Optically Stimulated Luminescence Research Articles

A review of the optically and thermally stimulated luminescence properties of aluminosilicates

This paper reviews the main literature describing models for thermoluminescence (TL), optically stimulated luminescence (OSL) and radiophotoluminescence (RPL) in aluminosilicate materials, namely natural feldspar minerals and synthetic glasses. The work examines the different models proposed to explain the various luminescence phenomena and compares them with each other. The models include thermally and optically stimulated excited-state tunneling, band-tail state hopping, and ionization and transportation through the band-tail states and/or the conduction band. Temperature and stimulation wavelength are critical parameters, with one model or another dominating over different temperature and/or wavelength ranges. Some recommendations for future research are noted.

Effect of optical stimulation temperature on the TA-OSL background and signal

The impact of readout temperature on background during optically stimulated luminescence (OSL) measurement is reported in this study. The background signal on un-irradiated phosphors has been found to increase significantly with readout temperature for the samples studied in this work, Al2O3:C and CaSO4:Dy. This increase in background signal with rising stimulation temperature on un-irradiated phosphors may overlap with the thermally assisted OSL (TA-OSL) signal. This phenomenon was observed only in the case of phosphors and not with bare stainless steel (SS) discs/planchets, and hence, this background emission should not be confused with blackbody radiation. Moreover, the reported background emission was seen to be much larger than the blackbody radiation. Although the TA-OSL signal does increase with temperature, it does not increase proportionally to the background signal. Therefore, to determine the net increase in TA-OSL due to the rise in readout temperature, the increase in background signal should be taken into consideration.

Ghost age components in detrital thermochronology

Thermochronological dating of detrital samples is an important tool for understanding the thermal history of basins and their source regions. Detrital thermochronology data are often complex with apparent ages ranging over hundreds of million years due to variations in source-rock cooling age and rate, and the influence of post-depositional burial. A common strategy to interpret such data is to split a dataset into several age components by finite-mixture modeling. Herein, we describe for the first time a remarkable pattern of age components in some thermochronological datasets: two or more components showing ages that are approximately multiples of each other. We apply finite-mixture modeling to a log-normal age distribution (a random effects model) and show that these “ghost age components” are artifacts of inappropriately fitting discrete components to continuous age ranges. The striking pattern of the age components is a direct consequence of the underlying age distribution. For a continuous log-normal age distribution, the ghost components have approximately similar age ratios that depend on the overdispersion and the number of components. Due to their artifactual nature, ghost components appear in a range of dating methods, including fission-track, UPb and (UTh)/He dating, and in equivalent doses of luminescence dating. As they are not geologically meaningful, their occurrence hampers the geological interpretation of thermochronological data. We thus propose to carefully decide for the number of fitted components based on grain properties and additional geological information and to screen modeling results for the constant age ratios that are characteristic of ghost components.

New chronology evidence of prehistoric human activities indicated by pottery luminescence dating in the humid subtropical mountains of South China

The age of prehistoric human sites serves as a fundamental basis for studying the relationship between human activities and landscape changes in the humid subtropical mountains of South China. The presence of pottery in these archaeological sites is widespread and offers a valuable resource for precise dating purposes. The Longtoushan (LTS) site, located in the northern mountains of Fujian Province, contains a rich variety of pottery types from various periods, representing a rare multi-period stratigraphic overlap in this area and playing a crucial role in constructing the cultural sequence and lineage of prehistoric and ancient times in this region. In this study, we employed thermoluminescence (TL) and optically stimulated luminescence (OSL) techniques to establish the age of pottery samples collected from the LTS site situated in the upper Minjiang River region of southeast China for the first time, while also comparing our findings with other dating methods to construct a chronological framework for the site. The results showed that: (1) The samples analyzed in this study can be classified according to the peak strength of 325 °C TL signal at natural and regenerative doses of quartz. Samples with weak TL signal at 325 °C (type II samples) showed high recuperation and equivalent dose underestimation at a low preheat temperature (220 °C) in OSL test. (2) Conventional SAR procedures employed for type I samples are not suitable for type II samples. Type II samples require additional OSL stimulation towards the end of the cycle and an extended stimulation duration. (3) The application of various dating methods has revealed that the LTS site represents a long-term settlement in the humid subtropical mountains of South China, commencing around 4.6–4.4 thousand years ago (ka). Specifically, the dating of pottery pieces from kiln sites and tombs in the late Neolithic period provides a specific temporal reference for further understanding of prehistoric human culture and production behavior in the humid mountains of Fujian.

Light-induced fading effects on TL and OSL signals and feasibility of dose re-assessment with PTTL signals in BeO dosimeters

Abstract This study aims to investigate both light-induced fading effects on thermoluminescence (TL) and optically stimulated luminescence (OSL) signals under three different light sources (fluorescent, UV-254 and daylight) and dose reassessment with phototransferred TL (PTTL) signals in Beryllium oxide dosimeters. TL and OSL signals were deconvoluted for each light source. Accordingly, variations in the maximum peak temperature, activation energy, peak area value for the TL signal, and intensity and lifetime values for the OSL signal were monitored. Each peak, OSL component, and total area value exhibited different behaviors depending on the light source. Considering the total area condition, the TL intensity decreased by ∼90%, ∼80%, and ∼70% in UV-254, daylight, and fluorescent light exposure, respectively, at the end of the 120 min. On the other hand, the OSL total area intensity faded quickly for both UV-254 and daylight, while it decreased by ∼45% for fluorescent light. According to these results, regardless of TL and OSL measurements, the dosimeters should be kept primarily away from daylight and fluorescent light after irradiation, instead of UV-254, which is rarely encountered in daily life. The feasibility of dose reassessment using PTTL signals under UV-254 light was investigated within a wide dose range from 0.1 to 128 Gy. It is feasible to reassess doses between 0.5 and 32 Gy considering the total area intensity of PTTL signals. In conclusion, PTTL signals can be easily used in fields of the order of Gy, such as in reevaluating doses in radiotherapy applications.

Ce-doped magnesium borate glass-ceramic for optically stimulated luminescence dosimetry

Despite intensive research in optically stimulated luminescence (OSL) dosimetry, the number of materials with suitable properties for practical application remains limited. Among these, magnesium tetraborate (MgB4O7) has attracted attention as a potential host because of its effective atomic number, similar to those of water and living tissues, and the possibility of producing neutron-sensitive material by controlling the content of the 10B isotope. Specifically, Ce-doped MgB4O7 has been proposed as a promising OSL material for 2D dosimetry because of its rapid luminescence. While the literature on polycrystalline sintered MgB4O7:Ce is extensive, the objective of this work is to produce this material in glass-ceramic form, offering many advantages such as excellent formability into complex shapes, rapid mass production, easily controlled microstructure, and higher density (zero porosity) compared to conventional powder-sintered materials, potentially leading to dosimetric improvements. This paper describes the synthesis route and the effects of various thermal treatments of magnesium borate glass and the resulting glass-ceramics, along with their fundamental dosimetric properties. The samples heat-treated at 814 °C for 3 h (GC814) exhibited the most intense and stable thermoluminescence peaks, accounting for their lowest signal fading among the investigated treatment conditions. However, during the OSL readout, diminished intensity was observed. Analysis of the GC814 emission spectrum revealed TL peaks predominantly outside the used optical filter's primary transmittance range, likely contributing to the OSL signal reduction. Regardless of the thermal-treatment condition, all the samples presented excellent repeatability of the OSL response, with standard deviations ranging from 0.1 % to 0.7 %, underscoring the advantages of glass-ceramics over sintered ceramics. From step-annealing analysis, an optimal preheat treatment temperature was identified, and the activation energy of the three main peaks was determined. The encouraging results indicate the potential of this glass-ceramic as a practical OSL dosimeter and justify further investigation to optimize its OSL properties.

Arvicolinae rodents of Galería de las Estatuas (Sierra de Atapuerca, Burgos) and insights into MIS 5- to −4 climatic conditions in Northern Iberia

Well-dated Middle Palaeolithic sequences that lie beyond the limit of radiocarbon dating (i.e., >50,000 years ago) are critical for understanding the long-term palaeoecological changes that took place during Neandertal occupation of Europe and the Iberian Peninsula. Among the two pits excavated in Galería de las Estatuas site, GE (Sierra de Atapuerca, Burgos, Spain) represents such sequence, having been previously dated using a combination of single-grain optically stimulated luminescence (OSL) and U-series. This site is one of the few across Eurasia to have yielded both Neandertal remains and genetic evidence of Neandertal population replacements during marine isotope stage (MIS) 5 to the beginning of MIS 4 (120,000 to 70,000 years ago). Understanding the prevailing climatic and environmental conditions during the period of Neandertal occupation is therefore of great importance. Small mammal remains are one of the best proxies to interpret past environmental and climatic changes, and among these, the Arvicolinae species (Cricetidae, Rodentia) are particularly useful.Here we provide a revision of the small mammal associations at both Galería de las Estatuas pits undertaking detailed study of Arvicolinae species composition in both excavation pits. Additionally, we present new single-grain OSL dating results to refine the existing chronostratigraphic framework and better contextualise the past climatic changes inferred from the small mammal record. Our results indicate that the lower levels were formed in cold-temperate conditions, with a predominance of an open landscape and Atlantic-type climatic regime. Progressively upward through the sequences, we observe warmer and more humid conditions, with a stronger Mediterranean climate regime and increased development of forest areas, although still with a predominance of open meadows. Finally, both sedimentary sequences seem to end with a deterioration of these climatic conditions, and show a drier environment, dominated by open landscapes and a return to an Atlantic climatic regime. We conclude that at least two marked climatic changes can be identified at each pit (GE-I and GE-II), from MIS 5.4 through to the beginning of MIS 4, by studying the small mammal record together with OSL dating.

Timing and characteristics of co-seismic surface ruptures in the Yadong rift, southern Tibet

The Yadong-Gulu rift (YGR) is the most prominent and seismically active of the seven main ∼ NS-trending rifts in southern Tibet. Although the morphology of the southern YGR clearly indicates it has witnessed large earthquakes in the past, and despite its significant late Quaternary throw rates of ∼1 mm/yr, no large historical or instrumental earthquakes have been reported, including in the southernmost Pagri half-graben, in contrast to the northern part of the rift which is highly seismically active. Here, geomorphic characteristics helped us constrain the timing of a paleoearthquake that produced surface ruptures along the Pagri half-graben, used to document its past activity and evaluate its seismic hazard. We demonstrate that the co-seismic surface ruptures extend for ∼65 km along the Yadong normal fault, with a maximum vertical displacement ranging from 2 to 4.0 ± 0.1 m. Based on empirical relationships between magnitude, surface rupture length, and fault displacement, we suggest that this event may correspond to a Mw6.9–7.2 earthquake. Combined with previous studies, our radiocarbon (14C) and Optically Stimulated Luminescence (OSL) ages from three pits within the earthquake wedge across the surface ruptures constrain the paleoearthquake timing at 3470-2056 years BP. We suggest that the southern YGR currently has a high regional seismic hazard for a Mw6.8–7.1 earthquake, considering the significant throw rates and long timespan since the last strong event. Furthermore, we suggest that such different seismic activity and throw/extension rates between the southern and northern YGR may be explained by different upper crustal rheology behavior and mid-crustal structure.

Downstream change of luminescence sensitivity in sedimentary quartz and the rearrangement of optically stimulated luminescence (OSL) components along two large rivers

Recently, it has been proposed that the luminescence sensitivity of quartz grains, i.e. their luminescence response to unit dose, might be used for sediment fingerprinting. Sensitivity is determined both by the origin of quartz grains and the sedimentary processes they underwent. However, a more detailed understanding of the factors influencing sensitivity is essential in order to expand and specify the applicability of the parameter in sediment sourcing and geomorphological studies alike. In the present research, we examined the spatial changes of sensitivity parameters of coarse grain quartz in modern sediments of the largest rivers of the Carpathian Basin, Central Europe, to determine the role of source areas and transportation distance.Based on the luminescence analysis of 39 samples, quartz extracts with a Carpathian origin (catchment of the Tisza River have a significantly higher sensitivity, except the LM-OSL medium component, than those originating from the Alpine domain (catchment of the Danube River). No clear relationship could be identified between natural sensitisation and transportation distance. In terms of the Tisza the observed downstream increase of quartz sensitivity is due to high sensitivity quartz grains supplied by its tributaries. In the meantime, a recurring change was observed along the Danube, which can be attributed mostly to local erosional processes. Consequently, tributaries and erosion can overprint the potential downstream sensitisation of quartz grains in large rivers.Meanwhile, in terms of the Danube on sections where a significant downstream increase was detected in LM-OSL fast component sensitivity, LM-OSL medium component sensitivity systematically decreased. Additionally, during laboratory sensitization, the CW-OSL sensitivity of Danube samples increased considerably, whereas changes were more moderate in the case of Tisza samples. Moreover, in the case of Tisza-related quartz extracts, the 110°C TL sensitivity and the LM-OSL fast and medium components showed a strong correlation, indicating the stability of luminescence processes (trapping and recombination). Whereas, in the case of the Danube both LM-OSL components show a weak correlation with the 110°C TL intensity. All these indicate that Alpine-origin quartz grains are more susceptible to the rearrangement of electron traps and/or recombination centres, which can also be an indicator of sediment sources in Quaternary studies in the region.

Beachrock: A chronological benchmark for Late Holocene build-up on the coast of Israel

Beachrock formations are proxies of coastal morphodynamics, and are thus commonly utilized for paleoenvironment interpretations. Linear beachrock outcrops parallel to the shoreline are typical of the Mediterranean coastline of Israel. A new geomorphic and sedimentological analysis of beachrock, integrated with relative and absolute geochronology, characterizes their clastic composition and determines their ages. In-situ beachrock outcrops in the sandy beaches of the Sharon coast of central Israel are composed of quartz sand, shells and shell fragments, and show a significant contribution of fragmented rocks from the coastal cliff. Sections of beachrocks analyzed using portable Optically Stimulated Luminescence (pOSL) provided a relative chronological framework within and between the sections. The results show a moderate optic signal accumulation, indicating a gradual beach build-up during initial beachrock formation stages. Optically Stimulated Luminescence (OSL) ages indicate deposition of unconsolidated beach sediments dated to about 1600–800 years before present (BP). The sediment burial at the former foreshore enabled rapid consolidation in the intertidal zone.

Signals of soil formation during pre-glacial maximum on the byers peninsula (maritime antarctica)

The Maritime Antarctic is one of the most sensitive regions on Earth to warming, recording permafrost degradation and glacial retreat in the last 10 kyr. The timing of deglaciation and the pedological implications are still poorly elucidated in many ice-free areas of the Antarctic. The severity of the Last Glacial Maximum (LGM) across the Maritime Antarctic has limited paleoenvironmental records of pre-LGM terrestrial signals, constraining knowledge of climate trends in the Late Pleistocene. Byers Peninsula is one of the most extensive ice-free areas in the Maritime Antarctic. So, we hypothesized that soils in Byers Peninsula host Pleistocene sedimentological and pedological evidence of landscape evolution. This study investigated soil genesis in Byers Peninsula. Radiocarbon and OSL dates provided a chronology of nine soil profiles. Morphological, physical, and chemical analysis characterized soil formation. Isotopic composition of organic matter tracked the main photosynthetic processes. Endolithic soil organic matter in a pre-LGM soil indicates soil genesis at 31,690 cal yr BP, much earlier than the common age models of approximately 10,000 cal yr BP in previous studies. Burial and 14C ages in Cryosols formed on beach sediments above 70 m and on cliffs suggest marine terrace uplift and soil genesis in cliffs during the Late Pleistocene-Early Holocene. Younger Cryosols and Leptosols soils formed on raised beaches in Late Holocene. These findings suggest an older glacial retreat in the Maritime Antarctic. Soil proxies in potential pre-LGM ice-free areas are promising tools for paleoenvironmental reconstructions of the Maritime Antarctic.

Enhanced OSL emission from α- Al2O3 produced in the presence of halloysite nanocrystals

Aluminum oxide (Al2O3) compounds are extensively used in ionizing radiation dosimetry due to their high sensitivity when doped with carbon. However, their production is difficult and expensive, leading to much research on alternative ways to increase its sensitivity. This paper proposes a seed-mediated synthesis of α-Al2O3 by the combustion method with halloysite nanocrystals as seeds, which also have the ability to scavenge heavy metal ions. The dosimetric features were studied by radioluminescence (RL), thermoluminescence (TL), and optically stimulated luminescence (OSL). Scanning electron microscopy images and X-ray diffraction patterns pointed to the halloysite nanotubes (HNT) acting as heterogeneous nucleation seeds, and as adsorber centers for the chromium ions (Cr3+), as evidenced by the decreased crystallite size and Cr3+ RL emission. Decreased TL intensity upon increasing HNT content in addition to the RL data suggested that the Cr3+ ions strongly participate in the TL emission process as a luminescent center. Remarkable 6-fold enhanced OSL area intensity and 69-fold OSL initial intensity enhancement were registered from the samples seed-mediated by HNT, revealing that, by scavenging Cr3+, the HNT eliminated a luminescent center that competes with the OSL emission. Therefore, HNTs are promising nanomaterials to enhance the sensitivity of Al2O3 dosimeters with potential application in medical physics, where a decrease in the density of concurrent luminescent centers and an increase in OSL intensity were evidenced by the presence of HNT in Al2O3.

Late-Holocene sea-level markers preserved in a beach ridge system on Phra Thong Island, Thailand

Instrumental sea-level records are insufficient to understand the response of sea-level changes to global temperature on centennial timescales. Sea-level histories spanning at least the Common Era have not been widely studied in Southeast Asia. This period is crucial for providing a pre-industrial context to understand sea-level change with climate. Linking sea-level change to climate change is proxy dependant, with most proxies only providing decadal to centennial scale resolution of both sea level and climate. This study examines the efficiency of beach ridge stratigraphy as a proxy for reconstructing regional sea-level histories in the tropics. We present topographically corrected Ground Penetrating Radar (GPR) profiles from a prograded coast in Phra Thong Island, Thailand, where we identify downlap point marking the boundary between the foreshore and shoreface subzones and use this as a past low-tide marker. The low-tide markers were corrected (considering the tidal range) and then connected to approximate the past sea level. Optically Stimulated Luminescence (OSL) samples collected at locations slightly offset from the shore-normal GPR profile line were incorporated to create a relative sea-level record. Overall, the shore-normal GPR record shows a ∼ 1.06 m fall in sea level between ∼2660 and ∼ 370 years ago. The study also highlighted stepwise fluctuations in sea level that were not identified in previous studies. Between ∼2600 and ∼ 2200 years ago, the record indicates a steep fall in sea level, followed by a phase of relatively stable to slightly falling sea level between ∼2200 and ∼ 550 years ago. Finally, for the seaward side, between ∼550 and ∼ 350 years ago, the record indicates an accelerating sea-level fall. This study confirms that the investigation of tropical beach ridge systems using GPR and OSL techniques can be a highly efficient and effective means for reconstructing regional sea-level trends throughout the Common Era and beyond.

Late Quaternary history of the Kerch Strait — the stratotype region for the Black Sea

The Kerch Strait has periodically connected to the Black, Azov, and Caspian seas throughout its Late Quaternary history. The strait's deposits reflect the changes in the natural environment of the entire Ponto-Caspian region, which are a response to global climate change. Several studies have been done on the region's stratigraphy, biostratigraphy, geomorphology, and paleogeography. However, most of the current knowledge about the paleogeography of the area is based on the analysis of empirical data collected more than 25 years ago, and due to the lack of detailed geochronological studies, many palaeogeographical problems remain unresolved.This paper presents a reconstruction of environmental change in the Kerch Strait during the Late Quaternary. The reconstruction is based on the results of a comprehensive study of the sedimentary sequences in the Kerch Strait carried out by the author and colleagues over the past ten years. The study examines the deposits of two stratotype sections of the Karangatian (Eemian) transgression and the four boreholes’ sections in Tuzla Island in the central part of the strait.A biostratigraphic division of the Upper Quaternary deposits of the Kerch Strait was carried out based on a malacofaunal study. Mollusc assemblages corresponding to various paleogeographic stages of development were identified, and their paleoecological characteristics were described. Luminescence and radiocarbon ages made it possible to determine the time intervals of established paleogeographic stages in the strait's history. Detailed luminescence dating of the Karangatian transgression sediments of the Eltigen and Tuzla stratotype sections has been carried out for the first time.Six main stages in the Kerch Strait natural environment development were established in the Late Quaternary and correlated with global and regional climatic events: Karangatian, with three stages (MIS 5e-c); Tarkhankutian (MIS 5a); Post-Karangatian (MIS 4); Surozh (MIS 3); Neoeuxinian, with two stages (MIS 2); and Chernomorian (MIS 1). Two episodes of the Caspian waters flowing through the Kerch Strait into the Black Sea were identified in MIS 5c and at the end of MIS 2.

Compαrαtive chαrαcteristics of luminescent detector mαteriαls bαsed on α-Αl2O3-δ for neutron dosimetry

The optically stimulated luminescence (OSL) and the separation efficiency of the neutron and gamma components by OSL outputs were studied for samples of anion-deficient corundum (α-Αl2O3-δ) in ceramic and single-crystal forms with various neutron converters. For OSL dosimetry in mixed gamma-neutron fields, a detector material synthesized using ceramic technology consisting of a mixture of OSL active α-Αl2O3-δ and neutron-converter 6LiF powders in a ratio of 7:3 was selected as a promising one. The lower limit of the individual dose equivalent for such material under neutron irradiation does not exceed 30 μSv, and the dose dependence is linear up to 1 Sv.

Millennial and contemporary dynamics of the barrier estuary entrance at Moruya, SE Australia

ABSTRACT This study presents optically stimulated luminescence (OSL) dates, sediment coring, historical maps and charts and photography and airborne LiDAR to reconstruct the millennial and contemporary history of the Moruya River entrance. OSL dating reveals small estuarine beaches were active between 7000 and 5000 years ago, when the entrance was far more open than at present. At that time, a large flood-tide delta infilling a wide immature estuary is likely to have existed. Continued progradation of the Bengello barrier to the north, and the inception of the Moruya Heads barrier to the south from 4500 years onward, progressively constricted the river entrance. Several more low-energy estuarine beaches developed behind the Moruya Heads barrier and are dated to ~4400 and ~2800 years ago. Concurrently, the open mud basin of the estuary infilled with fluvial sediment. Following the arrival of Europeans in the region, in the early to the mid-1800s, engineering works were undertaken in stages to train the estuary entrance for navigation and have further constrained the system. OSL dating of beaches formed as a result of this activity concur with the historical accounts. These contemporary changes to the entrance have modified the estuary hydrodynamics and shifted the sediment transport and ecological regime of the lower estuary.

Climatically-driven development of late Quaternary fluvial geomorphology in the arid inland of Asia

The forcing mechanism behind river incision and terrace formation is one of hot topics in the study of fluvial geomorphology. This work focused on the late Quaternary alluvial sequence in the south piedmont of the Chinese Altay Shan in the arid inland of Asia. In order to reveal the mechanism controlling the development of late Quaternary fluvial features along the mountain front, we conducted detailed fluvial geomorphological investigations on eight rivers, including geomorphic mapping, optically stimulated luminescence (OSL) dating, and differential global position system (dGPS) surveying. By utilizing the Monte Carlo simulation with terrace data, the late Quaternary rates of river incision along the south piedmont of the Chinese Altay Shan were determined. The results show that (1) the terraces developed by the piedmont rivers are not more than four levels and the depth of river incision in the piedmont is only dozens of meters, with deeper valleys displayed by the western piedmont rivers; (2) terrace alluviums along the mountain front were accumulated during glacial stages, and the subsequent incision occurred during interglacial stages; (3) the rate of river incision was accelerated during the Holocene, when the regional climate was characterized by progressively increasing wetness. When combining with the regional tectonic setting, we propose that the climate could have played the key role in driving the alluvial accumulation and the subsequent incision in the south piedmont of the Chinese Altay Shan during the late Quaternary. Together with the similar observations from the northeastern margin of the Tibetan Plateau and the Tian Shan, we further propose that climatically-driven fluvial geomorphological development could be a common phenomenon during the late Quaternary in the arid interior of Asia.

Study of Thermoluminescence and Optically Stimulated Luminescence Properties of Synthesised CaB2O4 Nanoparticles Doped with Copper.

CaB2O4 nanorods doped with different concentrations of Cu were prepared by using co-precipitation method. The recorded Thermoluminescence (TL) and Optically stimulated luminescence (OSL) of CaB2O4:Cu samples for different concentrations of Cu irradiated with 6Gy of X-Ray shows that 0.05 at.wt% of Cu concentrations have higher sensitivity. The TL and OSL kinetic parameters of glow curves were evaluated using "tgcd" and conventional fitting methods. The TL glow curve of the CaB2O4:Cu have three individual glow peaks with maximum peak temperatures at 404.50, 453.04 and 484.02K respectively. The OSL glow curves of the CaB2O4:Cu nanoparticles follow non-first order kinetics which can be fitted with the sum of two first order decay curves.

OSL and radiocarbon dating of core TBF-1 on the outer shelf of the East China Sea and implications for late Quaternary stratigraphic correlation

It is crucial to establish a robust chronology for understanding late Quaternary sedimentation processes and environment changes in response to sea-level fluctuation on shelves. The shelf of the East China Sea (ECS) is featured by huge terrigenous sediment input and striking land -sea interaction during the late Quaternary. However, there remains controversy in chronostratigraphic rebuilding of transgression and regression deposits during eustatic-glacial cycles, mainly due to a lack of reliable dating data. In this study, an extensive comparison of 17 optically stimulated luminescence (OSL) and 15 AMS 14C ages from core TBF-1 (upper 40 m) provides a constraint in chronostratigraphic reconstruction since Marine Isotope Stage (MIS) 5. OSL ages range from 9.5 ± 0.7 to 67.3 ± 4.8 ka at depths from 2.00 to 28.00 m, while 14C ages range from 6645 to 41435 cal a BP at depths from 0.02 to 17.52 m. Regression analysis demonstrates a high level of agreement between OSL and 14C ages, with r2 values of 0.91 and 0.90, respectively. For Holocene sediments (U1), both OSL and 14C methods are applicable in tidal sand ridges, however, it should be noted that 14C ages may exhibit a young bias of up to 3 ka. For pre-Holocene sediments (U6-U2), OSL ages are robust within saturation limitation of OSL signal (De up to ca. 166 Gy), cross-checked by feldspar post-IR IRSL (pIRIR) dating protocol. Nevertheless, the shell 14C ages (11620 and 10390 cal a BP at depths of 13.95–14.56 m) in Last Glacial Maximum (LGM) fluvial sediments of U2 are significantly underestimated, because of their susceptibility to recrystallization and overgrowth, resulting in carbon exchange with environment. While the peaty layer's14C age in deltaic deposition (17.50 m, U5) was determined to be 36420 cal a BP, coincided with OSL age of 39.6 ± 3.9 ka. The chronostratigraphy since MIS 5 for core TBF-1 exhibits a significant correlation with previously published cores SFK-1, DZQ4, and DH02, on the ECS outer shelf. Through the evaluation of those underestimated 14C ages and saturated OSL ages, we re-elucidated the primary sedimentary facies and their respective formation periods. This sedimentary stratigraphic illustration exhibits significant consistency with eustatic-glacial cycles. The renewed chronological framework for ECS shelf allows better correlation between the late Quaternary sedimentary evolution and the land-sea interaction on open shelves dominated by siliciclastic sedimentation.

Quartz luminescence sensitivity enhanced by residence time in the critical zone

The emerging use of quartz luminescence properties to characterize Earth-surface processes shows promise, with optically stimulated luminescence (OSL) sensitivity proposed as a valuable tool for provenance or sediment history tracing. However, the geologic processes that lead to quartz sensitization remain unclear. Here we study the impact of source rock and surface processes on the luminescence properties of quartz sand from bedrock and modern and Late Pleistocene alluvium generated from a mountainous catchment in northern Utah, USA. Continuous wave and linear modulated OSL are used to characterize the luminescence sensitivity and intensity of the fast-decay component. We compare the OSL sensitivity with sand-grain provenance and with proxies for surface processes such as topographic metrics, cosmogenic 10Be-derived erosion rates, chemical weathering indices, and magnetic susceptibility. Late Pleistocene sediment has low OSL sensitivity and a weak fast-decay component, similar to bedrock samples from the source area. In contrast, modern alluvium is dominated by the fast-decay component and has higher and more variable OSL sensitivity, with no clear relationship to upstream bedrock source. There is, however, an inverse relationship between OSL sensitivity and catchment-averaged erosion rates and a positive relationship with chemical weathering indices and magnetic susceptibility. These metrics suggest that the modern alluvium has experienced increased residence time in the shallow critical zone compared to the Late Pleistocene sediments. We suggest that changes in hillslope processes between the effectively wetter, cooler Pleistocene and the dryer, warmer conditions of the Holocene enhanced the luminescence properties. The results suggest that climatic controls on rates and processes of chemical and mechanical weathering and sediment transport and residence within the critical zone are encoded in the luminescence properties of quartz sand.