Introduction

Getting Started

1. If you haven’t done it already, download Google EarthTM 5.0 from earth.google.com and install

it on your computer.

2. If you haven’t done it already, download the Essentials_3E_Geotours.kmz file and save a copy

to your desktop.1 (The Essentials_3E_Geotours.kmz file contains the Geotours for all chapters,

so you only need to download this once!):

For Essentials of Geology, Third Edition, go to:

www.wwnorton.com/studyspace/disciplines/geology.asp

3. Double-click the Essentials_3E_Geotours.kmz file, and Google EarthTM will open automatically

(or open Google Earth™ first, and then select File > Open to open the file).

4. In the left-hand sidebar you will see a Places panel, and in the Temporary Places folder you

will see an Essentials_3E_Geotours.kmz folder. Double-click this folder, and you will see an

Essentials_3E_Geotours folder. Double-click this folder, and you will see a list of Geotours for

each chapter.

5. Open the Geotour folder that you want to use and go explore!

1 By downloading Geotours.kmz you acknowledge that it was created solely to accompany Stephen Marshak's Essentials of Geology and is limited to use with only Stephen Marshak's 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.

Images provided by Google Earth™ mapping service/DigitalGlobe, TerraMetrics, NASA, Europa Technologies—copyright 2008. GT-1

Opening Google Earth™

To use a Geotour, start by opening Google Earth™. As the program initializes, an image of the globe set in a background of stars appears in a window. The toolbar across the top provides a window icon. Click on this icon and a left sidebar appears (Image

GP.1)—click on the icon again and the sidebar disap-pears so that the image becomes larger. The toolbar also provides a pushpin tool for marking locations, and a ruler tool for measuring distances. The sidebar contains information about locations and provides options for adding information to the screen image. For example, when you click on “borders,” “roads,” and “Populated Places” in the Layers panel, politi-cal boundaries, highways, and city names appear to provide a visual reference frame (Image GP.2). Any location you have marked with a pushpin appears in the sidebar within the Places panel. Double-clicking on the location in the sidebar will make the pushpin appear and will take you to the location. If you type a location in the Search panel at the top, a click on the magnifying glass icon will fl y you to the location.

GP.1 GP.2

See for yourself . . .

How to Use Google Earth™ to See Geologic FeaturesIn earlier editions of this book, we could provide photos of landscapes, but could not convey a 3-D image of a region from a variety of perspectives. Fortunately, web-based computer tools such as Google Earth™, NASA World Wind, or Microsoft Virtual Earth, now permit you to tour our planet at speeds faster than a rocket. You can visit millions of locations and see for yourself what geologic features look like in context. These tools provide a compilation of imagery in a format that permits you to go to locations quickly and view them from any elevation, perspective, or direction. You can examine boulders on a hillside, zoom to airplane height to see the landform that the boulders rest on, and then zoom to astronaut height to see where the landform lies in a continent. You can look straight down or obliquely, and you can stay in one position, circle around a location, or fl y like a bird over a landscape.

To help you use computer-visualization programs to understand geology, each chapter of this book includes a Geotour,with locations and descriptions of geologic features relevant to the chapter. Because only Google Earth™ can be used on both PC and Mac computers (as of this writing), we key the Geotours to the Google Earth™ format. Below, we provide a brief introduction to the use of Google Earth™ in the context of this book. Some of the details of procedures may change as Googleupdates the program. There’s not room for a complete tutorial, but you’ll fi nd that the program is so easy to use that you will be profi cient with it simply by working with it for a few minutes. The thumbnail images provided on this page are only to help identify tour sites. Go to wwnorton.com/studyspace to experience this fl yover tour.

Geotours

GT-2

The Basic Tools of Google Earth™

In Google Earth 4.3™, three navigation tools appear in the upper right-hand corner of the screen (Image GP.3): (1) The Look tool (circle with an eye in the center) allows you to rotate the view. You can do this either by clicking and dragging the mouse on or within the outer ring, or by rotating the view clockwise or counterclockwise by clicking on the left or right arrows, respec-tively. Double-clicking the N button reorients the view with north at the top of the screen. Clicking on the top arrow of the Look tool tilts the image to show an oblique view, whereas clicking on the bottom arrow rotates the perspec-tive back towards vertical. You can see this contrast by comparing the “Basic Tools-Vertical” and the “Basic Tools-Oblique” images of a site in the Andes Mountains of Bolivia (Lat 18°21'36.08"S, Long 66°0'13.95"W) from an altitude of 10 km (Images GP.4 and GP.5). Note that, because of the nature of the imag-ery used by Google Earth™, steep cliffs are distorted. Clicking and dragging the mouse in the inner circle of the Look tool performs both actions simul-taneously. (2) The Move tool (circle with a hand in the center) pans across the image. By clicking the arrows, you move a fi nite distance in the specifi ed direction. Clicking and dragging the mouse in the inner circle acts as a joystick and translates the view in any direction. (3) The vertical Zoom slider zooms the view up or down. You can either move the slider or click on the end of the bar. Clicking on the + end takes you to a lower elevation, whereas clicking on the – end takes you to a higher elevation. The slider offers better control. Using the “View” menu bar, you can click to display a bar scale in the lower left portion of the screen. Note that the default setting in Google Earth 4.3™ is to swoop (tilt) into a perspective view as you zoom closer. This auto-tilt behav-ior may be turned off in the Preferences (Options) menu.

On the Earth image, you will see a hand-shaped cursor. By dragging the cursor across the screen, you can move the image. If you quickly drag the hand cursor, while holding down the mouse, and then let go, the movement will continue. For additional information, see the Google Earth™ User Guide.

Working with Location and Elevation

(Lat 43°8'18.84"N, Long 77°34'18.36"W)

On the bottom rule of the window, you will see three information items. The location of the point just beneath the hand-shaped cursor on the screen is specifi ed on the left in terms of latitude (degrees, minutes, and seconds north or south of the equa-tor) and longitude (degrees, minutes, and seconds east or west of the of the prime meridian). Just to the right of the Lat/Long information, a number indicates the elevation of the ground surface just below the hand-shaped cursor. The next number to the right tells you how much of the image has streamed onto your computer—an image starts out blurry, and then as streaming approaches 100%, it becomes clearer. The number on the far right (“Eye alt”) indicates your viewing elevation.

To practice using these tools, enter the latitude and longitude provided above and zoom to a view-point 25,000 km (15,500 miles) out in space. You will see all of North America (Image GP.6). If you zoom down to 1800 m (5900 ft), you can see the details of Cobb’s Hill Park in Rochester, New York (Image GP.7). Tilt your image so you just see the horizon, and rotate the image so you are looking SW (Image GP.8). With this perspective, you realize that the bean-shaped res-ervoir sits on top of an elongate ridge.

GP.6

GP.8GP.7

GP.3

GP.4

GP.5

GT-3

Images provided by Google Earth™ mapping service/DigitalGlobe, TerraMetrics, NASA, Europa Technologies—copyright 2008.

Image Boundaries

(Lat 16°6'3.12"N, Long 75°48'25.84"E)

The globe that you see on your screen is a compilation of many separate satel-lite images merged by computer; some regions, therefore, look like a patch-work. To see this effect, fl y to the coordinates provided in India and look down from an elevation of 600 km (Image GP.9). Image boundaries may refl ect one or more of the following factors. (1) Resolution: The sharpness or clarity of images on Google Earth™ depend on the resolution of the image that is avail-able in the database. High-resolution images are clear at high magnifi cation, whereas low-resolution images appear grainy or pixelated at high magnifi ca-tion. Depending on the speed of your internet connection, it may take time for the full available resolution of an image to show up. The image is fully loaded when the blue circle in the lower right-hand corner has become solid. (2) Season: Some images show regions in the winter, when leaves are down and the ground is visible, whereas some show regions in summer, when the canopy of trees hides the ground. (3) Photo Tint: Not all satellite images are taken in the same way, so not all have the same basic color tint. Google Earth™ constantly updates images, as new ones become available, so a region that looks like a patchwork one day might not the next.

Finding Locations Using Latitude and Longitude

(Lat 48°52'25.26"N, Long 2°17'42.18"E)

You can fi nd towns, parks, and landmarks on the Earth using Google Earth™ by entering the name in the search panel in the upper left corner. For example, enter Arc de Triomphe, hit the return button, and you fl y to this well known land-mark in the center of Paris, France (Image GP.10). Many of the places you will visit in Geotours of this book are not, however, near a well-known landmark. Thus, to get you to a locality, we provide a latitude and longitude in the form:

Lat 48°52'25.44"N, Long 2°17'42.31"E

The fi rst number is the latitude in degrees, minutes (60' = 1°), and seconds (60.00" = 1'). Simply enter the latitude and longitude on your screen. When typing numbers into the space provided on the program, you can abbreviate as:

48 52 25.44N, 2 17 42.31E

Note that instead of typing in latitude and longitude, you can simply copy the “.kmz” fi les provided in this book’s website onto your computer. When you double-click on a fi le, it will open Google Earth™ and add all the locations referred to in the book to the “Temporary Places” folder. Then you simply need to click on the particular image referred to in a Geotour and the program will fl y you straight there.

Enjoy!Please take advantage of the Geotours provided in this book. They provide you with an understanding of geology that simply can’t appear on a printed page, and they are, arguably, as fun as a video game. Take control of the Google Earth™ tools, change your elevation and perspective, and fl y around the landscape. Geology will come alive for you, and explora-tion of the Earth may become your hobby.

GP.9

GP.10

PRELUDE

How to Use Google Earth™

Opening Google Earth™

To use a Geotour, start by opening Google Earth™. The program will initialize and an image of the globe, with a background of stars, will appear on your screen. A toolbar across the top of the window provides a window icon that allows you to switch from a full-screen view (no sidebar) to a partial-screen view (sidebar), a pushpin tool for marking locations, and a ruler tool for measuring distances (other icons that perform additional features are also available).

Panels Sidebar

The sidebar contains information about locations and provides options for adding information to the screen image.

The topmost panel in the sidebar is the Search panel. There you can type in a location in the text blank and click the magnifying glass to execute the search (and then fly directly to the location).

The middle area is the Places panel. It stores locations that either you create yourself or that you open using File > Open (e.g., this Geotour file). Clicking the box next to a name will toggle between showing/hiding the feature (note that showing an entire folder loads everything in the folder to memory, taking considerable time). Double-clicking the icon (recommended) or name of an item within a folder will take you to that location.

The lowermost panel in the sidebar is the Layers panel, which shows content provided by Google Earth™ and associated collaborators. For example, when you click on Borders and Labels in the Layers panel, country and state boundaries as well as city names will appear to provide a visual reference frame.

Any of these three panels may be hidden by toggling the triangle next to their respective name.

Places Panel

The Places Panel contains all of the Geotour Sites from the textbook, More Geotour Sites, and Worksheets organized by chapter (note: PC users will see +/- boxes that expand/collapse the folders).

Time Sequence & Flyover Controls

The top figure shows the controls for time-based sequences and historical animations. The lower figure shows the controls for automated flyover tours.

Navigation Controls

In Google Earth™ 5.0, three navigation tools appear in the upper right-hand corner of the screen:

• The Look tool (circle with an eye in the center) allows you to rotate the view. You can do this either by clicking and dragging the mouse on or within the outer ring, or by rotating the view clockwise or counterclockwise by clicking on the left or right arrows, respectively. Clicking (or dragging) the N button reorients the view with north at the top of the screen. Clicking on the top arrow of the Look tool tilts the image to show an oblique view, whereas clicking on the bottom arrow rotates the perspective back towards vertical (note: shift + scroll wheel provides a shortcut for this action). You can see this contrast by comparing the "Basic Tools-Vertical" and the "Basic Tools-Oblique" images of a site in the Andes Mountains of Bolivia. Note that, because of the nature of the imagery used by Google Earth™, steep cliffs are distorted. Clicking and dragging the mouse in the inner circle of the Look tool performs both actions simultaneously.

• The Move tool (circle with a hand in the center) pans across the image. By clicking the arrows, you move a finite distance in the specified direction. Clicking and dragging the mouse in the inner circle acts as a joystick and moves the view in any direction.

• The vertical Zoom slider zooms the view up or down. You can either move the slider or click on the end of the bar (the slider provides more detailed control). Clicking on the + end takes you to a lower elevation, whereas clicking on the – end takes you to a higher elevation. Using the “View” menu bar, you can click to display a bar scale in the lower left portion of the screen. Note that the default setting in Google Earth™ 5.0 is to swoop (tilt) into a perspective view as you zoom closer. This auto-tilt behavior may be turned off (On a Mac: Google Earth > Preferences > Navigation > Navigation controls or On a PC: Tools > Options > Navigation > Navigation controls).

• On the Earth image, you will see a hand-shaped cursor. By dragging the cursor across the screen, you can move the image. If you quickly drag the hand cursor, while holding down the mouse, and then let go, the movement will continue.

• For additional information, see the Google Earth™ User Guide (http://earth.google.com/userguide/v4/#navigating).

Information Bar

On the bottom rule of a Google Earth™ 5.0 window, you will see several information items.

On the far left side is a map scale that can be toggled on/off (View > Scale Legend).

The location of the point just beneath the hand-shaped cursor on the screen is specified in the center of the screen in terms of latitude (degrees, minutes, and seconds north or south of the equator) and longitude (degrees, minutes, and seconds east or west of the of the prime meridian). Note that you can change how these locations are displayed (On a Mac: Google Earth > Preferences or On a PC: Tools > Options).

In addition, the center of the screen also shows the approximate elevation of the ground surface ("elev") just below the hand-shaped cursor.

The number on the far right (“Eye alt”) indicates your viewing elevation.

Finally, on the far right side of the window is a blue circle that graphically shows if your computer is busy processing (e.g., streaming image data as you zoom in—at first the image starts out blurry, and then as streaming approaches 100%, it becomes clearer).

Hints & Tips

• Do not turn on all the folders at once as it will load everything in the Geotours at the same time.

• You can make the Panels sidebar wider by clicking and dragging on the right side of the Panels sidebar (the border between it and the main Google Earth™ window).

• You may turn off the auto-tilt feature (On a Mac: Google Earth > Preferences > Navigation > Navigation controls or On a PC: Tools > Options > Navigation > Navigation controls).

• Some subtle features are more easily seen by temporarily increasing the vertical exaggeration to 3 (On a Mac: Google Earth > Preferences or On a PC: Tools > Options). A good rule is generally keep the vertical exaggeration at 1 or 1.5.

• The Search and Layers panels can be hidden by clicking the triangle next to their name in order to see more of the Places panel.

• The Geotours are easier to interact with using a mouse (preferably with a scroll wheel) than with a trackpad.

• If things look flat and lack a third dimension, check that “Terrain” is turned on in the Layers panel.

• Please be patient as images are loading into cache as some placemarks will look incomplete until the images are completely loaded.

• Shift + scroll wheel changes the tilt of the view, whereas shift + left mouse button allows both rotation and tilting.