Deserts (The Extreme Earth)

201 Pages·2008·5.815 MB·English

by  Pete Aleshire

Deserts
Peter Aleshire
Foreword by
Geoffrey H. Nash, Geologist
For Elissa, who has been with me for 30 years: not long in geologic time,
but everything in my lifetime
DESERTS
Copyright © 2008 by Peter Aleshire
All rights reserved. No part of this book may be reproduced or utilized in any form or
by any means, electronic or mechanical, including photocopying, recording, or by any
information storage or retrieval systems, without permission in writing from the publisher.
For information contact:
Chelsea House
An imprint of Infobase Publishing
132 West 31st Street
New York NY 10001
Library of Congress Cataloging-in-Publication Data
Aleshire, Peter.
Deserts / Peter Aleshire.
p. cm. — (The extreme earth)
Includes bibliographical references and index.
ISBN-13: 978-0-8160-6434-2
ISBN-10: 0-8160-6434-2
1. Deserts—Juvenile literature. I. Title. II. Series.
QH88.A44 2008
551.41'5—dc22 2007008245
Chelsea House books are available at special discounts when purchased in bulk quantities
for businesses, associations, institutions, or sales promotions. Please call our Special Sales
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Text design by Erika K. Arroyo
Cover design by Dorothy M. Preston/Salvatore Luongo
Illustrations by Melissa Ericksen
Printed in the United States of America
VB FOF 10 9 8 7 6 5 4 3 2 1
This book is printed on acid-free paper.
Contents
GGGGGGGGGGGGGGGGGGGGG
Foreword vii
Preface ix
Acknowledgments xi
Introduction xii
Origin of the Landform: Deserts 1
Section I: Deserts of North America 5
1 G Sonoran Desert: Arizona and Northern Mexico 7
Saguaros Nourish Civilizations 9
Sky Islands Rise from Desert Seas 12
Organ Pipe National Monument Preserves Desert 14
Sky Islands Add Diversity 16
A Baffling Missing Persons Case 17
A Long Buildup and a Fast Collapse 20
More Clues in the Verde Valley 22
Casa Malpais: Death by Religious Warfare? 23
Superstition Mountains and
the Legend of the Lost Dutchman 25
Flowers Blossom in the Desert 26
The Lethal Secret of the Lost Dutchman 27
Buenos Aires: The Grassland Boundary 28
Gila River: Plight of the Desert 30
A Fragile Desert at the Mercy of Human Beings 31
A Massacre That Shocked the Nation 32
2 G Mojave Desert: California, Arizona 34
A Collision of Continents 35
The World in a Song 37
Death Valley: The Lowest, Hottest Place 38
Desert-Adapted Species Struggle 41
Creosote: The Oldest on Earth 42
Ice Age Desert Fish Hangs On 44
Joshua Tree National Monument:
As Lush As the Mojave Gets 44
The Edge of the Desert 46
Desert Bursts into Flower 48
It Takes a Fungus to Make a Soil 49
Rattlesnakes: Deadly Adaptations 50
Grand Canyon: A Transformed Sliver of the Mojave 51
Grand Canyon Reveals the History of the Earth 54
3 G Great Basin Desert: Utah, Arizona, Nevada 56
Great Basin: Terrible Thirst and Endless Sagebrush 56
Cataclysm Leaves Wealth of Minerals 60
A Lethal Barrier to Exploration 61
A Sagebrush Realm 62
Adapted to the Sagebrush Ocean 64
Invaders Unhinge an Ecosystem 66
Painted Desert: Cold Winds and Buried Dinosaurs 66
Condors Make a Comeback 68
The “Blueberries” That Predicted an Ocean 70
4 G Chihuahuan Desert: Arizona, Texas, Mexico 72
The Mystery of the Cataclysm 73
Century Plant Grows Fatally Tall to Survive 74
A Tale of Hungry Bats and Lush Flowers 74
Creatures That Never Take a Drink 76
Big Bend National Monument: Hard and Historical 78
Carlsbad Caverns National Park: Fantastic Realm 79
White Sands National Monument 81
Chiricahua Mountains: Between Two Deserts 82
Living on Algae’s Efforts 82
San Pedro River: A Linear Oasis 86
The Battle of the Bulls 89
Section II: Deserts around the World 91
5 G Sahara Desert: Northern Africa 93
Can Snail Shells Solve a Mystery? 94
A Mystery 1,000 Years Older Than Stonehenge 95
Telltale Stone Tools Yield Clues 96
A Devastating Desert Expansion 97
Blame the Plants for Speed of Sahara Expansion 98
The Geology of the Sahara 99
The World’s Biggest Sand Dunes 100
Sand Dunes Sing 102
The Ghost of Water 102
Living on Million-Year-Old Water 103
In the Grip of a Dry Climate 104
Plants Outwit Drought and Heat 105
Animals Also Evolve Ingenuous Adaptations 106
What Lies Ahead for the Sahara? 106
6 G Arabian Desert: Middle East 110
The Birth of an Ocean 111
Arabian Peninsula Nourished Civilization 111
The Arabian Horse 112
Hidden Riches of the Arabian Desert 113
A Landscape of Sand 114
For Deserts—Location, Location, Location 116
Plants Cope with Salt and Heat 117
Strange Animals Thrive in Harsh Conditions 118
The Ship of the Desert: The Camel 119
7 G Kalahari Desert: Southern Africa 121
The Original People 123
Studying the Human Mystery 125
The Bushman Diet Drug 126
A Fossil Desert 127
Great Animal Migrations 129
Weaverbird Communes 129
8 G Australian Deserts: Australia 133
Disastrous Explorations 134
Kangaroo Hops Happily through Hard Times 136
The Aboriginals: The Oldest Culture 138
Living in Dreamtime 139
9 G Gobi Desert: Central Asia 142
Assembling a Continental Desert 142
Cutting Off the Moisture 145
Plate Tectonics: The Restless Earth 145
Eastern Gobi Desert Steppe 146
Alshan Plateau and Junggar Basin Semi-Deserts 147
Sand and Soil 147
Wildlife of the Gobi Desert 147
Sand Dunes Swallow Dinosaurs 148
The First Indiana Jones 149
The First Bird 151
10 G Atacama: The Oldest Desert: South America 153
Detecting Life 157
A 22,000-Year Rainfall Record 158
El Niño Wreaks Havoc 160
Glossary 163
Books 167
Web Sites 169
Index 171
Foreword
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If you have ever visited a desert, or seen a movie or documentary set in
a desert, you might believe that little, if anything, could exist in such an
environment. A visitor to the Mohave Desert of California, for example,
may doubt that without regular rainfall, streams, or lakes, anything other
than a few well-adapted reptiles could flourish here. After all, we humans
would soon perish in an environment devoid of water to drink, not to
mention the toll extreme heat would play. Access to water is central to
our ability to grow crops and develop industry so deserts may seem for-
bidding and lifeless to us at first glance. Deserts are extreme environments
that are also biologically diverse, and this contradiction makes them in-
teresting to the scientists such as biologists, geologists, and archaeologists
who study them. You might think of a desert as a vast expanse of roll-
ing sand dunes, but many consist of a windswept stony pavement, bare
bedrock, salt-covered flats, or even ice fields or Arctic tundra. What they
share is the basic relationship between rainfall and evaporation. A desert
is defined as a region where evaporation exceeds rainfall or, generally, one
that receives less than 10 inches (25 cm) of rain per year. Because deserts
receive so little rain, geologists are able to study the rocks without a lot of
soil or vegetation getting in the way.
In Deserts, by Peter Aleshire, you will learn the ways deserts can
differ. You will learn about the sustaining sky islands of the Sonoran Des-
ert in Arizona and New Mexico that gather rainwater, allowing wildlife
to thrive throughout the seasons as one plant community after another
matures at different elevations. Another desert you will read about is the
Great Basin Desert in the American Southwest where evaporation over
thousands of years since the end of the last ice age caused the formation
of the Great Salt Lake and the accumulation of massive amounts of salt
and other minerals. Other deserts covered here are the Sahara of north-
ern Africa with the world’s tallest sand dunes and the Arabian Desert,
home to the perfectly adapted “ship of the desert” or camel.
Deserts are the product of where they are located on Earth because
they are produced by climatological factors such as dry winds and rain
G vii G
viii G Foreword
shadows behind mountains. Because of the movement of continents due
to plate tectonics, deserts now exist where forests previously grew and,
often, petrified wood has been left behind as proof of the changes caused
by climate.
Aleshire’s book is an introduction to the study of deserts that will
prove useful to a world where many signs point to a process of unprec-
edented change due to global warming. As areas of Earth are affected by
extreme weather patterns, change will come. Additional rainfall may ben-
efit some areas, while loss of regular rain may produce more arid, difficult
environments that make life harder for their inhabitants. Readers will find
this book an interesting study of some of the most forbidding yet diverse
areas on the planet.
—Geoffrey H. Nash, geologist
Preface
GGGGGGGGGGGGGGGGGGGGG
From outer space, Earth resembles a fragile blue marble, as revealed in
the famous photograph taken by the Apollo 17 astronauts in Decem-
ber 1972. Eugene Cernan, Ronald Evans, and Jack Schmitt were some
28,000 miles (45,061 km) away when one of them snapped the famous
picture that provided the first clear image of the planet from space.
Zoom in closer and the view is quite different. Far beneath the vast
seas that give the blue marble its rich hue are soaring mountains and deep
ridges. On land, more mountains and canyons come into view, rugged
terrain initiated by movement beneath the Earth’s crust and then sculpt-
ed by wind and water. Arid deserts and hollow caves are here too, exist-
ing in counterpoint to coursing rivers, sprawling lakes, and plummeting
waterfalls.
The Extreme Earth is a set of eight books that presents the geology
of these landforms, with clear explanations of their origins, histories, and
structures. Similarities exist, of course, among the many mountains of the
world, just as they exist among individual rivers, caves, deserts, canyons,
waterfalls, lakes, ocean ridges, and trenches. Some qualify as the biggest,
highest, deepest, longest, widest, oldest, or most unusual, and these are
the examples singled out in this set. Each book introduces 10 superlative
examples, one by one, of the individual landforms, and reveals why these
landforms are never static, but always changing. Some of them are inter-
nationally known, located in populated areas. Others are in more remote
locations and known primarily to people in the region. All of them are
worthy of inclusion.
To some people, the ever-shifting contours of the Earth are just so
much scenery. Others sit and ponder ocean ridges and undersea trenches,
imagining mysteries that they can neither interact with nor examine in
person. Some gaze at majestic canyons, rushing waterfalls, or placid lakes,
appreciating the scenery from behind a railing, on a path, or aboard a
boat. Still others climb mountains, float rivers, explore caves, and cross
deserts, interacting directly with nature in a personal way.
G ix G