Book review of Global Wrench Tectonics by Geir Lunde
“Why is there so much water in the sea?” was a question my 5 year old daughter asked me on a boat last summer. I came to the conclusion that I could not give her a good answer. I’m impressed by children who ask fundamental questions like this, and even more so by brave scientists like Professor Karsten Storetvedt whose questions shake our pre-conceived ideas about the Earth and encourage fresh thinking. Are we certain that the linear magnetic patterns observed in the ocean floor are acused by sea-floor spreading in combination with alternating geomagnetic polarities? Can we disregard the concept of polar wandering? How do we know? These questions alone are enough to engange my curiosity. Often we find that scenario building is a useful way to prepare for the future. Alternative theoretical frameworks may be in demand when we explore the history of the Earth.
In his recent book “Global Wrench Tectonics”, Professor Storetvedt presents a model for the Earth’s evolutin all the way from the very beginning to the prsent-day. This is a further development of the theory he presented in 1997 in “Our Evolving Planet, Earth History in New Perspective” (reviewed in JPG 22, 4, p462). The main elements of Global Wrench Tectonics are summarized in a post-script and this may be a good place to start for a reader who is not familiar with this theory:
“Starting from the basic postulate of a thick primordial crust and a relatively cold interior, it can be envisaged that continual degassing and related reorganization of interior mass has modified the crust and upper mantle progressively since Precambrian time, as well as having successively increased the volume of surface volatiles. The gradual build up of high hydrostatic pressures in the outer layers of the planet (the outer geosphere) led to eclogitization, gravity-driven sub-crustal attenuation, and related isostatic subsidence, eventually producing oceanic depressions – these reservoirs not only accomodating the increasing volume of surface water, but also providing the capacity to house the former extensive epicontinental seas, giving rise to the present dry continents. The inferred reorganization of internal matter is bound to have altered Earth’s moments of inertia periodically, instigating changes of planetery spin rate and intermittent events of polar wander. In turn, these dynamical changes set off a range of tectonomagmatic phenomena as well as producing significant palaeoclimatic and biogeographic changes. At later stages of Earth history, notably from the Jurassic onwards, attenuation and basification processes (“oceanization”) of the original felsic-sialic crust advanced more rapidly than before so that, by the early Tertiary, the deep oceanic depressions were approaching their present global distribution. In concert with the pronounced mechanical weakening associated with the major crustal-lithospheric thinning, the ensuing geodynamic event – the Alpine revolution – pitched the Earth into a tectonic calamity. During this period, inertia-driven relative continental rotations occurred for the first time in the Earth’s history. The extensive prediction-confirmation chain thus constructed ends with the modern world in which we find lofty mountain ragnes and the ‘mid’-oceanic ridges which represent the predominant ‘end’ products of a continuously changing physical world. In many ways, the new theory of Earth’s evolutionary history – Global Wrench Tectonics – represents a novel formulation that changes many of the commonly accepted theoretical generalizations of the Earth sciences.”
The new model, which is closely aligned to principles of classical physics, has the potential to become a general theory for the terrestrial planets. I strongly recommend this book to every person who is driven by curiosity and a true desire to understand. For professionals within planetary science, global geoscience, physics, biology and hydrocarbon exploration, it may open doors to the understanding of observations which are not easily explained within a conventional plate-tectonic scenario. As we gather data from Mars, the time is also right to take a fresh look at our own planet, the Earth. Surprising synergies may unfold!
Book review of Global Wrench Tectonics (2003) by Geir Lunde,
Managing Director at Geysir Petroleum, Norway
Published in Journal of Petroleum Geology vol 27, no2, April 2004