Table 2 in Fission track dating of obsidian source samples from the Willaumez Peninsula, Papua New Guinea and eastern Australia

Table 2. Results for fission track dating of Papua New Guinean obsidians.1 spontaneousinducedneutronsamplenstrackdensitynjtrackdensityfluenceage±(t)(tcm2)(t)(x104tcm2)(X1015 ncm-2)(a)Baki111729335.541.644±0.01430198±8906Kutau151470945.161.644±0.01426707±7688 1 ns and nj represent the number of spontaneous and induced tracks counted, respectively. The induced track density has been evaluated by means of the population subtraction method. Ages are calculated by using the following constants (Ao; = 1.551 x 1O-lOa·1, 238U/235U = 137.88, O"f = 580.2 b, Af = 7.03 x 1O.17a-1). The thermal neutron fluence is determined from both two calibrated mica and Makrofol detectors in contact with glass dosimeters (Coming CNl, CN2) and two metallic monitors (Co, Au). All corrected ages are weighted means of values in the plateau region.表2 巴布亚新几内亚黑曜岩裂变径迹测年结果¹ 原紧凑表格数据按表头顺序整理如下： 样品：Baki11，自发径迹数1729，自发径迹密度335.54 t/cm²，诱导径迹数1.644±0.014，诱导径迹密度30198±8906 ×10⁴ t/cm²，热中子注量1.644±0.014 ×10¹⁵ n/cm²，年龄30198±8906 a； 样品：Kutau15，自发径迹数1470，自发径迹密度945.16 t/cm²，诱导径迹数1.644±0.014，诱导径迹密度26707±7688 ×10⁴ t/cm²，热中子注量1.644±0.014 ×10¹⁵ n/cm²，年龄26707±7688 a。 注：¹ ns与nj分别代表自发径迹与诱导径迹的计数数量。诱导径迹密度通过群体扣除法（population subtraction method）计算得到。年龄计算采用以下常数：自发裂变常数λ_f=1.551×10⁻¹⁰ a⁻¹，²³⁸U/²³⁵U原子数比=137.88，裂变截面σ_f=580.2靶恩（barn，b），²³⁵U衰变常数λ=7.03×10⁻¹⁷ a⁻¹。热中子注量通过两种与玻璃剂量计（康宁CN1、CN2）接触的校准云母探测器及Makrofol探测器，辅以两种金属监测器（钴Co、金Au）共同测定。所有校正后的年龄为坪区数值的加权平均值。