specialization in the Earth sciences after the Second World War Improvements in transport, in communications, and in instrumentation were almost immediate effects of the cessation of the Second World War. Technological advances made during the hostilities were put to peaceful uses, especially in the USA. New requirements in natural resources, especially fossil fuels and building materials, were felt almost worldwide at this time, and economic needs were a spur to the development of both laboratory and field studies in the Earth sciences. The petroleum companies led the way in exploration geology and exploitation engineering, closely followed by the mining companies, mostly operating in other kinds of terrain. New service companies offering aerial photography, geophysical prospecting and analytical facilities were soon to appear in the developed countries for engagement in petroleum and mineral exploration. Somewhat later, computing services and information technology were to enhance the pace of research and development, and by the 1980s satellite photography and remote sensing were available on a commercial basis. The space programmes of NASA, the Soviet Union, and Europe prompted interest in lunar and planetary geology.
Meanwhile, both academic and commercial interests had given an enormous impetus to marine studies, as had strategic needs and, for the West, the expansion of Soviet sea power. Canada and the USA were very active in surveying and investing in the defence development of Alaska, the Canadian Arctic archipelago, and Greenland. Newly independent and developing countries were keen to attract investment in the exploitation and utilization of their natural resources. The market for qualified Earth scientists was large and international, and so there was a significant impetus to academic institutions to expand their teaching and research capabilities. All of this was favourable for the development of new fields within the Earth sciences. Expansion of universities and other research and teaching institutions began immediately after the war and was well under way in the early 1950s. By the mid- to late 1960s a further important factor came into play. This was a veritable revolution in the Earth sciences occasioned by the theory of plate tectonics. It provided a tremendous stimulus in virtually every branch of geological science, and it prompted the geological reconnaissance or re-examination of many parts of the world.
As a result of the general post-war stimulus and acceptance of plate-tectonic theory, there was a growing need for interdisciplinary studies and the breaking down of perceived distinctions between different members of the Earth science community. In the late 1970s and 1980s this was accentuated by growing environmental consciousness, emphasis upon the limits of non-renewable resources, and the effects of pollution. By this time technological innovations had greatly improved the speed, number, and effectiveness of both investigations and communications. Scientific capabilities had outstripped social and international competence in the use of science for the well-being of the planet. Basic science has extended its attractions while the applied Earth sciences have found increasing demands made upon them.
In the laboratory one of the most fruitful post-war areas of growth has been that of sedimentology. Both carbonate and clastic rocks have been subjected to new techniques of study, including ultramicroscopy, ion-probe analysis and mass spectrometry, and other forms of rapid analysis. The dynamics of clastic sediment transport and deposition have yielded to laboratory study. Geochemical and isotope studies have been of use in understanding the genesis, diagenesis, and geochronologial aspects of the evolution of sedimentary rocks. Organic geochemistry and microbiological studies have been undertaken in modern sedimentary environments and on ancient sediments. The role of organisms in generating sediment, and in leaving signs of their behaviour (as trace fossils) within it, have been notable areas of special study. The modelling of sedimentary facies and sedimentary environments has prospered, and sedimentary tectonics has developed as a discipline linking tectonic behaviour to the provenance and rate of supply of sediment types.
Experiment has become a widespread methodology in the study of mobile materials, under both atmospheric and aquatic conditions, and higher temperatures and pressures. Physical and chemical processes in crystalline rock genesis, volcanism, and mineral emplacement have been elucidated, and research in these areas continues to expand.
Palaeobiology has seen the spectacular expansion of knowledge of microfossils, with emphasis upon their use in biostratigraphy. Conodonts, palynomorphs, and nannofossils, in particular, have contributed to global biostratigraphy and correlation. Cladistic analysis has influenced evolutionary thinking and has been employed in studies of taxonomy and biogeography, particularly in response to the impact of plate tectonics. Palaeoecology has emerged as a significant part of palaeobiology, relating organisms to habitats of the past. More recently, taphonomy has become a topic of wide interest, especially since the discovery of new, exceptionally preserved fossil faunas.
In structural geology the interpretation of mesoscale structures and microstructures (petrofabrics) was a rapidly developing theme and has been joined by those of large-scale tectonics and, most recently, by neotectonics—that is, the study of structures that are young or still forming.
A topic of importance in correlation and palaeogeography has been palaeomagnetism, perhaps the most far-reaching branch of geophysics since the Second World War. It has been matched in significance by the development of isotope geochemistry as an invaluable aid to geochronology and palaeoenvironmental determinations.
Geophysical prospecting and exploration, for which the petroleum companies provided a lead, is now valuable to academic and applied geology alike. An important development, seismic stratigraphy, now provides data over both land and sea that bears upon the Mesozoic and Cenozoic evolution of the continental shelves.
Expanding specialist areas of applied geology have included hydrogeology, soil mechanics, rock mechanics, and engineering geology. More recently, studies of both the supply of extractable resources and waste disposal have greatly increased in number, detail, and size. In all these fields modelling is now an essential part of assessment programmes. The roles of statistics, data handling, and computing have grown steadily over the past 30 years or more, and all branches of the Earth science tree are becoming more quantitative, pure and applied alike.
D. L. Dineley
