Introduction The development of Earth-observation techniques based on the use of navigation signals can be traced back to the use of GPS in geodetic applications to provide astonishing precision, such as the determination to within a few centimetres of the relative positions of points on the Earth’s surface separated by several thousand kilometres. This ultra-precise positioning of fixed GPS re...

Mineral physicist Steven Jacobsen uses high pressure-temperature experimental techniques to investigate the properties of mantle mineral phases such as ringwoodite, the blue crystal (left) pictured through the top of a diamond-anvil cell. Jacobsen’s studies will help EPS seismologist Suzan van der Lee map the Earth’s interior as they attempt to identify the driving forces behind plate tectonics...

In the last decade, significant progress has been made toward understanding how plate tectonics is generated from mantle dynamics. A primary goal of plate-generation studies has been the development of models that allow the top cold thermal boundary layer of mantle convection, i.e. the lithosphere, to develop broad and strong plate-like segments separated by narrow, weak and rapidly deforming b...

Paleomagnetism is the only quantitative method available to test for lateral motions by tectonic plates across the surface of ancient Earth. Here, we present several analyses of such motions using strict quality criteria from the global paleomagnetic database of pre–800 Ma rocks. Extensive surface motion of cratons can be documented confi dently to older than ca. 2775 Ma, but considering only t...

The Sundaland core of SE Asia is a heterogeneous assemblage of Tethyan sutures and Gondwana fragments. Its complex basement structure was one major influence on Cenozoic tectonics; the rifting history of the north Australian margin was another. Fragments that rifted from Australia in the Jurassic collided with Sundaland in the Cretaceous and terminated subduction. From 90 to 45 Ma Sundaland was...

A simple model which relates the rate of seafloor creation and the age of the oceanic lithosphere at subduction to the rate of continental accretion can successfully explain the apparent differences between Archaean and Phanerozoic terrains in terms of plate tectonics. The model has been derived using the following parameters: (1) the spreading rate at mid-ocean ridges; (2) the age of the ocean...

The theory of plate tectonics came together in the 1960s, achieving wide acceptance after 1968. Since then it has been most successful framework for investigations Earth’s evolution. Subduction oceanic lithosphere, as engine that drives tectonics, played a key role theory. However, one biggest unanswered questions Earth science is how first subduction was initiated, and hence began. main challe...

[1] Reconstructing the thermal history of the Earth, consistent with the low concentration of heat-producing elements in convecting mantle as well as with modest secular cooling required by geological records, has been a major challenge in geophysics and geochemistry. By developing the self-consistent energetics of plate-tectonic mantle convection, we show that the low Urey ratio of convecting ...

Recent magnetic studies of Mars suggest hat (1) it possessed a periodically reversing magnetic field for the first -• 500 Myr of its existence and (2) plate tectonics may have been operating during this time. On Earth the geodynamo is thought to occur because of convection in the outer core. This paper estimates the amount of heat the Martian core can conduct in the absence of convection. It us...