Transcript RELATIVE DATING: Determining whether an object or an event is

Relative Dating
Superposition
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.
A. Law of Original Horizontality –
Sedimentary rocks form layers of horizontal
strata.
List the rocks in
order from
youngest to
oldest!
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
Folding
Cross Cutting
Unconformity
Faulting
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