Crystal size distribution analysis is a non-destructive, quantitative method providing insights into the crystallisation histories of magmas. Traditional crystal size distribution data collection requires the manual tracing of crystal boundaries within a sample from a digital image. While this manual method requires minimal equipment to perform, the process is often time-intensive. In this study we investigate the feasibility of using the Quantitative Evaluation of Minerals by SCANing electron microscopy (QEMSCAN) software for semi-automated crystal size distribution analysis. Four Apollo 15 mare basalt thin sections were analysed using both manual and QEMSCAN crystal size distribution data collection methods. In most cases we observe an offset between the crystal size distribution plots produced by QEMSCAN methods compared to the manual data, leading to differences in calculated crystal residence times and nucleation densities. The source of the discrepancy is two-fold: (1) the touching particles processor in the QEMSCAN software is prone to segmenting overlapping elongate crystals into multiple smaller crystals; (2) this segmentation of elongate crystals causes estimates of true 3D crystal habit to vary between QEMSCAN and manual data. The reliability of the QESMCAN data appears to be a function of the crystal texture and average crystal shape, both of which influence the performance of the touching particles processor. Despite these limitations, QEMSCAN is able to produce broadly similar overall trends in crystal size distribution plots to the manual approach, in a considerably shorter time frame. If an accurate crystal size distribution is required to calculate crystal residence time or nucleation density, we recommend that QEMSCAN should only be used after careful consideration of the suitability of the sample texture and average crystal shape.

中文翻译：

---

QEMSCAN作为半自动晶体尺寸分布分析的一种方法：来自阿波罗15号母马玄武岩的见解

晶体尺寸分布分析是一种非破坏性的定量方法，可提供对岩浆结晶历史的深刻见解。传统的晶体尺寸分布数据收集需要手动跟踪数字图像样本中的晶体边界。尽管此手动方法需要最少的设备来执行，但该过程通常很耗时。在这项研究中，我们调查了通过扫描电子显微镜（QEMSCAN）软件对矿物质进行定量评估进行半自动晶体尺寸分布分析的可行性。使用手动和QEMSCAN晶体尺寸分布数据收集方法对四个Apollo 15母马玄武岩薄层进行了分析。在大多数情况下，我们观察到QEMSCAN方法生成的晶体尺寸分布图与手动数据相比存在偏差，导致计算出的晶体停留时间和成核密度不同。差异的来源有两个：（1）QEMSCAN软件中的接触式粒子处理器易于将重叠的细长晶体分割成多个较小的晶体；（2）这种细长晶体的分割导致真实3D晶体习惯的估计在QEMSCAN和手动数据之间变化。QESMCAN数据的可靠性似乎是晶体质地和平均晶体形状的函数，这两者都会影响触摸式颗粒处理器的性能。尽管有这些限制，但QEMSCAN能够在相当短的时间内在晶体尺寸分布图中产生与手动方法大致相似的总体趋势。