Craton Deception: Geologists Challenge Conventional View of Earth’s Continental History and Stability — A new study challenges lon |
In this hypothetical cross-sectional view of the Earth’s crust and mantle during the breakup of the supercontinent Rodinia, a mantle plume initiates the peeling away process of the lower mantle. Credit: Lijun Liu
In a study led by Illinois geology professor Lijun Liu, researchers used previously collected density data from the Earth’s uppermost rigid layers of crust and mantle – known as the lithosphere – to examine the relationship between craton surface topography and the thickness of their underlying lithosphere layer.
Illinois geology professor Lijun Liu led a study that challenges today’s leading theories regarding continental history and stability. Credit: y L. Brian Stauffer, the team demonstrated that the traditional view of buoyant craton keels implies that most of the Earth’s cratons would be sitting about 3 kilometers above the sea surface, while in reality, their elevation is only a few 100 meters.
This deformation history is expressed in some of the more puzzling geophysical properties observed in the lithosphere, the study reports. “This is reflected in the strong dependence of crustal thickness on lithospheric thickness, an observation never made before this study,” Liu said. “In particular, there are two major uplift and erosion events in the past, when supercontinents Rodinia and Pangea each separated, the former causing what is known as the Great Unconformity – a feature in the Earth’s rock record shows no evidence of new deposition, only deep craton erosion.
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