Transcript Geologic Story of Minnesota

Geologic
Story
of
Minnesota
(as told by
its rocks)
Part II:
Phanerozoic
Rocks
Geologic Timescale
Today’s
Lecture
Evolution of the Penokean Mountains
JAY COOKE
HIBBING
St. CLOUD
1,000,000,000 Years Ago
Minnesota becomes the
stable interior of the
North American Continent
500,000,000 Years Ago
Shallow seas begin to
periodically flood Minnesota
The Cambrian Explosion of Life
Snowball Earth
The Trigger of the Cambrian Explosion??
The Carbon Cycle
Supercontinent Rodinia ~750 Ma
Paleozoic Epicontinental Seas
Geography of Middle Laurentia in Paleozoic Time
The Jordan Sandstone
Unconformity
Missing Fossils
Advanced Transgression
Regression
Paleozoic Formations of the Midwest
Twin
Cities
Ordovician Rocks of the Mississippi River Bluffs
P-Platteville Limestone
G-Glenwood Shale S-St. Peter Sandstone
G--
P
S
Mound Park
P
Minnehaha Falls
G-S
G-S
Ford Dam and Lock
P
Fossil Hunting in the Twin Cities
Lilydale Park (the Brickyard)
Paleogeography at the
End of the Paleozoic
Extinctions at the End of the Paleozoic
Snowball
Earth?
Western Interior Seaway
Cretaceous Deposits
in Minnesota
Conglomerate and sandstone on banded iron
formation in north-central Minnesota
Deeply weathered gneiss in
Southwestern Minnesota
Lignite and shale in southern Minnesota
The
Coleraine
Formation
High
Sediment
Production
Why don’t
dinosaur
fossils occur
in Minnesota?
Low
Sediment
Production
The
Break-up
of
Pangea
The Bedrock Geology of Minnesota
is Complete