The Pulse of the Earth

Problems of current interest relating to the earth's physical history will be discussed in this volume. Each chapter constitutes a subject in itself, but the sequence I have chosen will, I hope, show and explain the deeper correlation of several terrestrial pro cesses which, at first sight, appear to be heterogeneous. The geologist follows the changing face of the earth, the oscillations of the sea-level, the pulsation of folding and mountain-building, the periodicity of the ice-ages, the rhythmical cadence of Life. Just as the physician will draw his conclttsions from outward symptoms when examining his patient, so the geologist tries to discover the deeper significance of the sequence of observed phenomena by ieeling the pulse of the earth. The many additions and revisions which have had to be made in this second. edition include three new chapters, several new sections in other chapters, I09 new textfigures, I2 tables and 2 plates. A leu) fundamental geological terms have been explained in Chapter I.

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Problems of current interest relating to the earth's physical history will be discussed in this volume. Each chapter constitutes a subject in itself, but the sequence I have chosen will, I hope, show and explain the deeper correlation of several terrestrial pro­ cesses which, at first sight, appear to be heterogeneous. The geologist follows the changing face of the earth, the oscillations of the sea-level, the pulsation of folding and mountain-building, the periodicity of the ice-ages, the rhythmical cadence of Life. Just as the physician will draw his conclttsions from outward symptoms when examining his patient, so the geologist tries to discover the deeper significance of the sequence of observed phenomena by ieeling the pulse of the earth. The many additions and revisions which have had to be made in this second. edition include three new chapters, several new sections in other chapters, I09 new textfigures, I2 tables and 2 plates. A leu) fundamental geological terms have been explained in Chapter I.

Contenu
I. Space and Time.- The universe, the solar-system and the earth.- The birth of the moon.- The earth's interior.- The age of the earth and the universe.- The history of the earth's crust.- References.- II. Mountain-Chains.- Epochs of compression.- Mountain-building.- Subsided blocks.- References.- III. Basins and Troughs.- Continental basins and troughs.- Deep-sea basins and troughs.- Chronological relations to other phenomena.- References.- IV. Crust and Substratum.- Magmatic clans.- Tectonic and magmatic cycles.- A peridotite-Layer in the substratum.- Zonal migration of geosynclines; continents and ocean-floors.- Volcanism in basins.- Fragmentation and growth of continents.- Summary.- References.- V. Oscillations of the sea-level.- Regional transgressions and regressions.- World-wide transgressions and regressions.- References.- VI. The continental margin.- The surface of the shelf.- The influence of changing sea-level.- Subsidence of the shelf-area.- The marginal flexure of the continents.- Marine terraces.- The geophysical side of the problem.- Submarine valleys.- Summary and conclusions.- References.- VII. Island-Arcs.- The problem.- Physiographic features.- Earthquake zones.- Classification..- The Mechanism..- Geographic distribution of deep-focus earthquakes..- Deep-reaching shear-zones..- Terrestrial magnetism.- Volcanism and plutonism.- The andesite line..- Petrographic provinces..- Igneous rocks in geanticlinal belts,.- Igneous rocks in geosynclinal troughs..- Problems to be solved..- Deep-sea basins and troughs.- Isostatic anomalies.- The boundary of the Pacific Basin..- Single Arcs..- Double Arcs..- Synthesis.- General statement..- Site of the outer arc..- Time of origin and epochs of rejuvenation..- Origin of the double arc..- Deep-sea furrows..- Thevolcanic inner arc..- Basins and Troughs behind the inner arc..- Positive anomalies of Isostasy..- The inverted arc of Celebes..- Evolution.- Unsolved problems.- Summary.- References.- VIII. The Floor of the Oceans.- The major characteristics of the bottom-relief.- The Atlantic Ocean and the western part of the Inpian Ocean.- The Pacific Ocean.- The distribution of isobathic areas.- The problem.- Continental drift.- Submerged continents.- The hypothesis of permanence.- Trans-Oceanic mountain-chains.- The origin of continents and oceanic receptacles.- Summary.- References.- IX. Ice-Ages.- The periodicity of climates.- The earth's normal climate.- The abnormal character of present conditions.- The problem.- The relation between periodicity and physico-geographical factors.- The deeper causes of periodicity.- The rapid growth and subsequent retreat of an ice-cap.- Interglacial periods.- The Geographical location of an ice-cap.- The restricted influence of cosmic factors.- Summary.- References.- X. The Rhythm of Life.- The periodic differentiation of the flora.- References.- XI. Linear Patterns.- Planetary systems.- The problem.- Origin of the lineaments.- Older Theories..- Wandering of the Poles..- Periodical rejuvenation.- Dome-shaped elevations and rift-zones..- The North Sea Basin..- General conclusions..- Summary.- References.- XII. The pulse of the Earth.- Chronological relation of periodic events.- A fundamental problem.- References.- Appendix. Descriptions of Plates 18, and Tables I and II.- Plate 1. Caledonian epochs of compression.- Plate 2. Variscian epochs of compression.- Plate 3. Mesozoic epochs of compression.- Plate 4. Cenozoic epochs of compression.- Plate 5. Chronological analysis of the continents.- Plate 6 and Table I. Basins of the second group.-Plate 7. Distribution of Rock Clans.- Plate 8. Geology and gravity field in the East Indies.- Table I. see under plate 6.- Table II. Synopsis of the Pulse of the Earth.