Lab+10+History+of+life

Lab+10+History+of+life - EAS 1601 Lab 10 Geological Time,...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
EAS 1601 Lab 10 “Geological Time, History of Life & Fossils” Sample Prelab Quiz (Note: actual quiz may differ) 1. What is a fossil? 2. In what class of rocks (sedimentary, igneous, or metamorphic) would you find fossils? (Think back to your Rock Lab.) 3. Where (within several horizontal layers of rock that have not been overturned) would you expect to find: (a) The oldest fossils? (b) The youngest?
Background image of page 1

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

View Full DocumentRight Arrow Icon
EAS 1601 Lab 10 “Geological Time, History of Life & Fossils” Name______________________________ Lab Section ___________________ Purpose: In this lab you will learn how to interpret geologic cross sections and the fossil record, in order to study some part of Earth's history. Background Information: Telling the history of the earth requires placing events in sequence so that reference can be given to the relative and/or numerical time at which each event occurred. This helps to make sense out of the enormous expanse of time that has elapsed since the origin of the earth. Figure 1. Geological timescale. ( The figure and the supporting text are adopted from http://www.geo.ucalgary.ca/~macrae/timescale/timescale.html ) Few discussions in geology and earth science can occur without reference to geologic time. Geologic time is often discussed in two forms: 2
Background image of page 2
Relative time ("chronostratic") -- subdivisions of the Earth's geology in a specific order based upon relative age relationships (most commonly, vertical/stratigraphic position). These subdivisions are given names, most of which can be recognized globally, usually on the basis of fossils. Absolute time ("chronometric") -- numerical ages in "millions of years" or some other measurement. These are most commonly obtained via radiometric dating methods performed on appropriate rock types. The time scale depicted above is shown in its traditional form with oldest at the bottom and youngest at the top -- the present day is at the zero mark. Geologic time is finely subdivided through most of the Phanerozoic but most of the finer subdivisions (e.g., epochs) are commonly referred to by non-specialists only in the Tertiary. Because of the vast difference in scale, the younger intervals have been successively expanded to the right to show some of these finer subdivisions. Geologic sections, which are simply exposed cross-sections of rock bodies, can help us to unravel the sequences of events in Earth’s history. These sections essentially act as a log of events that occurred through time and therefore provide a means of relative dating. Bio- geologists and paleontologists can also use them to correlate the relative ages of rock formations. This is useful in finding natural resources, particularly fossil fuels. To establish a relative time scale and decipher the order of events we must apply some
Background image of page 3

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

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 02/08/2011 for the course EAS 1601 taught by Professor Lynch during the Spring '08 term at Georgia Tech.

Page1 / 13

Lab+10+History+of+life - EAS 1601 Lab 10 Geological Time,...

This preview shows document pages 1 - 4. Sign up to view the full document.

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