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True Polar Wander since the Early Cretaceous
Science (New York, N.Y.)
|March 28, 1975
Summary
Plate tectonics reconstructions reveal minimal true polar wander since the Early Cretaceous. Analysis of lithospheric plate motions indicates shifts within a few degrees, falling within measurement uncertainties.
Area of Science:
- Geophysics
- Plate Tectonics
- Geodynamics
Background:
- Understanding past plate motions is crucial for reconstructing Earth's geological history.
- True polar wander (TPW) refers to the movement of Earth's rotational axis relative to its surface.
Purpose of the Study:
- To reconstruct lithospheric plate motions from the Early Cretaceous to the present.
- To quantify the amount of true polar wander during this period.
- To assess the significance of reconstructed TPW in light of observational uncertainties.
Main Methods:
- Paleogeographic reconstructions of tectonic plates for three distinct time intervals.
- Analysis of plate displacements to determine best-fitting rigid rotations.
- Calculation of true polar wander based on rotational solutions.
Main Results:
- Lithospheric plate motions were successfully reconstructed for the specified time intervals.
- The best-fitting rigid rotations were identified for each interval.
- The calculated true polar wander was found to be minimal, generally within a few degrees.
Conclusions:
- The magnitude of true polar wander since the Early Cretaceous is small.
- The reconstructed TPW is within the range of uncertainty of the analysis.
- This suggests limited significant shifts in Earth's rotational axis relative to the lithosphere over the past ~145 million years.
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