Energy dispersive X-ray microscopy (EDX) is a widely available, inexpensive method of characterizing the in-situ elemental composition of samples in Earth and life sciences. Common protocols and textbooks focussing on material sciences address EDX analysis of metallic samples that can be polished perfectly, whereas geoscientists often investigate specimens with prominent topography and composed of light, difficult to resolve elements. This is further compounded by the scarcity of literature surrounding the methodology of SEM–EDX in the field of palaeontology, leading to common misinterpretations and artefacts during data acquisition. Here, the common errors in elemental composition obtained with EDX arising from surface topography and from parameters subject to user decisions are quantified. As a model, fossil bioapatite (conodonts) and abiotic Durango apatite are used. It is shown that even microscale topography can distort measured composition by up to 34%, whereas topographic features such as tilt with respect to the electron beam lead to differences of up to 85%. Working distance was not the most important parameter affecting the results and led to differences in composition of up to 13%, whereas the choice of standard and its levelling with the sample surface led to inaccuracy reaching 33%. EDX results can be also affected by beam damage and the effects of acceleration voltage on sample acquisition and resolution are quantified. An estimate is provided of the severity of errors associated with samples which cannot satisfy preparation requirements for EDX fully, such as holotypes, and with user decisions. Using a palaeontological example, recommendations are offered for the best parameters and the relative importance of error sources are assessed.

能量色散 X 射线显微镜 (EDX) 是一种广泛使用的廉价方法，用于表征地球和生命科学中样品的原位元素组成。专注于材料科学的通用协议和教科书解决了可以完美抛光的金属样品的 EDX 分析，而地球科学家经常研究具有显着地形且由轻质、难以解析的元素组成的样品。围绕古生物学领域 SEM-EDX 方法的文献稀缺进一步加剧了这种情况，导致数据采集过程中常见的误解和伪影。在这里，对由表面形貌和受用户决策影响的参数引起的 EDX 获得的元素组成中的常见误差进行了量化。作为模特，使用化石生物磷灰石（牙形石）和非生物杜兰戈磷灰石。结果表明，即使是微尺度形貌也会使测量的成分失真高达 34%，而诸如相对于电子束的倾斜等形貌特征会导致高达 85% 的差异。工作距离不是影响结果的最重要参数，导致成分差异高达 13%，而标准的选择及其与样品表面的平整度导致不准确度达到 33%。EDX 结果也可能受到光束损坏的影响，并且量化了加速电压对样品采集和分辨率的影响。提供了与不能完全满足 EDX 制备要求的样品相关的错误严重性的估计，例如全型标本和用户决策。以古生物学为例，