2. Bluff Great House
Northern San Juan Region
• Part of the “Chaco
Phenomenon”
• Built late 11th early 12th c.
• Studies
• Chaco era A.D. 1000-1150
• post-Chaco A.D. 1150-1250
6. Methods
•Qualitative measurements were taken using
• A High powered light
• An a microscope
•Variables I measured
(presence 1 - absence 0)
•Abrasions
•Fading
•Pitting
•Scratching
7. Examples of Use-Wear on White
Ware
Scratching &
Abrasions
Scratching
Fading & Pitting Fading
8. Example of Use-Wear on Utility
Ware
Scratching Pitting
Scratching & Pitting Abrasions & Pitting
9. Challenges
• Identifying use-wear on sherds
• Confirming the use-wear I saw
• Distinguishing between scratching and
manufactured marks
• Observing visible signs of pitting
11. Q & A?
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Editor's Notes
For my research project I conducted a ceramic use-wear analysis on a sample of 36 sherds taken from Test Unit 75 a & b-Room 58 at the Bluff Great House.
During my presentation I will discuss:
Where the Northern San Juan region is, why it is has been studied and how my use-wear analysis fits some of the questions researchers are debating
I will Talk about my Methods
The challenges I had during my analysis
And my conclusions
Bluff is located between Mesa Verde, Kayenta, Fremont and the Chaco Canyon cultural area and is one of 40 regional great houses that make up the “Chaco Phenomenon,” which is a shared regional system of styles in architecture of the great houses and a shared regional road system.
The Chaco regional system has been studied extensively in the last 25 yrs, most recently by Dr. Cameron who asked what role Bluff’s great house played outside of Chaco Canyon? And how was Bluff involved in the operation and development of the Northern San Juan regional system?
Dr. Cameron has used Bluff “as a starting point for exploring the Chaco and post Chaco eras in the northern San Juan region” (Cameron: 2007)
My research focused on a sample of 36 sherds, taken from Tu 75 Room 58. I wanted to see if there was a difference in use-wear on the ceramics during the Chaco and post-Chaco time period?
Test Unit 75 a-c is located on the back side of the great house (point this area out), and is located next to a terrace.
A stratagraphic trench was dug from Tu 78 to Tu75 (point this out) through the terrace in order to study any and all artifacts found.
In Tu 75 Room 58 there were 620 sherds recovered.
“a notable lack of ground stone from the site, suggest a dearth of domestic activities in the post-Chaco era. This evidence contradicts data from other sites that suggests increasing domestic use of the great houses in the post-Chaco era” (Cameron: 2007).
This is a profile of Test Unit 75 a-c Room 58.
Room 58 was a part of a tier of rooms that were attached to the north side of the eastern block of the great house during the Chaco era,
Room 58 was built around A.D. 1123
There was evidence of a t-shaped door that led to a room to the west but neither ever entered into the great house.
Room 58 may have been used as a storage unit during the post-Chaco era
and the room has been identified as being used for a trash deposit; household trash and other debris.
Illustration of Room 58(point out levels 1-4 and levels 8-9)
Levels 1-4 represent the post-Chaco era. In Levels 1 & 2 there was architectural collapse and deposits that washed in from other areas. I analyzed 2 utility and 2 white wares.
Level 3. I analyzed the use-wear on 17 sherds, 6 utility ware 11 white ware. In this level there were more Mc Elmo Black-on-white than Mesa Verde black-on-white and some general Pueblo III design styles that were found.
Level 4 contained nine sherds I analyzed 1 white ware. Presumably Mc Elmo black-on-white.
Levels 8 & 9 represent the Chaco era
Level 8 contained burned roof fall and parts of a Dolores Corrugated vessel & some Mancos black-on-white wares. I looked at 11 sherds all 11 were utility wares.
In level 9: 24 sherds were recovered. I looked at three, 2 utility and 1 white ware.
I didn’t analyze sherds from levels 5-7 so that I could keep my analysis specifically linked to the Chaco and post-Chaco time period levels.
There were not any particularly large sherds so I looked for sherds that came from either the bottom of a vessel, where the coils were started or from the lower body of the vessel thinking that this would be good area to find use-wear marks.
I started my analysis by looking through sherds from all the different levels of to try and identify visible patterns of use-wear.
I came up with four variables and used a dichotomous (de-ka-to-mous) scale to measure whether or not the sherd exhibited the presence or absence of the variable.
I identified fading on white wares only.
Most ceramic studies have been done on full pots or on sherds that have a large rim attached.
If I found visible traces of wear, I was confronted with trying to identify whether or not the use-wear occurred while being used for cooking and serving
during a stage in the manufacturing process,
while being excavated
or through a natural breakdown of the material while in the stratified levels.
I decided that if the scratches were uniform, on the diagonal and exhibited a pattern that they were made during manufacturing
but if the scratches were uniform in pattern and were contained to a long strip andappeared on top of the surface then I identified them as being made during use.
Pitting was easy to see but I wasn’t sure if it had been caused from temper expandsion during the firing process or if it was due to use-wear.
Again scratching and fading were the easiest to identify.
Explain this diagram
My question asked if there would be a difference in use-wear between the Chaco and post-Chaco eras.
The post-Chaco period over-all shows more use-wear… Besides pitting which occurred 50% less during the post-Chaco era all other variables showed a higher percentage of use-wear during the post-Chaco era…
abrasion occurred 30% more in post-Chaco…
scratching was 67% higher in post-Chaco…and fading was identified as occurring 31%.
Scholars have argued that the population declined after A.D. 1150 due to a drought. This study shows there was more activity on the ceramic wares during the post-Chaco era.
There remains the question of how the Bluff site was inhabited during late 12 century.
During the post-Chaco era Bluff’s rooms were broken up into several living quarters, with more people living at the site, which could account for the presence of the heavier use-wear
There is some evidence of ceramic wares being brought to the site as ritual offerings
I think a next step of study could be done on the absorbed residues on the sherds
This may lead to a better understanding of diet and which may lead to a greater understanding of who either inhabited the site or stopped by during the post-Chaco era.
