Dinosaurs under the Aurora

Roland A. Gangloff

Description

North to Alaska in pursuit of dinosaurs

In 1961, while mapping rock exposures along the Colville River in Alaska, an oil company geologist would unknowingly find the evidence for a startling discovery. Long before the North Slope of Alaska was being exploited for its petroleum resources it was a place where dinosaurs roamed. Dinosaurs under the Aurora immerses readers in the challenges, stark beauty, and hard-earned rewards of conducting paleontological field work in the Arctic. Roland A. Gangloff recounts the significant discoveries of field and museum research on Arctic dinosaurs, most notably of the last 25 years when the remarkable record of dinosaurs from Alaska was compiled. This research has changed the way we think about dinosaurs and their world. Examining long-standing controversies, such as the end-Cretaceous extinction of dinosaurs and whether dinosaurs were residents or just seasonal visitors to polar latitudes, Gangloff takes readers on a delightful and instructive journey into the world of paleontology as it is conducted in the land under the aurora.

Preface
Acknowledgments
1. The Arctic Setting
2. Tracks Lead the Way: Circumarctic Discoveries from Svalbard to Chukotka
3. A Black Gold Rush Sets the Stage for Discovery in Alaska
4. Peregrines, Permafrost, and Bonebeds: Digging Dinosaurs on the Colville River
5. Texas, Teachers, and Chinooks: Taking Field Work to a New Level
6. The Arctic during the Cretaceous: The Western Interior Seaway
7. Cretaceous Dinosaur Pathways in the Paleo-Arctic and along the Western Interior Seaway
8. Applying New Technologies to the Ancient Past
9. Natural Resources, Climate Change, and Arctic Dinosaurs
10. Future Expansion of the Arctic Dinosaur Record
Notes
Glossary
Literature Cited
Index

Sujets

• Sciences de la nature
• Biologie
• Natural History
• Life Sciences
• Sciences et techniques
• Biology
• Paleontology
• Evolution
• Animals
• 454 Life Sciences
• Science

Informations

• Publié par: Indiana University Press
• Date de parution: 10 juillet 2012
• Nombre de lectures: 0
• EAN13: 9780253007186
• Langue: English
• Poids de l'ouvrage: 2 Mo

Extrait

DINOSAURS UNDER THE AURORA
Life of the Past
James O. Farlow, editor
DINOSAURS
UNDER THE AURORA
Roland A. Gangloff
Indiana University Press
Bloomington and Indianapolis
This book is a publication of
Indiana University Press
601 North Morton Street
Bloomington, Indiana 47404-3797 USA
iupress.indiana.edu
Telephone orders
800-842-6796
Fax orders
812-855-7931
2012 by Roland A. Gangloff
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 and recording, or by any information storage and retrieval system, without permission in writing from the publisher. The Association of American University Presses Resolution on Permissions constitutes the only exception to this prohibition.
The paper used in this publication meets the minimum requirements of the American National Standard for Information Sciences-Permanence of Paper for Printed Library Materials, ANSI Z39.48-1992.
Manufactured in the United States of America
Library of Congress Cataloging-in-Publication Data
Gangloff, Roland A.
Dinosaurs under the aurora / Roland A. Gangloff.
p. cm. - (Life of the past)
Includes bibliographical references and index.
ISBN 978-0-253-00080-4 (cloth : alk. paper) - ISBN 978-0-253-00718-6 (ebook) 1. Dinosaurs-Alaska. 2. Paleontology-Cretaceous. 3. Geology, Stratigraphic-Cretaceous. 4. Geology-Alaska. I. Title.
QE861.8.A4G36 2012
567.909798 7-dc23
2012005738
1 2 3 4 5 16 15 14 13 12
CONTENTS
PREFACE
ACKNOWLEDGMENTS
1 The Arctic Setting
2 Tracks Lead the Way: Circumarctic Discoveries from Svalbard to Koryakia
3 A Black Gold Rush Sets the Stage for Discovery in Alaska
4 Peregrines, Permafrost, and Bone Beds: Digging Dinosaurs on the Colville River
5 Texas, Teachers, and Chinooks: Taking Fieldwork to a New Level
6 The Arctic during the Cretaceous
7 Cretaceous Dinosaur Pathways in the Paleo-Arctic and along the Western Interior Seaway
8 Applying New Technologies to the Ancient Past
9 Natural Resources, Climate Change, and Arctic Dinosaurs
10 Future Expansion of the Arctic Dinosaur Record

GLOSSARY
NOTES
LITERATURE CITED
INDEX
PREFACE
This book is written not just for the dinosaur enthusiast but for those readers that have an interest in the Arctic and Alaska. The discovery of dinosaurs in the Arctic of Alaska and the subsequent accumulation of a surprisingly rich record of these fossil animals challenged many widely held misconceptions about the ecology, biology, and biogeography of these fascinating beasts. These high-latitude discoveries also called into question the simplistic extinction scenarios that were advanced during the 1960s and 70s and that continue to fuel debate today. The Arctic of Alaska presented the author with unusual and exhilarating challenges. Some of the greatest difficulties stemmed from the size and remoteness of Alaska. However, the demands of working within the idiosyncratic world of Alaskan politics and economics make research of any kind in Alaska a truly unique experience. The reader will not only be treated to the excitement and exigencies that accompany paleontological field research in the Arctic environment but will also gain an understanding of just how the scientific process and scientists really work. In addition, the reader will get a feel and taste for Alaska, the place.
The first part of this story summarizes the last fifty years of the Arctic discovery of dinosaurs, whose remains are scattered throughout the vast circumarctic region. Then it goes on to describe Alaska s dinosaur record and to tell the fascinating story of their almost nondiscovery and its impact on the dinosaur extinction debate. Next, the narrative takes readers to the North Slope, introducing them to the methods and related challenges of fieldwork in Alaska s Arctic and detailing the extraordinary collection of dinosaur remains that has been accrued over the last twenty-five years. After placing these fossils and their interpretation in proper geologic, biologic, and time perspective, the book takes up the broader impacts and possible future directions of research on dinosaurs in Arctic Alaska and the rest of the circumarctic, considering how new technologies, global climate change, and the cold war that is erupting over the natural resources that have been sequestered beneath Arctic ice for eons may impact future research.
It is hoped that the reader will gain a new perspective on Alaska, the Arctic, and the scientific process and come away with a sense of how much has been learned about dinosaurs and their polar world some seventy million years ago.
ACKNOWLEDGMENTS
To the hundreds of volunteers, teachers, and students that gave their time, sweat, and blood to unearth the story of Alaska s Arctic dinosaurs, I am eternally thankful. Over my eighteen years of work in Alaska, I benefited greatly from the help and counsel of a host of colleagues. Some of the contributions of a number of these colleagues are described in the book, but I must acknowledge here the enormous contributions of time and valuable counsel of my Alaskan colleagues: Kevin May, Dave Norton, Anne Pasch, Don Triplehorn, Gary Selinger, and Gary Grassi. I must extend a special thank you to Canadian colleagues Philip Currie, Richard McCrea, David Eberth, Donald Brinkman, Darren Tanke, Grant Zazula, John, Storer, and David Evans, who, along with Thomas Rich, Patricia Vickers-Rich, Pascal Godefroit, Kyle Davies, M. K. Brett-Surman, Tony Fiorillo, and Mark Goodwin, generously shared their expertise, publications, and data. J rn Hurum, John Tarduno, and Patrick Druckenmiller shared their valuable insights and field images. David Smith, Karen Carr, Buff and Gerald Corsi provided graphics and their valuable time. Judy Scotchmoor, Robert Sloan, and James Farlow provided valuable editorial assistance to help make this book better.
DINOSAURS UNDER THE AURORA
1
THE ARCTIC SETTING

The Arctic Coastal Plain circa Seventy Million Years Ago
The Arctic coastal plain is crisscrossed by a host of meandering rivers that drain the northern slope of the rugged ancestral Brooks Range to the south. The rivers are pregnant with organic-rich sediment and rush headlong to the northern sea, being fed by melting snowfields and the common cloudbursts that sweep in from the Western Interior Seaway to the north and east. Large herds or aggregates of duck-billed dinosaurs move along river banks feeding on dense gardens of mud-loving horsetail rushes that have sprung forth from their subterranean rhizomes into the reawakening sunlight. 1 Monodominant patches of drought-resistant ferns are interspersed with clumps of herbaceous angiosperms and grasses on small ridges and levee slopes. 2 Stacks and tangles of lichen and moss-encrusted logs and branches form along the edges of sloughs and oxbow lakes. Large logs of deciduous conifers, such as Parataxodium from forests deep in the interior, have mixed with smaller ones that had spent their lives closer to where they now lie.
The rushes and ferns grow very rapidly due to the long, warm, lengthening days. The largest concentrations of duckbills are located along the margins of shallow sloughs, floodplain lakes, ephemeral ponds, and river banks with smaller groups strung out along the crowns of larger river levees. The rich bounties of aquatic plants that occupy the floodplain lakes and ponds are the targets of groups of duckbills like Edmontosaurus , who can use their spoonbill-like jaws to shovel in rhizome mats and clusters of plants similar to water ferns, duckweed, and water lilies.
Some small groups of duckbills venture into upland coniferous forests and come upon larger groups of ceratopsians such as Pachyrhinosaurus. The ceratopsians and duckbills selectively partake of mixes of deciduous conifer trees such as Parataxodium and Podozamites. Some hadrosaurs and ceratopsians feed on the leaves of these trees as well as on an understory of ferns, scattered cycadophytes ( Nilssoniocladus ), and the rarer clusters of mistletoe and sandalwood. Individual ceratopsians such as Pachyrhinosaurus select fruits such as Ampelopsis and Cissites. 3 On occasion, they take in insects and snails crawling over the leaves-a serendipitous protein treat. Only adults and subadults venture deep into the denser wooded areas and upland forests where Troodon and other gracile predators can hide and wait in ambush. These woodlands are too dangerous for the more vulnerable juveniles to feed in.
Hours later, the sky turns to an angry gray, filling with roiling masses of water-laden clouds that are being driven southward against a dark wall of mountains. Torrents of rain sweep down the mountain slopes and are channeled northward to the sea. A 100 miles away, the groups of Edmontosaurus are totally absorbed by their search for food, unaware of the rush of water that is coming their way.
A large group of Edmontosaurus , a few standing conspicuously above the rest, appears at the top of a large levee and stops to feed on the lush plant smorgasbord before descending to the edge of the fast-flowing river. While their fellow travelers are dining, a dozen of the larger individuals approach the river. Hesitating for just a moment, they plunge in, making enormous splashes as they push against the strong current. The rest of the group is now dominated by juveniles that are half to one-quarter the size of their adult and subadult attendants. Just as the adults finally reach the opposite shore and struggle up the opposite embankment, a larger group of adults and subadults catch up. Anxious to follow their leaders, they take the plunge, and this spurs the juveniles to follow. The water is shallow enough that most of the juveniles can just touch bottom. Just as this mix of adults, subadults, and juveniles makes it a quarter of the way across the river, a four-foot-high pulse of water reaches the struggling group, grea