Isotope Regions *Non-Discussion Reference Thread*

Discussion in 'Sand Canyon John Doe' started by mmarty, Dec 15, 2015.

  1. mmarty

    mmarty Verified Law Enforcement Nevada

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    Ok, I sent the new list off and it should be posted here soon. We are down to 48 names (approximately) on the list that we started that had around 3,000 I believe matching our John Doe. As far as tasks go, I can only think of checking these names against the circumstances and facts I have told you and see if there is a fit.

    The isotope testing results are as follows:

    (1) The individual was traveling within a month prior to his death; and

    (2) Approximately 1 to 1.5 months (4-6 weeks) prior to death, the individual resided
    in a region (“Iso-Region 1”) consistent with the Intermountain West, including
    portions of Lyon County, Nevada; and

    (3) Approximately 1.5 to 2 months (6-9 weeks) prior to death, the individual moved
    to “Iso-Region 1” from a region characterized by a cooler climate (“Iso-Region
    2”); and

    (4) Approximately 2 to 3 months (9-13 weeks) prior to death, the individual had
    moved or traveled through “Iso-Region 2”, an area consistent with more northern
    and higher elevation regions of the Intermountain West, including some isolated
    high elevation portions of Nevada.

    Again, any help on this case is greatly appreciated. Without citizens like you all on this forum this job would be insurmountable. This case is not only a "whodunit" but also a "whoisit".
     
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  3. RickshawFan

    RickshawFan Well-Known Member

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    Just so we have a basic framework, I found this website, which seems to have a relevant presentation of what isotope testing is about. http://www.sfu.museum/forensics/eng/pg_media-media_pg/isotopes/

    Another good explanation is a PBS Nova program: http://www.pbs.org/wgbh/nova/tech/stable-isotopes.html

    The only thing close to a helpful isotope distribution map I've found is inn Google books under Isoscapes. This whole book looks fascinating, actually.

    I had always thought of isotope testing as pertinent to archaeology (e.g. neolithic) and botanical elements (e.g. bristle cone pines) in archaeological sites. I'm excited to know that it gets applied to forensics.
     
  4. RickshawFan

    RickshawFan Well-Known Member

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    Were you able to find anything on the isotopes, Carbuff? I looked for a couple of hours a few days ago, but the only concept I could come up with was to use the blurry maps in Isoscapes, alongside my Walmart atlas and then get a general idea of where the MP might or might not have been.

    I was able to eliminate some possibilities because they are in Isotope Region 3. E.g. Yellowstone. Some E-W bound interstates also go through Region 3.

    There's an Isotope region 2 spot not to far from Wellington NV. It corresponds to the backside (east flank) of Yosemite.

    Interestingly, Tahoe does not seem to be Region 2.

    The other piece of information I couldn't quite figure out is: How long must a person be in a region for the isotope measurement for the region to show up? For instance, if you took a day trip to Yellowstone, will Region 3 show up in the Isotope test? Or would you have to, like, camp in Yellowstone backcountry for 2 weeks for it to register?
     
  5. carbuff

    carbuff Well-Known Member

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    I got this further information from Mmarty:

    Region 1:
    California
    Oregon
    Washington
    Idaho
    Wyoming
    Montana
    Nevada
    Colorado
    Utah
    North Dakota
    South Dakota

    Region 2:
    Montana
    Wyoming
    Idaho
    small areas of Washington, Oregon, Nevada, Utah and Colorado

    He also mentioned that it's not an exact science, so the edges aren't really precise. He'll try to get us the map next week.
     
  6. carbuff

    carbuff Well-Known Member

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    No, I didn't find anything better yet. I did find another good article though: http://www.forensicmag.com/articles/2007/01/tracing-unidentified-skeletons-using-stable-isotopes

    "In general, 18O decreases from the equator to the poles, and from the west coast of a continent to the interior. Also, 18O is lower in mountains, and on the lee-side of large mountain ranges like the Rockies."

    Which explains why Tahoe is a different region: it's at a lower altitude.
     
  7. carbuff

    carbuff Well-Known Member

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    Okay, I found one that sort of shows what we're looking at. (I got it through a friend of a friend whose husband is a climate scientist; he thinks the forensic zones are not quite identical to the climate zones shown on his map.) It shows the 180 isotope range from most (yellow) to least (dark blue). It's not labeled, and it's hard to see fine detail (for instance, it's not clear enough to see that Yellowstone Park is a different region), but it does give us a pretty clear idea where the regions might be.

    I did find a more detailed one, but it's under copyright so I can't post it.

    isotope zones.jpg
     
  8. bessie

    bessie Administrator Staff Member Administrator Moderator

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  9. ClaireNC

    ClaireNC WS Member

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  10. GGE

    GGE GGE=GonnaGetEm

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    Perhaps this could be useful. I haven't read through all of it yet.

    http://ecophys.utah.edu/uploads/3/1/8/3/31835701/407.pdf

    "A Framework for the Incorporation
    of Isotopes and Isoscapes in Geospatial
    Forensic Investigations"

    Particularly this section, perhaps:

    "17.4
    Application of Stable Isotope Analysis to Unsolved
    Murder Investigations"
     
  11. BigCityAccountant

    BigCityAccountant New Member

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    This has been bothering me for some time now. Wasn't the original owner of the vehicle tracked down in Colorado? So the UID had potentially traveled through Colorado based on the isotopes??? Could the old owner still have some connection to the UID?
     
  12. carbuff

    carbuff Well-Known Member

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    Mmarty, you had mentioned that it might be possible to get us a more detailed map of the isotope information. Did anything ever come of that? I know you're busy and working far beyond the call of duty, so if you haven't been able to get to it, we understand.
     

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