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We present stratigraphic, magnetic, diffuse reflectance spectrophotometric analyses, and chronologic data for the Chenarli loess–paleosol sequence in northeastern Iran. Eight loess units (LU) are identified, described, and constrained in time based on relative stratigraphy and luminescence dating from >130 ± 9.1 ka to ~9.8 ± 0.7 ka. Our data indicate that pedogenic magnetite/maghemite formation gives rise to magnetic enhancement in modern soil and paleosols. The top of LU 7 is demarcated by the well-developed last interglacial soil in which magnetic depletion occurred. We infer that magnetic depletion in this paleosol was produced by reducing conditions in a seasonally waterlogged soil during a warm and wet phase within Marine Isotope Stage (MIS) 5e. Units LU 6 to 1 record several episodes of dust accumulation and soil formation during the last glacial and Holocene. Increased dust accumulation rates occurred during middle-late MIS 3 and lasted into the late MIS 2, with a peak during the last glacial maximum (LU 2). These findings could be applicable to understanding magnetic enhancement/dissolution mechanism in the loess–paleosol sequences in study area. We infer paleoenvironmental changes in northeastern Iran relative to northern Iran, Eurasia, and China.

Lake Bosumtwi was created after a meteorite impact 1.07 Ma ago in an area that is highly susceptible for climate changes due to shifts of the tropical rain belt, as well as variation in dust dynamics. The sedimentary sequence records such changes in the tension field between the North African Monsoon (humid, wet) and the Harmattan (dry and dusty winds from the Sahara) and has been intensively studied. Drilling in 2004, supported by the International Continental Scientific Drilling Program (ICDP), recovered downhole logging data and sediment cores that allow for the analysis of the complete ~300 m lacustrine sequence. Yet, detailed climatic and environmental reconstructions for the record have not been completed, mostly due to the absence of a robust age model beyond 500 ka. In 2022, we obtained core scanning natural gamma ray data of the ~300 m lacustrine sedimentary sequence. Based on this data, we are generating an astronomical age model that can be directly compared to the independently dated sections, but extends farther back in time. Our age model will provide critical chronologic context for the numerous existing and new proxy data that illuminate past changes in climate, environment, and ecosystems. This breakthrough will allow a robust framework to analyse climatic interferences with archaeological findings that might shed new light on habitat availability for our ancestors in tropical Western Africa.

Loess-paleosol sequences are widely spread across central and southeastern Europe and are studied intensively, as they are important terrestrial archives that preserve paleoenvironmental and paleoclimatic information. In the Lower Danube Basin large areas are covered by loess, loess derivates, sandy loess, and sand dunes (Lehmkuhl et al., 2021). The exposed loess deposits reach several decameters in thickness. In contrast to other well-studied sites in the Lower Danube area, the investigated Balta Alba Kurgan (BAK) sequence is located close to the forelands of the Eastern Carpathians, an area that is largely underrepresented in loess research. High-resolution geochemical analyses identified the Eastern Carpathians as a main source region of the loess at this site (Pötter et al., 2021). The BAK sequence consists of loess with several intercalated paleosols and weaker pedogenetic horizons, reflecting Late Pleistocene environmental conditions. Furthermore, the Campanian Ignimbrite/Y-5 tephra is preserved that serves as a chronological marker horizon and which had severe ecological impact in southeastern Europe. A robust age model was established for the upper 10 m using a multi-method approach (luminescence dating, radiocarbon dating, magnetic stratigraphy, and tephrochronology) which shows that this part of the sequence covers the MIS 3/2 transition up to present (Scheidt et al., 2021). Here, we present further geochronological data obtained from luminescence dating and more detailed paleoenvironmental proxy data, widening our understanding of Late Pleistocene climate and environmental conditions in the northern Lower Danube Basin. ReferencesLehmkuhl, F., Nett, J.J., Pötter, S., Schulte, P., Sprafke, T., Jary, Z., Antoine, P., Wacha, L., Wolf, D., Zerboni, A., Hošek, J., Marković, S.B., Obreht, I., Sümegi, P., Veres, D., Zeeden, C., Boemke, B., Schaubert, V., Viehweger, J., Hambach, U., 2021. Loess landscapes of Europe – Mapping, geomorphology, and zonal differentiation. Earth-Science Reviews 215, 103496. doi:10.1016/j.earscirev.2020.103496Pötter, S., Veres, D., Baykal, Y., Nett, J.J., Schulte, P., Hambach, U., Lehmkuhl, F., 2021. Disentangling sedimentary pathways for the Pleniglacial Lower Danube loess based on geochemical signatures. Frontiers in Earth Science 9, 1–25. doi:10.3389/feart.2021.600010Scheidt, S., Berg, S., Hambach, U., Klasen, N., Pötter, S., Stolz, A., Veres, D., Zeeden, C., Brill, D., Brückner, H., Kusch, S., Laag, C., Lehmkuhl, F., Melles, M., Monnens, F., Oppermann, L., Rethemeyer, J., Nett, J.J., 2021. Chronological Assessment of the Balta Alba Kurgan Loess-Paleosol Section (Romania) – A Comparative Study on Different Dating Methods for a Robust and Precise Age Model. Frontiers in Earth Science 8, 598448. doi:10.3389/feart.2020.598448

As the world warms due to rising greenhouse gas concentrations, the Earth system moves toward climate states without historic precedent, challenging societal adaptation. One way to investigate these unprecedented conditions is to study past climates and ecosystems that shar similarities to our current and future ones. One such period is the Eocene (~56 – 33 Ma), during which the climate changed from a hot-house to a greenhouse state, comprising a wide range of atmospheric CO2 concentrations. However, our knowledge of the Eocene climate evolution is incomplete because of a lack of terrestrial records covering the entire period. To address this gap in our understanding, we propose to obtain drill cores at Geiseltal in Eastern Germany as part of the International Continental Scientific Drilling Program (ICDP).This former lignite quarry is famous for its exceptionally well-preserved Eocene mammal fossils, but its potential as a climate archive has not yet been explored due to the lack of existing drill cores. By drilling a maximum of three cores, we aim to create a spliced 100-120 m long record comprising the entire Eocene archived in Geiseltal as an alteration of lignite seems intercalated with fluvial strata. High-resolution, multi-proxy analyses of the obtained sediments will allow to generate a unique record of (sub)orbital climate variability under various atmospheric greenhouse gas concentrations. The integration of newly developed paleoclimate records with the existing paleoecological data will further help to inform how the terrestrial ecosystems reacted to long-term as well short-term changes, e.g., during hyperthermals. To advance this project, we welcome scientific input from a wide range of disciplines (e.g., stratigraphy, sedimentology, paleolimnology, paleobotany, paleontology, and organic/inorganic geochemistry) as well as are actively seeking interested groups and individuals to collaborate with us on this project.

Transparent data reporting is a crucial aspect of an integrated and reproducible stratigraphic approach. However, there is currently no set standard for doing so. Typically, lithological information can still be found as simple images in publications, rather than as importable vector graphics, or better yet, tabulated data. Another problem is that there is often confusion on stratigraphic depth, composite depth and interpreted age: there is no standard format for these parameters, and the way they are obtained is often difficult to replicate. This all impedes the compilation of published data into reliable stratigraphic databases. We suggest that standardised stratigraphic data formats and associated automated tests can solve this issue. We explore this in [1] the case of the quantified data contained in lithological logs, and in [2] age-depth conversion models, or depth-depth models for correlation between sections or for splicing.We define three types of numerical data in lithological logs:Bed nature and thickness (including thickness variations) Bed profile (to convey hardness, weathering, grain-size, facies, etc.) Discrete feature occurrences (e.g. fossils, minerals, sedimentary patterns) These data types are not defined based on geological arguments, but on the way they are digitised. Respectively, these are interval data, continuous time-series, and discrete data. Therefore, three data sub-formats can be rigorously defined, and serve as building blocks for a larger single data format that would be comprehensive of all numerical data found in lithologs. Based on this, the existing StratigrapheR package has been updated (version 1.3): it now offers a formalised way of documenting these types of information for lithological logs in a quantified way. StratigrapheR is freely available for R at https://CRAN.R-project.org/package=StratigrapheR.In StratigrapheR, discrete feature occurrences can be attributed to collections of symbols. Bed profiles can be formatted as time series, and “welded” to the side of lithologs. Layer content can be set as data tables for each bed, and can be illustrated by the colours or patterns of the beds in the litholog. Variations of thickness at the boundary of beds can also be “welded” to these beds in lithologs, as long as the variation does not interfere with the profile’s time series. Using a minimal set of formal rules, all these quantified data types can thus be standardised. We suggest that these concepts can be the basis for universal formats of numerical lithologs.For age-depth and depth-depth conversion models, we explore the reversibility aspect, i.e., the ability to retrieve the initial signal from one that has been transformed, e.g., correlated, spliced, or tuned. This involves taking the precision in depth and age into account, as well as formalizing hiatuses, and preserving relevant features of the original data/signals in all subsequent data files, such as parts of the signal commonly removed for processing (e.g., turbidites).

The continuing development of analytical methods for investigating sedimentary records calls for iterative re‐examination of existing data sets obtained on loess‐palaeosol sequences (LPS) as archives of palaeoenvironmental change. Here, we re‐investigate two LPS (Hecklingen, Zilly) in the northern Harz foreland, Germany, being of interest due to their proximity to the Scandinavian Ice Sheet (SIS) and the position between oceanic climatic influence further west and continental influence towards the east. First, we established new quartz OSL and polymineral IRSL chronologies. Both methods show concordant ages in the upper part of the Hecklingen profile (~20–40 ka), but in the lower part IRSL underestimates OSL ages by up to ~15 ka for the period 40–60 ka. Interpretations hence refer to the OSL data set. Second, we applied Bayesian age‐depth modelling to data sets from Hecklingen to resolve inversions in the original ages, also reducing averaged 1σ uncertainty by ~19% (OSL) and ~12% (IRSL). Modelled chronologies point out phases of increased (MIS 2, early MIS 3) and reduced (middle and late MIS 3) sedimentation, but interpretation of numerical rates is problematic because of intense erosion and slope wash particularly during MIS 3. Finally, previously obtained grain‐size data were re‐investigated by end member modelling analyses. Three fundamental grain‐size distributions (loadings) explain the measured data sets and offer information on intensity and – combined with modelled OSL ages – timing of geomorphic processes. We interpret the loadings to represent (i) primary loess accumulation, (ii) postdepositional pedogenesis and/or input of aeolian fine fractions, and (iii) input of coarse aeolian material and/or slope wash. The applied modelling tools facilitate detailed understanding of site‐formation through time, allowing us to correlate a strong peak in mean grain size at ~26–24 ka to the maximum extent of the SIS and increased influence of easterly winds., Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659

The Upper Pleistocene geoarchives in the south‐eastern Carpathian Basin are represented predominantly by loess–palaeosol records. In 2015, a 10 m sediment core composed of clay‐rich lacustrine sediments was recovered by vibracoring a dry lake basin located between the Vršac Mountains (Serbia) and the Banat Sands in the south‐eastern Carpathian Basin; a location relevant for placing regional archaeological results in a palaeoenvironmental context. Here, we present results from geoelectrical prospection and a lithostratigraphic interpretation of this sequence supported by a detailed granulometric study supplemented by ostracod analysis. An age model based on luminescence dating is discussed against sedimentological proxy data and its implication for palaeoenvironmental change. The cores show a stratigraphy of lighter ochre‐coloured and darker greyish sediment, related to the deposition of clay and silt trapped in an aquatic environment. Geophysical measurements show ~20 m thick lacustrine sediments. The grain‐size distributions including the variability in fine clay are indicative of a lacustrine environment. Fine particles were brought into the depositional environments by aquatic input and settled from suspension; also, direct dust input is constrained by grain‐size results. Riverine input and aeolian dust input interplayed at the locality., Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659, Program IDEI_Proiecte de Cercetare Exploratorie, Serbian Ministry of Education, Science and Technological Development

Two phases of archaeological investigation were performed in the Novi Sad City Museum at Petrovaradin Fortress. In this study, we summarize the results of geo-archaeological investigations of the second period of excavation inside the Novi Sad City Museum building. The fortress is situated on a Danube terrace with the top of the bedrock at ca.123 m asl. The investigated section consists of undisturbed fine-sandy silt. The grain-size distribution of the sediments indicates clearly its alluvial reworking but shows also a general similarity with typical primary loess in the region. All analyzed proxies indicate slightly stronger weathering in the upper part of the profile. Luminescence ages suggest that the investigated sequence covers the last glacial period and the terrace presumably formed during MIS 4. Subsequently, the Danube started its incision at the start of the next warmer period (MIS 3) onward. This terrace age and elevation enable us to derive an uplift rate of the terrace of ca. 0.73 mm/a for the last 60 ka, which seems to increase towards the present. Basal loessic material, in which artifacts occur, likely in the reworked position, indicate that the area close to today's Petrovaradin Fortress was already inhabited in MIS 5.

Insights into the climate variability of western Africa during the Pleistocene epoch have thus far been limited by the lack of well-dated, high-resolution terrestrial climate archives. The missing information on the climate evolution of western African hampers our understanding of the proposed pan-African evolution of our species. The ~294 m lacustrine sedimentary sequence raised from Lake Bosumtwi by the International Continental Drilling program in 2004, encompassing the last ~1.1 Ma, offers the best opportunity provide a climatic benchmark record in western Africa. However, the establishment of a chronology for this record has proven challenging. To try and improve our understanding of the climatic evolution during the last ~1.1 Ma in western Africa, we will use the high-resolution downhole logging data (natural gamma ray, GR) and magnetic susceptibility data from core logging from Site 5, which is situated in the centre of Lake Bosumtwi. To maximise the robustness of this record we will try to correlate data from downhole logs with core data. This approach has help improve interpretation of logging signals and environmental reconstructions for other long lake records, such as e.g. Lake Ohrid.

Understanding the evolution of lower latitude climate from the most recent glacial periods of the latest Pleistocene to post glacial warmth in the continental tropical regions has been obstructed by a lack of long and continuous time series. Here we examine sediments from Lake Chalco, located in the Valley of Mexico, central Mexico (19°30’N, 99°W). The basin represents a hydrological closed system surrounded by the Trans-Mexican Volcanic Belt aging from the Oligocene to the present. We use borehole logging to conduct a cyclostratigraphic analysis of the Lake Chalco sediments, and incorporate other available dating information. More than 400 m of sediments are logged for several geophysical properties including magnetic susceptibility and spectral gamma radiation.Gamma radiation can be used to identify elemental isotopes in the geological record, which is used for stratigraphic correlation and paleoclimatic investigations. Among the lake deposit of Chalco sub-basin, 388 total tephra layers (≥1 mm in thickness) were reported from the core description. Tephra layers with specific gamma ray signatures, presenting a challenge for extracting the primary signals caused by environmental and climatic agents. Here, we apply a tailored protocol to identify tephra layers embedded in other sediments using high-resolution gamma ray spectroscopy. This facilitates dividing the overall sediment column into representative horizons of tephra and non-tephra.After extracting the non-volcanic primary signal, we apply a suite of evolutive cyclostratigraphic methods to the Lake Chalco logging data, with a focus on gamma ray data. The high-resolution results suggest that the Lake Chalco sediments contain several rhythmic alterations with a quasi-cyclic pattern comparable with the Pleistocene benthic stack. This allow us to calculate a ~500-kyr time span for the sediment deposition in Lake Chalco. By using cyclostratigraphic analysis on data captured by geophysical downhole logging, we demonstrate the potentially broad applicability of this method for downhole logging data and provide further insight into the sedimentation history of Lake Chalco.

From 2019 to 2021, three cores were drilled at different locations in the southern German Swabian Alb as part of the SEPIA project (Sequence Stratigraphy of the Aalenian in Southern Germany). They comprise sediments of 200 to 250 m length and are penetrating Lower and Middle Jurassic strata from the Pliensbachian to Bathonian stages (~ 190-166 Ma). The aim of this project is the development of a sequence stratigraphic model of the South German Basin at the transition from the Lower to Middle Jurassic time. Conclusions should be drawn towards the source area of the sediments as well as on the influence of sea level fluctuations on sedimentation.Today, the Swabian Alb is a SW-NE trending mountain chain consisting of mainly carbonate rocks, and is one of the most distinctive regions in Germany where Jurassic strata is cropping out. During the middle Jurassic, Europe was almost completely covered by a shallow epi-continental sea including several small emerging areas or islands, located at latitudes about 15° lower than today. Southern Germany experienced predominant deposition of fine clastic sediments in a tropical climate. The most common sediments of this period are dark clays and oolithic ironstones, whereas condensation and discontinuity surfaces occur in many instances. Accommodation space for these sediments was not only generated by changes in sea level, but also by continuing subsidence of the area, explaining the inhomogeneous thickness and changes in facies of the sediments.The geophysical downhole logging data of the stratigraphic record is used to develop a lithological classification and correlation of the boreholes sediments by the application of a cluster analysis to the data. Furthermore, the downhole logging data is used to perform cyclostratigraphy in selected intervals. The focus of the intervals chosen for cyclostratigraphy lies on the Aalenian stage, as this stage holds the most continuous and extended record in all three boreholes. Predicted timespans of these intervals yield similar results of ~800-1100 ka for all three boreholes and might provide a new benchmark for progressive improvement, especially for cyclostratigraphic analyses of the Lower Aalenian Opalinusclay Formation.

Loess-Palaeosol-Sequences (LPS) are the most widespread aeolian sedimentary deposits providing climatic- and environmental records across continents. As dust sinks, they may archive information on dust source dynamics, if targeted source signals survived processes operating during production, transport, and syn- and post-depositional alteration of particles and sediments. Yet, our knowledge about such dynamics through palaeoenvironmental changes during the Upper Pleistocene remains vague. This limits our understanding of thresholds that may have (de-) activated dust sources causing major environmental changes in prevalent areas. We thus combine results of isotope- (87/86Sr, 143/144Nd) and major element (Si/Al) provenance proxies that react differently to pre-, syn- and post depositional alteration processes, with granulometry (U-ratio) and the anisotropy of magnetic susceptibility (AMS). Granulometry is recognised as an indicator for wind strengths and the primary magnetic fabric of loess deposits has been successfully used to reconstruct surface near wind directions. We apply our approach on the RP1 profile of the Schwalbenberg LPS that covers the late OIS 3 and the OIS 2 in centennial-scale resolution. The site is embedded in the Middle Rhine Valley (Germany) dividing the Rhenish Massif in its western and eastern part. Consequently, the Schwalbenberg seems appropriate to trace provenance shifts as it is linked to a distal dust source via the Rhine and as it is surrounded by potential local dust sources of the Rhenish Massif. Our results indicate shifts in source areas NNE-SSW off the site, contemporary with increasing frost dynamics and aridification. Both factors seem to enhance dust inputs from the Rhine system up to a threshold where the Rhenish Massif gets activated as a dominant source. Geochemical fingerprinting and AMS at the Schwalbenberg RP1 LPS reveal insights into dust source dynamics that allow for estimating their emission potential during Upper Pleistocene palaeoenvironmental changes.

Assessing the moisture history of Central Mexico reveals the responses of tropical areas to variation in past climate. Central Mexico has several long-lived lakes, which are potentially important paleoclimate archives. Lake Chalco in Central Mexico contains a ~300 m lacustrine sequence, which were deposited over a period of ~500,000 years. We conducted Spectral Gamma Ray (SGR) measurements across the lacustrine deposits of Lake Chalco to reconstruct the moisture availability over the past. The SGR data reflect the presence of naturally occurring radioactive elements including potassium (40K) and the equilibrium decay series of uranium (U) and thorium (Th). Natural sources of gamma radiation in lacustrine deposits of Lake Chalco are from volcanic ash deposition and detrital input of eroded sediments containing radioactive elements. However, redox conditions in the lake water influence the mobility of soluble U through conversion to more stable reduced phases. To extract the primary non-volcanic signals, we detected and removed signals from embedded tephra layers in the lacustrine sediments of Lake Chalco. We developed a moisture proxy by calculating the probability of authigenic U distributed across the lake sediments. We expect that an increasing U content in proportion to the content of K and Th indicate redox conditions in lake bottom water as a result of rising lake level. To evaluate this moisture proxy, we examined differences in the percent of the diatom species that are indicative of a deeper lake from literature. Results suggest that Lake Chalco likely formed prior or within MIS13, and the lake level rose gradually over time until the interglacial period of MIS9. Moisture levels are higher during the interglacial than glacial periods and interglacial periods show higher moisture variability. While glacial periods have less moisture, two periods, MIS6 and MIS4, still have a higher likelihood of authigenic U and more moist conditions. In order to determine potential regulators of moisture, we compared models containing the drivers of Earth’s orbital cycles, carbon dioxide and sea surface temperature. Carbon dioxide, eccentricity, and precession are all key drivers of the moisture content of Lake Chalco over the past 500,000 years. High levels of atmospheric CO2 have a positive effect on the moisture in Mexico while eccentricity and precession consistently have negative effects on lake moisture. Obliquity and δ18O have weaker effects on moisture in Mexico, probably due to the equatorial high-altitude region far away from poles, oceans and ice sheets.

The stratigraphic records of shallow-marine environments are not commonly regarded as excellent climate archives because of their presumed temporal incompleteness. However, a recent study of lower Pleistocene strata in the Western Foreland Basin, Taiwan, reveals high-resolution records of past climate oscillations preserved within shallow-marine strata. Deriving such narratives is made possible because of the high accommodation and sedimentation rates in the basin, which enhanced the completeness of the stratigraphic record.Here, we astrochronologically tune the Chinshui Shale and the lower part of the Cholan Formation of the Western Foreland Basin from approximately 3.5 to 2 Ma. These strata are calibrated to global deep-sea stable oxygen isotope (δ18O) records with established time scales detailing global climate change during the studied time period. The Chinshui Shale is mudstone-dominated and was deposited mostly in offshore settings, while the Cholan Formation comprises mainly heterolithic strata deposited in shallower settings (i.e., offshore transition, nearshore) of the paleo-Taiwan Strait. The data used herein are two borehole gamma-ray profiles through the Chinshui Shale and the Cholan Formation that have a proximal-distal relation to Taiwan. High gamma-ray values reflect clay-rich intervals and correlate to lower values of δ18O in the global reference records. Low gamma-ray values point to sand-rich packages and correlate with higher values of δ18O.Preliminary results show that the alternating clay-rich to sand-rich deposits during the late Pliocene to early Pleistocene are orbitally paced. The results allow us to i) tune the upper Pliocene–lower Pleistocene Chinshui Shale and lower part of the Cholan Formation, ii) refine the magneto-biostratigraphic framework established for this time interval in the Western Foreland Basin of Taiwan, and iii) lay the groundwork for connecting climatic changes in Taiwan during this time period to the wider frame of global climate change.

The characteristics of half-precession (HP) cycles (~9,000 - 12,000 years) is still poorly understood, despite their appearance in numerous records. We analyse HP signals in a variety of different marine and terrestrial proxy records from Europe and the Atlantic Ocean, investigate the temporal evolution of the HP signal from the early/middle Pleistocene to the present, and evaluate the potential of the HP to reflect the connectivity of climate systems over time.We apply filters on the datasets that remove the classical orbital cycles (eccentricity, obliquity, precession) and high frequency signals, and focus on the bandwidth of HP signals. Wavelet annalysis and correlation techniques are used to study the evolution of specific frequencies through the different records.In addition to a connection of HP cycles with interglacials, we observe a more pronounced HP signal in the younger part of several proxy records. Besides, we observe a trend of more pronounced HP signals in low latitude records compared to high latitudes. This is in agreement with the assumption that HP is an equatorial signal and can be transmitted northward via various pathways. The appearance of HP signals in mid- and high-latitude records may thus be an indicator for the intensity of the transporting mechanisms. We suggest that the African Monsoon plays a major role in this context, as its magnitude directly influences the climate systems of the Mediterranean and Southern Europe. In order to better understand the African climate variability, both equatorial marine and terrestrial records will be examined with respect to HP.

Sedimentary rocks can record signals produced by highly complex processes. These signals are generated by a progressive deposition of sediments which can be affected, mainly through the climate system, by regular astronomical cycles (i.e. Milankovitch cycles), and by irregular oscillations like the El Niño-Southern Oscillation. Also, usually through biological, chemical and/or physical post-depositional processes, the sedimentary records can be affected by pattern-creating heterogeneous processes. The noise in the signals further complicates the records, and the deposition rate (or sedimentation rate) can fluctuate, which greatly reduces the effectiveness of the classical stationary time-series analysis methods commonly used in cyclostratigraphy (i.e. the study of the cycles found in the sedimentary records). Faced with this multiplicity of processes, a common approach used in cyclostratigraphy is to reduce each signal to more manageable sub-signals, either over a given range of frequencies (e.g., by filtering), or by considering a continuum of constant frequencies (e.g., using transforms). This makes it possible to focus on the features of interest, commonly astronomical cycles. However, working with sub-signals is not trivial. Firstly, sub-signals have a certain amount of cross-cancellation when they are summed back to reconstruct the initial signal. This means that in filters and in transforms, wiggles that are not present in the initial signal can appear in the sub-signals. Secondly, the sub-signals considered often cannot be summed to reconstruct the initial signal: this means that there are processes affecting the signal which remain unstudied. It is possible to take cross-cancellation into account and to consider the entire content of a signal by dividing the signal into a decomposition: a set of sub-signals that can be added back together to reconstruct the original signal. We discuss here how to reframe commonly used time-series analysis techniques in the context of decomposition, how they are affected by cross-cancellation, and how adequate they are for comprehending the whole signals. We also show that decomposition can be carried out by non-stationary time-series methods, which can minimise cross-cancellation, and have now reached sufficient maturity to tackle sedimentary records signals. We present novel tools to adapt non-stationary decomposition for cyclostratigraphic purposes, based on the concepts of Empirical Mode Decomposition (EMD) and Instantaneous Frequency (IF), mainly: (1) a fast Ensemble Empirical Mode Decomposition (EEMD) algorithm, (2) quality metrics for decomposition, and (3) plots to visualise instantaneous frequency, amplitude and frequency ratio. We illustrate the use of these tools by applying them on a greyscale signal from the site 926 of the Ocean Drilling Program, at Ceara Rise (western equatorial Atlantic), especially to identify and characterise the expression of astronomical cycles. The main goal is to show that by minimising cross-cancellation, we can apply in real signals what we call the wiggle-in-signal approach: making the sub-signals in the decomposition more representative of the expression, wiggle by wiggle, of all the processes affecting the signal (e.g., astronomical cycles). We finally argue that decomposition could be used as a practical standard output for time-series analysis interpretation of cyclostratigraphic signals.

The study of astronomical climate forcing and the application of cyclostratigraphy experienced a spectacular growth over the last decades. In 2018, the first Cyclostratigraphy Intercomparison Project (CIP) workshop constituted the first attempt to compare different methodological approaches and unite the global community around standard, uniform and reliable procedures. Two major conclusions were: [1] There is a need for further organization of the cyclostratigraphic community (e.g. to streamline different methodologies); [2] Cyclostratigraphy is a trainable skill, but currently many universities lack specific resources for training and education. Today, a regular newsletter, a dedicated free open-access journal “Cyclostratigraphy and Rhythmic Climate Change (CRCC)”, a scientific podcast titled CycloPod, and an educational website “www.cyclostratigraphy.org” connect the cyclostratigraphy community. The newly created CycloNet (Research Foundation Flanders FWO Funding) expands this effort into a real and sustainable scientific research network with partners from all around Europe, and open to the global community. At the same time, CycloNet creates a platform for streamlining and integrating new multi-disciplinary approaches. The main scientific targets for CycloNet in the next five years are: [1] Set up a diverse and sustainable community structure, relying on exchange, interaction and training, [2] Boost research by novel methodological approaches applying advanced signal processing techniques, [3] Organize a second Cyclostratigraphic Intercomparison Project. With this poster, we reach out to the broader community to exchange ideas on concepts and activities that CycloNet can help to develop further towards the future.

The characteristics of half-precession (HP) cycles (~9,000 - 12,000 years) are still poorly understood, despite their appearance in numerous records. Previous studies on European terrestrial and marine records indicate a connection of the HP-signal to low latitudes. Here, we investigate HP-cycles in equatorial regions to study the assumed origin of this signal.Spectral analysis, evolutive approaches and correlation techniques are used on records from ODP Sites 662 and 663 to identify the HP-signal in elemental ratios reflecting e.g. terrigenuous input and/or bioproductivity. Filters have been designed to remove the classical orbital cycles (eccentricity, obliquity, precession), in order to isolate the HP-signal and to determine the temporal evolution of its presence and amplitude.We present first results of a larger project which has the overall objective to characterize the HP-signal across the Mid-Pleistocene Transition (MPT) at Sites 662 and 663. Over the course of the MPT, the ~100 kyr-eccentricity cycles supersede the 41-kyr obliquity as the primary driver of climate forcing. As precession is modulated by eccentricity, a similar relationship may be assumed for HP and eccentricity. Our preliminary analyses show an enhanced HP-signal in the younger, 100-kyr eccentricity world, but also in the late MPT which is partly influenced by the 41-kyr obliquity cycle. Cyclostratigraphic investigations of high-resolution XRF data will provide a clearer insight into the presence, amplitude and role of HP during the MPT and the late Pleistocene.

Millennial-scale palaeoclimate variability has been documented in various terrestrial and marine palaeoclimate proxy records throughout the Northern Hemisphere for the last glacial cycle. Its clear expression and rapid shifts between different states of climate (Greenland Interstadials and Stadials) represents a correlation tool beyond the resolution of e.g. luminescence dating, especially relevant for terrestrial deposits. Usually, comparison of terrestrial proxy datasets and the Greenland ice cores indicates a complex expression of millennial-scale climate variability as recorded in terrestrial geoarchives including loess. Loess is the most widespread terrestrial geoarchive of the Quaternary and especially widespread over Eurasia. However, loess often records a smoothed representation of millennial-scale variability without all fidelity when compared to the Greenland data, this being a relevant limiting feature in integrating loess with other palaeoclimate records. To better understand the loess proxy-response to millennial-scale climate variability, we simulate a proxy signal smoothing by natural processes through application of low-pass filters of δ18O data from Greenland, a high-resolution palaeoclimate reference record, alongside speleothem isotope records from the Black Sea-Mediterranean region. We show that low-pass filters represent rather simple models for better constraining the expression of millennial-scale climate variability in low sedimentation environments, and in sediments where proxy-response signals are most likely affected by natural smoothing (by e.g. bioturbation). Interestingly, smoothed datasets from Greenland and the Black Sea-Mediterranean region are most similar in the last ~15 ka and between ~50–30 ka. Between ~30–15 ka, roughly corresponding to the Last Glacial Maximum and the deglaciation, the records show dissimilarities, challenging the construction of robust correlative time-scales in this age range. From our analysis it becomes apparent that patterns of palaeoclimate signals in loess-palaeosol sequences often might be better explained by smoothed Greenland reference data than the original high-resolution Greenland dataset, or other reference data. This opens the possibility to better assess the temporal resolution and palaeoclimate potential of loess-palaeosol sequences in recording supra-regional climate patterns, as well as to securely integrate loess with other chronologically better-resolved palaeoclimate records.

The northern Carpathian Basin has important geological, paleoenvironmental, and archeological records that are key to our understanding of the first modern human occupation of Europe. However, the nature and timing of hominin settlements in the region during the Late Pleistocene remain poorly understood. New fieldwork at Seňa I, Slovakia, has identified the only known stratified open-air Aurignacian site in the region and assigned the assemblage to at least 33.5 ± 2.4 ka ago through infrared-stimulated luminescence dating. Additionally, new archeological and geoscientific data are presented. This paper discusses the Seňa I findings in the context of the regional archeological record and shows how they contribute to the establishment of clear time constraints for the Aurignacian in eastern central Europe.

The ~173-ka obliquity–related cycle indicated a nonlinear interaction between orbital forcing and climate system., Earth’s climate system is complex and inherently nonlinear, which can induce some extraneous cycles in paleoclimatic proxies at orbital time scales. The paleoenvironmental consequences of these extraneous cycles are debated owing to their complex origin. Here, we compile high-resolution datasets of total organic carbon (TOC) and stable carbon isotope (δ13Corg) datasets to investigate organic carbon burial processes in middle to high latitudes. Our results document a robust cyclicity of ~173 thousand years (ka) in both TOC and δ13Corg. The ~173-ka obliquity–related forcing signal was amplified by internal climate feedbacks of the carbon cycle under different geographic and climate conditions, which control a series of sensitive climatic processes. In addition, our new and compiled records from multiple proxies confirm the presence of the obliquity amplitude modulation (AM) cycle during the Mesozoic and Cenozoic and indicate the usefulness of the ~173-ka cycle as geochronometer and for paleoclimatic interpretation.

The Bodrogkeresztur loess-paleosol sequence in northeastern Hungary was investigated to improve our understanding of the paleoenvironmental conditions at the foothills of the Carpathians and their impact on the Gravettian population. The main part of the section is comprised of eolian deposits that enable the reconstruction of the paleoenvironmental conditions. This study comprises grain size, geochemical, color and rock magnetic analysis, as well as luminescence and radiocarbon dating. The chronological data place this section from later MIS 3 until present, but also suggest erosion of the sediment in the late MIS 2 and the (early) Holocene. Moreover, generally more humid conditions during late MIS3 and early MIS2 are observed, in comparison to other regions in the Carpathian Basin. Main dust source was most likely the Tisza floodplain, and the material was probably transported to the site from a northeastern wind direction. Increased weathering led to the formation of a well-developed MIS3 paleosol. The loess exhibits elevated values of frequency dependent magnetic susceptibility that highlight the relatively mild conditions during loess formation. Nevertheless, two loess layers with high sand abundance in the profile indicate colder and dryer conditions with increased eolian dynamics during short periods within MIS2. Finally, the Bodrogkeresztur section highlights the unique microclimatic conditions at the foothill areas of the Carpathian Basin, which may have offered a favorable environment for the Gravettian population.

Considerable efforts have been devoted to decipher the late Quaternary moisture and thermal evolution of arid central Asia. However, disparate interpretations still exist concerning different proxies. The spatial and temporal heterogeneities have inhibited a holistic understanding of general patterns and underlying mechanisms. To address these issues, two parallel cores (ONW I, 6.00 m; ONW II, 13.35 m) were retrieved in the Gobi Desert of Mongolia from lake Orog Nuur. Multidisciplinary investigations including geomorphological mapping, radiocarbon dating, sedimentological, palynological and ostracod analyses enabled us to gain a comprehensive dataset for vegetation development and hydrological variability over the last ~45 kyr. Higher lake levels during the Marine Isotope Stage (MIS) 3 and early MIS 2 (~35–~24 kyr) were probably caused by increased precipitation. The sharp transition of Termination I (~11 kyr) is indicated by sedimentological, palynological, and ostracod data. During the late Pleistocene, the lower area of the Orog Nuur catchment was dominated by Artemisia steppe and gradually altered to Chenopodiaceae desert steppe in the Holocene. The early Holocene is also characterized by a relatively humid environment. The humid pulses during the MIS 3 and the early Holocene were also recorded in other archives and are possibly the trait of a larger scale phenomenon in arid central Asia. Four major harsh climatic periods were documented in the core at ~43 kyr, ~36 kyr, during the global Last Glacial Maximum, and the Younger Dryas as playa phases. Reduced westerlies' moisture transport and a retreated East Asian Summer Monsoon influence probably caused those dry phases in the Gobi Desert of Mongolia.

Loess-paleosol sequences (LPS) represent an important terrestrial archive for the reconstruction of the paleoenvironmental evolution during the Last Glacial cycle in Europe. In the Rhine-Meuse area and the southwestern Germany, there are only few numerical ages determined with state-of-the-art luminescence methods, which limits the robustness of established chronostratigraphies. This study presents a comparative dating approach using quartz and feldspar post-infrared (pIRIR 290 ) optically stimulated luminescence (OSL) from fine- and medium-grained samples of five loess-paleosol sequences. Paleoenvironmental dynamics are reconstructed by high-resolution grain-size analysis. The OSL ages are evaluated as being robust and consistent with other records. Furthermore, we show that ages for hillslope deposits are sometimes overestimated due to low-frequency high-magnitude erosive processes. The integration of OSL ages, stratigraphy and high-resolution grain-size data contributes to a temporal more complete data record from Western and Central Europe. Secondly, we propose a combined stratigraphic model for LPS of the Last Glacial cycle, which is developed and discussed in the context of other key sites such as Havrincourt, Schwalbenberg II, Tonchesberg, Nussloch and Dolni Vĕstonice. Comparable chronologies and patterns in proxy data between sites with a large spatial distance suggest a possible semi-synchronous response to climatic changes in Europe. By combining our data with the Eifel-Laminated-Sediment-Archive (ELSA) and the NGRIP ice core, a relationship of loess archives and large-scale climatic signals is discussed and a proxydata based event-stratigraphy is developed. This model refines existing chronostratigraphic models and contributes to solve open discussion concerning the timing and demarcation of sedimentary units and sequences from for Western and Central Europe.