1. None of this whatsoever has been proven. But that’s what fun about it

2. MANTLE CORE MANTLE

3. Avalanches at the Core-Mantle Boundary, Geophysical Research Letters, vol 29 pp 41-1 to 41-4 (2002)

6. Please don’t let Charlie bite my finger…

7.  70% of density change as liquid core solidifies is due to exclusion of lighter element exclusion- leads to convection.  Excluded light elements remain in solution and freeze out as they rise (1000 o C temp drop I.C to CMB)  Light elements fall like snow onto undulating surface of CMB  Gathers like snow…how nice…  Exceeding the angle of repose will cause slumping, bringing core liquid with it.  Only need a few degrees slope.  Shear stress causes slumping- oblique impact?

8.  Must be oblique  Consider, for example, a comet with velocity 25 km/sec, radius 5 km  ΔΩ = mvR/I  If the magnetic field of the core is coupled to entrained Fe in the sediment, sudden acceleration could cause an avalanche.

10.  Trigger the disturbance of the geodynamo ◦ Implications for magnetic reversals

11.  SlumpingHeat re-distribution as cool precipitate mixes with hot liquid Fe, cooling the Fe and letting it fall due to density increase.  This may disturb large convection cells of the outer core, reduce the overall scale of flow and even change the dipole component.  Cells in close association may be also affected, driving an overall shut down of the geodynamo

12.  When the convective cells re-establish themselves, there is a 50% chance the magnetic field will reform in the reversed direction. Help. I have absolutely no idea where the hell I am I’m lost too mate…must be the geodynamo again. Game of chess?

13.  Mantle Plume initiation ◦ The part of the mantle that lost the ‘sediment’ blanket is exposed to hot Fe and rapidly heated  Maybe only from the largest of avalanches (thickness >>100m)

14.  Mantle plume initiation  Flood Basalts and Kimberlites

16.  Mantle plume initiation  Flood Basalts and Kimberlites If several avalanches are coupled from an intense impact, could result in separate but simultaneous plumes e.g simultaneous but spatially distant plumes at 61-62Ma (Larson et al. 1999)

17.  Meteor impacts and flood basalts have long been possible explanations for mass extinctions.  Flood basalts almost always seem to post- date the main phase of extinction  This would be satisfied by the impact avalanche model TIME??? Mantle plumes take millions of years to reach the surface- would destroy correlations. Kimberlite rates- 300km/s?

18.  Reversal in fall back breccia of 24-km Reis impact crater.  No reversal occurs with Chicxulub crater ◦ Ooooooooooo….. ◦ High iridium suggests impact was vertical (would have been ejected to space if oblique)??

19.  120-85Ma has no magnetic reversals  Linked to mantle plume activity (Larson and Olsen 1991) which created Ontong-Java plateau  The LARGEST, yes, the largest, volcanic province on Earth. Alaska, 30Km thick.

20. Slope recharge after 35Ma Crater subduction- candidates? Marine Extinction peak at 120Ma

21.  Decadal variations in avalanching ◦ Small avalanches more likely and thus common than larger ones