The 13C/12C ratio in human collagen was determined for 19 individuals from Hopewell sites in Wisconsin, Illinois, and Ohio and compared with 27 new measurements from individuals of Archaic, Mississippian, and Late Woodland affiliation. Additional measurements were made of elements in the food chain and on experimental animals fed on a diet of known composition containing maize. The similarity of the Hopewell measurements to those of nonmaize diets indicates that corn was of little importance in the Hopewell diet for those populations tested.
Procedures and equipment used in the University of Wisconsin laboratory have been described in previous date lists. Except as otherwise indicated, wood, charcoal, and peat samples are pretreated with dilute NaOH-NA4P207 and dilute H3P04 before conversion to the counting gas methane; when noted, marls and lake cores are treated with acid only. Very calcareous materials are treated with HCL instead of H3P04. Pretreatment of bone varies with the condition of the bone sample; solid bone with little deterioration is first cleaned manually and ultrasonically. The bone is treated with 8% HCL for 15 minutes, then dilute NaOH-Na4P2O7 for 3 hours at room temperature, washed until neutral, and the collagen extracted according to Longin (1971
Procedures and equipment have been described in previous date lists. Except as otherwise indicated, wood, charcoal, and peat samples are pretreated with dilute NaOH-Na4P2O7 and dilute H3P04 before conversion to the counting gas methane; marls and lake cores are treated with acid only. Very calcareous materials are treated with HC1 instead of H3P04.
Procedures and equipment used in the University of Wisconsin laboratory have been described in previous date lists. The preamplifiers and counting system were replaced in 1977 using modified EC & G Ortec components. Except as otherwise indicated, wood, charcoal, and peat samples are pretreated with dilute NaOH-Na4P2O7 and dilute H3PO4 before conversion to the counting gas methane; when noted marls and lake cores are treated with acid only. Very calcareous materials are treated with HCl instead of H3PO4. Pretreatment of bone varies with the condition of the bone sample; solid bone with little deterioration is first cleaned manually and ultrasonically. The bone is treated with 8% HCl for 15 minutes, then dilute NaOH-Na4P2O7 for 3 hours at room temperature, washed until neutral, and the collagen extracted according to Longin (1971). Charred bone is treated with dilute HCl, NaOH-Na4P2O7, and then dilute HCl again.
Procedures and equipment used in the University of Wisconsin laboratory have been described in previous date lists (Bender, Bryson & Baerreis 1965; Steventon & Kutzbach 1986). Except as otherwise indicated, wood, charcoal and peat samples are pretreated with dilute NaOH-NA4P2O7 and dilute H3PO4 before conversion to counting gas methane; when noted, marls and lake cores are treated with acid only. Very calcareous materials are treated with HCL instead of H3PO4.
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