[HN Gopher] Researchers accurately dating a 7k-year-old settleme...
       ___________________________________________________________________
        
       Researchers accurately dating a 7k-year-old settlement using cosmic
       rays
        
       Author : wglb
       Score  : 90 points
       Date   : 2024-05-28 02:00 UTC (21 hours ago)
        
 (HTM) web link (phys.org)
 (TXT) w3m dump (phys.org)
        
       | kentosi-dw wrote:
       | https://archive.ph/LOUmX
       | 
       | Website seems to be really slow for some reason. Hence providing
       | this.
        
         | s0rce wrote:
         | The article itself is open access
         | https://www.nature.com/articles/s41467-024-48402-1
        
       | senkora wrote:
       | This is very cool. The article is worth a read, but the TL;DR is
       | that a high cosmic ray event left a mark in a specific growth
       | ring on trees, and so it is possible to 1) loosely date a piece
       | of wood used in a building to within a few decades using carbon
       | dating and then 2) precisely date when it was cut down by
       | counting how far the marked growth ring is to the edge of the
       | tree.
        
         | hinkley wrote:
         | I remember a while back someone managed to build a many hundred
         | year sequence of growth rings by analyzing all of the
         | incremental construction in one town and aligning tree rings
         | from one piece of wood with the same rings in newer or older
         | pieces, using software not unlike reassembling DNA fragments,
         | but with growth rings.
        
           | apercu wrote:
           | I don't know about the rest of the world, but in the UK
           | dendrochronology is widely used for dating wood structures.
           | In England they have a database that can date (some) trees
           | back basically to any time of human existence in England. In
           | Ireland their data goes back before 5000 BCE.
           | 
           | Thanks Time Team. :)
        
           | Archelaos wrote:
           | The maximum is not just many hundred years. The Hohenheimer
           | Jahrringkalender based on pine trees of central Europe goes
           | back 12,460 years and people are working on extending it
           | backwards another 2,000 years.[1]
           | 
           | Such calendars are anchored in the present and require an
           | unbroken backward chain of quality wood samples from the same
           | region and the same tree species.
           | 
           | The advantage of the new method based on Miyake events is
           | that such events are so rare that they can be used to
           | determine an anchor point in the past, provided that external
           | evidence for a piece of wood can be used to make plausible a
           | time period for it in which there was only one such event
           | whose date is known from external evidence, such as ice core
           | drills.[2] From this single Miyake event tree ring one can
           | then work one's way forwards and backwards to establish a
           | tree ring chronology that does not need to be anchored in the
           | present.
           | 
           | One can even imagine that in the future it might be possible
           | to create such chronologies without a good time frame for a
           | single Miyake event, if two Miyake events are found at a
           | certain distance from each other in an otherwise unanchored
           | tree ring chronology.
           | 
           | [1] https://journals.uair.arizona.edu/index.php/radiocarbon/a
           | rti... (PDF)
           | 
           | [2] Confirmed Miyake events took place in 7176 BCE, 5259 BCE,
           | 660 BCE, 774 CE and 993 CE. Other candidates for Miyake
           | events are 12,350 BCE, 5410 BCE, 1052 CE and 1279 CE. See:
           | https://en.wikipedia.org/wiki/Miyake_event
        
             | hinkley wrote:
             | The number I thought I remembered sounded ridiculous in my
             | head so I underpromised, as it were.
        
       | James_K wrote:
       | I've never dated a settlement myself, but the conversation must
       | be awful.
        
         | rrr_oh_man wrote:
         | Once it reaches Large Town level it's not so bad.
        
       | bjornsing wrote:
       | TLDR: High cosmic ray events cause uptick in atmospheric
       | carbon-14. This is deposited in yearly growth rings of trees and
       | can be used as global alignment points for tree ring dating.
        
       | Conlectus wrote:
       | At first I was a bit confused why this was a big deal given that
       | Cosmogenic Radionuclide Dating[1] (which is based on cosmic rays)
       | has been a thing for a while. But it turns out this uses an
       | entirely different cosmogenic method based on atmospheric carbon
       | (combined with Dendochronology from the tree rings). Very cool!
       | 
       | [1]: https://en.m.wikipedia.org/wiki/Surface_exposure_dating
        
       ___________________________________________________________________
       (page generated 2024-05-28 23:00 UTC)