Daily question

1
DAILY QUESTION

• What velocity did you calculate for the Pacific
  plate?
• Is this plate velocity faster or slower than what
  weve talked about in class so far?
• Where is Samoa located?

2
THE HAWAIIAN ISLANDS
Result of a Mantle Plume

• Hawaii has a linear age progression, as apparent
  from the graphs made in class.
• Lava chemistry is unique to intra-plate
  volcanoes.
• Active volcanism at the young end of the chain,
  south east portion of chain ? Loihi and Kilauea
  (on the big island of Hawaii).

3
AGE VERSUS DISTANCE
70 Million Years of Hawaiian Volcanism
4
HAWAII-EMPEROR CHAIN
Hawaiian Islands, Ridges and Seamounts
5
SAMOAN ISLANDS
Western Samoa and American Samoa

• Samoa is located in the South Pacific.
• Samoa comprises several islands, but there also
  are seamounts in the area.
• Samoa is volcanic in origin, but is not located
  on a plate boundary, although rather close
• The big question Is Samoa caused by a mantle
  plume?

6
SAMOAN ISLANDS
Western Samoa and American Samoa

• Lava chemistry is unique.
• Islands and seamounts form a linear chain, alike
  Hawaii.
• Active volcano at southeast end of the chain ?
  Vailuluu seamount.
• However, there are active volcanoes in the middle
  of the island chain as well. Does this make
  sense?

7
SAMOAN ISLANDS
The Young End of a Hotspot Chain
8
SAMOAN ISLANDS
20 Million Years of Seamount Volcanism

• If Hawaii is the result of a mantle plume, is
  Samoa the result of a plume also?
• Does Samoa have an age progression, like Hawaii
  does?

9
SAMOAN ISLANDS
Determining the Age Progression of Samoa

• To determine if Samoa has an age progression you
  need to determine
• The age of each island or seamount.
• Distances from the currently active volcano.
• Determine if there is a trend from old to young.
• If so, calculate the plate velocity.

10
SAMOAN ISLANDS
Estimating the Age of Seamounts

• This time we dont know the ages, but you will
  calculate the age, assuming the same plate motion
  as for Hawaii.
• If you know the velocity of a plate, you can
  determine what the age of a seamount should be
  based on its distance from the hotspot.