Evaluating color reflectance spectral methods for estimating biogenic contents of South China Sea sediments

The biogenic contents of marine sediment cores are useful proxies for revealing past oceanic and climatic variability. Color reflectance spectral methods provide a rapid and non-destructive avenue for acquiring high-resolution biogenic content data from the split surfaces of marine sediment cores. This study presents new results on the applications of color reflectance methods for determining the biogenic contents of sediment cores retrieved from the South China Sea (SCS), a dynamic setting that receives biogenic components such as carbonate, total organic carbon (TOC), and opal from the sea, and terrestrial sediments transported by the Pearl River and Kao-Ping River from the north, and the Sunda Shelf from the south. Our study found that the color reflectance methods that are based on a regionally limited calibration provide more optimal estimates of the biogenic content of marine cores from the SCS than do basin-scale calibration methods. Though the regional calibrations appear to be successful, our analyses indicate the complexity of applying color reflectance methods in marine sediment core studies. We also performed a controlled experiment that was designed to quantitatively test how the carbonate content increased the influence of color reflectance changes, using outcropped, Pleistocene-aged sediment samples taken from the “Moon World (MW)” in southwestern Taiwan as control data. The results of this experiment suggest that the regression equations for estimating CaCO₃ content based on core data are not solely driven by input variables responding directly to CaCO₃ content changes, and that the composition of terrestrial sediment inputs into the SCS are complicated both spatially and temporally. Our studies also suggest that a better understanding of the compositional changes of terrestrial sediment inputs into the SCS will be required to minimize the uncertainties of biogenic content estimations by color reflectance methods.     

A Late Glacial–Holocene Tephrochronology for Glacial Lakes in Southern Ecuador

Despite the presence of numerous active volcanoes in the northern half of Ecuador, few, if any, distal tephras have been previously recognized in the southern one third of the country. In this article, we document the presence of thin (0.1–1.0-cm-thick) distal tephras comprising glass and/or phenocrysts of hornblende and feldspar in sediment cores from five glacial lakes and one bog in Las Cajas National Park (2°40′–3°00′S, 79°00′–79°25′W). The lake cores contain from 5 to 7 tephras, and each has a diagnostic major element geochemistry as determined from electron microprobe analysis of 710 glass shards and 440 phenocrysts of feldspar and hornblende. The loss of sodium with exposure to the electron microbeam causes a 10±7 wt.% (±1σ) reduction in Na content, which we empirically determined and corrected for before correlating tephras among the sediment cores. We use a similarity coefficient to correlate among the sediment cores; pair-wise comparison of all tephras generally yields an unambiguous correlation among the cores. Six tephras can be traced among all or most of the cores, and several tephras are present in only one or two of the cores. Twenty-six accelerator mass spectrometry ¹⁴C dates on macrofossils preserved in the sediment cores provide the basis for establishing a regional tephrochronology. The widespread tephras were deposited 9900, 8800, 7300, 5300, 2500, and 2200 cal yr B.P. The oldest tephras were deposited 15,500 and 15,100 cal yr B.P., but these are not found in all cores. Two of the tephras appear correlative with volcaniclastic strata on the flanks of Volcán Cotopaxi and one tephra may correlate with strata on the flanks of Volcán Ninahuilca; both volcanoes are in central Ecuador. The absence of tephras in sediment cores correlative with the numerous eruptions of active volcanoes of the past two millennia implies that the earlier eruptions, which did deposit tephras in the lakes, must have been either especially voluminous, or southerly winds must have prevailed at the time of the eruption, or both.     

Optical dating studies of quartz and feldspar sediment extracts

Continuing developmental work into optical dating has led to some clarification of the optical behaviour of quartz and feldspar sediment extracts. We have verified the key assumption intrinsic to the method — that the optical signal is zeroed completely upon exposure to daylight. We also show that the rate of zeroing in optical dating is much more rapid than it is in TL dating.Studies concerned with the extraction of the thermally stable signal from laboratory-irradiated samples showed that problems may arise from medium-to-high-temperature preheating of young samples. Optical alternatives to thermal stabilization were tested using dye and krypton lasers. Using a krypton laser we have succeeded in obtaining an equivalent dose of 0.0 ± 0.7 Gy for the quartz from a modern intertidal sand, and an average dose of 120 ± 22 Gy for the feldspar extract of a 70 ka sand unit. Both were obtained using six wavelengths, from the infrared to the violet, and no dependence on wavelength was found. We found that the photon energies of infrared and deep red light can stimulate luminescence in unirradiated quartz and feldspar extracts of sediments. This was not expected, and suggests that the process of trap emptying is more complex than we had envisioned, but implies a far greater than expected degree of technical flexibility for the optical dating method.     

Glacial–interglacial records of the reflectance of sediments from the Norwegian–Greenland–Iceland Sea (Nordic seas)

 The reflectance of sediments (gray level) were measured on 11 sediment cores from the Norwegian–Greenland–Iceland Sea (Nordic seas). The analyzed time interval covers the past five glacial–interglacial cycles. Although the results demonstrate that the gray-level method has a potential for stratigraphic purposes, it is indicated that gray-level changes in the Nordic seas are not necessarily driven by variations in the content of biogenic calcite. A detailed comparison of gray-level values with contents of total CaCO₃ (carbonate) and total organic carbon (TOC) reveals no overall causal link between these proxies. However, specific glacial core sections with layers containing organic-rich sediment clasts as a consequence of iceberg-rafting seem to correlate well with law gray-level values. Of those cores which show relatively high and comparable carbonate values in the last three main interglacial intervals (stages 11, 5.5, and 1), stage 11 is always marked by the highest gray-level values. A close inspection of the surface structure of the foraminiferal tests as well as the conduction of reflectance measurements on these tests leads to the conclusion that enhanced carbonate corrosion occurred during stage 11. The test corrosion not only affected the reflectance of the tests by making them appear whiter, it also seems responsible for the comparatively high gray-level values of the total sediment in stage 11. In contrast, the relatively low gray-level values found in stages 5.5, and 1 are not associated with enhanced test corrosion. This observation implies that variable degrees of carbonate corrosion can have a profound effect on total sediment reflectance. Received: 6 September 1998 / Accepted: 4 April 1999     

光释光测年中石英样品提纯方法的改进

为了解决光释光前处理中遇到的传统方法无法获得满足纯度石英的问题,通过大量对比实验,结合玻璃工艺中石英分离研究成果,最后获得了新的石英提纯流程,与传统方法相比,新方法通过化学分离避免了密度变化对石英长石分离的影响,从而解决了斜长石和岩屑在传统的重液分离中无法剔除的问题,新方法能够获得满足纯度要求和量要求的石英,同时,新方法比传统方法实验室工作效率更高。     

Dating recent floodplain sediments in the Hawkesbury‐Nepean River system,eastern Australia using single‐grain quartz OSL

Two fluvial sediment cores taken from a floodplain of the Hawkesbury‐Nepean River system in the Sydney region, eastern Australia are dated using Optically Stimulated Luminescence (OSL) to provide a reliable chronology essential for the management and planning of water resources. Nine charcoal ¹⁴C (AMS) dates constrain these OSL ages. Quartz extracted from seven OSL samples from each of the cores was measured using both single‐grain and multi‐grain OSL techniques. Three of the single‐grain natural dose distributions appear to be well bleached, but the others appear to be incompletely bleached to various degrees. Three minimum‐age models (MAM, MAM_UL and IEU) are applied to the single‐grain dose distributions. We conclude that these models give consistent age estimates. For one of the cores it appears to be necessary to use a minimum‐age model to obtain accurate ages, but in the other core incomplete bleaching is probably less important than postdepositional mixing and mixing during sampling. As a result, the burial age is probably best estimated using the weighted average of the individual single‐grain dose estimates. The application of multi‐grain OSL techniques to these samples results in an average apparent age overestimation of ～200 years, which is significant for these samples, but negligible for sediments older than a few thousand years. The intention is that the chronology obtained in this study will be used in conjunction with a proxy flood record, derived from floodplain sediments, to gain an understanding of the long‐term variability in periods of high and low rainfall in eastern Australia.     

Application of allochthonous organic carbon and phosphorus forms in the interpretation of past environmental conditions

Organic matter in sediments, for instance, carbon, nitrogen and phosphorus, can be used to reconstruct the paleoecological and pollution history of lakes and their catchment basins. In this paper, the contents of allochthonous organic carbon (allochthonous OC) and autochthonous organic carbon (autochthonous OC) in sediment cores taken from Wuliangsuhai Lake and Daihai Lake in northern China are quantified by using a binary model, and phosphorus forms in the sediment cores from the two lakes are extracted by sequential extraction techniques. The results indicate that the palaeoenvironment and paleoclimate of Daihai Lake and its catchment basin in the recent 250 years can be well reconstructed based on the content of allochthonous OC. The climate was relatively humid and warm in the period of 1865–2005, while relatively dry and cold in the period of 1765–1865. The sedimentary information of allochthonous OC in the 22–42-cm portion of the sediment cores in Daihai Lake corresponds to the final cold fluctuation of the Little Ice Age that occurred since the Middle Holocene. The difference of phosphorus forms in the sediment cores between the two lakes indicates that phosphorus input to the lakes and the correlation between phosphorus forms and distribution and the changes of environment are influenced by the eutrophication mechanisms and environmental conditions of the two lakes.     

释光技术在水成沉积物测年中的应用进展

准确获得水成沉积物的年龄是第四纪年代学重要的前沿问题之一。随着释光技术的发展,水成沉积物释光测年在如下方面有新的进展：具体释光技术的选择、释光测量方法、测年矿物的种类、矿物的粒级和获得等效剂量的统计方法等。线性调整光释光技术能够提取光释光信号中衰退快的组分;单片再生法应用广泛;单颗粒技术在挑选沉积时晒退充分的颗粒方面具有一定的优势;水成沉积物中的石英比长石更易晒退;较多的实验表明水成沉积物中的粗颗粒比细颗粒更易晒退;获得等效剂量的统计模型很多,但尚无一种统计模型适用于所有样品。在此基础上探讨了水成沉积物释光测年在气候、构造运动、冰川进退历史和人类活动主导的土壤侵蚀量变化研究中的意义及今后的研究方向,为全面了解该领域的最新研究进展提供参考。     

Clay minerals in SW Indian continental shelf sediment cores as indicators of provenance and palaeomonsoonal conditions: a statistical approach

Two sediment cores from the inner continental shelf of SW India, SK‐148/13 (4.66 m long; from 50 m water depth) and SK‐148/14 (5.37 m long; from 22 m water depth), were studied for provenance and palaeomonsoonal implications. Sediment layers at different depth intervals in these cores were estimated for clay minerals and organic matter content. Five surface sediment samples from the nearby Kali River estuary of the adjacent hinterland were also analysed for clay mineral contents. In both cores and Kali River sediments, smectite is the dominant clay followed by illite, and kaolinite or chlorite. Based on the similarities of the abundances of clay minerals and their relative wt‐% in the inner shelf sediment cores and in surface sediments of the estuary as demonstrated by significance tests, Al‐rich illite, and negligible contribution of clay from the deep‐sea and aeolian sources, it can be inferred that the sediments of the two inner continental shelf cores were derived from the adjacent hinterland. Application of statistical discordancy and significance tests on the down‐core variations in the crystallinity index (CI) of illite and organic matter content in the sediment cores indicates intense monsoonal (high rainfall) conditions at the adjacent hinterland during about 4300–6200 and 9300–10,400 years BP. These inferences are comparable to those from other well‐established palaeomonsoonal indicators such as sedimentation rates and mineral magnetic properties. The CI of illite, an easily determinable and climatically sensitive parameter, can thus be a reliable palaemonsoonal indicator for inner shelf sediment cores. The statistical methodology used in this work highlights the advantages of a quantitative interpretation of the data instead of the conventional qualitative visual examination.     

Bayesian methods applied to the interpretation of multiple OSL dates: high precision sediment ages from Old Scatness Broch excavations,Shetland Isles

In this paper, we illustrate the ways in which Bayesian statistical techniques may be used to enhance chronological resolution when applied to a series of OSL sediment dates. Such application can achieve an optimal chronological model by incorporating stratigraphic and age information. The application to luminescence data is not straightforward owing to the sources of uncertainty in each date, and here we present one solution to overcoming these difficulties, and introduce the concept of “unshared systematic” errors. Using OSL sediment dates from the site of Old Scatness Broch, Shetland Isles, UK, many measured with a high degree of precision, we illustrate some of the ways in which Bayesian techniques may be applied, as a tool for assessing systematic errors when combined with independent chronological information, and to determine the optimum chronological information for specific events and contexts. We provide a detailed procedure for the application of Bayesian methods to OSL dates using the widely available radiocarbon calibration programme OxCal.     

Direct and indirect luminescence dating of tephra: A review

In Quaternary studies, tephras are widely used as marker horizons to correlate geological deposits. Therefore, accurate and precise dating is crucial. Among radiometric dating techniques, luminescence dating has the potential to date tephra directly using glass shards, volcanic minerals that formed during the eruption or mineral fragments that originate from the shattered country rock. Moreover, sediments that frame the tephra can be dated to attain an indirect age bracket. A review of numerous luminescence dating studies highlights the method's potential and challenges. While reliable direct dating of volcanic quartz and feldspar as a component in tephra is still methodically difficult mainly due to thermal and athermal signal instability, red thermoluminescence of volcanic quartz and the far-red emission of volcanic feldspar have been used successfully. Furthermore, the dating of xenolithic quartz within tephra shows great potential. Numerous studies date tephra successfully indirectly. Dating surrounding sediments is generally straightforward as long as samples are not taken too close to the tephra horizons. Here, issues arise from the occurrence of glass shards within the sediments or unreliable determination of dose rates. This includes relocation of radioelements, mixing of tephra into the sediment and disregarding different dose rates of adjacent material.     

Bleaching of the post‐IR IRSL signal: new insights for feldspar luminescence dating

Post‐infrared (pIR) stimulated luminescence dating of sedimentary feldspar largely avoids the effects of anomalous fading that affect conventional infrared stimulated luminescence (IRSL) dating. However, optical resetting of pIR signals is more difficult than resetting the conventional IRSL signal, which may undermine the crucial assumption that pIR signals were effectively bleached upon deposition and burial of sediment grains. In this study, we quantify the bleaching properties of several pIR signals on various samples using laboratory‐simulated bleaching in full sunlight and water‐attenuated sunlight. Our data show that bleaching is most efficient under full spectrum conditions for all pIR signals and that pIR signals measured at elevated temperature are increasingly harder to bleach than IR and pIR signals measured at low temperature (e.g. IR at 50°C). All bleaching curves exhibit a very slow and steady decrease, indicating that a fixed un‐bleachable residual level cannot be reached within the 11 days of solar simulator exposure undertaken here. We show that the magnitude of a laboratory‐determined residual dose depends on the adopted bleaching protocol and cannot be used as a proxy for the dose that remains in the sample at the time of burial (remnant dose). Our data emphasize the importance of finding a balance between sufficient signal stability and a minimized contribution of a remnant dose when using pIR procedures for feldspar luminescence dating.     

Electrons in feldspar II: a consideration of the influence of conduction band-tail states on luminescence processes

 Most natural feldspars contain many charged impurities, and display a range of bond angles, distributed about the ideal. These effects can lead to complications in the structure of the conduction band, giving rise to a tail of energy states (below the high-mobility conduction band) through which electrons can travel, but with reduced mobility: transport through these states is expected to be thermally activated. The purpose of this article is twofold. Firstly, we consider what kind of lattice perturbations could give rise to both localized and extended conduction band-tail states. Secondly, we consider what influence the band tails have on the luminescence properties of feldspar, where electrons travel through the sample prior to recombination. The work highlights the dominant role that 0.04–0.05-eV phonons play in both the luminescence excitation and emission processes of these materials. It also has relevance in the dating of feldspar sediments at elevated temperatures. Received: 11 May 2001 / Accepted: 6 September 2001     

A robust feldspar luminescence dating method for Middle and Late Pleistocene sediments

Luminescence dating is used extensively to provide absolute chronologies for Late Pleistocene sediments. Nowadays, most optical dates are based on quartz optically stimulated luminescence (OSL). However, the application of this signal is usually limited to the last ～100 ka because of saturation of the quartz luminescence signal with dose. In contrast, the feldspar infrared stimulated luminescence (IRSL) dose–response curve grows to much higher doses; this has the potential to extend the datable age range by a factor of 4–5 compared with quartz OSL. However, it has been known for several decades that this IRSL signal is unstable, and this instability often gives rise to significant age underestimation. Here we test against independent age control the recently developed feldspar post‐IR IRSL approach to the dating of sediments, which appears to avoid signal instability. A physical model explaining our observations is discussed, and the method is shown to be accurate back to 600 ka. The post‐IR IRSL signal is reduced by exposure to daylight more slowly than that from quartz and low‐temperature IRSL, preventing its general application to young (e.g. Holocene) sediments. Nevertheless, this new approach is widely applicable (feldspar of appropriate luminescence behaviour is even more ubiquitous than quartz). These characteristics make this a method of great importance for the dating of Middle and Late Pleistocene deposits.     

The chronostratigraphy of the latest Middle Pleistocene aeolian and alluvial activity on the Island of Hvar,eastern Adriatic,Croatia

Pleistocene aeolian sands and alluvial deposits can frequently be traced along the Mediterranean coast. Such deposits also exist along the eastern Adriatic coast and the nearby islands. Four stratigraphical sections of these deposits were studied on the Island of Hvar with the purpose of establishing a chronological framework of the aeolian–alluvial depositional system, using luminescence dating and magnetic susceptibility stratigraphy. Luminescence dating was applied on coarse‐grained feldspar and quartz grains separated from the sands. Both quartz optically stimulated luminescence (OSL) and feldspar post‐IR infrared stimulated luminescence (pIRIR) age estimates are in good agreement, with values ranging between 167±24 to 120±12 ka (OSL) and 179±18 to 131±18 ka (pIRIR measured at 290 °C) after a fading correction for the pIRIR signal. The results can be clearly correlated to around the end of oxygen isotope stage (OIS) 6 and the beginning of OSI 5, indicating that the aeolian accumulation of sands was a result of the Penultimate Glacial and climate fluctuations at the beginning of the Last Interglacial. Variations in magnetic susceptibility (MS) data can be interpreted alongside these dating results; several stronger peaks detected at the very end of the Penultimate Glacial and the initial stage of the Last Interglacial cycle most probably indicates more intensive pedogenesis resulting from a more favourable climate, probably because of climate changes. Breccias related to major bounding surfaces in association with evidence of soil formation and bioturbation could be the result of more favourable climate conditions and changes during the transition from OIS 6 to OIS 5 (Penultimate Glacial–Last Interglacial). These results are in agreement with similar data from the wider Mediterranean area.     

Litho- and biofacies analysis of postglacial marine mud using CT-Scanning

Marine silty clay deposited during the Late-Wisconsinian postglacial marine transgression of eastern Québec (Goldthwait Sea) is ubiquitous in the sedimentary column of intertidal zones of the St-Lawrence Estuary. This mud is very compact and limits the penetration of organisms composing the modern Macoma balthica community. In order to describe the characteristics of intertidal sediments containing Goldthwait Sea mud, axial tomography (CT-Scan) is used. CT-Scan is a non-destructive method that can be used to describe sediment characteristics (grain size, mineralogy, primary and secondary sedimentary structures, fabric, shape and roundness, bedding contact), and to obtain high resolution, 3D representations of structures within sediment cores. Based on differences in the densities of analysed materials, the different lithologies, lithofacies, and organisms within the core can be discriminated, and a quantification of the volume occupied by the different components of the material can be made. Here, CT-Scan images provide information on the distribution, orientation and interweaving of thanatocœnosis shell beds that alternate with massive or faintly laminated postglacial marine mud beds, as well as on ichnofacies characteristics. In addition, we show 3D images of bioturbation structures within the recent sediment layer, which is distinguished from the underlying Goldthwait Sea mud. When coupled with conventional sedimentary (grain size statistics) and radiochronological (¹⁴C) analyses, these data provide information which is valuable for identifying depositional processes within sedimentary environments.     

Changing hillslope and fluvial Holocene sediment dynamics in a Belgian loess catchment

Floodplain deposition is an essential part of the Holocene sediment dynamics of many catchments and a thorough dating control of these floodplain deposits is therefore essential to understand the driving forces of these sediment dynamics. In this paper we date floodplain and colluvial deposition in the Belgian Dijle catchment using accelerator mass spectrometric radiocarbon and optical stimulated luminescence dating. Relative mass accumulation curves for the Holocene were constructed for three colluvial sites and 12 alluvial sites. A database was constructed of all available radiocarbon ages of the catchment and this database was analysed using relative sediment mass accumulation rates and cumulative probability functions of ages and site‐specific sedimentation curves. Cumulative probability functions of ages were split into different depositional environments representing stable phases and phases of accelerated clastic deposition. The results indicate that there is an important variation between the different dated sites. After an initial stable early and middle Holocene phase with mainly peat growth in the floodplains, clastic sedimentation rates increased from 4000 BC on. This first phase was more pronounced and started somewhat earlier for colluvial deposits then for alluvial deposits. The main part of the Holocene deposits, both in colluvial and alluvial valleys, was deposited during the last 1 ka. The sedimentation pattern of the individual dated sites and the catchment‐wide pattern indicate that land use changes are responsible for the main variations in the Holocene sediment dynamics of this catchment, while the field data do not provide indications for a climatological influence on the sediment dynamics. Copyright © 2011 John Wiley & Sons, Ltd.     

Identification and characterization of tsunami deposits off southeast coast of India from the 2004 Indian Ocean tsunami: Rock magnetic and geochemical approach

The December 2004 Indian Ocean Tsunami (IOT) had a major impact on the geomorphology and sedimentology of the east coast of India. Estimation of the magnitude of the tsunami from its deposits is a challenging topic to be developed in studies on tsunami hazard assessment. Two core sediments (C1 and C2) from Nagapattinam, southeast coast of India were subjected to textural, mineral, geochemical and rock-magnetic measurements. In both cores, three zones (zone I, II and III) have been distinguished based on mineralogical, geochemical and magnetic data. Zone II is featured by peculiar rock-magnetic, textural, mineralogical and geochemical signatures in both sediment cores that we interpret to correspond to the 2004 IOT deposit. Textural, mineralogical, geochemical and rock-magnetic investigations showed that the tsunami deposit is featured by relative enrichment in sand, quartz, feldspar, carbonate, SiO ₂, TiO ₂, K ₂O and CaO and by a depletion in clay and iron oxides. These results point to a dilution of reworked ferromagnetic particles into a huge volume of paramagnetic materials, similar to what has been described in other nearshore tsunami deposits (Font et al. 2010). Correlation analysis elucidated the relationships among the textural, mineral, geochemical and magnetic parameters, and suggests that most of the quartz-rich coarse sediments have been transported offshore by the tsunami wave. These results agreed well with the previously published numerical model of tsunami induced sediment transport off southeast coast of India and can be used for future comparative studies on tsunami deposits.     

Postglacial relative sea-level history: sediment and diatom records of emerged coastal lakes, north-central Kola Peninsula, Russia

Sediment cores recovered from four emerged lakes (54, 41, 22, and 7 m a.s.l.) provide new data on the deglaciation and relative sea-level history of the Murman coast, Kola Peninsula. The transition from marine to lacustrine sediment is identified in the cores by analysis of sediment physical properties and diatom assemblages. Fourteen AMS-radiocarbon ages on organic macrofossils isolated from core sediment provide chronology for the records. Basal ages from two of the cores indicate deglaciation of the area prior to 11000 BP. Radiocarbon ages associated with the marine-lacustrine sediment transition in the cores further constrain the emergence history of the area. The prominent late-glacial shoreline on the Murman coast (48 m a.s.l.) is dated to c . 10500–10300 BP, the emergence ages of lake basins 54 and 41 m a.s.l. Glaciofluvial terraces graded to this shore level indicate remnant glaciers on the north-central Kola Peninsula during the Younger Dryas.     

Advances and Issues in Luminescence Dating of Loess Deposits in Arid Central Asia

High-resolution loess deposits are widely distributed in Arid Central Asia (ACA) and provide important records associated with dust transportation, paleoenvironmental and paleoclimatic evolution. The chronology is the foundation of the research into loess deposits as an environmental archive. In recent decades, the gradually developed optical dating method has been increasingly matured and become an important approach to establishing the loess-paleosol sequences. Here, we summarized and discussed previous work on loess chronology mainly based on optical dating approach in ACA. The following understandings have been listed: ① In comparison with optical dating method, the suitable material for ¹⁴C dating is uncommon in ACA. However, the dating range of luminescence dating is more extensive, and the dating materials are accessible. Thus, the optical dating is widely applicable in the establishment of loess framework in this area. ② Until now, the quartz Single Aliquot Regeneration (SAR) method can be applied to the establishment of loess-paleosol sequence since last glacial period. But several issues remain unaddressed. For example, the Optically Stimulated Luminescence (OSL) signal sensitivity of quartz grains are low in some areas. Furthermore, the results of OSL dating of different grain sizes within a single sample are inconsistent in some areas. The solution of these problems still requires more methodological research. ③ The post-IR IRSL (pIRIR) and multiple elevated temperature stimulation (MET-pIRIR) protoCols of feldspar have basically overcome the anomalous fading issue in the traditional IRSL dating process. In ACA, the framework since MIS 7 can be established with K-feldspar luminescence dating method. Compared with quartz luminescence characteristics, the K-feldspar luminescence signals are more sensitive and exhibit a high saturation level. In specific applications, it is necessary to establish the age frame according to the luminescence sensitivity, the age of samples or other factors.