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Bermuda Today: Who Were Its Geologic Ancestors?  
                                                                                                 Amy Pearson

OBJECTIVE: To understand how the island of Bermuda came to be...


Modeling clay ( black or another dark color, green or yellow, white)
Water and an eye dropper or pipette
Plastic  container with tall sides,  a bucket, basin, or tall sided yogurt or sour cream
Soil and sand, approx. 3 tablespoons each
Diagrams -
Formation of Bermuda  (you will need Adobe Acrobat reader to download and view these diagerams)

Procedure and some Background Information:

Concept 1: Bermuda began as a seamount produced at the mid-Atlantic ridge approximately 110 million years ago. It moved westward with the plate and then 33 million years ago passed over a geologic hot spot that promoted volcanic activity.  This resulted in the production of the island of Bermuda.
Model 1: Construct a model of Mount Bermuda as a volcano using modeling black or dark modeling clay  inside a plastic container with tall sides.  Add water to show sea level being sure to demonstrate that this mountain is above sea level and has a crater on top.

Concept 2: The hardened layers of basalt lava were eroded for millions of years by wave, wind and rain action. This produced a sandy platform.
Model 2: Act as weathering and wave action to create a sea level platform from your volcano.

Concept 3: Corals and other marine life settle and grow on rim of platform. A circular reef (atoll) forms with a central lagoon that fills with water.
Model 3: Make the reef using yellow &/or green clay around edges of platform.

Concept 4: Ice Age begins approximately 2 million years ago.  Sea level falls significantly. Soil forms on top of dead Coral and as rain seeps into soil and sediments. Limestone forms.
Model 4: Remove water from your model with an eyedropper or pipette.  Add white clay to show hardened limestone and a bit of soil on top.

Concept 5: Ice Age winds down between 18,000 10,000 years ago. Sea level rises but ocean doesn't cover platform.
Model 5: Show that the sea level rises but does not cover the top of the  platform.

Concept 6: Corals again begin to develop at rim of platform.  Weathering occurs and much sand is produced by weathering.  Sand settles to form Bermuda.
Model 6: Using green and yellow clay, reconstruct reef.  Take some sand and sprinkle it on top of platform. Dunes form and harden into rock (lithification) at southern end of rim.

Model 7: Refer to diagrams below Show Bermuda Today!

Questions to consider:

1.In Model 3 a lagoon is created. What could be collected in the lagoon?

In November of 1963, Surtsey, a volcanic island rose from the Atlantic Ocean near Iceland.  Explain why a coral reef is unlikely to form here, as it did near Bermuda.  Support your answer with facts you research

BBSR and TCOE Coral Web Site Team 1999
Funded by a grant from the Goldman Foundation