.kau.edu
Locate the Historical geology webpage from the right-side menu.
Click on lab 1.0 and download the assignment.
Do your homework and resend it to my / print it out.
If you have an issue send me an or google it
My emial is:
Historical Geology Lab

22. References
Levin, Harold. The Earth through Time, Hoboken, New Jersey: John Wiley & Sons, 2003, p.2
Historical Geology Lab