1 / 19

Milankovitch Cycle Evolution and Uncertainty

Milankovitch Cycle Evolution and Uncertainty. Dave Waltham. Outline. C roll-Milankovitch cycles Application to c yclostratigraphy Earth-Moon system evolution The time-varying drag problem Time-evolution of CM cycles and their (big) uncertainties Beware!. Croll-Milankovitch Cycles.

amandaf
Download Presentation

Milankovitch Cycle Evolution and Uncertainty

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Milankovitch Cycle Evolution and Uncertainty Dave Waltham

  2. Outline • Croll-Milankovitch cycles • Application to cyclostratigraphy • Earth-Moon system evolution • The time-varying drag problem • Time-evolution of CM cycles and their (big) uncertainties • Beware!

  3. Croll-Milankovitch Cycles

  4. Cyclostratigraphy Wu et al, 2013. Time-calibrated Milankovitch cycles for the late Permian, Nature Communications

  5. Earth-Moon System Evolution

  6. Earth-Moon System Evolution da/dt = fa-5.5

  7. Earth-Moon System Evolution

  8. Earth-Moon System Evolution

  9. Time Varying Drag f= 2.01±0.03 x 1038 m6.5 s-1

  10. Time-Varying Drag Don Dixon f= 6.85±0.08 x 1037 m6.5 s-1 = (0.344±0.004) f0

  11. Time-Varying Drag OR

  12. Time-Varying Drag • Stochastic Variation • Log-normal variation • f = exp( m + s 2/2 ) • Secular Increase • Resonance in oceans is predicted to peak when day length ~ 27 hours (Webb, 1982)

  13. Time-Varying Drag • Stochastic variation • Monte-Carlo Simulation • Secular increase • Exponential approximation

  14. Time-Varying Drag • Geological Constraints • Tidal Rhythmites • Only really good ones are from Elatina/Reynella(Williams, 1989, 2000; Deubner, 1990) • 620±20 Ma • f = (0.51±0.02) f0

  15. Time-Varying Drag

  16. Time-Varying Obliquity

  17. Time-Varying Obliquity

  18. Web-based Tool

  19. Beware!

More Related