Deeply weathered soils cover most of the Piedmont physiographic province of the south-eastern United States of America (USA). These soils have traditionally been inferred to derive from weathered bedrock, but recent work (e.g. Ferguson et al., 2019) suggests that deposited sediments are more prevalent than recognized. Distinguishing sediment from weathered bedrock is integral to understanding critical-zone processes and overall Quaternary landscape evolution, yet the well-developed, red, clay-dominated Ultisols of this temperate and humid region mask differences between transported from non-transported material. Our goal is to determine if optically stimulated luminescence (OSL) methods can distinguish quartz sand from allochthonous (e.g. transported sediment) versus autochthonous (e.g. in situ weathered bedrock) material in soil-profile and core samples from the Redlair Observatory in southwestern North Carolina, USA. Here, we turn to OSL sensitivity and linear-modulated OSL (LM-OSL) to observe the intensity or lack thereof of the fast-decay luminescence component (most light-sensitive signal) in quartz grains from soil horizons and crystalline bedrock-derived saprolite. We find that quartz grains sampled from in situ weathered bedrock as well as from saprolotized clasts of rock have weak luminescence properties and are not dominated by a fast-decay luminescence component. In contrast, quartz grains from transported sediment (e.g. mobile regolith; colluvium; alluvium) contain sensitive grains with more dominant fast components. These results suggest that quartz luminescence sensitivity can be a tool to differentiate between in situ weathered bedrock and similar looking mobile regolith and colluvium over-printed by soil development.

深度风化的土壤覆盖了美利坚合众国（美国）东南部皮埃蒙特地貌省的大部分地区。这些土壤传统上被推断来自风化的基岩，但最近的工作（例如 Ferguson 等人，2019 年）表明，沉积物比公认的更为普遍。区分沉积物和风化基岩对于理解临界带过程和整体第四纪景观演化是不可或缺的，但是这个温带和潮湿地区发育良好的、红色的、以粘土为主的 Ultisol 掩盖了从非运输物质运输的差异。我们的目标是确定光激发发光 (OSL) 方法是否可以区分石英砂与异地（例如运输的沉积物）和本地（例如原位） 美国北卡罗来纳州西南部雷德莱尔天文台的土壤剖面和岩心样品中的风化基岩材料。在这里，我们转向 OSL 灵敏度和线性调制 OSL (LM-OSL) 来观察来自土壤层和结晶基岩衍生的腐泥土的石英颗粒中快速衰减发光分量（最光敏信号）的强度或缺乏. 我们发现从原位取样的石英颗粒风化的基岩以及来自腐生碎屑的岩石具有弱发光特性，并且不受快速衰减发光成分的支配。相比之下，来自输送沉积物（例如移动风化层、崩积层、冲积层）的石英颗粒包含具有更多主要快速成分的敏感颗粒。这些结果表明，石英发光灵敏度可以作为区分原位风化基岩和外观相似的移动风化层和土壤发育叠印的崩积层的工具。