Introduction to the geology of southern California and its native plants

545 Pages·2007·11.765 MB·English

by  Hall, Clarence A.;Holbrook, Lauri L

IntroductIon to the GeoloGy of
Southern calIfornIa and ItS natIve PlantS
the publisher gratefully acknowledges the generous
contribution to this book provided by the august and
Susan frugé endowment fund in california natural
history of the university of california Press foundation.
IntroductIon to
the GeoloGy of
Southern calIfornIa
and ItS natIve PlantS
clarence a. hall, Jr.
Photography by Lauri L. Holbrook
University of California Press
Berkeley Los Angeles London
University of California Press, one of the most distinguished univer­
sity presses in the United states, enriches lives around the world by
advancing scholarship in the humanities, social sciences, and natural
sciences. its activities are supported by the UC Press foundation and
by philanthropic contributions from individuals and institutions. for
more information, visit www.ucpress.edu.
University of California Press
Berkeley and los angeles, California
University of California Press, ltd.
london, england
© 2007 by the regents of the University of California
library of Congress Cataloging­in­Publication Data
Hall, Clarence a.
introduction to the geology of southern California and its native
plants / Clarence a. Hall, Jr.; photography by lauri l. Holbrook.
p. cm.
includes bibliographical references and index.
isBn 978­0­520­24932­5 (alk. paper)
1. Geology—California, southern. 2. endemic plants—California,
southern. i. title.
Qe89.H345 2007
557.94'9—dc22 2006037614
Manufactured in China
10 09 08 07
10 9 8 7 6 5 4 3 2 1
the paper used in this publication meets the minimum requirements
of ansi/niso Z39.48­1992 (r 1997) (Permanence of Paper)
Cover: Desert sunflower (Geraea canescens) in Death valley, 2005.
Photographer: larry Blakely.
in Memoriam
Mildred e. Mathias (1906–1995), UCla Professor of Botany

the scientist does not study nature because it is useful; he studies it
because he delights in it, and he delights in it because it is beautiful.
if nature were not beautiful, it would not be worth knowing, and if
nature were not worth knowing, life would not be worth living.1
jules henri poincaré (1854–1912)
1“le savant n’étudie pas la nature parce que cela est utile; il l’étudie parce qu’il y prend
plaisir et il y prend plaisir parce qu’elle est belle. si la nature n’était pas belle, elle ne vaud­
rait pas la peine d’être connue, la vie ne vaudrait pas la peine d’être vécue.” Jules Henri
Poincaré, 1908, science and Méthode, Paris, e. flammarion (publishers). the english trans­
lation is from H. Poincaré, 1921 [translation by G. B. Halsted of Poincaré’s contributions],
the foundations of science [science and Method, p. 359–546]: new york, the science
Press, 553 p. Continuing with the translation by Halsted: “. . . but [beauty] has nothing
to do with science. i mean that profounder beauty which comes from the harmonious or­
der of the parts and which a pure intelligence can grasp . . . on the contrary, intellectual
beauty is sufficient unto itself, and it is for its sake, more perhaps than for the future good
of humanity, that the scientist devotes himself to long and difficult labors.” (p. 366–367).

contentS
acknowledGmentS xiii astrochronology 40
Geochronology 41
radiometric age Dating 41
Part one
How radiometric Dating Works 41
Introduction
rocks and Minerals Dated by various
radiometric Methods 47
1 this Book 3 Correlating Geologic ages/stages 47
the importance of european stages 48
2 Prologue to Geology of
Great valley Group 48
Southern california 5
Mammal ages 51
some early studies of Geology 5 Molluscan stages 54
the Geologic Map 6 Microfossil stages 56
Geologic explorations in California 6 Glacial and interglacial stages 59
some significant Contributions to the Geology evolution 63
of California 6
5 Plate tectonics 64
Mid­oceanic ridges and trenches 64
Part two
san andreas fault and Continental
the earth and Geologic time
Drift 65
Continental Drift 65
Magnetism and Paleomagnetism 66
3 earth materials 11
Magnetic signatures of rocks 66
the Universe 11
Magnetic reversals 66
early Universe 11
sea­floor spreading 66
solar system 11
Hot spots and Mantle Plumes 69
the earth 12
faults 69
rocks 15
transform faults 70
igneous rocks 15
fracture Zones 71
sedimentary rocks 23
triple Junctions 71
Metamorphic rocks 33
Moving Plates 71
4 Geologic time 38 supercontinents 72
Biostratigraphy 40 Plate Boundaries 72
Magnetostratigraphy 40 Continental Margins and orogenies 73