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Intermittent plate tectonics?
1Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, NW, Washington, DC 20015, USA.
Science (New York, N.Y.)
|January 5, 2008
Summary
Subduction may not be continuous, as ocean closure can halt it globally. Earth
Area of Science:
- Geodynamics and Plate Tectonics
- Planetary Science
- Earth Sciences
Background:
- Continuous subduction is a common assumption in Earth science.
- Subduction zones can terminate due to ocean closure and supercontinent assembly.
- Pacific-type basin closure could significantly reduce global subduction.
Purpose of the Study:
- To investigate the hypothesis that subduction has not operated continuously throughout Earth's history.
- To explore the consequences of subduction flux variations on Earth's thermal and continental evolution.
Main Methods:
- Analysis of geological evidence for past Pacific-type basin closure.
- Evaluation of mechanisms for subduction termination and initiation compensation.
- Review of data supporting a minimum in subduction flux during the Mesoproterozoic.
Main Results:
- Evidence suggests Pacific-type basin closure has occurred in Earth's past.
- A direct compensation mechanism for subduction loss/gain is absent.
- Data indicate a potential minimum in global subduction flux in the Mesoproterozoic.
Conclusions:
- Dramatic reductions or temporary cessations of subduction are hypothesized for Earth's history.
- Variations in subduction continuity have significant implications for planetary evolution.
- Understanding subduction history is crucial for comprehending Earth's thermal and continental development.
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