The document discusses how dynamic processes affect the relationship between seafloor age and area over time. It finds that plate tectonics and continental drift, through processes like ridge formation, rifting, dispersal, and aggregation, change the age distribution of ocean floors in a time-dependent way. The distribution evolves through alternating periods of high and low heat flow associated with Wilson cycles of plate boundary reorganizations. 3D spherical convection models that include plate-like behavior or drifting continents are needed to reproduce the young ages of subducted seafloor implied by constraints.

2. Dynamic causes of the relation between area and
age of the oceanfloor
N. Coltice, T. Rolf, P.J. Tackley, S. Labrosse
Science (336) – April 2012

5. Atsteady-state…

6. Time dependent
Time 1 Time 2

7. Estimatedevolution of the age distribution
Becker et al., 2009

8. 3D spherical convection
withplate-likebehavior
and continental rafts

10. Age (Myrs)

11. Age (Myrs)

12. Age (Myrs)

14. Wilson cycle model
High heat flow Moderateheat flow
New ridges - rifting Dispersal
Lowheat flow
Aggregation

15. Conclusions
•Seafloor age constraint: continents and plate-like behavior are needed for
young seafloor “subduction”
• Formation of plate boundaries and continental aggregation/dispersal
change the age distribution
• Time dependence of the distribution is the rule
• Distribution changes its shape through Wilson cycles

17. 3D sphericalwithplate-likebehavior
OR
with continents (no plate-likebehavior)