Relative Dating Superposition Original Horizontality Faulting Tilting/Folding Intrusions...

Relative DatingSuperposition

Original Horizontality

Faulting

Tilting/Folding

Intrusions

Unconformities

Geologic Columns

Rock Puzzles

I. RELATIVE DATING: Determining whether an object or an event is older or younger than other objects or events.

Relative Age?

• Layer 1

• Layer 2

• Layer 3

• Layer 4

II. SUPERPOSITION: Younger rock lie above older rock.

List the rocks in order from youngest to

oldest!

A. Law of Original Horizontality – Sedimentary rocks form layers of horizontal strata.

III. Disturbed Rock Layers: Events are younger than the rock layers

A. Faulting – a break in the Earth’s curst where one rock layers will slide

B. Intrusions – when molten rock squeezes into existing rock and cools

C. Folding & Tilting – When internal forces bend or tilt rock layers

D. Unconformities – a surface that represents an area where there is a missing piece of geologic rock

FaultingCross CuttingFolding

Unconformity

Faulting

Intrusions

IV. Geochronology - the science of dating and determining the time sequence of events in the history of the Earth.

IV. Geochronology - Key

V. GEOLOGIC COLUMNS

An ideal sequence of rock layers that

contain all fossils and rock formations on Earth arranged

from oldest to youngest.

MICHIGANS GEOLOGIC COLUMN: How did geologist get this information?

MICHIGAN BASIN

• Originally shaped like a bowl

• Great sea covered MI during Paleozoic Era

• Layers formed from 24 – 30 retreats and transgressions of water or oceans

• Information taken from core samples

http://www.geo.msu.edu/geo333/MIbasin.html