This study presents the merit of visible‐spectrum scanning reflectance spectroscopy (VIS‐RS) as a rapid technique for determining the concentration of chlorophyll a (Chl a) and its derivatives in lake sediments. In a 25,000‐yr sediment record from Lake Challa, in East Africa, we found that VIS‐RS values correlate with Chl a concentrations measured by High Performance/Pressure Liquid Chromatography. Observed variation in sedimentary values of RABD660;670 appears linked to proxies of climatic moisture balance as well as to a seismically‐derived lake‐level reconstruction over this period, indicating that VIS‐RS can be used as a proxy for long‐term paleo‐hydrological change. Changes in the reflectance of Lake Challa sediments are likely related to differences in the preservation/degradation of algal pigments in response to changes in water‐column depth and the stability of stratification. The connecting mechanism may be that during lake lowstands, more frequent injection of oxygen to (near‐) bottom waters enhance the breakdown of labile organic compounds before permanent burial. We suggest that fast and inexpensive VIS‐RS scanning, although less specific than HPLC in quantifying individual pigments, provides accurate data on down‐core variations in the concentration of Chl a and its derivatives in lake sediments, hence allows to reconstruct long‐term changes in the hydrology of climate‐sensitive lakes. The main prerequisite for its successful application is that temporal variation in lake hydrology over the period of interest has not appreciably affected sedimentation dynamics at the core site, since major changes in sediment texture and organic content are likely to create confounding effects in the VIS‐RS signature.

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This study aims at analyzing the mineralogical, chemical, and structural characteristics of flint raw material used for the production of prehistoric stone tools in NW Belgium. Understanding these characteristics is important to recognize their value for tool making and even tool use during prehistory. Due to its formation process, flint is defined by a wide variety of internal structures, chemical variations, and impurities. Moreover, alteration processes cause additional chemical and structural changes complicating the study of this material. Archaeological artifacts often display alteration features, mostly expressed as patination or burning, leading them to be regularly discarded from the functional analysis of lithic tools. By not incorporating these artifacts, our understanding of the investigated assemblage is biased. It is therefore important to investigate the influence of flint characteristics on its weathering behavior, and the impact of preservation of prehistoric use‐wear traces on flint artifacts. The characteristics of flint raw material and natural patination were studied using a combination of different techniques, such as macroscopic analysis, optical microscopy, X‐ray fluorescence, and high‐resolution X‐ray computed tomography. This resulted in a detailed description and distinction of the different flint variants used on prehistoric sites in NW Belgium and a good understanding of patination.

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A laboratory-based X-ray fluorescence (XRF) methodology is presented for standardless quantified analysis based on a monochromatic X-ray spectrometer coupled to Monte Carlo aided quantification. This procedure will be valuable for many scientific fields (e.g. archaeology, geology, etc.) where the unique nature of the investigated samples calls for the application of non-destructive techniques. To illustrate the value of the methodology, a case study is presented where flint artefacts from the Scheldt basin are analyzed in an attempt to provenance them. So far, little geochemical research has been done in this area. Our results contribute to the creation of a database that will help assign lithic artefacts to specific geological outcrops and will aid further research in this field.