Plate Tectonics of Central America

This topic submitted by Emily Davis ( davisea1@muohio.edu) at 8:18 PM on 3/19/06.

Jeremy enters the bowels of Lighthouse Cave, San Salvador, Bahamas.

Tropical Field Courses -Interdisciplinary Studies-Miami University

Plate Tectonics of Central America
Emily Davis
March 19, 2006
Dr. Hays Cummins
Costa Rica- GLG 412

I. Intro
I will cover the development Central America from its formation as an island arc, explain its development into a land strip, explore theories explaining possible movement in the future and introduce my own hypothesis about subduction reversal. Plate Tectonics is integral to understanding all other areas study, to be able to understand current problems we must always begin at the source. This makes it a worthy topic for research. The study specifically of the Plate Tectonics and Drift of Central America is mostly unknown. It has been rarely studied, and the topic offers few resources. Dr. Siever a Geology Professor at Yale states it best; ÒThe history of the Caribbean [is] still an inexplicable geological problem. Ò

II. Island Arc Formation
1. Spreading ridges, Subduction, Island Arc formation.
a. spreading ridge
b. cooling of oceanic lithosphere during movement
c. subduction zone
d. depth of subducting lithosphere. P=mv.
2. Asthenosphere flow corner
a. How magma gets hot enouph to emerge.
b. "Magic Point"
3. Fluid Gravetational Insability.
a. Rayleigh- Taylor instability
b. Diaper formation
4. Angles of Subduction
a. Effects on Volcano Position
b. Costa Rica vs. Nicaragua angles of subduction.
5. Island Arcs are actually lines.
a. caused by fractures
b. caused by differences of curvature.

III. Becoming a land strip.
1. Caribbean plate subducting under the Pacific Plate.
2. Reversal of subduction.
3. Eastward movement of the Island arc.
4. Island intersection with North America.
5. Ice Age lowers water table to form land bridge.
6. Separation of the Pacific plate.
7. Tectonic condition of Central America today.

IV. Mantel Flow Theory. Future movement of Central America.
1. Assumptions
a. Two separate layers of mantel low, which are independent.
b. Continental roots in the lower-mantel.
2. Movement of upper mantel from Pacific to Atlantic.
3. Undertow Theory.
a. Upper mantel movement pulls lithosphere that has roots in upper-mantel
b. Lava differences in Nicaragua and Costa Rica.
c. Differences in the angle of subduction.

V. Explaining the Reversal of Subduction.
1. The subducting lithosphere is pushed backward by the upper mantel movement as the top lithosphere is pulled downward by the mantel movement and is subducted. Causing the top plate to turn into the subducting plate therefore reversing subduction.

Resources:

Alvarez, Walter. "Eastbound sublithosphere mantel flow through the Caribbean gap and it's relevance to continental undertow hypothesis." Terra Nova 2001: 333-337.

Erickson, Jon. Plate Tectonics. New York: Facts on file, 1992.

Marsh, Bruce. 'Island- Arc Volcanism.' Earth's History, Structure and Materials. Ed. Brian Skinner. Loas Altos: Sigma Xi, 1980. 99-110.

Peacock, Simon, Peter Keken, Stephen Holloway, and Bradley Hacker. "Thermal Structure of Costa Rica- Nicaragua Subduction Zone." Physics of the Earth and Planetary Interiors 2005: 187-200.

Reddish, Paul. Spirits of the Jaguar: The natural history and ancient civilizations of the Caribbean and Central America. London: BBC Books, 1996.

Scotese, Christopher. Evolution of the Caribbean Sea. 1999. PALEOMAP Project. 17 Mar. 2006 .

Siever, Raymond. 'Continental Drift and Plate Tectonics.' Environmental Evolution. Ed. Lynn Margulis, and Lorraine Olendzenski. London: MIT Press, 1992. 215-243.

Next Article
Previous Article
Return to Topic Menu