Lecture 11.1: Relative Dating

Topic: Summary

Introduction

Relative Dating Principles

Introduction to Relative Dating

• the law of Superposition
  • in an undisturbed and or undeformed sequence or rock layers, the older rock is at the bottom
• in determining the rocks and rock layers, different techniques may be used

Law or Superposition

• Formulated by Nicolas Steno (1638 - 1689)

  

  Nicolas Steno

  • a Danish atomist

• the law simple states that, in an undeformed or undisturbed layer of sedimentary rocks, the rock layer found at the bottom is the oldest, and consequently, the youngest rock layer is found at the top

• in the sequence of rock layers (aka strata)

  

  the younger rock layers overlay the older strata in the Grand Canyon.

Law of original Horizontality

• while observing the deposition of sediments during floods, Steno observed that this layers of sediments were deposited in a horizontal manner
  • this observation allowed his to formulate the Law of Original Horizontality
    • states that sediments are generally deposited in a horizontal manner.
      • if you observe tilted sedimentary rock layers or strata, it means that it was disturbed by geologic forces in the past

Principle of Lateral Continuity

• states that sedimentary rocks and/or sediments extend laterally in all directions until such time that it thins-out or terminated by the edges of a basin in a depositional environment

Principal of Cross-cutting relationship

Subtitle 3

1. insert process here
2. step 2 of the process
3. step 3 of the process

• this → into this → to this
• ↑ increase in smth
• ↓ decrease in smth