Land-sea Correlation Research Articles

Global warming-induced Asian hydrological climate transition across the Miocene\u2013Pliocene boundary

Across the Miocene–Pliocene boundary (MPB; 5.3 million years ago, Ma), late Miocene cooling gave way to the early-to-middle Pliocene Warm Period. This transition, across which atmospheric CO2 concentrations increased to levels similar to present, holds potential for deciphering regional climate responses in Asia—currently home to more than half of the world’s population— to global climate change. Here we find that CO2-induced MPB warming both increased summer monsoon moisture transport over East Asia, and enhanced aridification over large parts of Central Asia by increasing evaporation, based on integration of our ~1–2-thousand-year (kyr) resolution summer monsoon records from the Chinese Loess Plateau aeolian red clay with existing terrestrial records, land-sea correlations, and climate model simulations. Our results offer palaeoclimate-based support for ‘wet-gets-wetter and dry-gets-drier’ projections of future regional hydroclimate responses to sustained anthropogenic forcing. Moreover, our high-resolution monsoon records reveal a dynamic response to eccentricity modulation of solar insolation, with predominant 405-kyr and ~100-kyr periodicities between 8.1 and 3.4 Ma.

Land-sea correlations in the Eastern Mediterranean region over the past c. 800 kyr based on macro- and cryptotephras from ODP Site 964 (Ionian Basin)

Direct correlations between terrestrial and marine climate-proxy records are essential in order to determine potential lead/lag relationships in the response of the terrestrial and marine realms to climate forcing. In the Eastern Mediterranean region, such land-sea correlations have not yet been established beyond c. 200 ka. To explore the potential of tephra layers for Late and Middle Pleistocene land-sea correlations in the Eastern Mediterranean region, we have revisited yet unconfirmed tephra layers previously reported from Ocean Drilling Program (ODP) Site 964 (Ionian Basin) for the past c. 800 kyr in order to identify their origin and examine potential terrestrial counterparts. Using major- and trace-element glass analyses, we confirmed the presence of seven visible tephra layers with ages from 623 to 38 ka. These tephra layers represent known tephra isochrons from Italian volcanic centers (Y-5, Y-7, X-6, and V-0) and three yet unknown eruptions from Etna (623 ka), the Campanian Volcanic Zone (CVZ; 238 ka), and Pantelleria (238 ka). Because the majority of the previously reported tephra layers from ODP Site 964 were identified as clastic layers of non-volcanic origin, cryptotephra analyses were carried out for cores spanning Marine Isotope Stages (MIS) 13 to 9 (500–320 ka). This effort yielded 19 cryptotephra layers originating from Santorini volcano, the CVZ, possibly Roccamonfina volcano, and an undefined source in either the Aeolian Islands or the South Aegean Volcanic Arc. Two tephra layers are correlated with potential equivalents from terrestrial archives on the Italian and Balkan Peninsulas, including tephra isochrons SC5/A7/OH-DP-1966 (c. 493 ka; Mercure basin, Acerno basin, and Lake Ohrid) and TP09–65.95 (c. 359 ka; Tenaghi Philippon) that represent an unknown eruption of Roccamonfina and the Cape Therma 1 eruption of Santorini, respectively. Direct linking of the marine record from ODP Site 964 with the terrestrial records from Tenaghi Philippon, Lake Ohrid, and the Acerno basin via tephra tie points allowed us to circumvent shortcomings of the individual age models, and to obtain a comprehensive picture of climate variability in the greater Eastern Mediterranean region for the MIS 13–9 interval.

Land-sea correlation in southeastern Brazil during the last 7.4 cal ka BP: Vegetational, climatic and oceanographic inferences

The vegetation history and climate in southeastern Brazil, as well as the oceanic dynamics of the tropical Atlantic Ocean offshore, were reconstructed for the last 7.4 cal ka BP. This reconstruction was based on pollen, fern spores and dinoflagellate cysts identified in a marine core (CF10–04B). It was possible to verify the presence of an ombrophilous forest from 7.4 cal ka BP. Near the base of the PI zone low concentrations of pollen and fern spores are recorded, along with low frequencies of forest taxa and fern spores and an increase in pollen types of open vegetation, suggesting less humid climatic conditions than currently observed in the coastal regions of Southeastern Brazil. The assemblages of dinoflagellate cysts suggest a neritic zone with warm upper column temperature, high salinity and oligotrophic environment (evidenced by the presence of O. centrocarpum, Spiniferites spp. and L. machaerophorum). An increase in Tropical Waters (TW) and the approximation of the Brazilian Current (BC) in the middle shelf of southeastern Brazil in the mid-Holocene probably influenced the low accumulation of cysts, pollen grains, fern spores, and their associations. It is still possible to verify that at approximately 4.6 cal ka BP, an increase in the rainfall in the southeastern Brazilian region was probably the fundamental factor for the expansion of vegetation, mainly based on the considerable increases in hygrophytic and aquatic plants. The marked increase in the accumulation of dinoflagellate cysts, with the dominance of autotroph taxa (mainly O. centrocarpum, followed by Spiniferites spp), evidences the warmer waters of the BC and more intense surface upwelling of the South Atlantic Central Water (SACW).

Land–sea correlations in the Australian region: 460 ka of changes recorded in a deep-sea core offshore Tasmania. Part 2: the marine compared with the terrestrial record

We present an array of new proxy data and review existing ones from core Fr1/94-GC3 from the East Tasman Plateau. This core is positioned at the southern extreme of the East Australia Current and simultaneously records changes in both oceanography and environments both in offshore and in southeastern Australia. Microfossils, including planktonic and benthic foraminifera, ostracods, coccoliths and radiolarians, were studied to interpret palaeo-oceanographic changes. Sea-surface temperature was estimated using planktonic foraminifera, alkenones and radiolaria. From the silicate sediment fraction, the mean grain size of quartz grains was measured to detect the changes in wind strength. An XRF scan of the entire core was used to determine the elemental composition to identify provenance of the sediment. We also compare these data with a pollen record from the same core provided in an accompanying article that provides the longest well-dated record of vegetation change in southeastern Australia. In an area of slow sedimentation, Fr1/94-GC3 provides a continuous record of change in southeastern Australia and the southern Tasman Sea over approximately the last 460 ka. We determine that the East Australian Current varied in intensity through time and did not reach the core site during glacial periods but was present east of Tasmania during all interglacial periods. The four glacial–interglacial periods recorded at the site vary distinctly in character, with Marine Isotope Stage (MIS) 9 being the warmest and MIS 5 the longest. Through time, glacial periods have progressively become warmer and shorter. Deposition of airborne dust at the core site is more substantial during interglacial periods than glacials and is believed to derive from mainland Australia and not Tasmania. It is likely that the source and direction of the dust plume varied significantly with the wind regimes between glacials and interglacials as mean effective precipitation changed.

Land-sea correlations in the Australian region: 460 ka of changes recorded in a deep-sea core offshore Tasmania. Part 1: the pollen record

Long, well-dated records of climate change in Australia are rare because most of the continent is prone to deflation and sediments are difficult to date beyond 40 ka. Deep-sea cores, containing terrigenous material, provide an ideal alternative to terrestrial records, because of continuous sedimentation and a robust chronology derived from oxygen isotopes. In this paper, the first of a series of two, we present pollen and spores data from core Fr1/94-GC3 from the East Tasman Plateau. This core is positioned at the southern extreme of the East Australia Current and simultaneously records changes in both oceanography and environments both offshore and in southeastern Australia. In an area of slow sedimentation, this core provides a continuous record of vegetation change in southeastern Australia and the southern Tasman Sea over approximately the last half a million years. Through time, glacial periods have progressively become warmer and shorter. Alpine plant taxa become more restricted with time and rainforest taxa expand to a far more restricted degree during the present interglacial period than the previous one, representing a fundamental shift in the vegetation of Tasmania. We apply transfer functions to reconstruct past rainfall and land temperatures based on the palynoflora that are then compared against the marine proxy record.

Interactions between climate change and human activities during the early to mid-Holocene in the eastern Mediterranean basins

Abstract. This paper focuses on early Holocene rapid climate change (RCC) records in the Mediterranean zone, which are under-represented in continental archives (9.2 to 8.2 ka events) and on their impact on prehistoric societies. This lack of data handicaps the general interpretation of climate impacts on human societies, which flourished in recent years. Key questions remain about the impact of early Holocene cooling events on the Mediterranean climate, ecosystems and human societies. In this paper, we discuss some examples from river and lake systems from the eastern to central Mediterranean area (central Anatolia, Cyprus, northeastern and northwestern Greece) that illustrate some palaeohydrological and erosion variations that modified the sustainability of the first Neolithic populations in this region. Results allow us to present direct land–sea correlations and to reconstruct regional long-term trends as well as millennial- to centennial-scale climatic changes. In this context, we question the socio-economic and geographical adaptation capacities of these societies (mobility, technology, economic practices, social organisation) during the “early Holocene” interval (11.7 to 8.2 ka), which corresponds partly to the Sapropel 1 deposition in the eastern Mediterranean sea.

Exploring the source-to-sink residence time of terrestrial pollen deposited offshore Westland, New Zealand

The occurrence of terrestrial palynomorphs in Quaternary marine sedimentary sequences allows for direct land–sea correlations and provides a means for transferring Marine Isotope Stage chronologies to terrestrial records that extend beyond the range of radiocarbon dating. Both of these important applications require an implicit assumption that the lag between pollen release and final deposition on the seafloor – here referred to as source-to-sink residence time – is negligible in relation to the chronological resolution of the sedimentary sequence. Most studies implicitly assume zero lag, and where studies do take palynomorph residence time into account, its magnitude is rarely quantified. In Westland, New Zealand, fluvial transport is the main source of delivery of terrestrial pollen offshore to the adjacent East Tasman Sea. We radiocarbon-dated organic matter carried and deposited by contemporary Westland rivers that drain catchments with varying degrees of disturbance. The ages obtained ranged widely from essentially modern (i.e., −57±22calyr BP) to 3583±188calyr BP, suggesting that precisely constraining the residence time in this region is unlikely to be achieved. We also compared the timing of four palynomorph events characterising Westland's late Pleistocene, along with the well-dated Kawakawa/Oruanui Tephra (KOT), between marine core MD06-2991 and four terrestrial records from Westland. Critically, all palynomorph events and the KOT are chronologically indistinguishable with respect to the independently dated marine and terrestrial records, supporting the general principle of transferring the marine chronology onto the terrestrial records in this setting. In other regions, particularly those lacking the high soil production and erosion rates that characterise Westland, we suggest that similar tests of marine residence time should be conducted before assumptions of zero or negligible lag are invoked.

Synchronous onset of the Messinian evaporite precipitation: First Mediterranean offshore evidence

The Messinian Salinity Crisis (MSC) was a major ecological crisis affecting shallow and deep-water settings over the entire Mediterranean basin. However, the evolution of the MSC and its ecological impacts have mainly been explained on the basis of sediments from onshore outcrops. Lack of complete and physically connected records from onshore and offshore settings has inhibited comprehensive understanding of basin behaviour during the MSC. Herein we present a continuous record from an intermediate-depth basin on the Balearic Promontory that comprises late Tortonian–Messinian marls and evaporitic beds from the first MSC phase (i.e., Primary Lower Gypsum-PLG stage). Well-log and biostratigraphic data allow us establishing a large-scale calibration to the astronomical solutions, and to correlate pre-MSC sediments with classical rhythmic successions outcropping onshore. Thickness and characteristic sedimentary patterns observed in the offshore evaporitic records resemble those from marginal PLG sequences. Furthermore, seismic reflectors from a Bedded Unit (BU), which corresponds to an evaporitic interval according to well-to-seismic ties, are correlated with the onshore PLG sequences. This correlation constitutes the first attempt to link well-known marginal sequences with intermediate-depth offshore settings, which have previously only been studied through seismic imaging. Our time-calibration provides direct evidence supporting a synchronous onset of the PLG phase between onshore and offshore settings along the southwestern Balearic Promontory margin. Those BU reflectors, which were positively correlated to the PLG, were likely precipitated offshore the continental shelf at Messinian times. These results suggest that gypsum precipitation and/or preservation was not always limited to 200 m water-depths and could occur in non-silled basins. Finally, we only found a major erosion at the top of the PLG sequences, implying that the MSC drawdown occurred after the precipitation of the onshore lower evaporites. Studied sequences provide new insights into the PLG precipitation/preservation settings, as well as into the land-sea correlations of MSC units, and thus could potentially help refine current MSC models.

Land–sea correlations in the Australian region: post-glacial onset of the monsoon in northwestern Western Australia

Deep-sea core Fr10/95-GC17, collected offshore North West Cape at the western tip of Western Australia, is located beneath the path of the Leeuwin Current. This shallow, warm and low salinity current is an offshoot of the Indonesian Throughflow that transfers water and heat from the West Pacific Ocean into the Indian Ocean. The location is at the edge of the Indo Pacific Warm Pool, the source of large-scale transfer of moisture and heat from the ocean to the atmosphere. For this core, we combine previously published data with new research and use a revised chronology to re-examine the timing of climate change during the last 34,000 years in the tropics of northern Australia. The age model for the core is based on 15 radiocarbon dates complemented by luminescence ages and an oxygen isotope record. This study draws on an extensive range of analyses that have been performed on the core, including micropalaeontology of planktic and benthic foraminifera and coccoliths, stable isotopes analysis of foraminifera and their faunal composition, clay content, sediment composition and pollen analyses. Sea-surface and land temperatures are estimated from the foraminifer faunal analyses and from pollen spectra, respectively. The clay fraction and sediment composition and radiogenic isotopes of that fraction helped identify changes both on land and at sea: changes such as rainfall as shown by river discharge, and oceanic current tracing by neodymium, strontium and lead isotopes obtained from sediments.The most significant finding is that a major threshold was crossed at 13kaBP. Prior to that time, rainfall over NW Western Australia was low as was sea-surface temperature (SST); river discharge to the ocean was also low as a result of the lack of monsoonal activity and finally, ocean alkalinity would have been lower than at present due to the uptake of atmospheric CO2. By 13kaBP, the entire system moved away from glacial period conditions. The Indo-Australian monsoon commenced in and offshore northwestern Western Australia. SST and land temperature increased dramatically and ocean alkalinity changed due to the formation of a “barrier layer” (a low salinity cap), over the Indo Pacific Warm Pool. During the Holocene, river discharge and the land and ocean temperatures did not covary, for example, the highest rainfall did not coincide with the highest SST. Finally, the last 5ka saw a strengthening of ENSO in the region.

Deglacial and Holocene vegetation and climatic changes in the southern Central Mediterranean from a direct land–sea correlation

Abstract. Despite a large number of studies, the long-term and millennial to centennial-scale climatic variability in the Mediterranean region during the last deglaciation and the Holocene is still debated, including in the southern Central Mediterranean. In this paper, we present a new marine pollen sequence (core MD04-2797CQ) from the Siculo-Tunisian Strait documenting the regional vegetation and climatic changes in the southern Central Mediterranean during the last deglaciation and the Holocene. The MD04-2797CQ marine pollen sequence shows that semi-desert plants dominated the vegetal cover in the southern Central Mediterranean between 18.2 and 12.3 ka cal BP, indicating prevailing dry conditions during the deglaciation, even during the Greenland Interstadial (GI)-1. Across the transition Greenland Stadial (GS)-1 – Holocene, Asteraceae-Poaceae steppe became dominant till 10.1 ka cal BP. This record underlines with no chronological ambiguity that even though temperatures increased, deficiency in moisture availability persisted into the early Holocene. Temperate trees and shrubs with heath underbrush or maquis expanded between 10.1 and 6.6 ka, corresponding to Sapropel 1 (S1) interval, while Mediterranean plants only developed from 6.6 ka onwards. These changes in vegetal cover show that the regional climate in southern Central Mediterranean was wetter during S1 and became drier during the mid- to late Holocene. Wetter conditions during S1 were likely due to increased winter precipitation while summers remained dry. We suggest, in agreement with published modeling experiments, that the early Holocene increased melting of the Laurentide Ice Sheet in conjunction with weak winter insolation played a major role in the development of winter precipitation maxima in the Mediterranean region in controlling the strength and position of the North Atlantic storm track. Finally, our data provide evidence for centennial-scale vegetation and climatic changes in the southern Central Mediterranean. During the wet early Holocene, alkenone-derived cooling episodes are synchronous with herbaceous composition changes that indicate muted changes in precipitation. In contrast, enhanced aridity episodes, as detected by strong reduction in trees and shrubs, are recorded during the mid- to late Holocene. We show that the impact of the Holocene cooling events on the Mediterranean hydroclimate depend on baseline climate states, i.e. insolation and ice sheet extent, shaping the response of the mid-latitude atmospheric circulation.

Holocene marine tephrochronology on the Icelandic shelf: An overview

Currently the Late-glacial and Holocene marine tephrochronology on the shelf around Iceland comprises 130 tephra layers from 30 sediment cores ranging in age from 15,000 years cal. BP to AD 1947. A vast majority of the cores and tephra layers are from the North Iceland shelf. Much fewer tephra layers have been found on the South and West Iceland shelf. The early Holocene Saksunarvatn ash and Vedde Ash are the only tephra layers identified on all investigated shelf areas. For the last 15,000 years correlated tephra layers from the shelf sediments around Iceland to their terrestrial counterparts both in Iceland and overseas are 40 of which 26 are terrestrially dated tephra markers. Thirty correlations are within the last 7050 years. The terrestrially dated tephra markers found on the shelf have been used to constrain past environmental variability in the region, as well as marine reservoir age. The marine tephra stratigraphy on the North Iceland shelf has revealed variations in volcanic activity in Iceland further back in time than terrestrial records in Iceland. The numerous tephra layers identified in the sediments on the shelf demonstrate the potential of marine tephrochronology for dating purposes, land-sea correlation, marine reservoir estimations and reconstruction of past volcanic activity of Icelandic volcanoes.

Implications of Luminescence dating of terrestrial sediments in Land Sea Correlations

Implications of Luminescence dating of terrestrial sediments in Land Sea Correlations

Tephra stratigraphy on the North Icelandic shelf: extending tephrochronology into marine sediments off North Iceland

Tephra stratigraphical and tephrochronological studies of marine core MD99‐2275 on the North Icelandic shelf have revealed 58 new tephra horizons within the last 7050 cal. a BP, bringing the total number of identified tephra layers to 76. So far, over 100 tephra layers have been identified in the entire core spanning the last 15 000 years. The majority of the newly identified tephra layers are basaltic in composition and originate from the most active volcanic systems in Iceland, namely Grímsvötn, Veidivötn‐Bárdarbunga and Katla. A total of 40 tephra layer land–sea correlations have been made within this time period, of which 16 represent absolutely dated tephra markers. In addition, two tephra marker series are revealed in the marine sediments and in the terrestrial tephra stratigraphy, located between c. 2300–2600 and between 5700–5900 years. For the last 15 000 years, 21 tephra markers have been recognized. The marine tephra layer frequency (TLF) reveals two peaks, within the last 2000 years, and between 5000 and 7000 years ago. It shows the same general characteristics as the terrestrial TLF curve in Iceland, which indicates that marine sediments can yield important information about volcanism in Iceland. This is useful in time segments in which terrestrial records are poor or non‐existent. The study contributes to a high‐resolution tephrochronological framework on the North Icelandic shelf, with core MD99‐2275 representing a potential stratotype section in the area, and for the northern North Atlantic–Nordic Seas region, as well as being an important contribution to the Lateglacial–early Holocene volcanic history of Iceland.

Late Pleistocene to Holocene tephrostratigraphic record from the Northern Ionian Sea

A detailed tephrostratigraphic study supported by stable isotope (δ18O) analyses and AMS 14C dating was carried out on a high sedimentation rate deep-sea core recovered in the northern Ionian Sea. Eight tephra layers were recognised, all originated from explosive eruptions of southern Italian volcanoes. These tephra layers are correlated with terrestrial proximal counterparts and with both marine and lacustrine tephra already known in the central Mediterranean area. The oldest tephra (dated at ca. 19.4ka cal BP) is tentatively correlated to the Monte Guardia eruption from Lipari Island. Two other rhyolitic tephra layers were correlated with the explosive volcanic activity of Lipari Island: Gabellotto-Fiumebianco/E-1 (8.3ka cal BP) located close to the interruption of Sapropel S1 deposit, and Monte Pilato (ca. AD 1335) in the uppermost part of the core. The Na-phonolitic composition of the other five recognised tephra layers indicates the Somma-Vesuvius as the source. The composition is quite homogeneous among the five tephra layers, and fits that of the Mercato proximal deposits. Beyond the striking chemical similarity with the Mercato eruption, these tephra layers span over ca. 2000years, preventing correlation with the single well known Plinian eruption of the Somma-Vesuvius. Therefore, at least two of these tephra layers were assigned to an interplinian activity of the Somma-Vesuvius between the eruptions of Mercato and Avellino, even though these eruptions remains poorly constrained in the proximal area. By contrast, the most prominent tephra layer (2mm white tephra visible at naked eyes) was found within the S1a Sapropel interval. Despite the possible complication for the presence of similar eruption with different ages we argue that Mercato is probably a very good marker for the onset of sapropelic condition in the Ionian Sea and can be used for land-sea correlations for this important climatic event. More in general, these data allow a significant update of the knowledge of the volcanic ash dispersal from Lipari and Somma-Vesuvius volcanoes.

540 A marine palynological study from off north-western Africa as a tool for land-sea correlation in the Late Pliocene

540 A marine palynological study from off north-western Africa as a tool for land-sea correlation in the Late Pliocene

105 Land-sea correlation of early Pleistocene glacial : interglacial cycles in the southern North Sea

105 Land-sea correlation of early Pleistocene glacial : interglacial cycles in the southern North Sea

Proposal for Pliocene and Pleistocene land–sea correlation in the Italian area

The present study attempts a correlation between calcareous plankton (foraminifera and nannofossils) and terrestrial (pollen and mammal fauna) bioevents in Italy and Mediterranean Sea, through the last 3.3 million years, within a standard chronostratigraphical time scale. The approach was basically interdisciplinary and considered biochronological, biostratigraphical, chronostratigraphical, climatostratigraphical, and tephrochronological data. Despite different timing and mode characterised evolution of marine and continental organisms in relation to their ecology and relationships with environment, the main biota changes seem related with severe climate changes. The short interval of the known global scale Pliocene warmth (∼3.0 Ma) has been documented by the last significant expansion of the warm subtropical forest before the progressive disappearance of its main components and possibly by the paracme of some nannofossil species. The first evidence of cooler conditions near 2.8 Ma has been mainly indicated by both the progressive decrease of subtropical to warm temperate pollen taxa and by the notable change in the ecological structure of mammalian faunal complexes as well as by the first incursion of left-coiled cold N. pachyderma into the Mediterranean. The first glacial phases related to Northern Hemisphere ice-sheet growth (∼2.5 Ma) are indicated by the drastic drop of Discoaster spp. and by the first (cyclical) expansion of steppe or cooler coniferous forests, as well as by the progressive dispersal of mammalian taxa dwelling in open landscapes. The most significant biotical changes have been observed during the Calabrian–Ionian transition; several calcareous plankton appearances and extinctions occurred across marine isotope stages 25–20, together with the expansion of cold steppes (glacials) and the progressive disappearance of the most thermophilous arboreal and non-arboreal taxa. The late Early to Middle Pleistocene terrestrial faunal “revolution” actually was not an “abrupt” phenomenon, which started from about 1.3 Ma giving rise to a progressive reconstruction of mammalian faunal complexes, which ended during the early Ionian. The last node of 1.2 Ma obliquity cycles, centred at about 0.9 Ma, significantly influenced changes in the structure and composition of palaeocommunities. After the Ionian, fluctuations in biota assemblages, without any significant appearance–extinction events, testify that the new oceanographical and climate system is related to dominant periodicity of 100 ky in glacial–interglacial cycles. Although the changes observed in fossil assemblages do not always correspond to the standard chronostratigraphical boundaries, the data suggest that the Piacenzian–Gelasian and Calabrian–Ionian transitions are also noticeable by large, even if gradual, biota modifications.

Land–sea correlation between Late Holocene coastal and infralittoral deposits in the SE Iberian Peninsula (Western Mediterranean)

The well-exposed systems of prograding beach ridges on the Carchuna–Calahonda (Granada) and Campo de Dalías–Roquetas (Almería) coastal plains continue offshore as infralittoral prograding wedges (IPW). The Holocene IPW is a narrow morpho-sedimentary unit up to 2.5 km wide which develops seaward from the lower edge of the shoreface to 15–20 m depth, extending to a well-defined break of slope at water depths of 35–40 m. These IPWs have been recognized and studied using very high-resolution seismic profiles (TOPAS) and multibeam data (EM-3000D). In detail they are complex morpho-sedimentary units in which internal structures are closely linked to the pattern of progradation of the adjacent coastal plains. When longshore currents produce significant littoral drift, the IPWs are composed of several minor units arranged in offlap, which accrete parallel or oblique to the main shoreline. Therefore, it is possible to correlate progradational units in the coastal plain (H-units, sensu[Goy, J.L., Zazo, C., Dabrio, C.J., 2003. A beach-ridge progradation complex reflecting periodical sea-level and climate variability during the Holocene (Gulf of Almería, Western Mediterranean). Geomorphology 50, 251–268]) and subunits in the IPW, but special care is required depending on the local arrangement of morpho-sedimentary units. Besides, it is not realistic to draw conclusions regarding the age of the subunits inside a given IPW without adequate dating, as the number of subunits will greatly vary from place to place depending on local factors, magnitude of sea-level oscillations, and sediment supply.

Climate dynamics in the borderlands of the Aegean Sea during formation of sapropel S1 deduced from a marine pollen record

To unravel the climatic and environmental dynamics in the borderlands of the Aegean Sea during the early and middle Holocene, and notably for the interval of sapropel S1 (S1) formation, we have analysed terrestrial palynomorphs from a marine core in the northern Aegean Sea. The qualitative results were complemented by quantitative pollen-based climate reconstructions. A land–sea correlation was established based on pollen data and sediment lightness measurements from the same core, and previously published benthic foraminifer data from a nearby core.The borderlands of the Aegean Sea underwent a transition from an open vegetation to oak-dominated woodlands between ∼10.4 and ∼9.5kacalBP. A coeval increase in winter precipitation suggests that moisture availability was the main factor controlling Holocene reforestation. The ∼50% higher winter precipitation during S1 formation relative to “pre-sapropelic” conditions suggests a strong contribution from the borderlands of the Aegean Sea to the freshwater surplus during S1 formation. The humid and mild winter conditions during S1 formation were repeatedly punctuated by short-term climatic events that caused a partial deforestation and a reorganisation within the broad-leaved arboreal vegetation. In the marine realm, these events are documented by improved benthic oxygenation. The strongest event represents the regional expression of the 8.2ka cold event and led to an interruption in S1 formation. Except for the interval of S1 formation, the pollen-derived winter temperatures correlate with the smoothed GISP2 K+ series. They support the previously published, marine-based concept that the intensity of the Siberian High strongly controlled the winter climate in the Aegean region. During S1 formation in the Aegean Sea, however, climate conditions in the borderlands were more strongly affected by the monsoonally influenced climate system of the lower latitudes.

Land–sea correlation of Middle Pleistocene temperate sub-stages using high-precision uranium-series dating of tufa deposits from southern England

High-precision U-series dating allows a direct correlation to be made between terrestrial records of the penultimate interglacial (Marine Oxygen Isotope Stage 7 (MIS 7)) in Britain and sub-stage climate forcing in the marine oxygen isotope sequence. U-series ages of surficial tufa deposits are of sufficient precision to correlate discrete episodes of temperate conditions with individual warm sub-stages within MIS 7. Furthermore, detailed biostratigraphy allows periods of faunal turnover to be correlated with cold climates and lowered sea level. Ecological and environmental conditions in Britain during MIS 7 are therefore driven by the short-lived, sub-stage climate forcing that is observable in the marine isotope record. It is clear that interglacial climates are highly dynamic, producing multiple climatic optima and a diverse range of environments within single warm episodes. Consequently sub-stage records of climate forcing are crucial frameworks for reconstructing terrestrial records of environmental change.