Chemical Investigations on Ancient Near Eastern Archaeological Ivory

9 Chemical Investigations on Ancient Near Eastern Archaeological Ivory Artifacts. Fluorine and Nitrogen Composition

Downloaded by CORNELL UNIV on October 18, 2016 | http://pubs.acs.org Publication Date: June 1, 1978 | doi: 10.1021/ba-1978-0171.ch009

N. S. BAER—Conservation Center, Institute of Fine Arts, New York University, 1 East 78th St., New York, NY 10021 T. JOCHSBERGER—Arnold & Marie Schwartz College of Pharmacy and Health Sciences of Long Island University, Brooklyn, NY 11216 N. INDICTOR—Chemistry Department, Brooklyn College, CUNY, Brooklyn, NY 11210

Specimens of ivory excavated at Ancient Near Eastern sites (Acem Hüyük, Anatolia; Hasanlu, Northwest Iran; Khorsabad, Iraq, Megiddo, North Palestine; and Nimrud, Iraq) have been analyzed for carbon, hydrogen, fluorine, nitrogen, and ash. The decrease in nitrogen content as collagenous material was removed and replaced, in part, by inorganic salts was general to all sites. Similarly, hydrogen and carbon contents decreased, and ash increased. The results of fluorine analyses were less general with some degree of site specificity. These data are applied to the development of criteria for artifacts of uncertain provenance. The possibility of chemical alteration of the composition of modern ivory to obtain compositions similar to those of ancient ivory is considered.

T n a recent study we examined samples taken from ivory artifacts excavated at Hasanlu, Acem Hiiyiik, and Nimrud. Elemental analyses were obtained for carbon, hydrogen, and nitrogen ( I ) . The results for specimens of known provenance were used to develop preliminary criteria for Ancient Near Eastern archaeological ivory artifacts of uncertain provenance. The useful results obtained i n that work suggested an extension of similar observations to other excavation sites i n the Ancient Near East (Megiddo and Khorsabad). The range of analyses was extended to include fluorine. 0-8412-0397-0/78/33-171-139$05.00/l © 1978 American Chemical Society

Carter; Archaeological Chemistry—II Advances in Chemistry; American Chemical Society: Washington, DC, 1978.

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II


Table I. Ancient Near Eastern Archaeological Sites and Period Attributions of Specimens Examined Site

Period (Century B.C.)

Hasanlu Acem H i i y i i k Nimrud Khorsabad Megiddo

9th 19th-18th 9th-8th 8th 13th-12th

Description Northwest Iran, Period I V Anatolia Iraq Ancient D u r Sarrukin, Iraq North Palestine

A variety of analytical methods have been applied to dating prehistoric bone (2). Included among them are changes i n elemental composition accompanying systematic changes in buried bone. The slow exchange of ionic species from groundwaters with hydroxyapatite, the major inorganic component of bone, is accompanied by an increase in fluoride ion concentration with the partial conversion to fluorapatite. The nitrogen and carbon content decrease as the collagenous material is removed by several mechanisms including hydrolysis and biological attack ( 3 , 4 , 5 ) . The many environmental factors—including p H , temperature, moisture, and groundwater ion content—which affect the rate of protein decay suggest that systematic behavior may not be assumed for new sites whose environment may only superficially parallel that of sites previously investigated. The results of carbon, hydrogen, nitrogen, fluorine, and ash analyses are reported here for five archaeological sites (Table I ) . These data are compared with those for ivories of unknown provenance. Experimental Sample Preparation. Samples from artifacts were obtained by drilling deeply (ca. 2 cm) into the artifact with a carbon steel spade drill, discarding the initial superficial material. About 2-3 mg per drilling was available for analysis. For expendable fragments, the surface was cleaned by mechanical scraping with a scalpel. Analyses. Analyses of ash, carbon, and hydrogen by combustion; nitrogen by Dumas or micro-Kjeldahl; and fluorine by spectrometry were obtained from the Schwarzkopf Microanalytical Laboratory, Woodside, N Y 11377. The radiocarbon date was obtained from Teledyne Isotopes, Westwood, N J 07675. Analytical Errors. The uncertainties for the analytical methods are: ash by combustion residue, ± 0.3% absolute; carbon, ± 0.05 mg; hydrogen, ± 0.3% absolute; nitrogen, by Dumas, ± 5 /JL, or by micro-Kjeldahl, =b 1 f i g ; and fluorine, by spectrometry, ± 1 tig (6). Errors associated with impurities introduced into or present in the ivory matrix, e.g., inorganic salts from groundwater replacing collagenous material during burial or organic adhesive materials used i n the field or


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BAER E T A L .

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Ancient Near Eastern Ivory Artifacts

conservation laboratory to strengthen friable specimens, have been discussed previously ( J ) .


Results and Discussion Related Materials. Table II gives results of elemental analyses for ivory, bone, and related materials. The modern specimens all demonstrated high levels of nitrogen and carbon similar to those of modern ivory. Severe aqueous extraction of beefbone with boiling water removed less than half of the organic matter originally present. This suggests that artificial removal of the proteinaceous material from ivory artifacts to simulate the effects of archaeological burial is difficult without fragmentation of the artifact. The mastodon, mammoth, and ancient walrus samples retained their proteinaceous material although they represented fossil specimens. The fluorine levels observed for modern materials were, i n general, comparable with those observed i n other work ( 7 , 8 ) . Included are the data of Jaffee and Sherwood (9) for modern and fossil manatee rib specimens from Florida waters and land-pebble phosphate deposits, respectively. The modern specimen shows a somewhat higher fluoride level than generally observed for modern bone. Since this sample was taken from an articulated skeleton ( U S N M 228478), only a small sample was taken. It is possible that preparation of the skeleton for display or the small sample size reduced the representativeness of the measurement. Table II. Carbon, Hydrogen, Nitrogen, Fluorine, and Ash Analyses for Specimens of Ivory and Related Materials 0

Specimens Elephant ivory (Africa) Elephant ivory (Africa)—treated Mammoth tusk ( N . E . Siberia) ° Mastodon" Sperm whale tooth Whale bone (rib) Hippopotamus tooth Boar tooth (Aitape, New Guinia) Walrus tusk (Alaska) *—fossil Beefbone" Manatee rib (Florida)—modern' Manatee rib (Florida)—fossil'

6

Ash (%)

C (%)

H (%)

N" (%)

F (%)

53.32 56.50 54.24 56.04 66.02 71.62 60.36 65.57 60.46 68.68 59.98 93.25

16.25 15.18 15.64 16.85 12.28 11.85 12.64 12.25 15.16 10.94

3.51 3.33 3.78 3.24 2.49 2.11 3.04 2.49 2.89 2.19

5.52 5.30 5.37 5.78 4.23 3.03 4.25 3.86 4.75 3.52

0.04 1.34 0.06 0.02 0.07 0.15 0.04 0.02 0.01 0.02 0.21 3.57

— —

— —

— —

° A l l analyses by Dumas method. Treated in boiling aqueous I.OF N a F 1 hr. Pleistocene Epoch, courtesy The American Museum of Natural History. Courtesy The American Museum of Natural History. * Collagenous material extracted with boiling water for 2 hr. Miocene or Pliocene; after Jaffee and Sherwood (#). 6 e

d

f


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Table III. Designations of Ancient Ivory Specimens from Khorsabad, Ancient Dur Sarrukin, Iraq (8th Century B.C.) and Megiddo, North Palestine (13th-12th Century B.C.) Accession Number

Specimen

Description

0

Khorsabad V I Khorsabad V I I Khorsabad V I I I Megiddo I Megiddo I I

A A A A A

17611 22166 17610 22267 15601

white fragment blue—black fragment white (encrusted) fragment white-yellow fragment white-yellow (encrusted) fragment


° Oriental Institute, University of Chicago.

Table IV. Analyses of Ancient Ivory Specimens from Khorsabad, Ancient Dur Sarrukin, Iraq (8th Century B.C.) and Megiddo, North Palestine (13th-12th Century B.C.) Specimen

Color

Khorsabad V I Khorsabad V I I Khorsabad V I I I Megiddo I Megiddo I I

white white—black white white—yellow white-yellow

Table V .

Specimen Elephant ivory Elephant ivory (treated) Mastodon Hasanlu Hasanlu Nimrud Megiddo Acem H i i y i i k Khorsabad "Khorsabad" "Assyrian" "Gupta" 0

6

Ash (%)

C (%)

H (%)

87.7 93.3 85.3 78.9 81.3

3.3 2.6 3.9 7.0 6.0

0.8 0.4 1.0 1.5 1.4

N (%)

F (%)

Chemical Investigations on Ancient Near Eastern Archaeological Ivory

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