Transcript The Islands of Blowtorches

Timeline of Hawaiian History
85 mya:
Earliest
Emperor
Seamounts
visible today
are formed
65 mya: The
dinosaurs
(not native to
Hawaii)
become
extinct
NOT to scale!
43 mya:
Catastrophic
event causes
bend in
Hawaiian
chain
5 mya:
Island
of
Kauai
forms
300-750 AD
Polynesians
arrive from
Tahiti in
outrigger
canoes
1 mya:
Island of
Hawaii
forms
1900:
Hawaii
becomes a
US territory
1778: British
explorer Captain
James Cook
lands on Hawaii
1983:
Kilauea
Volcano
begins to
erupt
1959:
Hawaii
becomes a
US state and
the age of
tourism
begins
The Hawaiian Islands Overview:
Quick Facts
STATE FLAG OF HAWAII
Plate Tectonics
and the Hawaiian Chain
The Hawaiian Chain
The Hawaiian Islands
and the Emperor Seamounts
And The Story of Pele, Fire Goddess!
6,000 km
long!
Over 80
volcanoes!
Why are these volcanic islands all lined up?
Further Investigation:
Compare Hawaii to Other Pacific Island Chains!
Oldest
Oldest
Oldest
Youngest
Youngest
Oldest
Youngest
Youngest
Say, look at all them islands lined up
so nice…
Could these four island groups (and more)
have been formed by the same process?
…YES!!!!
(but how?)
The Pacific Plate
And Neighbors!
THE PACIFIC PLATE…
• is currently moving west-northwest at a
speed of 7 centimeters per year.
• is subducting under Asia and sliding
past North America.
• is spreading off the coast of the Pacific
Northwest.
What does this have to do with Hawaii?
Common Sense: If a small area in the mantle distorts the crust that passes above it, the distortion in
the crust will form a trail, which gets younger in the direction OPPOSITE to the crust’s movement.
Observation: The Hawaiian Islands and other Pacific island chains are trails of volcanic islands,
which get younger in the direction OPPOSITE to the crust’s movement.
Theory: The Pacific island chains were formed as the Pacific plate slid over strange and mysterious
“areas” in the mantle. …To be explained later!
Why does the Hawaiian chain have that big
bend in it?
The rocks at the bend are 43 million
years old.
Something happened 43 million years
ago that caused the Pacific Plate to
change direction as it was sliding
over the strange and mysterious
“area” that distorted it…
But no one knows what!!
Anyway… let’s get down to a question with an answer:
Just what are these strange and
mysterious “areas”???
HOT SPOTS!!!!
(aka blowtorches)
All the Hawaiian
islands were formed
by volcanic eruptions
above the Hawaiian
Hot Spot.
What is a hotspot ?
“…a volcanic region at the
earth’s surface directly
above a rising plume of hot,
plastic mantle rock.”
Where does the rock that makes up the
Hawaiian islands come from?
MAGMA!
We’ve got hot spots all over the place
Other examples of hot spots include:
Cape Verde (off the coast of Senegal), Galapagos
Islands (off the coast of Equator), Society Islands
(French Polynesia), Tristan da Cunha (southern
Atlantic), Yellowstone, Ethiopia Plateau, Lord How
(near Sydney), Iceland, and many more.
This graph shows the age of the Hawaiian
volcanoes
This shows the heights of these
volcanic land masses and their
erosion due to age.