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1.
Middle to late Holocene alluvium, identified as Quaternary alluvial unit 4 (Qa4), along Kanab Creek in southern Utah, USA was dated using optically stimulated luminescence (OSL) on quartz sand, and by radiocarbon dating of detrital charcoal. Entrenchment beginning in 1882 AD created arroyo walls that expose up to 35 m of the Qa4 alluvium. The stratigraphy and sedimentology suggest that fluvial aggradation along the study reach occurred rapidly. Due to the high sediment supply, short transport distances and semi-arid climate with flashy discharge, partial bleaching (zeroing) of the luminescence signal was expected to be a problem for OSL dating. We approached this problem by first using small-aliquot (∼20 grains) and single-grain dating of quartz sand to reduce the number of grains contributing to the OSL signal. Second, we used statistical parameters based on single-grain and small-aliquot equivalent dose (De) distributions of bleached sediment to help identify partial bleaching and to inform if a minimum age model (MAM) should be used for age calculation. Comparison of results with radiocarbon ages demonstrates the success of OSL dating on Kanab Creek arroyo-fill deposits, although careful attention should be paid to the sedimentary facies and stratigraphy of the targeted sample horizon to minimize the effects of partial bleaching. Thin, decimeter-scale plane-bedded and ripple cross-bedded sandy lithofacies were found to be the best target for OSL dating, as these sediments showed minimal evidence for incomplete solar resetting. Additionally, results generally indicate that better-bleached sediments are found in downstream reaches. Age control from these arroyo-fill deposits was acquired in order to fulfill larger research goals of understanding regional arroyo incision and aggradation cycles. 相似文献
2.
After the Salawusu and Shuidonggou sites, the Wulanmulun site found in 2011 is another important Paleolithic site in Ordos, China, due to its numerous stone artifacts and animal fossils. Here, we carry out a combined luminescence and radiocarbon dating of the site. The luminescence dating was done on coarse-grained quartz from 24 sediment samples using a single-aliquot regenerative-dose (SAR) protocol. The radiocarbon dating was performed on ten charcoal samples and one bone sample using acid-base-acid (ABA) and acid–base-wet oxidation-stepped combustion (ABOx-SC) pretreatments. The results showed that: (i) although some samples show relative large (>20%) overdispersion in De distribution (small aliquots), the quartz grains are considered to be sufficiently bleached before burial; (ii) the quartz OSL ages of ∼4–65 ka obtained for the samples are generally stratigraphically consistent and reliable; (iii) the radiocarbon ages obtained using the ABA pretreatment procedure are much younger than the corresponding OSL ages, and the radiocarbon ages obtained using the ABOx-SC method are beyond or close to the laboratory background. The radiocarbon ages obtained using the ABA treatment were considered to be underestimated. This implication is that caution must be taken for dating Chinese Paleolithic (>25 ka) using the ABA pretreatment procedure on carbon samples. Finally, the cultural layers from the Wulanmulun site are deduced to be between 50 and 65 ka. 相似文献
3.
在青藏高原东北缘海原断裂带刺儿沟古地震剖面上不仅保存了地震活动的崩积楔遗迹,还发现多层炭屑以及与人类活动有关的铁渣、陶片等遗物,文中运用14C测年法和经红外释光照射后的绿光释光测年法(Post-IR OSL)分别对剖面上的炭屑、烘烤黏土、沉积物等样品进行年龄测定和比对,获得了各炭屑层和人类活动遗迹的年代。测定的人类活动遗迹年代与海原周缘历史记载的强震发生时间序列比对结果表明,刺儿沟人类活动遗迹的形成可能与历史地震无关,过去以炭屑年代作为地层年代来限定古地震发生的时代,建立的古地震事件时序的结果可能不正确,上述工作为进一步研究海原断裂带的强震复发规律和海原地区考古提供了重要的基础资料 相似文献
4.
Reliable age dating of coastal sedimentary landforms is crucial for inferring storm frequencies and magnitudes from geological archives. However, in highly energetic coastal settings, radiocarbon dating is often biased by reworking and/or poorly constrained marine reservoir effects. Due to this, most cyclone-driven sediment archives from the semiarid coast of NW Australia – a region frequently affected by tropical cyclones but with a historical record limited to ∼150 a, and therefore strongly in need of long-term data inferred from geological evidence – are affected by chronological inaccuracies. Optically stimulated luminescence dating (OSL) may overcome these shortcomings by dating the transport of sediment directly. In turn it may be related to other challenges when applied to cyclone deposits from semiarid environments. The cyclone-induced washover fans at Point Lefroy, NW Australia, are composed of a heterogeneous mixture of coral fragments, shell hash and siliciclastic sand. This makes them particularly prone to high dose scatter resulting from a combination of partial bleaching, sediment mixing and dose-rate heterogeneity. The washover fans are further characterised by a discontinuous nature of cyclone deposition, as indicated by erosional features and macroscopic brunification horizons. By using a combination of quartz single grain dating, autoradiography, alpha counting and gamma spectrometry, sediment mixing and dose rate heterogeneity are identified as the main sources of dose scatter. The resulting chronology allows us to discriminate at least four well constrained phases of washover fan activity at ∼180, ∼360, ∼870, and ∼1300 a ago. Older but less well constrained activity phases occurred ∼1950, ∼2300, and ∼2830 a ago. While these phases of increased cyclone activity correlate with depositional units separated by potential palaeosols, OSL ages, quasi-continuous portable OSL reader measurements and gamma spectrometry measured with increased sampling resolution point to deposition of distinct washover units within a very short period of time. However, unambiguous discrimination between deposition of individual units by single events and deposition by several cyclones within periods of only a few decades is currently not possible. 相似文献
5.
Lakes over the inner Tibetan Plateau (TP) are very sensitive to the regional environmental transformations and climate changes. Well-preserved lake sediments around these lakes provide critical geomorphological and sedimentary evidence that can be used to infer the past hydroclimate changes. In this study, a lacustrine section from a sandy shoreline (∼74 m above the modern lake) situated to the northwest of modern Dawa Co in the inner TP was investigated using both luminescence and radiocarbon dating methods. Our results demonstrated: (1) the quartz optically simulated luminescence (OSL) dating yielded much younger ages (∼4 ka) than that of the post-infrared IRSL (pIRIR) dating of the K-feldspar fraction; (2) fading test showed g-values ranging between 1.34 and 4.46%/decade for quartz OSL signals, which is considered to be responsible for the underestimation of the corresponding ages; (3) the AMS 14C age of the charcoal sample from the section is in line with the K-feldspar pIRIR225 ages, confirming the reliability of the pIRIR225 dates and the underestimation of the quartz OSL ages. The anomalous fading of quartz OSL signals and the consequent age underestimation have been reported in several other lakes on the TP, we presented here for the first time firm evidence of the phenomenon with the help of a robust independent control of AMS 14C age of the charcoal. Based on the pIRIR225 and AMS 14C ages, we conclude that Dawa Co underwent a prominent highstand during the early Holocene (∼9–7 ka), which was probably controlled by the large amounts of glacial meltwater input and the increased monsoonal precipitation. 相似文献
6.
This study applies single-grain optically stimulated luminescence (SG OSL) dating of quartz sand temper to Intermountain Ware ceramics recovered from four archaeological sites in northwestern Wyoming, USA. We show that SG OSL dating can strengthen and further refines existing archaeological site chronologies in certain settings. The SG OSL results are compared to multi-grain infrared stimulated luminescence (IRSL) dating of the polymineral (feldspar and quartz) silt fraction in the ceramic paste of the same sherds. Results from the two methods are statistically indistinguishable, although coarse-grained quartz SG OSL ages have consistently lower standard error terms due to higher relative sensitivity and avoidance of anomalous fading calculations. Moreover, the SG OSL results produced precision at two-sigma standard error greater than or equal to associated calibrated radiocarbon ages. SG OSL dating of quartz temper from Intermountain Ware ceramics provides more reliable site occupation timing than radiocarbon dating, which can be conditioned by incorporation of old wood and contamination from young soil carbon. This study highlights the importance of SG OSL dating on sherds from buried contexts when exposure to wildfires may have occurred, as ceramics recovered from the ground surface of one site after a high-intensity fire produced near-modern apparent ages, suggesting they were thermally reset during the fire. We suggest SG OSL should be applied to date similar ceramics with quartz temper to determine site age and bolster regional chronologies. 相似文献
7.
Optically stimulated luminescence (OSL) techniques have been applied to investigate the potential for dating the deposition of upcast mounds associated with qanat ventilation shafts at the site of a medieval qanat located in Aragón, Spain. Coarse quartz grains, extracted from sediment samples taken from excavated sections of several mounds, possessed sufficiently strong OSL to enable an evaluation of equivalent dose by applying the single aliquot regenerative procedure to small aliquots, each containing an individual bright grain. The OSL dates for both palaeosol and overlying upcast indicate that a chronostratigraphic record has been preserved within the mounds investigated, and micromorphological analysis of thin sections of sediment blocks taken from the mounds is shown to provide an essential means of verifying the characteristics of the strata, in particular, the critical interface of upcast and the ancient ground surface. The earliest OSL dates for basal deposits taken from two separate sections of the same mound are in agreement, placing the mound construction during the first half of the 13th century A.D. However, in two other mounds the OSL dates for the deposition of upcast are internally consistent with the stratigraphy but significantly later, dating to the 16th and 17th centuries A.D. We interpret the differences between the dates for the upcast deposition to be the result of partial erosion of the upper shaft and later repair of the mounds, and this finding underlines the importance of both examining multiple mounds in the same qanat system and the internal structure of each sampled mound. This exploratory work demonstrates the potential for wider application of OSL for dating this important type of subterranean irrigation feature in the study of both the archaeology of human settlement and palaeoenvironmental change in arid regions. 相似文献
8.
The thick alluvial conglomerate sequences around the Tibetan Plateau have been notoriously difficult to date. Here we use the cosmogenic nuclide burial dating method to date the Yumen and Jiuquan formations, a ∼900 m thick fanglomerate found in the Hexi Corridor, the foredeep of the Qilian Shan, and exposed in the Laojunmiao anticline. We date 16 sites with simple burial dating and 2 sites with isochron burial dating, and use these dates to reinterpret the magnetostratigraphy of the section. We suggest that the bottom of the Yumen Formation, defined by a progressive unconformity, is around 5 My. Taking this timing as the initiation of anticline growth, the long-term crustal shortening rate at the ramp zone in western Qilian Shan is about 0.72 mm/yr, consistent with those obtained from middle and eastern Qilian Shan. The boundary between the Yumen and Jiuquan Formations is near ∼1.2 My. Three other angular unconformities are dated to ∼2.6–3.1, ∼2.2–2.5, and ∼1.2–1.7 My, respectively. Burial dating offers a robust chronology for these deposits, and when combined with paleomagnetic stratigraphy offers much tighter precision. 相似文献
9.
The present study aims at testing the possibility of using the in-situ cosmogenic burial dating technique on deltaic deposits. The sequence analyzed is exposed along the Ligurian coast (north-west Italy) and is made of proximal marine and continental deposits previously considered Pliocene or Plio-Quaternary in age. In the study area two allostratigraphic units were recognized. The lower unit represents the evolution of a small coarse-grained delta developed in a fjord or embayment environment. The coarsening/shallowing upward trend observed within the sections, from bottom to top, suggests that the delta prograded rapidly in the landward portion of the canyon placed opposite to the paleo-river outlet. Within the deltaic sequence the transgressive and highstand system tracts were recognized. The unit 2 is composed by several alluvial fan systems deposited in small incised valleys developed within the previously, uplifted deltaic deposits and successively incised by a braided river system. In-situ produced cosmogenic nuclides were used in order to date the age of the deposition of the deltaic deposits. Results suggest that the studied deltaic sediments belonging to the unit 1 were deposited between 1,300,000 and 200,000 year ago thus during the Lower to Middle Pleistocene, whereas the unit 2 was deposited during the Middle Pleistocene as a consequence of a tectonically driven uplift phase. Furthermore samples collected within the prograding part of the delta show the higher denudation rates. The obtained results demonstrate that burial ages and related erosion rates inferred from cosmogenic nuclides concentrations can be considered as a very useful tool to reconstruct the sea level changes over the past 1 million year. 相似文献
10.
Dating alluvial fan surfaces in Owens Valley,California, using weathering fractures in boulders 
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下载免费PDF全文 Mitch D'Arcy Duna C. Roda Boluda Alexander C. Whittaker Alfredo Carpineti 《地球表面变化过程与地形》2015,40(4):487-501
A wide range of sedimentological and geomorphological field research depends on the availability of accurate and detailed depositional age models. Although exposure dating techniques such as cosmogenic nuclide and luminescence dating are now widely available, they remain expensive and time‐consuming, and this frequently limits the density of age constraints and the resolutions of age models for many study areas. We present a simple and effective, field‐based approach for extending and correlating existing age models to un‐dated surfaces. In Owens Valley, California, we make use of detailed beryllium‐10 (10Be) chronologies reported for four different alluvial fan systems, to precisely calibrate the rate at which weathering fractures are enlarged in granitic surface boulders. We show that these fractures have widened at a time‐integrated rate of 1.05 ± 0.03 mm ka?1 for at least 140 ka at this location, and this relationship can be represented by a linear regression that makes them ideal chronometers for surface dating. Our analysis offers a new approach to refining the uncertainties of both surface erosion rate and cosmogenic age estimates at this location. Ultimately, we integrate our observations to devise a robust age calibration for clast fracture widths in Owens Valley, and we demonstrate its application by estimating the ages of 27 additional local fan surfaces. We present an updated and extended stratigraphy for eight Sierra Nevada fan systems in total, with exceptional age control. This novel approach to dating sedimentary surfaces is inexpensive and easily applied in the field, and has the potential to significantly increase the temporal and spatial density of age constraints available for a particular study area. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
11.
Loess and fluvial sand are important materials for dating river terraces and alluvial fans. This study focuses on the methodological aspects of dating loess and fluvial deposits from the northern flank of the Tian Shan range, China, using sand-sized quartz and potassium (K) feldspar. Luminescence characteristics of quartz and K-feldspar were studied for searching suitable dating procedures. Our results indicate that 1) most quartz aliquots were contaminated by feldspar, and were dated using a post-infrared optically stimulated luminescence (post-IR OSL) procedure. A Fast ratio acceptance threshold of 15 can be applied to select these aliquots with post-IR OSL signals dominated by quartz OSL; 2) the multi-elevated-temperature post-IR IR stimulated luminescence (MET-pIRIR) procedures are applicable for K-feldspar. A test dose of ∼30% of the natural dose is appropriate for dating of older (>10 ka) samples. An Age (T, t) plateau test can be used to evaluate the dating results; 3) for the loess samples, both quartz and K-feldspar were well bleached and are suitable for dating. Dating using K-feldspar is preferred for its higher efficiency; 4) for the fluvial sand samples, only the quartz grains were fully bleached. Single-aliquot dating of quartz gives reliable ages. 相似文献
12.
Little work has been undertaken on combined dating of sedimentary quartz grains using electron spin resonance (ESR) and optically stimulated luminescence (OSL) techniques in Australia. This study aims to assess the suitability of a combined ESR and OSL dating approach for establishing improved chronologies of Middle-Late Pleistocene deposits within the Naracoorte Cave Complex (NCC), South Australia. Here, we apply ESR and OSL dating in tandem to a series of samples collected from three different NCC sites: Whale Bone, Specimen and Alexandra cave. ESR quartz dating focuses on the multi-centre (MC) approach, which involves comparative evaluations of Al and Ti centre signals, while paired luminescence dating focuses on single-grain OSL analysis and includes examination of multi-grain averaging effects. The comparative ESR-OSL dating results exhibit broad agreement for deposits spanning 50–150 thousand years, with either the Ti–H or Al centre ages overlapping with paired OSL ages at 2σ in nearly all cases. MC ESR evaluations (Al v Ti–Li v Ti–H age assessments) indicate incomplete resetting of the bleachable Al centre signal for a small number of samples. Two-thirds of samples exhibit Ti–Li ages that are significantly older than corresponding Al centre ages, which is unexpected from a bleaching kinetics perspective and may indicate a broader reliability issue for Ti–Li palaeodose evaluation with these particular samples. Our findings: (i) support the applicability of both palaeodosimetric dating methods in this depositional setting; (ii) highlight the merits of applying combined ESR-OSL analyses in tandem, and; (iii) provide one of the first reliable evaluations of quartz ESR MC dating for samples with natural dose ranges as low as only a few tens of Gy. These results show that the Whale Bone, Specimen and Alexandra cave sites are temporally related and can be used to derive multi-site reconstructions of faunal assemblages and palaeoenvironmental history. 相似文献
13.
Fossil oyster reefs are indicators of past sea levels, and their formation is usually dated by means of radiocarbon. However, radiocarbon dating of the shells from coastal areas may be complicated by the varying sources of carbon. Here we applied optical dating methods to date the samples from above and below a fossil oyster bed in a section on the coast of Bohai Bay, China. The optical ages of the sediments were used to constrain the oyster bed. Single-aliquot regenerative-dose procedures using the OSL signal from fine grain quartz, the IRSL and post-IR OSL signals from polymineral fine grains were employed to determine equivalent dose (De). The behaviors of the different luminescence signals from quartz and polymineral grains during De measurements were examined. The results showed that the quartz OSL signal is more reliable than the polymineral IRSL and post-IR OSL signals with respect to dating for these coastal samples. The optical ages indicated that the oyster reef formed between ca. 6.2 and 5.0 ka. 相似文献
14.
Constant slip rate during the late Quaternary along the Sulu He segment of the Altyn Tagh Fault near Changma,Gansu, China 总被引：1，自引：0，他引：1
The question of whether millennial‐scale geological slip rates are consistent with decade‐scale geodetic slip rates is of great importance in evaluating the nature of continental deformation within the Tibetan Plateau. We determined the time‐averaged slip rate of the Sulu He segment of the Altyn Tagh Fault, near Changma in Gansu Province, China, based on geomorphic analysis, remote sensing data, and cosmogenic 10Be surface‐exposure age dating. Quaternary alluvial fan deposits in the study area (Qf1, Qf2, Qf3) are displaced by left‐lateral movement along the Altyn Tagh Fault. Because of the large accumulated displacement of these fans, some of them have become disconnected from the fan apexes that are directly linked to the debris‐source areas in the piedmont of the Qilian Shan to the south. The total minimum offsets are estimated to be about 429 ± 41 m for Qf1, about 130 ± 10 m for Qf2, and 32 ± 1 m for Qf3. The 10Be surface‐exposure ages obtained for Qf1 and Qf2 are 100–112 ka and 31–43 ka, respectively. Accordingly, the slip rate since the period of Qf1 and Qf2 depositions is calculated to have been about 3.7 mm/yr. 相似文献
15.
Cosmogenic nuclide depth-profiles are used to calculate the age of landforms, the rates at which erosion has affected them since their formation and, in case of deposits, the paleo-erosion rate in the source area. However, two difficulties are typically encountered: 1) old deposits or strongly affected by cosmogenic nuclide inheritance often appear to be saturated, and 2) a full propagation of uncertainties often yields poorly constrained ages. Here we show how to combine surface-exposure-dating and burial-dating techniques in the same profile to get more accurate age results and to constrain the extent of pre-depositional burial periods. A 10Be–26Al depth-profile measured in an alluvial fan of SE Iberia is presented as a natural example. 相似文献
16.
An up to 15 m thick alluvial fan and aeolian sandsheet complex is exposed in the upper Senne area, on the southern slope of the Teutoburger Wald Mountains (NW Germany). The origin and age of these deposits have been controversially discussed for many years, ranging from Saalian glaciofluvial to periglacial Weichselian deposits. In order to provide a high-resolution chronological framework for the deposits, we conducted luminescence dating of 12 samples from two localities (Oerlinghausen and Augustdorf pits). Both coarse-grain potassium-rich feldspar and quartz minerals were used for luminescence dating. Feldspar was measured using an elevated temperature post-IR infrared stimulated luminescence (IRSL). Quartz was measured using optically stimulated luminescence (OSL) with a conventional single aliquot regenerative dose (SAR) protocol. Feldspar results tend to overestimate quartz ages for the lower part of the sections (alluvial plain and alluvial fan facies) but are consistent with quartz ages for the upper part of the sections (aeolian facies). Quartz ages from both central and minimum age models suggest deposition during the Late Pleistocene Pleniglacial to Late Glacial. 相似文献
17.
Helene Valladas Norbert Mercier Laurence Froget Jean-Louis Joron Jean-Louis Reyss Panajotis Karkanas Eleni Panagopoulou Nina Kyparissi-Apostolika 《Quaternary Geochronology》2007,2(1-4):303-308
The lowest stratigraphic unit of Theopetra cave (Greece) contains a Middle Palaeolithic sequence radiocarbon dated to between 46 and 35 ka BP; at the limit of this dating method. The upper part of this sequence has yielded late Middle Palaeolithic lithic assemblages containing several early Upper Palaeolithic artifacts. To get more precise dates for the human occupation of the cave, burnt flint specimens from these Middle Palaeolithic layers were dated by thermoluminescence. The dates obtained are coherent and indicate that the first human occupation of the cave took place at the end of isotopic stage 6 or more probably at the beginning of stage 5, much earlier than previously proposed. In the light of this new evidence, it is reasonable to assume that: (a) Theopetra contains the oldest dated Middle Palaeolithic deposits of Greece and (b) that the assemblages first interpreted as “Transitional Middle/Upper Palaeolithic” industries may be the result of post-depositional mixing of cultural material. 相似文献
18.
Sediments of river deltas provide valuable records of past coastal environments. Optically-stimulated luminescence (OSL) dating has become an alternative to radiocarbon dating for constraining the sediment chronology in large deltas that allow for sufficient sunlight bleaching of sediments during the fluvial transport. However, its applicability to smaller deltas with mountainous riverine systems has not been confirmed yet. To check this, we examine multiple signals from two Holocene sediment cores in the wave-dominated Thu Bon River delta in central Vietnam. Two cores were collected, respectively, 3.9 km and 1.2 km inland from the present shoreline and both show a >-25-m thick succession of coarsening-upward mud to sand deposits. Coarse grains (180–250 μm in diameter) of quartz and K-feldspar, and fine grains (4–11 μm in diameter) of quartz and polymineral were extracted from the upper and lower parts of the cores for multi-grain measurements of quartz OSL, and of feldspar infrared-stimulated luminescence (IRSL) at 50 °C (IR50) and post-IR IRSL at 175 °C (pIRIR175) to determine burial ages. In addition, facies analysis and radiocarbon dating were conducted. The landward core consists of transgressive to early regressive estuarine and prodelta facies, which is overlain by a sandy beach-shoreface facies. The seaward core consists of a relatively simple shallowing-upward succession from muddy prodelta facies to sandy beach-shoreface facies. All luminescence ages except for pIRIR175 of fine grains are mostly consistent with the radiocarbon ages. Instead, pIRIR175 ages of fine grains are significantly overestimated with variable offsets. OSL and IR50 of fine grains provide reasonable age estimates, as these grains were likely well bleached during the transport even along a short and steep mountainous river. Consistent age estimates of all signals from sand indicate that sand was well-bleached in the beach and shoreface owing to the frequent sediment reworking by waves and currents. These results support the hypothesis that luminescence dating is applicable to Holocene wave-dominated deltas and reiterate that comparing different luminescence signals is an effective way to check reliability of the age estimates in environments where the sunlight bleaching is not ensured. 相似文献
19.
Sedimentary records from the inner-shelf of the East China Sea (ECS) are unique for the reconstruction of post-glacial palaeoclimate and sea-level changes. So far, the chronology of sediment succession from this region has mainly been based on radiocarbon dating, which might be problematic due to reworked deposition or old carbon contamination. In this study we tested the applicability of optically stimulated luminescence (OSL) dating to a drilling core (ECS-DZ1) taken from the northern ESC. A total of 20 OSL samples and two radiocarbon samples were collected from the upper 58 m of this core. The results indicate the likely sufficient reset of OSL signal of fine-grained (4–11 μm) quartz before burial, and thus reliable chronology for the studied core sediments. For one sample, however, the extracted coarse-grained (100–200 μm) quartz overestimated the deposition age significantly, presumably resulting from partial bleaching prior to deposition. The fine-grained quartz ages are generally consistent with the stratigraphical order, and the reliability of these OSL ages are further validated by two selective robust 14C dates. The chronological framework of core ECS-DZ1 reveals striking sedimentation-rate changes. By comparison with other chronostratigraphical records, we infer that post-glacial deposition history (since ∼15 ka) of the study site is likely related to regional sea-level rise and delta-estuary environment evolution, as well as strengthened human activities and/or coastal currents. 相似文献
20.
Optically stimulated luminescence (OSL) dating of sand samples from stabilized (or inactive) coastal dunes in Denmark provides information on the age of the termination phase of the last major aeolian activity period. A total of 26 sand samples were taken from four different coastal dunefields around the North Sea, Skagerrak and Kattegat coasts of Denmark. The OSL dates indicate that the last major phase of aeolian activity terminated between ad 1860 and 1905. Most of the dunes examined in this study were active around 1820, during a period documented to have been very stormy. A dune management scheme started around 1792, and this no doubt was a major cause of dunefield stabilization, but an overall decline of storminess, particularly spring and summer storminess, around the end of the 19th century must also have contributed to the increasing inactivity of coastal dunes. The new OSL dates on aeolian sand movement agree well with historical data and data from topographic maps on dune movement. This agreement supports the observation from earlier work that OSL dating of recent aeolian sand movement is accurate over the last few decades to centuries. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献