February 20- test 2

February 20- test 2 - GEO 1401 Test 2 Notes February 20,...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
GEO 1401 Test 2 Notes February 20, 2008 Plate Tectonics 3 Types of plate tectonics o Diverging o Converging- crevices o Transformation- shifting side to side Divergent Plate Boundaries - a line along which new 2 adjacent plates move apart from each other Ocean ridges Spreading centers Rift zones (on the continents) o Divergent margins- places where new oceanic lithosphere is created o Magma is extruded onto the seafloor and forms PILLOWS Spreading rates o Distance/time= spreading rate (miles per hour) o Measure the age of the seafloor and the width of rocks with that age o Spreading rates vary between 2 to 20 centimeters per year o Average rate worldwide is 3 to 4 cm/year Origin and evolution of divergent plate boundaries 1. Begin as rift zones on the continents. Pulling apart of continental crust 2. As the continent is pulled apart, basaltic magma is extruded into the rift valley. (oceanic crust is being formed) 3. The valley floor sinks and is filled with sea water Physical aspects of Divergent margins 1. State of stress- tensional or pulling
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 3

February 20- test 2 - GEO 1401 Test 2 Notes February 20,...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online