On the interpretation of the apparent form of the geoid and of the terrestrial heat flow

A comparison is made between the approach of the data on gravity and heat flow by the concepts of Wunderlich (1966) and the present author (Van Bemmelen, 1966). Wunderlich's model of physical interpretation is based on an erroneous idea of the meaning of the form of the geoid, as determined by artificial satellites. The new model of the earth's evolution, presented by the author, offers a promising way of interpretation, which is based on physico-chemical principles

Mesozoic-Cenozoic orogenic belts — Data for orogenic studies. A.M. Spencer (Editor), 1974. Scottish Academic Press, Edinburgh, xvi + 809 pp., £ 30.00 : book review

This compendium is a laudable attempt to make available tectonic data from Mesozoic- Tertiary orogens, aiming at a convenient and essentially objective presentation. This volume presents a great wealth of data concerning Mesozoic-Tertiary orogens, but even these facts are not always as unbiased as would be desirable for the inductive- deductive procedure of scientific verification. Moreover, for a more comprehensive understanding of the geodynamic evolution of the earth's crust, it is also necessary to make a relativistic analysis of the deformations and transformations of the lithospheric frame around these younger orogens. Nevertheless, this first volume on the long road of comprehensive, objective, and clear presentation of basic data can be strongly recommended to all students of geodynamics

The evolution of the Indian Ocean Mega-Undation : Causing the indico-fugal spreading of gondwana fragments

In the first section the geomechanical model of mega-undations is elaborated: 1. (1) The lower mantle may have a Newtonian viscosity, but the upper mantle, which is largely in a crystalline state, shows an Andradean viscosity, with hot-creep phenomena and the formation of lamellae separated by zones or planes of high strain rate. 2. (2) Reliable solutions of the mechanics in the fault planes of earthquake foci indicate that the spreading of the mega-undations is characterized in the outer 400 km by the farther advance of the higher structural levels with respect to the underlying ones: whereas the movements in the foci of deep earthquakes underneath the Japan Sea and South America indicate a reverse process, the lower blocks moving faster towards the Pacific than the overlying ones. This is explained by the geomechanical model of the mega-undations. 3. (3) The crest of the mega-undations shifts in the course of time, either gradually or by steps. The effects of such shifts are discussed and illustrated. 4. (4) Four stages of evolution of mega-undations are distinguished: 4.1. (a) young 4.2. (b) early mature or precocious 4.3. (c) late mature or ripe, and 4.4. (d) fossil mega-undations. These stages are illustrated by type examples. In the section on the development of the Indian Ocean Mega-Undation this geomechanical model is tested by an analysis of the geotectonic evolution of the Indian Ocean and the surrounding shields. It appears that there is a good correspondence between the expectations according to the hypothetical model (prognoses) and the geotectonic observations (diagnostic facts). This reinforces our confidence in the adequacy of the functioning of the model. The latter might be tested further by tectonic experiments, namely, by the centrifugation of models at a reduced scale

Earth-science reviews : International magazine for geo-scientists : Elsevier, Amsterdam, Volume 1, 1966. Subscription prices: £4.10.0 or Dfl.45.00 per volume of four issues

Announcement of the launch of a new geological journal, entitled: Earth-Science reviews, international magazine for geo-scientists

Appendix to the contribution by G.B. Engelen on the origin of the Bermuda Rise

The basic concepts of the contribution, according to the undation theory as it stands presently are as follows. The earth’s surface is not a pure ellipsoid of rotation, but a geoid which shows extensive bulges and depressions (geo-undations). The physico-chemical processes disturb the theostatic and gyroscopic equilibrium in the deep cambium so that circulations of matter (mass circuits) result. There will be a tendency to westward drift (for example in North and South America), or to the cyclonical and anticyclonical drifting apart of the crustal fragments belonging to older continents (such as the parts of Olim-Gondwana spreading anticyclonically around the Indian Ocean). The geodynamic evolution of the earth can be seen as a chain reaction (alternation of equilibrioturbal processes of a physico-chemical character and equilibriopetal processes of a hydrodynamic character). This basic concept is neither mobilistic nor fixistic, but it does require a relativistic point of view in the analysis of the deformations of various dimensions which are superimposed on each other

De geologische geshiedeni van Indonesie

x, 139 p.; 21 cm

Mesozoic-Cenozoic orogenic belts — Data for orogenic studies. A.M. Spencer (Editor), 1974. Scottish Academic Press, Edinburgh, xvi + 809 pp., £ 30.00 : book review

This compendium is a laudable attempt to make available tectonic data from Mesozoic- Tertiary orogens, aiming at a convenient and essentially objective presentation. This volume presents a great wealth of data concerning Mesozoic-Tertiary orogens, but even these facts are not always as unbiased as would be desirable for the inductive- deductive procedure of scientific verification. Moreover, for a more comprehensive understanding of the geodynamic evolution of the earth's crust, it is also necessary to make a relativistic analysis of the deformations and transformations of the lithospheric frame around these younger orogens. Nevertheless, this first volume on the long road of comprehensive, objective, and clear presentation of basic data can be strongly recommended to all students of geodynamics

The Alpine loop of the tethys zone

The Alpine loop in Europe results from semi-autochthonous crustal movements which are restricted to the mobile Tethys zone. Its evolution cannot be explained by a uniform northward drift and push of the African continent; it has to be sought, in the first place, in geodynamic processes occurring in the upper mantle directly underneath that section of the Tethys zone. The evolution of the Alpine mountain system in Europe can be compared with the Alpine orogenesis in Indonesia (the Sunda mountain system). On the other hand, the Alpine orogenesis in the Himalayan section is mainly the effect of the northward drift of the Indian subcontinent. It is concluded that mountain and island arcs are not the result of palaeomagnetically established continental drift or a still hypothetical ocean-wide spreading of the ocean floor

The importance of the geonomic dimensions for geodynamic concepts

An analysis is made of the importance and interrelation of the parameters of length, time, pressure and temperature, and their bearing upon concepts regarding the earth's evolution. This leads to a tentative model of the chain of reactions caused by the continuous escape of the endogenic energy from the earth's interior