GEOL 1425 1st Edition Lecture 2Outline of Last Lecture I. Overview of GeoscienceII. Types of scientist related to GeologyIII. Earth as a wholeIV. Earth systemsOutline of Current Lecture I. Declination/inclinationII. Earth’s magnetismIII. Earth’s compositionCurrent Lecture- Declination: angle between true north and magnetic north- Inclination: angle between line of force and earth’s surface- Anything magnetic will line up with the lines of force associated with the Earth’s magnetic field. I.e: magnetic minerals in rocks and compass needles. - Earth’s magnetic field results from electrons in the earth’s core moving rapidly.- Magnetic minerals in rock will line up with existing magnetic field as they crystalize. This allows for geologist to determine where the past magnetic fields on earth were. - Some rocks from the same time period will indicate the magnetic field to be at different places. This is due to apparent polar wandering from continent to continent. - Magnetic poles can switch. Literally the once North Pole becomes south and vice versa. This has occurred 18 times in 5million years. On average=switch every 278000 yrs. Present position of poles has held for 500000 yrs. - Poles switch due to random changes in electrons. - Northern lights come from solar winds (charged particles released by sun) that get diverted by the magnetic field along the lines of force. These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- Mid Atlantic Ridge- off coast of Iceland- magnetic survey done on rocks along sea floor. Found alternating bands of normal/reverse polarity. Shows the sea floor spreading- Continents are 14x older than the ocean floor. This is b/c the continents are less dense so they float. Also, the ocean floor is constantly being created and destroyed. Older sea floor sinks into the mantle near subduction zones/trenches while new sea floor is being created along
View Full Document