What's the Mainstream Explanation for This?

Chris dunnett, considered like his modern successor on these engineering topics was an eight i think that's his photo actually he was allowed to go in and examine the core. The mainstream explanation for this so from petri's day like 150 years ago it's always been denied that it's a spiral groove they just flat out like nope it's concentric rings they say it's just like rings on it. When you when you have a spiral groove on a core we can now use that to determine how fast did thisCore get cut  what if you assume that that that groove is part of the cutting process there's the difference between the two.