09 GEOS 1004 - GEOS 1004, SPOTILA Lecture 8, 9/22/09...

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

View Full Document Right Arrow Icon
GEOS 1004, SPOTILA Lecture 8, 9/22/09 Geologic principles II: the rock record and geologic time *One of the most important contributions of geoscience has been discovering the age and history of the earth. It is as important as the discovery that the sun is the center of the solar system, or that the universe extends far beyond the solar system. Heat within the earth is maintained by radioactive elements in the mantle and core. Collectively, large groups have repeatable, measurable decay rate, so we can statistically predict the probability of a given atom decaying in a certain period of time. Radioactivity is Systematic 1) an isotope always decays at the same rate 2) rates have been measured precisely Age of Earth = 4.6 billion years (4.6 Byr = 4.6 Ga = 4,600,000,000 = 4.6x109 yrs) *What is this based on? geologic timescale = -variable resolution, eons, eras, periods, epochs -resolution decreases back in time (more divisions towards the present) WHY? -terminology is based on original timescale which was relative
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.

This note was uploaded on 09/09/2011 for the course GEOG 1004 taught by Professor Staff during the Fall '07 term at Virginia Tech.

Page1 / 3

09 GEOS 1004 - GEOS 1004, SPOTILA Lecture 8, 9/22/09...

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