[el_don_almighty]

The kimberlite source of these phytoliths and their age makes me question our confidence in their origination from the arctic surface. Is it at all possible this material was cycled through plate tectonics which subducted it from a southern source and eventually ejected far north through volcanic action? I mean, a lot could happen over 48M years...

[mapt]

The sort of trip it would need to go through to make that journey doesn't make survival of the fossil very plausible.

[sturadnidge]

Even a 'microscopic siliceous structure', which is what they're talking about here? To be clear, I am in no position whatsoever to challenge your statement, just curious as to why it would be unlikely for something invisible to the human eye to be shifted around the planet via plate tectonics (which seems entirely plausible to the layperson that I am).