The unknown cooling-rate history of natural silicate melts can be investigated using differential scanning heat capacity measurements together with the limiting fictive temperature analysis calculation. There are a range of processes occurring during cooling and re-heating of natural samples which influence the calculation of the limiting fictive temperature and, therefore, the calculated cooling-rate of the sample. These processes occur at the extremes of slow cooling and fast quenching. The annealing of a sample at a temperature below the glass transition temperature upon cooling results in the subsequent determination of cooling-rates which are up to orders of magnitude too low. In contrast, the internal stresses associated with the faster cooling of obsidian in air result in an added exothermic signal in the heat capacity trace which results in an overestimation of cooling-rate. To calculate cooling-rate of glass using the fictive temperature method, it is necessary to create a calibration curve determined using known cooling- and heating-rates. The calculated unknown cooling-rate of the sample is affected by the magnitude of mismatch between the original cooling-rate and the laboratory heating-rate when using the matched cooling-/heating-rate method to derive a fictive temperature/cooling-rate calibration curve. Cooling-rates slower than the laboratory heating-rate will be overestimated, while cooling-rates faster than the laboratory heating-rate are underestimated. Each of these sources of error in the calculation of cooling-rate of glass materials—annealing, stress release and matched cooling/heating-rate calibration—can affect the calculated cooling-rate by factor of 10 or more.

天然硅酸盐熔体的未知冷却速率历史可以使用差示扫描热容量测量和极限虚拟温度分析计算进行研究。在天然样品的冷却和再加热过程中发生了一系列过程，这些过程会影响极限假想温度的计算，从而影响样品的计算冷却速率。这些过程发生在缓慢冷却和快速淬火的极端情况下。在冷却时在低于玻璃化转变温度的温度下对样品进行退火导致随后确定的冷却速率过低达几个数量级。相比之下，与空气中黑曜石更快冷却相关的内应力会导致热容量曲线中增加放热信号，从而导致对冷却速率的高估。要使用虚拟温度方法计算玻璃的冷却速率，必须创建使用已知冷却和加热速率确定的校准曲线。当使用匹配的冷却/加热速率方法推导出虚构的温度/冷却速率校准曲线时，计算出的样品的未知冷却速率受原始冷却速率与实验室加热速率之间的失配幅度的影响. 比实验室加热速率慢的冷却速率将被高估，而比实验室加热速率快的冷却速率被低估。