Davidson

Preliminary mineralogical and chemical study of Pre-Madisonville and Madisonville horizon

Fort Ancient ceramics

Michelle M. Davidson

Faculty Mentors:Tammie L. Gerke, PhD (Department of Physics and Geology)A. Gwynn Henderson, PhD (Kentucky Archaeological Survey)

Northern Kentucky UniversityHighland Heights, KY 41099

Abstract

Fort Ancient ceramics can be divided into two distinct groups referred to as Pre-Madisonville (A.D. 1000-1400) and Madisonville (A.D. 1400-1750), based on stylistic features. Ceramics from these two periods were analyzed to test the hypothesis that Pre-Madisonville peoples utilized a large number of local clay sources and that Madisonville peoples utilized a limited number of clay sources. X-ray diffraction and x-ray fluorescence analyses were conducted on 15 ceramic sherds from the Thompson, Fox Farm, and Petersburg sites. Each site is a multi-component Fort Ancient site located in the Middle Ohio River Valley.

The mineralogy of the ceramics from all three sites are indistinguishable both temporally and spatially and contain quartz, micas, and trace amounts of feldspars. Compositional variation for the ceramics was documented between the sites using multivariate statistics and bivariate plots. Ceramics from the Petersburg site appeared to be distinguishable temporally, but not spatially. Ceramics from the Thompson and Fox Farm sites are distinguishable spatially, but not temporally. Thus, it appeared that the changes in the style of ceramics between the Pre-Madisonville and Madisonville correspond to a change in clay sources at the Petersburg site, but not at the Thompson and Fox Farm sites.

IntroductionArchaeologists consider the introduction of

ceramics a profound technological leap. Ceramic styles evolved following the introduction of ceramic technology. This evolution of ceramic technologies and styles gives ceramic artifacts high diagnostic value. Ceramic sherds and vessels can be easily associ-ated with specific prehistoric cultures and/or time peri-ods, and in some cases, with specific activities. Thus, ceramics are some of the most analytically useful arti-fact classes found on prehistoric sites.

Archaeologists have traditionally categorized ceramic types based on qualitative observations of temper, surface treatment, and morphology. Although the value of this kind of analysis has been recognized, identification of the mineralogy of ceramic paste has been less often used (Carr and Komorowski 1995; Isphording 1974; Kamilli and Steinberg 1985; Lizee et

al 1995; Lynott et al 2000; and Steponaitis et al 1996). However, these types of studies have been conducted in areas with a limited number of clay sources. Miner-alogical analyses of clays and ceramic pastes could help establish the source of clays used in the ceramic industries of certain cultures, temporal periods, or spe-cific sites. This might shed some light on prehistoric trade, travel routes, and procurement strategies.

The manufacture of ceramics began in the Middle Ohio River Valley (MORV) (Figure 1) approximately 3000 years ago. Several different prehistoric cultures made pottery in this region, such as the Adena, Hopewell, Newtown, and Fort Ancient cultures. The most recent MORV ceramic producers were the Ft. Ancient peoples (A.D. 1000-1750). The high number of possible clay sources in the MORV (Birkeland 1999) may have contributed to the lack of sourcing studies in this region.

Norse Scientist 91

Davidson

.The Ft. Ancient culture was not static throughout its 750-year history (Henderson 1998; Pollack and Henderson 1992, 2001). Archaeologists have docu-mented many important changes in Ft. Ancient culture after A.D. 1400. Archaeologists refer to the period of Ft. Ancient culture from A.D. 1400 to approximately 1750 as the Madisonville Horizon. The Ft. Ancient period circa A.D. 1000-1400 will be referred to as the Pre-Madisonville Period for the purposes of this study. The shift from the Pre-Madisonville period to the Mad-isonville horizon is marked by:

1) Changes in physical layout of villages from those that were circular with a central plaza to villages com-posed up of scattered house clusters;

2) An increase in village size with a corresponding decrease in the number of villages, which may reflect an aggregation of small villages;

3) Changes in burial practices from placement of bod-ies in low earthen mounds, around village central pla-zas, or the dead being buried in areas adjacent to house clusters;

4) An increase in exchange of exotic goods with other cultures outside of the MORV, as evidenced by marine

shell ornaments possibly from Mississippian chiefdom societies in eastern Tennessee; and

5) A marked change in ceramics both stylistically and in vessel form diversity.

Several Pre-Madisonville sub-regional ceramic styles, such as Anderson, Fox Farm, Baum, and Jessa-mine, give way to the pan-regional Madisonville style (Sharp 1990; and Turnbow and Henderson 1992). Jars, which predominated during the Pre-Madisonville period, are joined by bowls, pans, and colanders during the Madisonville Horizon. Archaeologists postulate that greater interaction among and between Ft. Ancient villages (i.e., potters sharing information) may account for the pan-regional ceramic homogeneity in ceramic style and vessel form that developed after A.D. 1400.

The most obvious change in Madisonville Hori-zon ceramics is a thinning of the vessel walls and an appearance more refined to the modern eye. This may reflect an improvement in firing techniques. It is also possible that whereas the Pre-Madisonville people uti-lized local, low quality clay sources, the Madisonville people utilized a limited number of high quality clay sources. Because archaeologists have not incorporated

Figure 1. Modified map of the Middle Ohio River Valley from Henderson, 1992. Site locations are indicated by filled triangles.

92 Norse Scientist, Northern Kentucky University

Davidson

the identification of the mineralogy and chemistry of ceramic pastes and clay sources in their analyses of Ft. Ancient ceramics, they do not know whether available clays at Ft. Ancient can be distinguished from each other on a sub-regional basis or, most importantly, whether the changes identified in Ft. Ancient ceramics also extend to the kinds of clays Ft. Ancient potters used.

Did all Ft. Ancient potters after A.D. 1400 use clay from a few particular sources (which might be reflected in ceramics with uniform pastes), or did Ft. Ancient potters continue to use the same sources of clay they had used previously? The purpose of this study is to determine whether changes in the use of clay sources mirror the changes documented in Ft. Ancient ceramic technology, vessel form, and style after A.D. 1400.

MethodsSite Descriptions

The northern Kentucky three, multi-component sites chosen for this study, were Thompson (15Gp27), Fox Farm (15Ms1), and Petersburg (15Be6, Figure 1). Potsherds were chosen from these sites because they are within or adjacent to the Middle Ohio River Valley and contain vertically and/or horizontally stratified, chronometrically dated Pre-Madisonville and Mad-isonville components.

Thompson. Thompson is located in northwestern Greenup County, Kentucky. It lies in the floodplain on the south bank of the Ohio River. The site is situated near the western edge of the Cumberland Plateau where it borders the Knobs (Henderson, 1992). The bedrock of the Cumberland Plateau consists of Penn-sylvanian and Mississippian sandstones, conglomer-ates, and shales alternating with high grade coal beds (Bailey and Winsor 1964).

Fox Farm. Fox Farm is located in southern Mason County, Kentucky. It lies in an upland setting approxi-mately 2.5 km south of the North Fork of the Licking River (Turnbow 1992). It is located in the Outer Blue-grass physiographic region, which is underlain by Upper Ordovician limestones (McFarlan 1961). This site sits on a broad, gently rolling ridge top that exhib-its mild karst topography (Turnbow 1992).

Petersburg. Petersburg is located in northwestern Boone County, Kentucky. It lies in the floodplain immediately adjacent to the south bank of the Ohio River in the Hills of the Bluegrass region (Henderson 1993). Boone County is underlain by Upper Ordovi-cian limestones, shaly limestones, and shales. Streams in this area contain glacial gravels, sands, and silts (Webb and Funkhouser 1932). In addition, Petersburg is underlain by Pleistocene and Holocene alluviums (Swadley 1972).

Sample Selection and Preparation

Sample Selection. Five body sherds were obtained from each Pre-Madisonville Period and Madisonville Horizon component at each site (Table 1). All of the sherds were shell tempered and ranged in size from 4

to 6 cm2 (Figure 2). Recognizing the diversity of vessel types in the Madisonville Horizon, care was taken to select sherds exhibiting definite morphological charac-teristics of a jar.

Potsherd Preparation. A portion of each potsherd was ground to a particle size of 5 to 10 microns using a tungsten-carbide ball mill. A portion of the powder from each potsherd was pressed into a pellet using a Spex 3624 B X-Press for x-ray fluorescence analysis. Each pellet was held at 20 tons for one minute.

Analytical Conditions

X-Ray Diffraction Analysis. The powders were then analyzed using a Seimens D-500 x-ray diffraction sys-tem with a copper x-ray tube in the Geology Depart-ment at the University of Cincinnati. The 2θ ranged from 2o to 50o with a step of 0.05o. A count time of 1 second was used at each step. The 2θ range of 2o to 50o was chosen because it covered a wide range of clay and other silicate mineral compositions.

X-Ray Fluorescence. A Rigaku 3070 x-ray fluores-cence spectrometer, located in the Geology Depart-ment at the University of Cincinnati, was used to analyze all of the potsherds. The samples were ana-lyzed for SiO2, TiO2, Al2O3, Fe2O3 (total iron), MnO, MgO, CaO, Na2O, K2O, P2O5, Nb, Zr, Sr, Rb, th, Pb, Zn, Cu, Ni, Cr, and V. Intensity data were converted to weight percent, or parts per million (ppm), using multi-ple regressions applied to USGS and NIST soil and

Norse Scientist 93

Davidson

sedimentary rock standards and loss of ignition (LOI) data. A small portion of each ground sherd was heated to 1000 oC for one hour to determine the LOI values.

Table 2 lists theresults of the XRF analysis and LOI values for each sherd.

94 Norse Scientist, Northern Kentucky University

Davidson

ResultsXRD Results and Interpretation

The mineralogy of the Pre-Madisonville and Mad-isonville sherds from the Thompson, Fox Farm, and Petersburg sites are presented in Figures 3 through 5, respectively. These figures were used to assess the temporal variability of the mineralogy of the sherds. Each figure contains a representative XRD trace for the Pre-Madisonville and Madisonville sherds for a given site. The vertical axis represents the intensity of

the x-ray signal and the horizontal axis represents the 2θ range in each figure. All traces contain a strong cal-cite peak, because of the fresh water shell temper present in all of the sherds. There may be calcite in the sherds, which is inherent to the source clays, but I was not able to distinguish it from the shell temper. The predominant mineralogy for both the Pre-Madisonville and Madisonville sherds for all three sites is quartz, mica (probably chlorite), and trace amounts of feld-spars. Thus there appear to be no temporal changes in the mineralogy of the sherds within each site.

a) Thompson Pre-Madisonville sherds.

b) Fox Farm Pre-Madisonville sherds.

c) Petersburg Madisonville sherds

Figure 2. Examples of fresh water shell tempered sherds from each site.

Norse Scientist 95

Davidson

96 Norse Scientist, Northern Kentucky University

Davidson

Figures 6and 7 depict representative traces from each site. Figure 6 is an analysis of the Pre-Madison-ville sherds, and Figure 7 is an analysis of the Mad-isonville sherds. These figures were used to assess the regional variability of the mineralogy of the sherds. The mineralogy for both the Pre-Madisonville and the Madisonville sherds from all the sites is predominantly quartz, micas (probably chlorite), and trace amounts of feldspar. Thus, it is clear that there is little to no regional variability in the mineralogy of the sherds.

Also, based on the mineralogy of the sherds, I determined an approximate temperature range for their firing. Clays, which were used to make the sherds, are typically referred to as hydrous silicates (DHZ 1992). When heated above 500 oC the hydroxyl component is driven off. This results in a collapse of the clay struc-ture, which results in mica-like structures. If the clays are heated to approximately 900 oC or higher, the clays

become vitreous and form porcelain. When the sherds in this study were analyzed there were no peaks for clays or glasses. Thus the sherds in this study were probably fired above 500 oC but below 900 oC

XRF Results and InterpretationMajor, minor, and trace element data are presented

in Table 2. PCA analysis was applied to assess if the temporal and regional relationships of the sherds were reflected in their chemistry. Based on their chemistry, divergence in the samples was assessed by applying a variance-covariance matrix to the data set. Fresh water shells and clays incorporate calcium (Ca) and stron-tium (Sr) into their structures. Concentrations of these elements can be as high or higher in shell material than in clays (Lizee et al 1995), therefore, they were excluded from this analysis. Phosphorous was also excluded because of atypically high concentrations for

Figure 3. Representative XRD traces for the Pre-Madisonville and Madisonville sherds from the Thompson site. Q = quartz, M = micas, and F = feldspars.

Figure 4. Representative XRD traces for the Pre-Madisonville and Madisonville sherds from the Fox Farm site. Q = quartz, M = micas, and F = feldspars.

Norse Scientist 97

Davidson

MORV clays, which suggests that it might also be a temper component rather than a clay component..

The population of sherds were best separated by chromium (Cr) and lead (Pb). First, the temporal varia-tions for each site were evaluated. Figure 8 is the Thompson site (see Figure 1). The Pre-Madisonville and Madisonville clusters overlapped between 33 to 66%. The Pre-Madisonville cluster displayed the greatest range in both Cr (11.2 to 65.3 ppm) and Pb (14.9 to 53.5 ppm) concentrations compared to the Madisonville cluster (Cr 36.7 to 56.9 ppm and Pb 21.2 to 46.6 ppm). Figure 9 is the Fox Farm site (see Figure 1). The Pre-Madisonville and Madisonville clusters overlap strongly. The Pre-Madisonville sherds had Cr concentrations that range from 52.4 to 100.1 ppm com-pared to the Madisonville sherds that range from Cr 66.5 to 126.2 ppm. The Pb concentrations displayed greater variations between the two clusters. The Pre-Madisonville cluster had a limited range from 15.4 to

20.8 ppm while the Madisonville sherds displayed a larger range from 9 to 22.9 ppm. Figure 10 is the Petersburg site (see Figure 1). The Pre-Madisonville sherds had high Cr (39.1 to 73.0 ppm) and Pb (13 to 16.6 ppm) concentrations compared to the Madison-ville sherds (Cr 12.4 to 48.8 ppm and Pb 10.1 to 11.9 ppm). The Pre-Madisonville and Madisonville clusters have the best separation at the Petersburg site and the greatest degree of overlap at the Thompson siteNext, the spatial variability was evaluated (Figure 11). I observed that the Fox Farm and Petersburg sites over-lapped between 40 to 60%. The Petersburg site appeared to share a common boundary with the Thompson site. I observed that the Fox Farm and Thompson sites did not overlap. Based on the small data set, I distinguished sherds from the Fox Farm and Thompson sites based on their Cr and Pb concentra-tions. However, I could not distinguish sherds from Fox Farm and Petersburg and probably would not be very successful in trying to distinguish Petersburg and Thompson site sherds based on their Cr and Pb con-centrations.

ConclusionsWe reached the following conclusions:

1) The mineralogy of the Pre-Madisonville and Mad-isonville ceramic pastes are indistinguishable both temporally and spatially.

2) The ceramic pastes in this study were probably fired to about 700 oC. This is based on the comparison of the XRD traces.

3) The chemical composition of the of the Pre-Mad-isonville and Madisonville ceramic pastes are not tem-porally unique for Thompson and Fox Farm but are spatially unique from each other. I could not identify them temporally on the basis of chemical composition alone.

4) The chemical composition of the Pre-Madisonville and Madisonville ceramic pastes are unique temporally for Petersburg but are not unique spatially from the Fox Farm or Thompson site. Thus one could not iden-tify them spatially on the bases of chemical composi-tion alone.

5) At the Fox Farm and Thompson sites the Pre-Mad-isonville and Madisonville Ft. Ancient peoples

Figure 5. Representative XRD traces for the Pre-Madisonville and Madisonville sherds from the Petersburg site. Q = quartz, M = mica, and F = feldspars.

98 Norse Scientist, Northern Kentucky University

Davidson

.appeared to have used the same clay source(s). How-ever, at the Petersburg site it appeared that the Mad-isonville peoples used different clay sources than the Pre-Madisonville peoples.

AcknowledgementsI would like to thank the William S. Webb Museum of Anthropology for the use of Ft. Ancient potsherds, and the Department of Geology at the University of Cin-cinnati for use of the XRD and XRF. I would also like

Figure 7. Representative XRD traces for the Madisonvillesherds from all three sites. Q=quartz, M=mica, and F=feldspars.

Figure 6. Representative XRD traces for the Pre-Madisonvillesherds from all three sites. Q=quartz, M=mica, and F=feldspars.

Norse Scientist 99

Davidson

to thank Drs. Warren D. Huff and J. Barry Maynard at the University of Cincinnati for their time and conver-sations.

ReferencesBailey HH, Winsor JH. 1964. Kentucky soils. Misc.

Pub. 308. U.K. Agricultural Experiment Station in Cooperation with U.S.D.A. Soil Conservation Service.

Birkeland PW. 1999. Soils and geomorphology. Oxford: Oxford University Press. 103 p.

Carr C, Komorowski JC. 1995. Identifying the clay mineralogy of rock temper in ceramics using x-radiography. Am Antiquity 60(4): 723-749.

Deer WA, Howie RA, Zussman J. 1992. An introduction to the rock-forming minerals 2nd ed. New York: Longman Scientific and Technical. 1992. 696 p.

Henderson AG. 1993. Middle Fort Ancient villages and organizational complexity in central Kentucky

[dissertation]. Lexington, KY: University of Kentucky.

Henderson AG. 1993. Prehistoric research at Petersburg (15BE6), Boone County, Kentucky: archaeological report 289. Program for Cultural Resource Assessment. Lexington, KY: University of Kentucky.

Henderson AG. 1992. Introduction. In: Henderson AG, editor. Fort Ancient cultural dynamics in the middle Ohio valley. Madison: Prehistory Press. p. 2.

Henderson AG, Pollack D. 1992. The Thompson Site. In: Henderson AG, editor. Fort Ancient cultural dynamics in the middle Ohio valley. Madison: Prehistory Press. p. 31-50.

Isphording WC. 1974. Combined thermal and x-ray diffraction technique for the identification of ceramic ware temper and paste minerals. Am Antiquity 39 (3): 477-483.

0

10

20

30

40

50

60

70

10 15 20 25 30 35 40 45 50 55 60

Pb (ppm)

Figure 8. Test of temporal variability: Thompson. The filled diamonds represent Pre-Madisonville and the filled squares represent Madisonville sherds.

100 Norse Scientist, Northern Kentucky University

Davidson

Kamilli DC, Steinberg A. 1985. Archaeological Geology. New Haven: Yale University Press..

Lizee JM, Neff H, Glascock MD. 1995. Clay acquisition and vessel distribution patterns: neutron activation analysis of late Windsor and

Figure 10. Test of temporal variability: Petersburg. The filled diamonds represent Pre-Madisonville and the filled squares represent Madisonville sherds.

0

10

20

30

40

50

60

70

80

6 8 10 12 14 16 18 20

P b (ppm)

20

40

60

80

100

120

140

0 5 10 15 20 25

Pb (ppm)

Figure 9. Test of temporal variability: Fox Farm. The filled diamonds represent Pre-Madisonville and the filled squares represent Madisonville sherds.

Norse Scientist 101

Davidson

Shantok tradition ceramics from southern New England. Am Antiquity 60(3): 515-530.

Lynott MJ, Neff H, Price JE, Cogswell JW, Glascock MD. 2000. Inferences about prehistoric ceramics and people in southeast Missouri: results of ceramic compositional analysis. Am Antiquity 65(1): 103-126

McFarlan AC. 1961. Geology of Kentucky. Kentucky Department of Economic Development in cooperation with the Kentucky Geological SurveyPollack D, Henderson AG. 1992. Insights into Fort Ancient culture change: A view from south of the river. In: Cultures before contact: the late prehistory of Ohio and surrounding regions. Ohio Archaeological Council. p. 194-227.

Pollack D, Henderson AG. 1992. The possible role of salt production in Fort Ancient cultural development from A.D. 1200 to 1550. Research in Economic Anthropology, Supplement 6. p. 77-99.

Sharp WE. 1990. The Fort Ancient period. The archaeology of Kentucky: past accomplishments and future directions. Kentucky Heritage Council, State Historic Preservation Comprehensive Plan Report No. 1. 2: 467-471.

Steponaitis VP, Blackman MJ, Neff H. 1996. Large-scale patterns in the chemical composition of Mississippian pottery. Am Antiquity 61(3): 555-572.

Swadley WC. 1972. Geologic map of parts of the Lawrenceburg, Aurora, and Hooven quadrangles, Boone County, Kentucky. Washington, D.C.: U.S. Geological Survey.

Turnbow CA. 1992. The Fox farm site. In: Henderson AG, editor. Fort Ancient cultural dynamics in the middle Ohio valley. Madison: Prehistory Press. p. 51-68.

Turnbow CA, Henderson AG. 1992. Ceramic analysis. In: Henderson AG, editor. Fort Ancient cultural dynamics in the middle Ohio valley. Madison: Prehistory Press. p. 113-135.

Webb WS, Funkhouser WD. 1932. Archaeological survey of Kentucky. Reports in archaeology and anthropology. Lexington, Kentucky: University of Kentucky.

0

20

40

60

80

100

120

140

8 13 18 23 28 33 38 43 48 53 58

Pb (ppm)

Figure 11. Test of spatial variability: All the sherds. The sherds are represented as filled triangles for Thompson, filled squares for Fox Farm, and filled diamonds for Petersburg.

102 Norse Scientist, Northern Kentucky University