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I'm pretty sure it's mostly tree rings that they use to calibrate it since they are pretty much perfect for it as each ring absorbs carbon for a single year and
by cwmma 2y ago
I'm pretty sure it's mostly tree rings that they use to calibrate it since they are pretty much perfect for it as each ring absorbs carbon for a single year and then stops so you get a two for one of basically a stack of samples each for a different year covering a broad span of time.
- louky 2y agoDendrochronology (dating cut trees via counting rings/size/ratios) has its own subjective interpretations, and different databases that don't always line up.
- andrewla 2y agoIn the early days of radiocarbon dating these were pretty much the exclusive source of calibration curves (since the coverage is so comprehensive). There were many problems encountered through this that led us to using a combination of different heuristics. Primary among those considerations was that the dendrochronology record is of pretty limited timeframes -- we have very few samples going back more than a couple of hundred years. And the study of carbon-14/12 ratios in dendrochronology led to deeper questions: there appears to be a significant geographic variation; the change in c14/12 ratio is non-monotonic (i.e. there are times of sufficiently increased historical C14 that samples from that era are indistinguishable from samples in a later era). This has led to a ton of research into calibration methodologies, leaving many questions that are still open today.