Geo 1001 - Paper Faults

This page contains a number of links to large GIF images that you can print, cut, fold and tape to form paper models of different fault types. Use the models to answer the questions below. At the bottom of the page there is a link to the questions' answers, but don't use this link until you have worked with the models to arrive at your own conclusions.

FAULT TYPE IDENTIFICATION

Different tectonic stresses will result in different types of fault movement. So if you can identify what type of motion has occurred along a fault plane, you can also identify what type of stress produced that motion. Geologists study an area’s fault patterns to make interpretations of its present and past tectonic history. To identify past fault motions, geologists have to rely on the geometry of rock units that have been offset along the fault. Identifying fault motion by this method takes some practice and it can be difficult to visualize the three-dimensional nature of the rock units from simple two-dimensional image.

IDENTIFYING FAULT MOTION – STEP BY STEP 

MODELS 1 & 2
Models 1 and 2 both show a single fault that cuts a series of flat-lying rock layers and a vertical igneous intrusion. For each model, try to determine what type of fault motion occurred along the fault. Was it normal, reverse, right-lateral or left-lateral motion? For each of the models, what type of tectonic stress most likely created this fault?

Model 1

Model 2


MODELS 3 & 4
Models 3 and 4 both show a single fault that cuts a series of tilted rock layers. Because the rock layers are tilted, there are two possible types of fault motion that could create the geometry seen in each fault model. For each model, try to determine which two types of fault motion might have been responsible for the present pattern.
 
Model 3

Model 4


MODELS 5, 6, 7 & 8
Models 5, 6, 7 and 8 all show faults that cut a series of tilted rock layers and an igneous intrusion. The addition of the intrusion should allow you to identify a single type of fault motion that created this geometry.  Was the fault motion normal, reverse, right-lateral or left-lateral motion? For each model, what type of tectonic stress created this fault?

Model 5

Model 6

Model 7

Model 8

Answers