Socony Mobil radiocarbon dates, [Part] 1.

Abstract

The samples in this list were measured by the methane proportional counter method reported by Burke and Meinschein. Shell samples were mechanically cleaned and washed with water. Where necessary, cold, very dilute HCl was used to remove the powdery exterior. Sedimentary wood and mud or clay samples were treated with hot concentrated HCl and washed with water before burning. Four other types of materials recovered from sediments were dated: 1) the total organic C, 2) benzene-soluble organic material, 3) foraminiferal tests, and 4) "dispersed carbonate." The foraminiferal samples were recovered from the sediment by washing on a 120-mesh screen. These were then converted to carbon dioxide by acid treatment. "Dispersed carbonate" was recovered in the form of CO (sub 2) by acid (HCl) treatment of the sediment wash which had been depleted of Foraminifera. The total organic C samples were recovered by combustion to CO (sub 2) after all carbonates had been removed by acid treatment. Organic extractables were also converted to CO (sub 2) by combustion. The errors given include contributions from the following sources: 1) Standard statistical counting error, 2) Background variation. This is taken as equal to the rms deviation from the mean of background determinations made during a period of time beginning well before and ending well after the counting of the sample in question. 3) Variation in counting rate of the modern standard. This is determined in the same way as 2). Not included are errors due to doubt about the half-life of C (super 14) or the correctness of our modern standard. The age calculations are based on a C (super 14) half-life of 5,568 years. Our modern standard is hackberry wood grown about 1940. This wood gives a counting rate which is 94.6 + or - 1.3% of the U.S. National Bureau of Standards oxalic-acid standard.