earthquakes 1

earthquakes 1 - -oldest rocks are always found on...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
Earthquakes august 29 th , 2007. Earthquakes don’t kill people, buildings do. I. Geologic Time i. Relative time. 1. compares which is older based on layering in the ground. 2. Absolute time i. Done by radioactive decay – 1950s. ii. Absolute time scale (# of years before present) 1. time since rock cooled from melt 2. date comes from ratio of apparent radioactive isotope relative to daughter isotope produced by radioactive decay. a. u238 (uranium) -> pb206 (lead) half life of 4.49 x 10^9 years b. c14 -> n14 half life of 5570 years c. k40 (potassium) -> argon40 half life of 1.19 x 10^10 oldest rocks 3.8 Ga (billions of years ago) found in Greenland
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: -oldest rocks are always found on continent, not ocean 1. oldest rocks in ocean are only 200 Ma (millions of years) oldest mineral 4.2 Ga found in Australia Earth is 4.6 Ga -age of meteor called carbonaceous chondrile-never heated above 200 degrees Celsius 1. date these rocks that have never been part of planet = 4.6 Ga Mendel 1840s Genetics A. paradigm – all encompassing theory/idea that explains multiple observations and puts into coherent whole. i. Paradigm shift – idea shift ii. Plate tectonics 1. 1965- 10% believed in plate tectonics and its movements 2. 1970 – 98% believed 3....
View Full Document

This note was uploaded on 01/23/2009 for the course GEOL 240Lxg taught by Professor 12:30-01:50pm during the Fall '07 term at USC.

Ask a homework question - tutors are online