This preview shows pages 1–2. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: The reversals take about 5 10 3 years, with the main reversals about every 10 6 years. One of the main uses of this has been to look at sea-floor spreading. If we look at the morphology of, say, the mid-Atlantic ridge, we see a complex fracture pattern following the line of the ridge: If we cross the ridge from A to B and measure the magnetic field directions we find a pattern mirrored about the ridge line: the pattern is tge line: the pattern is the sort of reversal pattern we saw above: The time-scale is known from the previous diagram,which tells us the rate of sea-floor spreading. This has been crucial in developing the theory of continental drift. Typical rates of sea-floor spreading are: near Vancouver c.2.9metres/yr; off Peru c. 4.5 metres/year; these are typical values....
View Full Document
This note was uploaded on 12/15/2011 for the course AST AST1002 taught by Professor Emilyhoward during the Fall '10 term at Broward College.
- Fall '10