Last Interglacial Research Articles

High temporal resolution paleoclimate reconstruction by the analysis of growth patterns and stable isotopes of fossil shells of the long-lived bivalve Mercenaria stimpsoni from MIS 5e, 7 and 9

High temporal resolution paleoclimate reconstruction by the analysis of growth patterns and stable isotopes of fossil shells of the long-lived bivalve Mercenaria stimpsoni from MIS 5e, 7 and 9

Predicting the Potential Distribution of the Endangered Pyrethrum tatsienense in China Using an Optimized Maxent Model Under Climate Change Scenarios.

Climate change can significantly impact the ecological suitability and diversity of species. Pyrethrum tatsienense, a critically endangered species in China, requires a thorough understanding of its habitat distribution and the environmental factors that affect it in the context of climate change. The Maxent algorithm was used to examine the key factors influencing the distribution of P. tatsienense in China, using data from 127 species occurrences and environmental variables from the Last Interglacial (LIG), Last Glacial Maximum (LGM), Mid-Holocene (MH), current, and future scenarios. The Maxent model was optimized utilizing the R package ENMeval, providing the most accurate predictions for suitable habitats across various scenarios. Results show that suitable regions for P. tatsienense encompass approximately 15.02% (14.42 × 105 km2) of China, predominantly on the Qinghai-Tibetan Plateau. The mean UV-B of the highest month (UVB3: 39.7%), elevation (elev: 28.7%), and the warmest season of precipitation (Bio18: 17.4%) are the major limiting factors for suitable habitat. The optimal species distribution ranges are identified as > 7500 J m-2 day-1 for UVB3, 2700-5600 m for elev, and 150-480 mm for Bio18. Predictions for the historical climate indicate the presence of refugia at the junction of Sichuan, Tibet, and Qinghai. The MH predictions show an increase in climatic suitability for P. tatsienense compared to the LIG and LGM, with an expansion of suitable areas westward. Future climate change scenarios indicate that the potential suitable habitat for P. tatsienense is expected to increase with increasing radiative forcing, with higher latitude regions becoming new marginally suitable habitats. However, predicted environmental changes in western Tibet may drive the loss of highly suitable habitats in the future. These findings enhance our understanding of how environmental factors impact the habitat suitability of P. tatsienense and provide valuable insights for developing effective management and conservation strategies for this important species.

Architectural development of a land-attached carbonate platform in the African–Arabian Desert Belt: the late Pleistocene to Holocene evolution of the Al Wajh Platform, NE Red Sea, Saudi Arabia

ABSTRACT Carbonate platform architectures are indicators of environmental changes, such as sea level, climatic variations, and tectonic influence, which all control platform evolution. While analog studies on modern carbonate platforms have predominantly focused on tropical settings, limited attention has been given to arid and semiarid environments, although many ancient carbonate sequences were developed under these settings. This study aims to bridge this gap by investigating the Al Wajh carbonate platform lagoon in the NE Red Sea, Saudi Arabia, using geophysical and remote-sensing data to unravel its architecture and development since the last interglacial highstand (MIS 5e). We collected and analyzed sub-bottom profiles extending over 675 km and airborne lidar multibeam bathymetry data covering an area of 1700 km2. Surface sediment samples and vibracores with a maximum penetration of three meters were integrated to strengthen our interpretation. Furthermore, a recently published Red Sea sea-level curve was used to establish an age model and supplemented by available climate data to reconstruct depositional models. The Al Wajh lagoon is a “bucket” structure hosting five distinct depositional units since the late Pleistocene: U0 (pre-MIS 5e and MIS 5e), U1, U2, U3, and U4 (MIS 1), which are composed of five hydroacoustic facies, ranging from mounded to wavy laminated facies. Based on combining climate data, sea-level curves, and platform topography with our geophysical data, we conclude that the lagoon hosts carbonate, siliciclastic (fluvial and eolian), and potentially evaporitic deposits of open-marine and playa-lake origin. Intriguingly, karst architecture (i.e., sinkholes, caves, and collapsed cavities) is absent despite intermittent pluvial episodes and exposure during the late Pleistocene. Data analysis indicates that the Al Wajh lagoon architecture and development since the late Pleistocene are controlled by a combination of antecedent topography, sea-level variation, climate fluctuation, siliciclastic influx, carbonate production, and reef growth and drowning. Finally, insights from this study enhance our understanding of the architecture and sedimentary infill of ancient land-attached carbonate platforms deposited in a mature rift basin under alternating arid and pluvial climate settings.

40Ar/39Ar geochronologic and paleoenvironmental constraints to glacial termination III and MIS 7e, 7c, and 7a sea level fluctuations on the Tyrrhenian Sea coast of Italy

We provide detailed sedimentological, paleontological, and tephrochronological data on a complex sedimentary succession cropping out in the Tyrrhenian coastal area of central Italy, which was deposited in response to sea-level rise during MIS 7, coeval with the Latera phase of activity in the Vulsini Volcanic District. Diffuse intercalations of primary volcanic layers erupted during this phase and their geochronologic and chemostratigraphical characterization based on 40Ar/39Ar dating and EMP analyses, allowed for the identification of three stacked aggradational successions separated by erosive phases and their correlation with the Oxygen isotope record and phases in the relative sea-level curve. The ages of the tephra layers strictly frame the sedimentation in the interval of 253–206 ka, providing independent dating to glacial Termination III and to the three sea-level oscillations during MIS 7e, 7c, and 7a.Moreover, micro- and macrofaunal-based analyses provide information on the paleoenvironments and bathymetry during the highstands, which complement the geomorphological analysis reconstructing the inner edges of the corresponding marine terraces, allowing us to assess precise maximum sea level reached during MIS 7e and MIS 7a.The results of this multidisciplinary study enable us to establish in great detail the chronology, dynamics, relative amplitude, and effects of the sea-level fluctuations in the Tyrrhenian Sea during the whole MIS 7, providing independent, precise geochronological constraints for this period.

Large mammal faunas and ecosystem dynamics during the late Middle to early Late Pleistocene at Grotta Romanelli (southern Italy)

Since the beginning of the XIX century, Grotta Romanelli gained recognition in European stratigraphy as an important site for the Late Pleistocene, due to the attribution of its basal sediments to the Last Interglacial (MIS 5e). Its abundant archaeological and paleontological findings made the cave a key reference point for the study of human evolution and faunal dynamics in the larger Mediterranean area over approximately the last 130,000 years. After a century, a new chronostratigraphic reassessment of Grotta Romanelli revised the timeframe of its lower levels, predating them to the late Middle Pleistocene.In this study, we re-evaluate selected historical museum collections from the so-called “lower complex” of Grotta Romanelli and examine the new fossils excavated between 2015 and 2022. We identify three main mammal assemblages associated with three different interglacial periods spanning the last 350,000 years. Our findings offer new insights into terrestrial ecosystems in Mediterranean Europe from the late Middle Pleistocene to early Late Pleistocene. Additionally, they provide valuable information to the biochronological framework of the European large mammal faunas.

Late Pleistocene–Holocene palynology and paleoceanography of İmralı Basin, Marmara Sea: Pollen-spore, dinoflagellate cyst and other NPP zonations

The Marmara Sea is the oceanographic gateway that links the hypersaline Eastern Mediterranean Sea with the hyposaline Black Sea via Straits of Dardanelles and Bosphorus, respectively, and also occupies a transitional vegetation and climatic regime between the Mediterranean and Euxinic phytogeographic ecosystems. Recent palynological studies of long cores from the shallow İmralı Basin perched on the southeastern slope of the Marmara Sea reveal that major paleoecological changes accompanied the isolation and reconnection of the Marmara Sea during the last two Pleistocene glacial–interglacial cycles. Here, we use data primarily from two İmralı Basin cores to determine new quantitative zonations for the pollen-spore, dinoflagellate cyst (dinocyst) and other non-pollen palynomorph (NPP) assemblages in sediments representing the last ∼30 cal ka. A gap in one core is closed using data from three short gravity cores. Twenty-four radiocarbon ages and 20 correlation-ties for sapropel and ash layers from these five cores provide an essentially complete record for the past 30 cal ka. Use of a full suite of palynomorph data (pollen and spores, fungal spores, dinocysts and other phytoplankton, aquatic parasites/saprophytes, zoo-planktonic and zoo-benthic NPPs) shows for the first time that fluctuations in aquatic palynoassemblages during the glacial periods are more complex than simple salinity or temperature responses. The changes involve food web-level turnovers in trait- and size-based food web components in which potential parasites/saprophytes appear critically important.Pollen stratigraphies reveal a significant loss of Euxinic tree taxa by MIS 3c, with only partial recovery in MIS 1. The Euxinic forest elements are replaced by cultivars and other indicators of anthropogenic influences during the MIS 1 that is also marked by a dry interval and corresponding in part with the 4.2 cal ka Eastern Mediterranean Drought Event. The dinocyst zones for the last ∼30 cal ka show a clear turnover from assemblages dominated by brackish Ponto–Caspian taxa to marine assemblages at ∼11.7 cal ka. This phytoplanktonic signal lags slightly behind (a) the vegetation and shift in the other NPP commencing ∼13.2 cal ka, the initial marine incursion at 13.8 cal ka, and the arrival of coccolithophores at ∼13 cal ka. Comparison to published MIS 6 and 5 data reveals higher MIS 2–1 species diversity, reappearance of the MIS 6 marker Impagidinium inaequalis, and the emergences of Pyxidinopsis psilata f. quadrata, cf. Boreadinium breve, and Peridinium spp. of Brenner 2005. The pre-reconnection microbiota is dominated by the unicellular alga Sigmopollis, spikes of colonial Pediastrum algae, the saprophytes/parasites cf. Multiplicisphaeridium and Chytridiomycota. This microbiota is displaced by the post-reconnection assemblage dominated by Botryococcus coenobia, various Platyhelminth egg capsules and ostracod lining-types that persist through the Holocene. A distinctive transitional microbiota with Discocotyle-type turbellarian egg capsules marks the Bølling–Allerød warming, followed at ∼13.3 ka by a marine assemblage with micro-foraminiferal linings and crustacean eggs. The interglacial marine phase of MIS 1 in İmralı Basin has much higher dinocyst species diversity than MIS 5e, reflecting Neolithic impacts (agriculture, land clearance) and expanded shipping trade. Initial marine flooding in the Marmara Sea during both interglacials are marked by sapropel deposition but variations of ravinement surface erosion, and marine deep water residence time in a stratified Marmara Sea are potentially important factors underlying hypoxia/anoxia and sapropel deposition.

Opposing Changes in Indian Summer Monsoon Rainfall Variability Produced by Orbital and Anthropogenic Forcing

AbstractFuture projections indicate that Indian Summer Monsoon Rainfall (ISMR) faces a “wetter and more variable” climate. However, the reasons remain uncertain. The Last Interglacial (LIG) climate provides a potential analog for future warming. Investigating ISMR responses to these two warming scenarios could help understand the causes of ISMR changes. Using PMIP4 simulations, we find that ISMR became “wetter and more stable” during the LIG, contrasting the future climate. The opposing changes in ISMR variability are related to divergent changes in the El Niño‐Southern Oscillation (ENSO) amplitudes, ENSO‐ISMR relationships, and ENSO‐induced large‐scale atmospheric circulation anomalies. During the LIG, orbital forcing weakened ENSO variability and its impacts on ISMR. A westward positioning of ENSO shifted the atmospheric circulation anomalies westward, suppressing extreme ISMR anomalies. These processes are supported by atmospheric model simulations. Our results suggest that different warming patterns (dynamic effects) are more critical than moisture‐increasing effects in controlling regional climate variability.

Sedimentological evidence of Late Pleistocene Shorelines in Oman

As the climate crisis intensifies, estimating sea-level rise will become increasingly relevant, in particular assessing changes in the relative sea level in different regions. One key to comprehending global sea-level changes is the study of past sea-level highstands. Many regional studies help refine the reconstruction of paleo sea levels globally. Thus far, the Middle East remains understudied.This paper presents evidence for Quaternary sea-level variations along the shores of the western Indian Ocean. Eight coastal outcrops along the northern and eastern coasts of Oman are presented in detail. The sedimentological evidence for sea-level highstands varies within the study area. However, in relation to recent sea-level conditions, all of these marine and beach deposits are now found well above the environments where such formations would typically form. Dating the timing of sea-level highstands remains a challenging task within the study area. In different studies, attempts to 14C date samples from that area were unsuccessful, as the time of sediment deposition lies beyond the dating limit of 14C, precluding a Holocene formation of these sediments. Thus, the sediments are regarded as deposits formed during Pleistocene sea-level highstands, presumably during MIS 5e. For some sections, optically stimulated luminescence dating could provide a solution, as igneous source rocks supply quartz and feldspar. This paper aims to localise eight sea-level related outcrops along the Omani coast and depict their potential for future work, which should include dating and elevation measurements. Through this, our work contributes to the ongoing effort to globally identify records of sea-level changes, as well as providing insights into the regional setting in Oman.

Changes in the Asian ITCZ During the Last Interglacial, the Last Glacial Maximum, and the Mid‐Holocene

AbstractWe investigate the position and intensity changes of the Intertropical Convergence Zone (ITCZ) over Asia (50°E−135°E) relative to the preindustrial period annually and seasonally during the Last Interglacial (LIG), Last Glacial Maximum (LGM), and mid‐Holocene (MH) using available models from phases 3 and 4 of the Paleoclimate Modeling Intercomparison Project. The multi‐model mean shows that the June–July–August ITCZ variations generally dominate the annual changes. The Asian ITCZ shifts northward over western Asia and southward over the eastern side in both the LIG and MH, and the opposite occurs in the LGM. Its intensity varies with longitude similarly for the LIG and MH and generally weakens in the LGM. Precipitation changes associated directly with ITCZ indices are primarily caused by the dynamic term in the LIG and MH, while both dynamic and thermodynamic terms play roles in the LGM, with major contributions from the convergence components.

The northernmost Polish Eemian palaeolake near Łęczyce − Stratigraphic and palaeoecological implications for a MIS 6a − MIS 5d sediment record

We report the results of high-resolution multi-proxy studies of a 10 m thick sedimentary profile from Łęczyce, Poland. It reveals a continuous lacustrine succession from the Eemian Interglacial. On this basis, we have distinguished seven sedimentary units (U7a-U7f) and ten local palynological zones (LPAZ Lec 1 − Lec 10), revealing the evolution of the lake from the moment of dead-ice melting, through the continuous filling of the lake basin with organic mud, to the final stage of shallowing and transformation into a peat bog. This northernmost known Eemian site was investigated for the first time, therefore, the reconstructed changes in local conditions were correlated with global changes from the final phase of the penultimate glaciation through the Eemian Interglacial to the beginning of the last glaciation. The results show that the melting of dead ice blocks at this site was delayed compared to central Poland, with lacustrine processes starting as glaciolimnic sedimentation. Furthermore, the delayed start of vegetation development around the lake resulted in the absence of a Pinus-Betula-Ulmus E2 level. During the Eemian, local conditions were generally stable, and sedimentation took place in a relatively deep basin with well-defined epilimnion and hypolimnion zones. Climatic instability at the end of the Eemian resulted in reduced vegetation cover. During the first climatic deterioration in the Weichselian (presumably the Herning Stadial), lacustrine sedimentation was reduced and the deposition of fine-grained mineral material predominated. This was followed by the complete drying out of the lake and the development of soil formation. The subsequent climatic warming (Brørup Interstadial?) recorded in the uppermost part of the profile (U7f) was characterised by the plant community Lec 10 (Carpinus-Corylus-Picea) and was presumably warmer than commonly assumed. Multi-proxy studies show that the development of the lake was more similar to that of southern Scandinavia than to that of Poland.

Early Neanderthal mandibular remains from Baume Moula-Guercy (Soyons, Ardèche).

We provide an ontogenetically-based comparative description of mandibular remains from Last Interglacial deposits (MIS 5e) at Baume Moula-Guercy and examine their affinities to European and Middle Eastern Middle-to-Late Pleistocene (≈MIS 14-MIS 1) Homo. Description of the M-G2-419 right partial mandibular corpus with M1-3 (15-16.0 years ±0.5 years) and mandibular fragments M-F4-77 and M-S-TNN1 is with reference to original fossils, casts, CT scans, literature descriptions, and virtual reconstructions. Our comparative sample is ontogenetically based and divided into a Preneanderthal-Neanderthal group and a Homo sapiens group. These groups are subdivided into (1) Preneanderthals (≈MIS 14-9), Early Neanderthals (MIS 7-5e), and Late Neanderthals (MIS 5d-3), and (2) Middle (MIS 5) and Upper (MIS 3-Pre-MIS 1) Paleolithic and recent H. sapiens. Standard techniques were employed for developmental age and sex determinations and measurements. The M-G2-419 mandible possesses corpus features that link it most closely with the Sima de los Huesos Preneanderthal and Early Neanderthal groups. These include mental foramen position, number, and height on the corpus, anterior marginal tubercle position, and mylohyoid line orientation. Metrically, the M-G2-419 mandibular corpus is small relative to adults in all groups, but the thickness/height relationship is like the adult condition. The thickness of the corpus is more like Neanderthal children than adolescents. Molar crown features suggest affinities with the Preneanderthal-Neanderthal group. The Moula-Guercy mandibles possess a combination of Neanderthal-associated features that provides insights into MIS 7-5e paleodeme variation and the timing of appearance of MIS 5d-3 Neanderthal facial features.

Late Middle Pleistocene Wolstonian Stage (MIS 6) glaciation in lowland Britain and its North Sea regional equivalents – a review

Two major glaciations have been identified on land in England during the Middle Pleistocene. The earliest occurred during the Anglian Stage (= Elsterian, c. Marine Isotope Stage, MIS 12), evidence for which is best developed in lowland Britain, as well as offshore in the southern North Sea and Irish Sea basins. The second took place during the late Middle Pleistocene, with the most compelling evidence found in the West Midlands, intermediate between the Hoxnian (= Holsteinian; broadly MIS 11) and Ipswichian (= Eemian; broadly MIS 5e) interglacial stages during the Late Wolstonian Substage. Until recently this younger glacial episode was less clearly represented in the Pleistocene record and, as a result, had been little studied and weakly defined. Interpreted as the Moreton Stadial glaciation during the Late Wolstonian Substage (= Late Saalian Substage/Drenthe Stadial, c. MIS 6), it was originally recognized in the English Midlands, subsequently being identified in Yorkshire, Lincolnshire and northern East Anglia, and potentially further SW as far as the Bristol Channel. Mapping, in particular by members of the British Geological Survey, however, resulted in the Wolstonian Stage glacial deposits being thought to pre‐date the stage. This was particularly so in East Anglia where there was considerable controversy concerning the number and relationships of glacial sequences, during the 1970–1980s. Yet to the west of East Anglia there remained unequivocal evidence for glaciation during the stage, particularly in Fenland and the eastern English Midlands. Recent radiometric dating across lowland Britain on glacial sediments long thought to belong to a glaciation event in the Wolstonian Stage have now placed a geochronological control on the established regional stratigraphy and confirmed that glaciation occurred in two phases between 199 and 147 ka during the Late Wolstonian Substage. The glacial events of the British Middle Pleistocene can clearly be correlated with the European continent.

Cryogenic-Lateral Hypothesis of the Formation of the Parent Rock of Soddy-Podzolic Soils Using the Example of the Ryshkovo Paleosol (MIS 5e) in the Taneyev Quarry, Kursk Region

Cryogenic-Lateral Hypothesis of the Formation of the Parent Rock of Soddy-Podzolic Soils Using the Example of the Ryshkovo Paleosol (MIS 5e) in the Taneyev Quarry, Kursk Region

Evaluating the vulnerability of Tetracentron sinense habitats to climate-induced latitudinal shifts.

Exploring the changing process of the geographical distribution pattern of Tetracentron sinense Oliv. and its main influencing factors since the last interglacial period can provide a scientific basis for the effective protection and management of the species. The MaxEnt model was used to construct the potential distribution areas of T. sinense in different periods such as the last interglacial (LIG), the last glacial maximum (LGM), the mid-Holocene (MID), and the current and future (2050s and 2070s). On the premise of discussing the influence of dominant environmental factors on its distribution model, the suitable area changes of T. sinense under different ecological climate situations were quantitatively analyzed. (1) The AUC and TSS values predicted by the optimized model were 0.959 and 0.835, respectively, indicating a good predictive effect by the MaxEnt model; the potential suitable areas for T. sinense in the current period are mainly located in Southwest China, which are wider compared to the actual habitats. (2) Jackknife testing showed that the lowest temperature in the coldest month (Bio6), elevation (Elev), seasonal variation coefficient of temperature (Bio4), and surface calcium carbonate content (T-CACO3) are the dominant environmental factors affecting the distribution of T. sinense. (3) From the last interglacial period to the current period, the total suitable area of T. sinense showed a decreasing trend; the distribution points of T. sinense populations in mid-Holocene period may be the origin of the postglacial population, and Southwest China may be its glacial biological refuge. (4) Compared with the current period, the total suitable area ranges of T. sinense in China in the 2050s and 2070s decreased, and the centroid location of its total fitness area all migrated to the northwest, with the largest migration distance in 2070s under the SSPs 7.0 climate scenario. Temperature was the principal factor influencing the geographical distribution of T. sinense. With global warming, the range of T. sinense suitable areas will show a shrinking trend, with a shift toward higher-latitude regions. Ex situ conservation measures could be taken to preserve its germplasm resources.

Early diagenetic microbial induced cementation in Late Pleistocene (MIS 5e) shallow-water marine deposits of the Taranto Gulf (South Italy)

Early diagenetic microbial induced cementation in Late Pleistocene (MIS 5e) shallow-water marine deposits of the Taranto Gulf (South Italy)

Incision and rock uplift along the Lower Seine River since Marine Isotope Stage 8

ABSTRACTThe study of alluvial terraces helps in reconstructing the past geometries of rivers and makes it possible to assess the rate and pattern of fluvial incision and bedrock uplift. The fluctuations of river base levels are particularly variable and complex during the Late Quaternary in the lower course of rivers due to the interplay of responses to sea‐level fluctuations, tectonics and glacio‐isostasy. In this paper, the geometry and chronology of Manoir Brésil, an outcrop of alluvial terraces of the Lower Seine River, northern France, are investigated through a multidisciplinary study. Fluvial incision during MIS 8 in the Lower Seine in relation to sea‐level drop is recorded by an erosional surface cut into the chalk bedrock. This surface is covered by MIS 7 tidal deposits and then by younger, mostly periglacial colluvium (head). Manoir Brésil is therefore considered to be a chronological equivalent of the nearby, well‐studied Tourville‐la‐Rivière outcrop. The deposits are affected by post‐MIS 7 cryoturbation processes. Based on the local elevation of MIS 7 tidal deposits and erosional surfaces at Manoir Brésil, a minimum bedrock uplift rate of 25–40 m/Ma and an erosion rate of 125 m/Ma during glacial periods can be proposed. A regional correlation of the MIS 8 erosional surface is increasingly deformed by uplift towards the North, making it difficult to correlate the fluvial deposits along the Seine without precise chronological control. We interpret this regional tilt as the result of isostasy rebound after glaciations, consistent with the distribution of the elevations of MIS 5e and MIS 7 marine deposits along the English Channel.

Last interglacial and MIS 9e relative sea-level highstands in the Central Mediterranean: a reappraisal from coastal cave deposits in the Cilento area, Southern Italy

A revaluation of the relative sea-level (RSL) indicators in the Baia di Infreschi (Cilento, Southern Italy) supported by new 30 U/Th dating on speleothems indicates that the upper level of Lithophaga burrows identified by Bini et al. (2020) at ∼9 m a.s.l. and correlated to the Last Interglacial (LIG) highstand should be referred to the highstand of the MIS 9e, whereas the local RSL for the highstand of the LIG is now reassessed at 5.3 ± 0.18 m a.s.l. The upper level of the Lithophaga marker can be followed for ∼12 km along the coast, suggesting a substantial absence of important relative tectonic movements. In the Baia di Infreschi an additional marine indicator, a notch sealed by a flowstone dated ∼110 ka, indicates several phases of RSL stationing below the maximum highstand of the LIG. The presence of flowstones as low as 2 m a.s.l. dated to the MIS 7 shows that the highstand of MIS 7 was probably below the present sea level. All these evidences allow us to reassess the stratigraphy of some archaeological caves in the area, indicating that the sedimentary successions preserved there are older than what was previously believed.

Sea-level oscillations within the last interglacial: Insights from coral reef stratigraphic forward modelling

Understanding past sea-level variations is essential to constrain future patterns of sea-level rise in response to warmer climate conditions. Due to good preservation and the possibility to use various geochemical methods to date fossil sea-level index points, the Last Interglacial (Marine Isotope Stage, MIS, 5e, 130–116 ka) is often regarded as one of the best climate analogs for a future warmer climate. MIS 5e coastal stratigraphic sequences, such as fossil coral reefs, are characterized by abrupt shifts in their geological facies, steps within the reef topography or backstepped morphologies, which have been often interpreted as proxies for abrupt sea-level fluctuations within the interglacial. However, the observational evidence and magnitude of such abrupt changes are controversial. Here, we run nearly 50 thousand simulations of a 2D kinematic reef model that can reproduce coral reef growth and demise through time. Our aim is to investigate the parameters of space, the sea-level scenarios, and the processes which multiple-stepped MIS 5e fossil reefs form. As inputs to the model, we use both published and synthetic sea-level histories (17 sea-level curves, with different sea-level oscillation patterns), and a wide range of reef growth and marine erosion rates, and bedrock foundation slopes. Our results show that the only sea-level history that could explain the generation of an emerged MIS 5e backstepped reef is a first sea-level peak followed by an abrupt rise in sea level and a second short-term peak. Any other multiple-stepped stratigraphy can be explained by the interplay between reef growth, marine erosion, and bedrock slope.

Indicative meanings of geological sea-level indicators in the Solent region and Sussex coast (south coast of England) and implications for uplift rates

The Solent Region and Sussex coastal plain in southern England have preserved palaeo-sea-level indicators from multiple interglacial periods, with a particularly complete record of deposition throughout the last interglacial. However, as yet, none of the research on these indicators has fully addressed the relationship of the different types of deposits preserved to mean sea-level. In this paper we apply recent approaches to estimating past relative sea-levels based on applying modern analogues to understand the indicative meaning of these indicators. We also apply a synchronous correlation model previously developed on rapidly uplifting coastlines to assess uplift rates. The uplift rates required to match the elevations of sequences suggest a significant decrease in uplift rates between the Late Wolstonian Substage and Ipswichian Stage; that is, the c. 240 and c. 125 ka sea-level highstands, broadly equivalent to marine isotope stages (MIS) 7 and 5e. This coincides in time with the final opening of the Straits of Dover. Supplementary material: Fossil data from sites that have not previously been published are available at https://doi.org/10.6084/m9.figshare.c.7172532

Unstable interdecadal relationship between the Pacific Decadal Oscillation and eastern China summer precipitation in simulated warm interglacial epochs and twenty-first century

The modern connection between the Pacific Decadal Oscillation (PDO) and eastern China summer precipitation (ECSP) at the decadal scale has been extensively studied. However, whether this correlation is stable during the warmer backgrounds in the past and future remains unclear. Clarifying this issue may yield meaningful insights into past PDO reconstruction and decadal climate projection in eastern China (EC). Based on the FGOALS-f3-L, which performs best in reproducing the observed PDO pattern and the decadal PDO–ECSP relationship among 10 models under the framework of the coupled Model Intercomparison Project phase 6 (CMIP6), we find an unstable relationship between the PDO and ECSP at the decadal scale during the last Interglacial (LIG), mid-Holocene, and the twenty-first century under the Shared Socioeconomic Pathway (SSP) SSP5–8.5 scenario. The PDO-related ECSP roughly shows a west–east dipole pattern with excessive precipitation in the east during the LIG, whereas the mid-Holocene witnesses a generally decreased ECSP, except for South and Northeast China. Under the SSP5–8.5 scenario, the PDO-related decadal ECSP exhibits excessive precipitation in the west but a deficit in the east, especially in South and Northeast China. This instability is ascribed to changes in the vertical motions and moisture divergence associated with various configurations of large-scale atmospheric circulations from the lower to upper troposphere. Furthermore, these diverse atmospheric circulation patterns relate to the variations in the convective heating over the western North Pacific and the propagation of extratropical Rossby waves, which are connected with the different PDO patterns and the mean state differences in the westerly jet stream locations during the past and future warm periods