Transcript geology of the hawaiian islands

Geology of the Hawaiian Islands
Objectives:
1.
Describe island formation.
2.
List stages of Hawaiian volcano formation.
3.
List volcanoes which make up the Big Island.
4.
Identify active volcanoes in the Hawaiian Islands.
5.
Tell the ages of the Hawaiian Islands.
6.
Describe pioneer and climax communities.
7.
Define endemic, indigenous, exotic species, and give
examples found in the Hawaiian Islands.
Hawaiian Island Formation
• Islands formed as the
Pacific Plate moved
northwest over a "hot
spot”
– hot spot = hot plume of
mantle material rising
through the crust
– Video
• Niihau and Kauai were the
first major islands to
form, followed by Oahu,
Molokai, Lanai, Maui,
Kahoolawe, and the Big
Island.
Island Formation
• Emperor Seamounts and
Northwestern Hawaiian
Islands are older
– lie to the northwest
• The Big Island is made up of
five volcanoes:
–
–
–
–
–
Kohala (extinct)
Mauna Kea (dormant)
Mauna Loa (active)
Hualalai (active)
Kilauea (active and currently
erupting)
**USGS does not acknowledge
“dormant”
Northwest Hawaiian Islands
Island Formation
• Lo'ihi
– New island forming
– 13,000 ft high above the sea
floor but is still 3,000 ft below
the ocean’s surface.
• Oldest northwest Hawaiian
islands began forming 70
million years ago
– Kauai approx. 5 mya
– Big Island at 0.8 mya.
Video
• http://www.history.com/shows/how-theearth-was-made/videos/how-was-hawaiiformed#how-was-hawaii-formed
Stages of
Island Formation
1.
(Active Volcano) Then, Pacific plate moves
northwest and the island is cut off from the
magma source and becomes extinct.
1.
(Eroded Island) Over time, erosion and
weathering gradually break down the island
into the ocean, but coral reefs grow.
1.
(Atoll) Eventually all that is left above ocean
level is an atoll, which are circular-shaped
coral reef remnants that once surrounded the
island.
1.
(Seamount) Once the islands and surrounding
reefs drop completely below sea level they
are called “seamounts”.
Arrival of life to Hawaii
Pioneer communities – organisms
that first settle on the barren
lava
– mostly producers
– plant seeds dropped by birds
“wings”, ocean currents “waves”,
“winds”
Types of Species
a) indigenous – naturally occurring species
• arrived on the islands through the air or water
naturally
• But also occur in other places
Types of Species
b) endemic – naturally occurring
species found only in Hawaii
• Examples:
– Hawaiian Lionfish
– Hawaiian Sergeant
– Waxy Cowry
– Banded Spiny Lobster
– Laurent's Hermit Crab
– Hawaiian Monk Seal
**Both indigenous and
endemic are native
Types of Species
c) exotic/introduced – species
brought by humans
• usually threaten indigenous
species due to lack of
natural predators
• examples:
– feral pigs
– rats
– Mongoose
• “Invasive Species” –
exotic species that take
over environments
Invasive Species
• Gorilla
ogo
• “ogo” =
seaweed
Fountain
Grass
Mongoose
Coqui Frog