william smith going to diff places of country similar

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

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: - going to diff places of country, similar countries - same period of time - time ranges of species over lap, look at various species Fossils that are particularly useful for this purpose are called index fossils. - bottom = primitive earlier species - something that existed for a short time, more useful in terms of dating rocks 3 1/25/2013 - rocks erode, losing time (gap in time, rock goes missing) Missing Time and Unconformities The rate of sediment deposition is not uniform through time. Significant pauses in sediment deposition may occur, or in extreme cases, rock can be removed by erosion. - this unconformity is famous in Scotland Under these circumstances, “time” (in the form of rock) goes missing. - tilted by crunching of layers, wearing down of rocks Surfaces representing these slices of missing time are called unconformities. Horizontal sedimentary rocks horizontal sedimentary rock Example of an angular unconformity Tilted sedimentary rocks tilted sedimentary rocks Example of How These Relative Dating Principles Can Be Used - relative time of events picture for test? - faulting, erosion, layers ontop, faulting, erosion to level 11 Dealing With Absolute Time Use knowledge of the behaviour of radioactive materials to date minerals, rocks and geologic events (specifically the behaviour of decay in radioactive isotopes of certain elements) (same protons, diff number of neutrons) Radioactive Isotopes: Varieties of atoms of a particular element differing in their number of neutrons and having the ability to spontaneously decay to produce daughter products and energy. 4 1/25/2013 ratio of parent iso...
View Full Document

This document was uploaded on 02/25/2014.

Ask a homework question - tutors are online