Ceramic compositional analysis projects Funded by the Begole Archaeological Research Grant Program

Size: px

Start display at page:

Download "Ceramic compositional analysis projects Funded by the Begole Archaeological Research Grant Program"

Agnes Lee
5 years ago
Views:

Anza-Borrego desert: Seeking provenience and technology Patrick Quinn and Margie

desert through compositional analysis Patrick Quinn and Margie Burton 2008 Ceramic

Patrick Quinn 2009 Ceramic production and distribution at a Late Prehistoric

1 Ceramic compositional analysis projects Funded by the Begole Archaeological Research Grant Program 2006 Compositional analysis of prehistoric ceramics from the Anza-Borrego desert: Seeking provenience and technology Patrick Quinn and Margie Burton 2007 Exploring prehistoric ceramic raw material resources in the Anza-Borrego desert through compositional analysis Patrick Quinn and Margie Burton 2008 Ceramic analysis and cultural interpretation of the Stacked Stone Site David Broughton and Patrick Quinn 2009 Ceramic production and distribution at a Late Prehistoric hunter-gatherer seasonal occupation site CA-SDI-813, Anza-Borrego Desert State Park Patrick Quinn and Margie Burton

Background Inspired by formal homogeneity of abundant ceramics in desert region

and detailed approach to ceramic compositional analysis may offer information

2 Background Inspired by formal homogeneity of abundant ceramics in desert region of eastern San Diego County Different ware types have been identified in hand specimen (e.g. Rogers 1930s, Waters 1980s): Tizon brown ware, Colorado buff ware More systematic and detailed approach to ceramic compositional analysis may offer information about pottery production and distribution; hence a better understanding of pre-contact cultural development of the region since ca. 500 AD Brown ware Buff ware

3 What is ceramic compositional analysis? Type of scientific archaeological approach Examines composition of ceramics ( recipes ) What they are made of and how they were made Two main approaches: Thin section petrography mineralogy; microstructure can be seen with magnification Analytical chemistry - elemental composition determined by irradiation, X-rays, lasers. INAA, XRF, XRD, ICP-MS etc. Different approaches have advantages and disadvantages Best to combine two or more techniques

4 Thin section petrographic analysis Sophie van Heymbeek University of Sheffield

5 Previous ceramic compositional studies in southern California Compositional analysis already applied to socal ceramics Important studies include Hildebrand et al. (2002), Griset (1996) CRM studies such as Wade (1999), Guerrero (2004) Applied petrography and chemistry to sites in mountains and coastal plain Important findings include general westwards movement of populations related to desiccation of Lake Cahuilla Total number of sherds analysed is still small c. 500 Problems with comparison of data due to different chemical approaches and presentation of petrographic data

6 Project Aims Assess the compositional diversity of ceramics found in the desert Explore archaeological issues, such as: Craft production (raw materials, technologies) Cultural identity (as expressed through pottery-making traditions) Movement of people and pots Interaction between social groups

Archaeological sites and ceramic samples 2006-2007 Seven sites on western desert margin previously recorded by Wallace, Ezell, and Seidel.

SDI-343 and SDI-2336 in Collins Valley in Cahuilla territory in north of park SDI-10571 and SDI-10573 in Bow Willow Canyon and SDI-955, SDI-956

7 Archaeological sites and ceramic samples Seven sites on western desert margin previously recorded by Wallace, Ezell, and Seidel. Collections curated at BARC. SDI-343 and SDI-2336 in Collins Valley in Cahuilla territory in north of park SDI and SDI in Bow Willow Canyon and SDI-955, SDI-956 and SDI-963 in Indian Valley in Kumeyaay territory in south of park All sites were temporary camps, except CA-SDI-343 which was part of village of Los Coyotes All sites have milling features, stone tools and abundant ceramic sherds Selected 70 diagnostic sherds, 4-27 per site

8 18 different fabric groups were identified on the basis of mineralogy, petrography, texture, and microstructure Selected petrographic classes

9 Fabric Group 7: Collins Valley and Indian Valley CA-SDI-343 CA-SDI-955 CA-SDI-956

10 Fabric Group 6: Indian Valley and Bow Willow Canyon CA-SDI-963 CA-SDI-10573

Bulk chemical analysis performed by University of Missouri Research Reactor Center (MURR) Anza-Borrego sherds plotted with data from previous study by Hildebrand et al.

11 Bulk chemical analysis performed by University of Missouri Research Reactor Center (MURR) Anza-Borrego sherds plotted with data from previous study by Hildebrand et al PCA plot of NAA data Findings: 1. Most Anza-Borrego sherds were classified as chemical groups IMP-2 and IMP-3 (new). IMP-2 considered by Hildebrand et al. (2002) to represent Rogers Salton Brown type 2. Some sherds classified as IMP-1A; equivalent to Water s Tumco Buff and Topoc Buff types 3. Only three mountain sherds - classified in group SDI-2, representing residual weathered igneous clays and equivalent to Tizon Brown ware

Raw material sites and samples 2007-2008 Carried out program of raw material prospection Assessed

sites and elsewhere in the park Processed, fired and analysed clay samples with both chemistry and

Anza-Borrego ceramics to thin sections of ceramics from Stacked Stone Site (Broughton 2008) and

12 Raw material sites and samples Carried out program of raw material prospection Assessed availability of clays and tempers in the vicinity of the sites Collected geological materials near sites and elsewhere in the park Processed, fired and analysed clay samples with both chemistry and petrography Thin sectioned hard rock samples Compared raw material samples to ceramics Also compared Anza-Borrego ceramics to thin sections of ceramics from Stacked Stone Site (Broughton 2008) and Wikalokal (Hildebrand et al. 2002; Gallucci 2001, 2004) in Laguna Mountains George Jefferson State Parks Paleontologist/Geologist

Raw material prospecting revealed very few good clay sources close to study sites All sites are in granitic valleys and have sandy soils Ceramic production may not have taken place at most sites

13 Raw material prospecting revealed very few good clay sources close to study sites All sites are in granitic valleys and have sandy soils Ceramic production may not have taken place at most sites There were some compositional matches with local raw materials: Ceramics may have been made in Collins Valley from metamorphic material Some southern sites may have used broadly local quaternary sedimentary deposits

Results - Raw material choices Potters utilised a wide range of different raw materials to produce ceramics Residual weathered igneous clays from mountains Quaternary or Holocene alluvium at foot of

14 Results - Raw material choices Potters utilised a wide range of different raw materials to produce ceramics Residual weathered igneous clays from mountains Quaternary or Holocene alluvium at foot of mountains in western desert Residual(?) metamorphic clays Fine Cenozoic marine and nonmarine sediments of Salton Trough Raw materials determined to some extent by natural availability Potters may also have preferred specific raw material types

Results Clay preparation techniques Coarse clays may have been cleaned Evidence for crushing and rehydration of pulverised clays Several types of temper: Sand Crushed rock Crushed sherds

15 Results Clay preparation techniques Coarse clays may have been cleaned Evidence for crushing and rehydration of pulverised clays Several types of temper: Sand Crushed rock Crushed sherds or grog in many fabric classes Perhaps plant matter Repeated recycling of ceramics More than one type of temper found in some ceramics Tempering may not have always been purely functional

16 Fabric Group 17 - grog temper Fabric Group 13 - Non-functional grog temper Fabric Group 9 - Sand and grog temper

Results Forming and firing techniques Relic coils picked out by

vessel walls by surface may indicate beating with paddle Degree of

moderately well fired but varied Firing atmosphere seen in colour

technology appears poorly controlled, such as in bonfire or pit

17 Results Forming and firing techniques Relic coils picked out by alignment of particles in thin section Alignment of particles to vessel walls by surface may indicate beating with paddle Degree of firing suggested by optical activity of clay matrix Ceramics were moderately well fired but varied Firing atmosphere seen in colour of clay Oxidation and reduction often within same sherd Firing technology appears poorly controlled, such as in bonfire or pit firing Techniques revealed in thin section largely match ethnographic accounts (e.g. Rogers 1936; Campbell 1999) provide evidence of antiquity and cultural continuity Oxidized Fabric Group 3 Reduced Campbell (1999)

ethnohistoric trails (e.g. Cline 1979 - Tom Lucas) may indicate actual routes taken Can track movement over c.

18 Results - Movement of pots and people Much of the ceramics appear to have been transported to the sites The distribution of these ceramics and possible raw material sources provides an indication of general direction and scale of movement Comparison with ethnohistoric trails (e.g. Cline Tom Lucas) may indicate actual routes taken Can track movement over c. 40 miles Ceramics moved eastwest, west-east and perhaps north-south-- evidence of seasonal migration and crossing of ethnolinguistic boundaries Kumeyaay trails - Cline (1979)

19 Results - Cultural Patterning Few differences in craft practise detected between north (Cahuilla) and south (Kumeyaay) Range of techniques used to produce ceramics found at sites in both areas Some compositional differences may be explained by raw material availability Non-local origin of much of ceramics confuses picture Strong sampling bias due to small numbers of sherds analysed

20 Mine Wash CA-SDI-813 Late Prehistoric seasonal habitation site

21 Mine Wash site CA-SDI-813 Excavated by CA State Parks archaeologists Two phases of Late Prehistoric occupation, 1100 years ago and years ago. Sampled 115 sherds from several levels within Units A5, B1, and B3 in February 2010

consist of sandy soil unsuitable for pottery

22 Conducted raw material prospecting in the vicinity of the Mine Wash site, February 2010 Local raw materials consist of sandy soil unsuitable for pottery manufacture Mine Wash site Red dots=locations of geological samples

23 Sedimentary clays from the desert to the east dominate the tested sherd sample from the Mine Wash site, CA-SDI-813 Grog tempered fine sedimentary fabric Sand & grog tempered micaceous sedimentary fabric

Residual weathered igneous fabrics occur in one excavation unit only.

Biotite-rich granitic fabric Coarse granitic residual igneous fabric Amphibole-rich residual igneous

Pottery appears to have been brought to the site mainly by people travelling westwards, but some pottery

24 Residual weathered igneous fabrics occur in one excavation unit only. These fabrics are similar to those found at sites in the Laguna Mountains to the west of CA-SDI-813. Biotite-rich granitic fabric Coarse granitic residual igneous fabric Amphibole-rich residual igneous fabric Preliminary results suggest that all ceramics at the site are non-local in origin (i.e. pottery was not made at CA-SDI-813). Pottery appears to have been brought to the site mainly by people travelling westwards, but some pottery appears to have been brought by people travelling eastwards from the mountains. Are these the same or different people?

. CA-SDI-813 Summary Collins Valley Cahuilla territory Compositional analysis has revealed an unexpected level of diversity in plain desert ceramics This can be attributed to different

desert margin due to lack of raw materials A possible exception is the village of Los Coyotes in Collins Valley High ceramic diversity at individual sites may be explained by

25 . CA-SDI-813 Summary Collins Valley Cahuilla territory Compositional analysis has revealed an unexpected level of diversity in plain desert ceramics This can be attributed to different recipes of raw materials and a craft technology characterised by microtraditions possibly representing individual potters or social groups Local production is not common in the western desert margin due to lack of raw materials A possible exception is the village of Los Coyotes in Collins Valley High ceramic diversity at individual sites may be explained by movement/regularly repeated occupation events Pottery moved in many directions for significant distances along seasonally travelled routes between environmental zones and crossed linguistic/ethnic boundaries

Joan Schneider" Sue Wade" Bonnie Bruce" Dr. George Jefferson" Dr.

26 Thanks to:" Begole Archaeological Research Grant Program" Colorado Desert Archaeological Society" Anza-Borrego Foundation & Institute" Dr. Joan Schneider" Sue Wade" Bonnie Bruce" Dr. George Jefferson" Dr. John Hildebrand" Suzanne Moramarco" University of Missouri Research Reactor Archaeometry Lab (MURR) and the National Science Foundation"

Mineralogical and technological investigation of pottery and raw materials for ceramic production. Tel el Farcha, Nile Delta. Egypt.

Maciej Pawlikowski* Mineralogical and technological investigation of pottery and raw materials for ceramic production. Tel el Farcha, Nile Delta. Egypt. */Cath. Mineralogy, Petrography and Geochemistry