Would have bet money on stromatolites…

[ScottBlooded]

So this one comes to me from twitter, I would have bet anything that these were stromatolites but the age would be too young for that if the poster is correct about the formation. Geological? Thoughts? 

[Ludwigia]

I couldn't say if these are stromatolites, but those structures exist up to the present, so they certainly aren't too young.

[ScottBlooded]

3 minutes ago, Ludwigia said:

I couldn't say if these are stromatolites, but those structures exist up to the present, so they certainly aren't too young.

Oh no way, for some reason I had it in my mind they were only like a Cambrian/pre Cambrian thing. Good to know thanks!

[Rockwood]

I wouldn't take that bet. I think a much closer look is needed to confirm that these are stromatolites though. 

[DPS Ammonite]

The rock looks like an example of spheroidal weathering. Note the fractures between the lobes. Granite can weather the same way. The rock is fractured, then each block weathers from the outside to the inside like an onion.

See picture from:

https://en.m.wikipedia.org/wiki/Spheroidal_weathering

 

Definition from Mindat:

https://www.mindat.org/glossary/spheroidal_weathering

[supertramp]

it resembles onion skin weathering in igneous rocks; is it possible considering the local geology?

[doushantuo]

orbicular granite , of the type that can be found at Separation Point, New Zealand

which boils down to : rock without biogenic origin

edit : so I more or less agree with DPS and Supertramp 

Edited 39 minutes ago by doushantuo