The Pulse of the Earth

394 Pages·1947·23.03 MB·English

by  J. H. F. Umbgrove D. Sc. (Leyden), Hon. F. R. S. E., Hon. Memb. N. Y. Ac. Sc. Memb. R. Netherl. Ac. Sc. (auth.)

J. H. F. Umbgrove
The Pulse of the Earth
THE PULSE OF THE EARTH
X.V. VAK DE GARDE & co's DRliKKERIJ, ZALTHOWI!EL
The Pulse of the Earth
BY
]. H. F. UMBGROVE
D. Sc. (LEYDEN)
HoN. F. R. S. E.; HoN. MEMB. N. Y. Ac. Sc.
MEMB. R. NETHERL. Ac. Sc.
PROFESSOR OF GEOLOGY AT DELFT
HoLLAND
SECOND EDITION
W1th 8 partly coloured plates, 204 textjigures and I2 tables
Springer-Science+Business Media, B.V.
1947
Additional material to this book can be downloaded from http://extras.springer.com.
ISBN 978-94-017-5641-9 ISBN 978-94-017-5902-1 ( eBook)
DOI 10.1007/978-94-017-5902-1
Copyright I947 by Springer Science+Business Media Dordrecht
OriginallypublishedbyMartinus Nijhoff, The Hague, Rollandin 1947.
Softcoverreprint ofthe bardeover Istedition 1947
All ri{;hts reserved, including the right to translate or to reproduce
this book or parts thereof in any form.
In memory of
A. C. U mbgrove-Gordon
my Mother
with sincere feelings of gratitude
CONTENTS
Pages
LIST OF ILLUSTRATIONS XIII
PREFACE . XXI
CHAPTER I. SPACE AND TIME
lNTRODUCTION . . . . . . . . . . . . . . . . . . . . . 1
THE UNIVERSE, THE SOLAR-SYSTEM AND THE EARTH . . . . . 2
Cosmic dimensions. Spiral galaxies. The expanding universe. The origin
of the solar-system.
THE BIRTH OF THE MOON . . . . . . . . . 6
The earth and the moon. Lunar volcanism.
THE EARTH'S INTERIOR . . . . . • . 8
Interpretation of seismic data. Two different theories on the internal
constitution of the earth.
THE AGE OF THE EARTH AND THE UNIVERSE 12
Geological figures. Astronomical methods and the age of meteoritEis.
THE HISTORY OF THE EARTH'S CRUST ... , . , . 15
Precambrian and later history. Alterations of the earth's aspect. A geo
logical cycle. Erosion. Sedimentation. Geosynclines. Folding. Facies.
Unconformity. Magma. Periodicity. Contents of the following chapters.
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
CHAPTER II. MouNTAIN-CHAINS
lNTRODUCTION . . . . . . . . . . . . . . . . . . . . . . 26
Analysis of the earth's structural history. Mountain-chains of different
ages. Epochs of compression. Classification of mountain-belts.
EPOCHS OF COMPRESSION . . . . . . . . . . . . . . . . . . 29
The enormous extent of Pre-Cambrian areas. The foundering of older
zones and a presumed accretion of the continents. Centrifugal migration.
Dynamic centra of tectonic activity. Alternating increase and decrease
of compression. A deep-seated cause and world-wide movements. Excep
tions. The influence of the basement. Intersecting structures. Absence
ot
centrifugal displacement.
MouNTAIN-BUILDING . . . . . . . . . . . . . . . . . . . . . 33
Epoc"hs of compression and elevation. Rejuvenation. The extent of
mountains-belts of various ages.
SUBSIDED BLOCKS . . . . . . . . . . . . . . . . . . . . . . . , . 35
Appalachia and Nova Scotica, Llanoria, Cascadia, Scandia, the submerg-
ed area west of the Congo-Basin, Melanesia. Periods of foundering.
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
CHAPTER III. BASINS AND TROUGHS
lNTRODUCTION 43
Characteristics of basins and troughs. Nomenclature and systematic
division.
CONTINENTAL BASINS AND TROUGHS 45
Marginal deeps. Intramontane troughs and idiogeosynclines. N uclear
basins. Discordant basins.
Umbgro\'('
VIII CONTENTS
Pages
DEEP-SEA BASINS AND TROUGHS . . . • . . . . . . . . . . . . . . 54
Examples in the East-Indies and a comparison with continental types.
The abnormal character of the present situation. Periods of rejuvena
tion of the continental and submarine.relief. An open question.
CHRONOLOGICAL RELATIONS TO OTHER PHENOMENA . . • . . . . 62
Relations to periods of mountain-building and decreasing compression.
A deep internal terrestrial process of world-wide activify.
REFERENCES . . . . • • • . . . . . . . . . . . . . 64
CHAPTER IV. CRUST AND SUBSTRATUM
lNTRODUCTION . . . • • • . • . • • . . . . • . . . . . . . . . . 66
The composition of the earth's crust and its substratum. Sial and sima.
Contineutal and oceanic sectors. Volcanic and petrographic consequen
ces.
MAGMATIC CLANS • . . . . • . . . . • . , . . . . . . . . , . • . 70
Theory of the origin of igneous rocks belonging to the pacific and
mediterranean clans of differentiation from a parental magma-layer
of olivirre basalt. Other theories.
TECTONIC AND MAGMATIC CYCLES . • . • . . . . • • • • • . . . . . 76
Crustal folding and the root of a mountain-chain. Belts of isostatic ano
malies in the East and West Indies. The magmatic phenomena associat
ed with a subsiding and subsequently buckling crust.
APERIDOTITE-LAYER IN THE SUBSTRATUM .•...•.•...•.•. 81
The relation of peridotite intrusions to certain epochs of down-buck
ling of a sialic mountain-root.
ZONAL MIGRATION OF GEOSYNCLINES; CONTINENTS AND OCEAN-FLOORS 82
The pattern of continental shields. The origin of continents and ocean
floors. A primordial, world-wide sialic layer. The origin of an interme
diate layer in the earth's crust.
VOLCANISM IN BASINS . • . • • . . . . • . . . . . • 84
The occurrence of basic rocks and the absence of acid rocks.
FRAGMENTATION AND GROWTH OF CONTINENTS . . • . • • 84
Contineutal rejuvenation. Periodical supply of sialic melts from the
substratum.
SUMMARY 86
REFERENCES . . . . . • . • . . . . . • . 87
CHAPTER V. ÜSCILLATIONS OF THE SEA-LEVEL
lNTRODUCTION . • • . • . , . . , , • . • 89
REGIONALTRANSGRESSIONSAND REGRESSIONS . 89
The alternation of fresh and salt-water bodies in the Baltic Region.
Other examples of local rhythms.
WORLD-WIDE TRANSGRESSIONSAND REGRESSIONS ... 92
The synchronism and huge extent of the major trans- and regressions.
Possible causes and coincidences with other phenomena. The amount of
positive and negative shifts of the sea-level. An important problematical
question.
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
CHAPTER VI. THE CONTINENTAL MARGIN
INTRODUCTION . . • . . • . . . . . . . . . . . . . . . . . . 97
Problems of the continental shelves and the oceanic coasts of the
continents. Classification of continental shelves.
THE SURFACE OF THE SHELF ................. . 100
Hypsometrie relation between sea-level and shelf-surface. Older theories
on the origin of the shelf. The problern of the shelf-edge at the isobath of
200 meters.
THE INFLUENCE OF CHANGING SEA-LEVEL . . . . . . . . 104
Amount of eustatic changes. Their possible influence on the grading of
the surface of the shelf.
SUBSIDENCE OF THE SHELF-AREA 106
CONTENTS IX
Pages
Formations on the outer shelf-surface originally deposited in the littoral
zone. Deeper surfaces of the shelf.
THE MARGINAL FLEXURE OF THE CONTINENTS • • . . . . . . • . . • . 109
Phenomena showing a widespread rejuvenation of the oceanic borders
of the continents.
The theory of the marginal flexure.
MARINE TERRACES • . . • . • . 114
The most recent movements along the marginal flexure. Possible
dating of the different shelf-surfaces.
THE GEOPHYSICAL SIDE OF THE PROBLEM . . • . • . . 117
Gravity at the continental margin. The hypothesis of periodical con
vection currents in the marginal part of the continents. Correlation with
other periodical phenomena.
SUBMARINE VALLEYS . . . . . . . . • • . . . . • . • . • . • . . 120
General statement. Classification. Cases to be excluded. The notched
shelf-edge. Hypotheses involving a Subaerial origin. Hypotheses invol-
ving submarine agencies. Gorges extending over the surface of the shelf.
Submarine canyons showing a dendritic river-like pattern.
SuMMARY AND CONCLUSIONS . 139
REFERENCES . . . . . . . . . . . . . . . . . . . . 141
CHAPTER VII. lSLAND-ARCS
lNTRODUCTION . • • . • . . . . . . . . . . . . • • . • . • . . . 144
Geographkai distribution. Phenomena associated with island-arcs.
Their Counterpart on the continents.
THE PROBLEM . • • . . . • . . • . • . • . . • . • • . • . 145
Restrictions. Short outline of problematic questions to be examined.
PHYSIOGRAPHie FEATURES • • • . • • • • . • • . • • • • • . 146
Genetic classifications. Angle of arc-curvature. The notion of deep
reaching thrustplanes. A simple working hypothesis based on physio
graphic evidence.
EARTHQUAKE ZONES 153
C 1 a s s i f i c a t i o n.
Normal-, intermediate-, and deep foci.
T h e M e c h•a n i s m.
Distribution of dilatations and compressions. Similarity of the me
chanism giving origin to normal tectonic earth shocks and deep-focus
earthquakes.
Geographiedistribution of deep-focus earthquakes.
Exceptional position of the western and southeastern Pacific.
D e e p-r e a c h i n g s h e a r-z o n e s.
The action of deep-reaching shear-zones and the theory of convection
currents.
TERRESTRJAL MAGNET15M . . . . . . . . . . . . . . . . . . . . . . 163
Agreement with the theory of thermal convection currents. Possible
relation between districts of deep-focus earthquakes and anomalies
of the vertical component of terrestrial magnetism.
VOLCANISM AND PLUTONJSM ............ . 165
T h e a n d e s i t e I i n e.
The boundary between sialic and basaltic sea-floor in the Pacific.
P e t r o g r a p h i c p r o v i n c e s.
Distribution of igneous rocks belonging to the pacific and mediterranean
provinces. Their mode of origin.
I g n e o u s r o c k s i n g e a n t i c l i n a I b e I t s.
Plutonism and volcanism in the inner arc. Their mutual relations to
epochs of compression. Longitudinal faults and rift-valleys. Volcano
tectonic depressions.
I g n e o u s r o c k s in g e o s y n c 1 in a 1 t r o u g h s.
Their relation to epochs of compression.
X CONTENTS
Pages
P r o b 1 e m s t o b e s o l v e d.
A summing up of eight problematic points regarding the origin and site of
plutonic and volcanic phenomena.
DEEP-SEA BASINS AND .TROUGHS , • . . • • • • . , . . . . • • , . . 170
Types of troughs associated with island-arcs. Discussion of a theorv on
their origin. "
lSOSTATIC ANOMALIES . • • . . . • . . . . • . . . . . . , . . • . 172
T h e b o u n d a r y o f t h e P a c i f i c B a s i n.
Oceanic fields of positive anomalies and the theory of convection
currents. Relation to physiographic and seismic phenomena and to
the petrographic character of the sea-floor.
S i n g 1 e A r c s.
Gravimetrie profiles across the islands Guam and Yap. Geological
interpretation.
D o u b l e A r c s.
Isostatic anomalies in the East- and West Indies. Relations to the
topography of the sea-floor. Factors controlling the formation of a
single or a double island-arc.
SYNTHESIS ••••..••.................... 177
G e n e r a l s t a t e m e n t. ·
S i t e o f t h e o u t e r a r c.
Crustal waves due to increasing compression. Crustal down-buckle in the
zone of strong seismic activity.
T i m e o f o r i g in an d e p o c h s o f r e j u v e n a t i o n.
Time öf örigin of the crustal root and epochs of rejuvenation. Origin
of a belt of Serpentines and other ultrabasic rocks. Respectable antiquity
of the zone.
Origin of the double arc.
Crustal waves accompanying the zone of strongly negative anomalies.
Origin of deep-sea furrows. due to isostatic rise of the negative zone.
Origin of the double arc. Central depression on the outer arc. The volcanic
inner arc and the geosynclinal troughs on their continentward side.
Different types of deep-sea basins. Raised reef-limestones.
D e e p-s e a f u r r o w s.
Remarkable situation of the island Sumba. Relation of its site to the
belt of negative anomalies and the submarine topography.
T h e v o 1 c a n i c i n-n e r a r c.
Restrietion of volcanism to the concave side of anisland festoon. Perio
dical manifestation of volcanism on the inner arc. Absence of volcanism
on the' outer arc. Interpretation of Upper Tertiary volcanic rocks on is
lands of the outer arc and on Sumba. The double row of volcanoes in the
northern Moluccas. The distribution of active and extinct volcanoes
in the Southern Moluccas.
B a s i n s a n d T r o u g h s b e h i n d t h e i n n e r a r c.
Idiogeosynclines. The site of igneous rocks of the mediterranean clan.
Deep-sea basins.
Positive an o m a 1 i es o f I so s t a s y.
Possible cause of their origin. Relation to the belt of negative anomalies
and to periodical epochs of compression in the earth's crust.
T h e i n v e r t e d a r c o f C e I e b e s.
Absence of a voicanic "inner" arc. Plutonism and volcanism at the
convex side of the negative zone. Tentative interpretation of the major
structural features of Celebes.
EvoLUTION • • • . • • • • . • • • • • . • • • • • . • • • • • • • 200
The question of evolutionary stages represented by different types of
island-arcs. Island-arcs and mountain-belts on the continent.
UNSOLVED PROBLEMS ••••..••••••••••• , ••• , • 205
Absence of island-arcs along the southwestern and eastern borders of
the Pacific. Japan and the Philippine archipelago.
SUMMARY 208
REFERENCES • . . . . • • • . . • . . . . • • 214