Heavy liquid density separation is commonly utilised in isolating specific minerals from bulk sediment for luminescence dating. K-feldspars are commonly separated from other minerals by isolating the <2.58 g cm⁻³ fraction which yields infrared stimulated luminescence (IRSL) signals conducive to dating. However, initial measurements of the IRSL and thermoluminescence (TL) signals from the <2.58 g cm⁻³ fraction of alluvial fan sediments from the Hajar Mountains, northern Oman, were atypical of K-feldspar luminescence signals reported in the literature. In this study, three different density separates (<2.58 g cm⁻³, 2.58–2.54 g cm⁻³ and <2.565 g cm⁻³) were trialled to attempt to isolate pure K-feldspar samples for dating, to measure K-feldspar IRSL signals which are not contaminated with inputs from other feldspar, quartz and/or heavy mineral signals. The mineralogy of these separates was explored using microscopy, X-ray diffraction and mass spectrometry. We found that despite more refined heavy liquid density separation, the proportions of K-feldspar in these separates had a maximum of 40% by weight, remaining significantly contaminated by other minerals. IRSL and TL signals were atypical of K-feldspar for all density separates and it is likely that there is a contribution of signal from IR-sensitive contaminants, such as muscovite. This highlights the importance of investigating the mineralogy of samples for luminescence dating, especially in regions where little prior work has been undertaken.

重液密度分离通常用于从大块沉积物中分离特定矿物以进行发光测年。钾长石通常通过分离 <2.58 g cm ^-3的部分与其他矿物分离，这会产生有助于测年的红外受激发光 (IRSL) 信号。^{然而，来自阿曼北部 Hajar 山脉的 <2.58 g cm -3}冲积扇沉积物部分的 IRSL 和热释光 (TL) 信号的初始测量结果与文献中报道的钾长石发光信号不同。在这项研究中，三种不同的密度分离（<2.58 g cm ^-3、2.58–2.54 g cm ^-3和 <2.565 g cm ^-3) 尝试分离纯钾长石样品进行测年，以测量未被其他长石、石英和/或重矿物信号输入污染的钾长石 IRSL 信号。使用显微镜、X 射线衍射和质谱法对这些分离物的矿物学进行了探索。我们发现，尽管重液密度分离更加精细，但钾长石在这些分离物中的比例最大为 40%（重量），仍然受到其他矿物的严重污染。IRSL 和 TL 信号对于所有密度分离都不是钾长石的典型信号，并且很可能有来自 IR 敏感污染物（例如白云母）的信号的贡献。这突出了研究样品矿物学以进行发光测年的重要性，