1 Cosmology and the Earth
2 Journey to the Center of the Earth
3 Drifting Continents and Spreading Seas
4 The Way the Earth Works: Plate Tectonics
5 Patterns in Nature: Minerals
6 Up from the Inferno: Magma and Igneous Rocks
7 A Surface Veneer: Sediments, Soils, and Sedimentary Rocks
8 Metamorphism: A Process of Change
9 The Wrath of Vulcan: Volcanic Eruptions
10 A Violent Pulse: Earthquakes
11 Crags, Cracks, and Crumples: Crustal Deformations and Mountain Building
12 Deep Time: How Old Is Old?
13 A Biography of Earth
14 Squeezing Power from a Stone: Energy Resources
15 Riches in Rock: Mineral Resources
16 Unsafe Ground: Landslides and Other Mass Movements
17 Streams and Floods: The Geology of Running Water
18 Restless Realm: Oceans and Coasts
19 A Hidden Reserve: Groundwater
20 An Envelope of Gas: Earth’s Atmosphere and Climate
21 Dry Regions: The Geology of Deserts
22 Amazing Ice: Glaciers and Ice Ages
23 Global Change in the Earth System

Organize

Learn

Connect

Norton Gradebook

Instructors now have an easy way to collect students’ online quizzes with the Norton Gradebook without flooding their inboxes with e-mails.

Students can track their online quiz scores by setting up their own Student Gradebook.

Chapter 8: Metamorphism: A Process of Change

Geotours

Reduce Text SizeIncrease Text SizeEmailPrint Page

download Download Geotours.

Getting Started :

  1. If you haven’t done it already, download Google Earth™ and install it on your computer.
  2. If you haven’t done it already, download the Geotours.kmz file and save a copy to your desktop. (The Geotours.kmz file contains the Geotours for all chapters, so you only need to download this once!)

    By downloading Geotours.kmz you acknowledge that it was created solely to accompany Steve Marshak's Earth: Portrait of a Planet and Essentials of Geology and is limited to use with only Steve Marshak's Earth: Portrait of a Planet and Essentials of Geology and may not be reproduced, stored in a retrieval system, or transmitted in any form by any means for any other purpose without the written permission of the publisher.

  3. Double-click the Geotours.kmz file and Google Earth™ will open automatically.
  4. In the left-hand sidebar you will see a Places menu, and in the Temporary Places folder you will see an EARTH_3e.kmz file. Double-click the file and you will see a list of Geotours for each chapter.
  5. Then open the Geotour folder you want to explore! If you’d like to read more about the features of Geotours see Using Geotours, or go to our Helpful Resources section.

STOPS ON GEOTOUR 8: Precambrian Metamorphic Terranes

  • Wind River Mountains, Wyoming
    • See also Worksheet Problem 1
    • "What a Geologist Sees" Geofeatures: Two Flat Irons and Glacial Valley; Overlay: Geologic Map
  • Canadian Shield, East of Hudson Bay
    • See also Worksheet Problem 2
  • Pilbara Craton, Western Australia

GEOTOUR 8 WORKSHEET

A metamorphic terrane is a region of crust composed of metamorphic rock. In unvegetated exposures you can see regional grain (the map trend of foliations), nonconformities between basement (metamorphic rock) and cover (overlying sedimentary strata), and contacts between different rock types. Explore these examples!


  • Wind River Mountains, Wyoming
    1. Turn on the overlay “Geologic Map” under the WAGS folder and make it semi-transparent. This overlay is a geologic map of the Wind River Mountains showing the different rock units exposed in the region. Each rock unit is indicated by a different color and/or pattern. Some abbreviations for the unit names are also shown on the map. For example, Wgn is Precambrian gneiss, and Wg is Precambrian granite. Note that the bands of color along the NE side of the range represent Paleozoic and Mesozoic Strata (uK, for example, is Upper Cretaceous), and the yellows on the map are Cenozoic sediments.


  • (a) Use the transparency slider to make the map transparent. Then change your elevation and tilt, and fly around the range. Are the high peaks in the range within the Precambrian metamorphic areas or in the sedimentary layers?

    Why?

  • (b) Recall that a flat iron, or cuesta, is an asymmetric ridge of sedimentary rock—the “dip slope” on one side is parallel to bedding, whereas the “scarp” on the other side is a cliff that cuts across bedding. Find the flat irons of the Wind Rivers. Based on the orientation of the flat irons, are the beds tilted (dipping) to the NE or SW?

  • (c) Find the contact between the metamorphic rocks and the tilted sedimentary strata in the Wind Rivers. A contact is the boundary surface between two geologic units. This contact, between metamorphic rocks and sedimentary rocks, is known as a nonconformity (these will be discussed further in Chapter 12). Is the contact a straight line on the map, or is it scalloped (i.e., it consists of short curved segments that connect at a V).

    Why?

  • Canadian Shield, East of Hudson Bay
    2. Click on the placemarks for Problem 2 to see outcrops of Precambrian metamorphic rock in the Canadian Shield. You will have a view of intricate curves defined by the trend of the foliation. Geologists interpret the features highlighted by the placemarks to be folds formed when the layering was contorted (deformed) without breaking in response to shearing. Is this interpretation consistent with the concept that these rocks were deformed during metamorphism?




First Name:
Last Name:
Your Email Address:
Your Professor's Email Address:

Print this Page « Return to Chapter 8 Study Plan