Jemez Historic Site includes the remains of at least one and possible two Spanish missions. Also located in the Jemez Mountains, we got a ton of obsidian. There hasn't been major excavations out at the site since the 1970s (maybe 60s) and a little in the early 2000s. However, in both cases, no one bothered with obsidian hydration. I am not saying it is not worthwhile, but if your emphasis is on chronometrics, dendro is going to be a better bet and in our case there were enough diagnostic ceramics to parse out what dated to when for the most part. All this being said, I do not think I have ever used obsidian hydration to date a site. I am no expert. If it works when dealing with such a refined date range, I would be surprised, but please let me know if you have success.

Matt



Matthew J. Barbour
Site Manager

Jemez Historic Site
PO Box 143
Jemez Springs, NM 87025
email: [log in to unmask]
office: 575.829.3530
cell: 505.220.3270

________________________________________
From: HISTORICAL ARCHAEOLOGY [[log in to unmask]] on behalf of Linda Hylkema [[log in to unmask]]
Sent: Wednesday, April 09, 2014 11:59 AM
To: [log in to unmask]
Subject: Obsidian hydration on historic sites

Hi all,

We are starting the analysis phase of a major excavation on a California
mission site (ca 1780-1840's). We have a number of pieces of obsidian
(debitage and formal artifacts). My consultants are proposing hydration on
25 pieces from the assemblage. We have already sourced all of it (except
pieces that are too small) with our XRF. Sources are the same as what has
been traditionally found in pre-contact sites of the region. My questions
are:

1. What would be gained from dating obsidian from a a site with such a
tight temporal margin, and such a recent one at that? Establishing
calibration markers for comparison for other late period sites??

2. If determined to be a relevant task, would would be a statistically
valid sample from an assemblage of about 200 pieces that includes 20
projectiles? I know that's a hard, if not impossible, question without
knowing more about my site, but any insight would be appreciated. If you'd
like more details about the site to answer my questions, please feel free
to contact me off-line. It's a rich site, and we excavated fifty-six
discrete pit features full of mission trash, which is where all the
obsidian is from.

At this point, I'm not convinced that it will add substantially to our
interpretation of the site.

ANY insight is appreciated.

Linda


*Linda Hylkema*
*Cultural Resources Manager, Santa Clara University*
W: *408-554-4513* | C: *408-219-5748* | F: *408-551-1709* | 500 El Camino
Real, Santa Clara, CA 95053