Plate Tectonics of Montana and Northern Rockies-Introduction

Introduction to Plate Tectonics

Plate tectonics has revolutionized the earth sciences. The world wide distribution of oceans, mountains, continents, volcanos, earthquakes, and major petroleum and mineral deposits are now understood in terms of the motion of a small number of plates or rigid pieces of the outer shell of the earth that are all moving with respect to one another. The study of fossils, glaciers, deserts, ancient climates, volcanos, seismic waves, fluid mechanics, and high-pressure rock deformation all contribute to the unraveling and understanding of these large scale motions. Thirty years ago this topic was on the frontier of research for earth scientists. Now the basic concepts are part of the K-12 curriculum; and many websites on the Internet--see below--have elaborate graphics to illustrate the ideas, mechanisms, and processes.

Rather than repeat discussions which appear elsewhere, here are some of the best websites for learning about plate tectonics. A short article on plate tectonics that presents key concepts appeared in Amateur Astronomy & Earth Sciences Magazine. The U.S. Geological Survey published an Internet version of its booklet, The Dynamic Earth: the Story of Plate Tectonics. It is divided into 8 chapters; and thus, loads quickly. It is easy to read and has excellent photos and graphics. A 4 MB Zip file is also available in .pdf format for the Acrobat Reader. This is one of the best introductions if you can spend an hour or so.

One of the websites at the University of Pittsburgh has an on-line version of the geology textbook, Planet Earth and the New Geosciences. Unit 3 and Unit 4 in this text cover plate tectonics. There are many, many photos of earthquake damage and volcanos related to the motion of the plates (and thus, the units take a while to load into your browser). Maps showing the distribution of earthquakes are color-coded for depth. Also at the University of Pittsburgh website are animations (generated from the data of Chris Scotese at the University of Texas at Austin) for the last 550 million years showing the motions of the continents to form the supercontinent, Pangea, and its subsequent breakup. (The animation is slow to load on your browser.)

The following topics are covered at the U.S. Geological Survey website on plate tectonics:

Vertical Chemical Structure of the Earth: crust, mantle, core

Vertical Mechanical Structure of the Earth: lithosphere, asthenosphere, core

Horizontal Mechanical Structure of the Earth: tectonic plates

Types of Plate Boundaries: divergent, convergent, transform fault

Subduction

History of the Ocean Basins: magnetic stripes

Hotspots

Driving Mechanisms

Plate Tectonics of Montana (Page 1 of 14)