230Th dating results of speleothem records from two caves, central-eastern and northeastern Brazil

d234U = ([234U/238U]activity - 1)x1000.d234Uinitial was calculated based on 230Th age (T), i.e., d234Uinitial = d234Umeasured x e**l234xT.Corrected 230Th ages assume the initial 230Th/232Th atomic ratio of 4.4 ±2.2 x10-6. Those are the values for a material at secular equilibrium, with the bulk earth 232Th/238U value of 3.8. The errors are arbitrarily assumed to be 50%.B.P. stands for "Before Present" where the "Present" is defined as the year 2000 A.D.

d₂₃₄U = ([²³⁴U/²³⁸U]放射性活度比 - 1) × 1000。初始d₂₃₄U（d234Uinitial）基于铀230钍（²³⁰Th）年龄（T）计算得到，即d234Uinitial = 实测d₂₃₄U（d234Umeasured）乘以以自然常数e为底的（λ₂₃₄×T）次方。校正后的²³⁰Th年龄默认初始²³⁰Th/²³²Th原子比值为4.4±2.2×10⁻⁶。该比值对应处于长期放射性平衡的物质，其全球整体的²³²Th/²³⁸U比值为3.8，误差被人为设定为50%。B.P.即"Before Present"（距今），其中"Present"（现今）定义为公元2000年。