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A new low-cost method is described for obtaining narrow blocks of the friable Nicola bed, the local marker for the Neogene–Quaternary system (Pliocene–Pleistocene series) boundary at the type section at Monte San Nicola, southern Sicily. The Global boundary Stratotype Section and Point (GSSP), which also defines the Gelasian Stage and is dated at 2.58 Ma, is placed at the base of a marly layer immediately overlying the sapropelic microlaminated Nicola bed. Sedimentary structures and ichnofabrics revealed by X-ray computed tomography (CT) and polished surface observations show the rapid onset of anoxia marking the base of the Nicola bed, followed by progressive dysoxia indicated by the trace fossil Chondrites isp. alone. The top of the Nicola bed is bioturbated over an interval of several centimeters, which obscures precise recognition of the GSSP horizon. The overlying marl is characterised by the presence of Chondrites isp. accompanied by Planolites isp. and Thalassinoides isp. indicating a return to higher oxygen levels in the bottom waters, although a brief return to poor oxygenation is interpreted from the temporary absence/rarity of Chondrites isp. Trichichnus isp. is prevalent throughout the interval immediately above the Nicola bed, and its lowest extent revealed by CT may serve at least locally as an independent marker for the GSSP level. In general, we recommend the careful study of any sapropel before placing a GSSP at its upper or lower boundary or midpoint. • The Neogene/Quaternary boundary, ∼2.58 Ma, at the type section at Monte San Nicola is revisited. • A new field method is described for collecting friable and microfractured rock blocks. • The sapropelic Nicola bed has been subjected to ichnofabric analyses using polished sections and X-ray computed tomography. • Observations reveal a shift from oxic to anoxic conditions at the onset of Nicola bed deposition followed by improving oxygen levels. • The Nicola bed top is bioturbated, obscuring precise recognition of the GSSP level. [ABSTRACT FROM AUTHOR]

The Quaternary System/Period and Pleistocene Series/Epoch were defined in 2009 by the Global boundary Stratotype Section and Point (GSSP) for the Gelasian Stage/Age (2.58 Ma), which aligns with Marine Isotope Stage (MIS) 103 and approximates the Gauss–Matuyama Chron boundary, contrary to earlier reports. The Vrica GSSP (1.80 Ma) was repurposed in 2011 to define the Calabrian Stage, effectively completing the Lower Pleistocene Subseries/Subepoch. The candidate for the Middle Pleistocene Subseries (and proposed Chibanian Stage) GSSP (∼774 ka) is the Chiba section, Japan. It aligns with MIS 19 and approximates the Matuyama–Brunhes Chron boundary (∼773 ka). The Upper Pleistocene Subseries, with a base traditionally marked by the onset of the Last Interglacial, is not yet defined by GSSP. The Holocene Series/Epoch was formally defined in 2008 by a GSSP in the NGRIP2 Greenland ice core with an age of 11,700 yr b2k (before 2000 CE) and in 2018 was subdivided, using climatic events at 8.2 and 4.2 ka, into the Greenlandian, Northgrippian and Meghalayan stages/ages and their corresponding Lower/Early, Middle, Upper/Late subseries/subepochs. The Northgrippian GSSP (8236 yr b2k) is defined in the NGRIP1 Greenland ice core, and the Meghalayan GSSP (4250 yr b2k) in a speleothem from Meghalaya, India. This subdivision formally introduces the rank of subseries/subepoch, and incorporates by far the briefest of all stages into the geological time scale. Using ice cores and a speleothem for GSSPs is unique to the Holocene. The presently undefined term Anthropocene is already used extensively and, like Holocene subdivisional terms, its functionality will be enhanced by formal definition. The Anthropocene should not be confused with anthropogenic: it reflects a tipping point in the Earth System response to the marked intensification of human impacts, not simply the fact of human impact. The geological Anthropocene, as currently envisioned, would start in the mid-twentieth century, holding the rank of series, and terminating the Holocene but not interfering with its subdivision other than to terminate the Meghalayan Stage. [ABSTRACT FROM AUTHOR]

Merritts et al. (2023) misrepresent Paul Crutzen's Anthropocene concept as encompassing all significant anthropogenic impacts, extending back many millennia. Crutzen's definition reflects massively enhanced, much more recent human impacts that transformed the Earth System away from the stability of Holocene conditions. His concept of an epoch (hence the 'cene' suffix) is more consistent with the strikingly distinct sedimentary record accumulated since the mid-20th century. Waters et al. (2022) highlighted a Great Acceleration Event Array (GAEA) of stratigraphic event markers that are indeed diverse and complex but also tightly clustered around 1950 CE, allowing ultra-high resolution characterization and correlation of a clearly recognisable Anthropocene chronostratigraphic base. The 'Anthropocene event' offered by Merritts et al., following Gibbard et al. (2021, 2022), is a highly nuanced concept that obfuscates the transformative human impact of the chronostratigraphic Anthropocene. Waters et al. (2022) restricted the meaning of the term 'event' in geology to conform with usual Quaternary practice and improve its utility. They simultaneously recognized an evidence-based Anthropogenic Modification Episode that is more explicitly defined than the highly interpretive interdisciplinary 'Anthropocene event' of Gibbard et al. (2021, 2022). The advance of science is best served through clearly developed concepts supported by tightly circumscribed terminology; indeed, improvements to stratigraphy over recent decades have been achieved through increasingly precise definitions, especially for chronostratigraphic units, and not by retaining vague terminology. [ABSTRACT FROM AUTHOR]

Near the Pliocene–Pleistocene (Neogene–Quaternary) boundary during Marine Isotope Stage (MIS) 104 at around 2.6 Ma, the intensification of Northern Hemisphere glaciation (iNHG) was marked by a southward shift of the North Atlantic Current and Arctic Front and a concurrent drop in sea surface temperature (SST) in the mid-latitudes of the North Atlantic. Here we evaluate two Mg/Ca-based sea-surface temperature reconstructions for the 2.78–2.52 Ma interval using the planktonic foraminifera Globigerina bulloides and Globigerinoides ruber (white) sensu stricto as the biotic carriers (SST bul and SST rub ), and a reconstruction based on the alkenone saturation index (SST alk ). The Mg/Ca-based SST estimates begin to diverge from one another significantly during MIS G3 (∼2.66 Ma), culminating during MIS 104 (∼2.60 Ma), and remaining distinctly different for the remaining 80 kyr of the studied interval. The magnitude of this divergence (ΔSST rub-bul ) is caused mainly by a decrease in SST bul , with SST rub remaining relatively constant. We attribute this difference to a drop in SST during the early-spring blooming season of G. bulloides that was less pronounced during the late-summer blooming season of G. ruber . Using ΔSST rub-bul as a seasonality indicator, we show that seasonality increased significantly owing to a drop in early spring temperatures from MIS 104 onwards, and peaked during glacial episodes. Maximum seasonality occurred during MIS 104 in coincidence with a major expansion of the circum-Atlantic ice sheets, particularly the North American ice sheet. This expansion appears to have had a critical influence on global climate and especially seasonality. [ABSTRACT FROM AUTHOR]

Marked by a progressive increase in the amplitude of climate oscillations, an evolving waveform, and a shift towards a quasi-100 ky frequency, the Early–Middle Pleistocene transition (EMPT), previously known as the Mid-Pleistocene Transition (or Mid-Pleistocene Revolution) (1.4–0.4 Ma), represents a fundamental transformation in the Earth's climate state. The EMPT began with a substantial change in climate dynamics and ended with the Mid-Brunhes Event, signaling the establishment of a new steady state. The reasons for the EMPT while uncertain appear to involve a non-linear response of the Earth climate system. The physical and biotic responses to this transition, amplified by the growth of Northern Hemisphere ice sheets, have been profound. Two important chronostratigraphic markers characterize the EMPT, the Jaramillo Subchron (1.070–0.988 Ma) and the Matuyama–Brunhes Chron boundary (∼773 ka). The latter has been chosen as the primary guide for the Lower–Middle Pleistocene Subseries boundary, as it lies at the approximate midpoint of the EMPT and aids in global recognition both in marine and terrestrial deposits. The Jaramillo Subchron has received less attention, but the late Early Pleistocene is important in Europe because it saw the progressive transition from the Villafranchian to Galerian mammal faunas, and expansion of hominins into western and northern Europe. The Jaramillo Subchron is represented by Marine Isotope Stages (MIS) 31 to 28, with MIS 30 already showing the asymmetrical (sawtooth) pattern characteristic of the Middle Pleistocene. Indeed, while variation in the 40-ky band (obliquity) remains strong throughout the EMPT, low frequency variability begins at around 1250–1200 ky, which coincides with a progressive increase in global ice volume. Against a backdrop of increasingly severe glacial cycles, notably during MIS 36, 34, 24–22 (the so-called “0.9 Ma event”), 16 and 12, pronounced phases of warming are also documented globally, including the “super-interglacial” MIS 31. The early phase of the EMPT is characterized by important glaciations beginning with MIS 36 and continuing to MIS 24–22, a major intensification of the East Asian monsoon system, intensification of loess deposition in northern Europe, development of open landscapes in western Siberia, increased fluvial incision, higher amplitude sea-level change, and spread of large mammals across northern Eurasia, and a strong reduction in the North Atlantic thermohaline circulation. In Europe, the loss of thermophilous plant taxa during the EMPT and indeed throughout the Quaternary is a reminder of the progressive cooling that took place here and elsewhere. [ABSTRACT FROM AUTHOR]

The Quaternary System/Period represents the past 2.58 million years and is officially subdivided into the Pleistocene and Holocene series/epochs, with the base of the Holocene assigned an age of 11,700 calendar years before AD 2000. The two lowest stages of the Pleistocene, the Gelasian (base 2.58 Ma) and the Calabrian (base 1.80 Ma), have been ratified and these effectively constitute the Lower Pleistocene Subseries. All other official subdivisions are pending. For the Middle Pleistocene Subseries, three candidate global boundary stratotype sections and points (GSSPs) are under consideration: the Valle di Manche in Calabria and Montalbano Jonico in Basilicata, both in southern Italy, and the Chiba section in Japan. The Matuyama–Brunhes Chron boundary (∼773 ka) serves as the principal guide for the base of the Middle Pleistocene. The base of the Upper Pleistocene Subseries is generally agreed to coincide approximately with that of the last interglacial (Marine Isotope Substage 5e ∼130 ka): the Fronte section near Taranto in southern Italy represents a possible candidate GSSP, but an Antarctic ice core might also serve this purpose. A tripartite subdivision of the Holocene, with subseries/stage boundaries at 8200 and 4200 years B.P., is also under consideration. Additional fine-scale formal subdivision of the Quaternary is being explored, with the Last Glacial Maximum serving as a test case. The “Anthropocene” is both an informal and undefined interval of time that includes the present day. Its duration, formal/informal status, rank, and method of definition are all under debate, with one suggestion that it be defined as a formal unit beginning with the world's first nuclear bomb explosion, on July 16th 1945. Suggested and proposed GSSPs are compared and critiqued. The history leading to ratification of the Quaternary Period in 2009 is examined drawing upon published and unpublished material. [ABSTRACT FROM AUTHOR]

Abstract: Revised diatom and new dinoflagellate cyst and benthic foraminiferal data from the eastern Baltic Sea have refined our understanding of Eemian (Last Interglacial; 131–119.5 ka) sea-level change on the Russian Karelia, a former seaway linking the Baltic to the White Sea. Results from Peski, eastern Baltic show the initiation of marine conditions just before 131 ka in the latest Saalian, after the opening of a connection to the North Sea. Following the onset of the Eemian marine highstand and the opening of the White Sea connection at around 130.25 ka, near-fully marine conditions persisted in the eastern Baltic area for ca 6 kyr, until ca 124 ka. For most of the Eemian, a strong thermal stratification in the eastern Baltic resulted from an Arctic and possible North Atlantic water component from the White Sea merging with warmer waters from the North Sea. From ca 124 ka, decreasing salinity indicates the end of the marine highstand and a simultaneous closure of the Baltic Sea–White Sea connection, i.e. a duration of ca 6 kyr for this seaway. The main influence of White Sea inflow appears to be restricted to the eastern Baltic area, although a large submerged area in the Russian Karelia associated with temperate Atlantic waters could have assisted in creating a more oceanic climate for Central Europe. [Copyright &y& Elsevier]

Abstract: New and emerging policies that aim to set standards for protection and sustainable use of soil are likely to require identification of geographical risk/priority areas. Soil degradation can be seen as the change or disturbance in soil quality and it is therefore crucial that soil and soil quality are well understood to protect soils and to meet legislative requirements. To increase this understanding a review of the soil quality definition evaluated its development, with a formal scientific approach to assessment beginning in the 1970s, followed by a period of discussion and refinement. A number of reservations about soil quality assessment expressed in the literature are summarised. Taking concerns into account, a definition of soil quality incorporating soil''s ability to meet multifunctional requirements, to provide ecosystem services, and the potential for soils to affect other environmental media is described. Assessment using this definition requires a large number of soil function dependent indicators that can be expensive, laborious, prone to error, and problematic in comparison. Findings demonstrate the need for a method that is not function dependent, but uses a number of cross-functional indicators instead. This method to systematically prioritise areas where detailed investigation is required, using a ranking based against a desired level of action, could be relatively quick, easy and cost effective. As such this has potential to fill in gaps and compliment existing monitoring programs and assist in development and implementation of current and future soil protection legislation. [Copyright &y& Elsevier]

Abstract: The Kazhdumi Formation of the Bangestan Group is a well-known source rock that has produced abundant oil in most petroleum fields in the Zagros Basin, which stretches from northwest to southwest Iran over hundreds of kilometres. The formation reaches a thickness of 230m at the type section in northwest Zagros but thins out to 40–50m in wells studied from the South Pars giant petroleum field, where it comprises mainly grey shales with occasional intercalations of marls and sandstones. South Pars, best known as the Iranian part of the world''s largest non-associated gas field, contains small quantities of oil above and below the Kazhdumi Formation. Palynology has been used to assess the age and palaeoenvironment of the Kazhdumi Formation and to evaluate its petroleum potential. A total of 68 ditch cutting samples recovered from five wells, of which four are oil-prone, have been analyzed. An age between late Albian and Cenomanian is established for the formation based on dinoflagellate cyst biostratigraphy, and four palynofacies types have been recognized using the relative proportions of terrestrial elements, marine palynomorphs and amorphous organic matter (AOM). The ratio of terrestrial to marine elements is high in most samples, indicating a nearshore sedimentary environment. Twenty-two samples from the four oil-prone wells were also selected for geochemical analysis using Rock-Eval pyrolysis. Results show that the Kazhdumi Formation at South Pars, in contrast to the Zagros Basin, is gas-prone (predominantly type III kerogen), thermally immature, and poor in terms of hydrocarbon generation. It could not have produced the oil in those oil-prone wells studied. [Copyright &y& Elsevier]

Abstract: Measurement of microstructural gradients at the aggregate/cement paste interfacial transition zone (ITZ) in hardened mortar and concrete is commonly performed via quantitative image analysis of multiple micrographs of specimen surfaces, using a scanning electron microscope. However, due to the random orientation of interfaces sectioned by the specimen surface, measurements of the microstructural gradients at the interface have an unknown angular component, and thus have an unknown error. We present a method for the identification of interfaces that are perpendicular to the specimen surface, and therefore, are more suitable for accurate ITZ analysis. This method employs simple optical and electron imaging techniques on petrographic thin-sections. Use of 3D laser scanning confocal microscopy helped to validate the method. Quantitative 2D image analysis of backscattered electron micrographs, captured over three angular classes of interface gives an indication of this error in the determination of interfacial porosity and anhydrous cement content. [Copyright &y& Elsevier]

Abstract: This paper presents for the first time a method for the accurate segmentation of complex (multi-phase) natural aggregate particles, from greyscale backscattered electron images (BEI) of hardened concrete, so that interfacial porosity may be measured. Energy dispersive X-ray (EDX) spectra are collected from phases present in aggregate particles to identify the most abundant and therefore useful elements to be captured during later mapping. Appropriately captured energy dispersive X-ray dot maps are used to progressively construct a multi-phase composite aggregate binary mask, for aggregate particles composed of more than one mineral. The mask image is then re-processed in combination with the backscattered image, to produce an accurate hardened cement paste (HCP) porosity mask, which is used to measure the distribution of interfacial porosity around aggregate particles. [Copyright &y& Elsevier]

A rich organic-walled dinoflagellate cyst and pollen record from the Licze borehole in northern Poland has been used to reconstruct the hydrographic history of the southeastern Baltic Sea during the Last Interglacial (Eemian Stage, Late Pleistocene). Warm, saline waters (ca. 10–15 psu) entered the site from the North Sea within the first few hundred years of the Eemian, corresponding to the Pinus–Betula (E1) or Pinus–Betula–Ulmus (E2) regional pollen assemblage zones (RPAZ). By about 300 years (beginning of RPAZ E3), dinoflagellate cyst assemblages were already indicating summer sea-surface salinities in excess of about 15 psu and temperatures that perhaps exceeded 27°C. Warm and saline conditions of 15–20 psu or more, at least twice present levels, persisted throughout the early Eemian. A rise in sea level at Licze appears to correlate with a similar event in eastern Denmark, as both coincide with the increase in Corylus (ca. 750 years into the interglacial). This sea-level rise might therefore have a basinwide extent, and appears to correspond to an opening of the Danish Belts. There is little if any evidence of arctic waters throughout the sequence. Whereas dinoflagellate cysts reflect sustained high salinites within the upper water column, a concomitant increase in abundance of the chlorococcalean alga Pediastrum within the Carpinus–Corylus–Alnus (E5) RPAZ indicates an escalating freshwater input, presumably from the proto-Vistula whose mouth was nearby. This suggests the development of a thin, seasonal, low-salinity surface layer below which dinoflagellates lived in more saline waters. Increasing fluvial influence suggests shallowing through RPAZ E5. This study is the first to document dinoflagellate cysts from the Eemian of the southeastern Baltic Sea, and reveals a flora with distinctive Lusitanian/Mediterranean affinities. [Copyright &y& Elsevier]

The Nordland Group is an important stratigraphical unit within the upper Cenozoic of the northern North Sea. At its base lies the Utsira Sand, a dominantly sandy regional saline aquifer that is currently being utilized for carbon dioxide sequestration from the Sleipner gas and condensate field. A ‘mudstone drape’ immediately overlies the Utsira Sand, forming the caprock for this aquifer. The upper part of the Utsira Sand was recently dated as Early Pliocene, but the precise age of the overlying Nordland Group mudstones has remained uncertain. Dinoflagellate cyst, pollen and spore, foraminiferal and stable isotopic analyses have been performed on these mudstones from a conventional core within the interval 913.10–906.00 m (drilled depth) in Norwegian sector well 15/9-A-11. The samples lie closely above the Utsira Sand. Results give a Gelasian (late Late Pliocene) age for this interval, with a planktonic foraminiferal assemblage at 913.10 m indicating warm climatic conditions and an age between 2.4 and 1.8 Ma. An abundance of the cool-tolerant dinoflagellate cysts Filisphaera filifera and Habibacysta tectata at 906.00 m, along with evidence from pollen and foraminifera, points to deposition during a cool phase of the Gelasian. Dating the mudstone drape provides useful insights into depositional processes. It seems likely that the Utsira Sand, a basinal lowstand deposit, became progressively starved of clastic input as sea level rose and shorelines retreated. The mudstone drape is interpreted as a highstand deposit, perhaps including a maximum flooding surface. Overlying prograding wedges of the Nordland Group form a regressive succession, characterized by increased sedimentary input and rates of deposition of at least 25 cm per 1000 years, which is more than five times that of the Utsira Sand.This is the first published study of a dinoflagellate cyst assemblage from the Upper Pliocene of the northern North Sea. The new dinoflagellate cyst species Echinidinium nordlandensis Head sp. nov. and Echinidinium sleipnerensis & Riding sp. nov. are formally described. [Copyright &y& Elsevier]

A complete and optimized scheme of lettered marine isotope substages spanning the last 1.0 million years is proposed. Lettered substages for Marine Isotope Stage (MIS) 5 were explicitly defined by Shackleton (1969), but analogous substages before or after MIS 5 have not been coherently defined. Short-term discrete events in the isotopic record were defined in the 1980s and given decimal-style numbers, rather than letters, but unlike substages they were neither intended nor suited to identify contiguous intervals of time. Substages for time outside MIS 5 have been lettered, or in some cases numbered, piecemeal and with conflicting designations. We therefore propose a system of lettered substages that is complete, without missing substages, and optimized to match previous published usage to the maximum extent possible. Our goal is to provide order and unity to a taxonomy and nomenclature that has developed ad hoc and somewhat chaotically over the decades. Our system is defined relative to the LR04 stack of marine benthic oxygen isotope records, and thus it is grounded in a continuous record responsive largely to changes in ice volume that are inherently global. This system is intended specifically for marine oxygen isotope stages, but it has relevance also for oxygen isotope stages recognized in time-series of non-marine oxygen isotope data, and more generally for climatic stages, which are recognized in time-series of non-isotopic as well as isotopic data. The terms “stage” and “substage” in this context are best considered to represent climatostratigraphic units, and thus “climatic stages” and “climatic substages”, because they are recognized from geochemical and sedimentary responses to climate change that may not have been synchronous at global scale. [ABSTRACT FROM AUTHOR]

Marine Isotope Stage (MIS) 19 is an important analogue for the present interglacial because of its similar orbital configuration, especially the phasing of the obliquity maximum to precession minimum. However, sedimentary records suitable for capturing both terrestrial and marine environmental changes are limited, and thus the climatic forcing mechanisms for MIS 19 are still largely unknown. The Chiba composite section, east-central Japanese archipelago, is a continuous and expanded marine sedimentary succession well suited to capture terrestrial and marine environmental changes through MIS 19. In this study, a detailed oxygen isotope chronology is established from late MIS 20 to early MIS 18, supported by a U-Pb zircon age and the presence of the Matuyama–Brunhes boundary. New pollen, marine microfossil, and planktonic foraminiferal δ 18 O and Mg/Ca paleotemperature records reveal the complex interplay of climatic influences. Our pollen data suggest that the duration of full interglacial conditions during MIS 19 extends from 785.0 to 775.1 ka (9.9 kyr), which offers an important natural baseline in predicting the duration of the present interglacial. A Younger Dryas-type cooling event is present during Termination IX, suggesting that such events are linked to this orbital configuration. Millennial- to multi-millennial-scale variations in our δ 18 O and Mg/Ca records imply that the Subarctic Front fluctuated in the northwestern Pacific Ocean during late MIS 19, probably in response to East Asian winter monsoon variability. The climatic setting at this time appears to be related to less severe summer insolation minima at 65˚N and/or high winter insolation at 50˚N. Our records do not support a recently hypothesized direct coupling between variations in the geomagnetic field intensity and global/regional climate change. Our highly resolved paleoclimatic and paleoceanographic records, coupled with a well-defined Matuyama–Brunhes boundary (772.9 ka; duration 1.9 kyr), establish the Chiba composite section as an exceptional climatic and chronological reference section for the Early–Middle Pleistocene boundary. [ABSTRACT FROM AUTHOR]

Strains of a dinoflagellate from the Salton Sea, previously identified as Protoceratium reticulatum and yessotoxin producing, have been reexamined morphologically and genetically and Pentaplacodinium saltonense n. gen. et sp. is erected to accommodate this species. Pentaplacodinium saltonense differs from Protoceratium reticulatum (Claparède et Lachmann 1859) Bütschli 1885 in the number of precingular plates (five vs. six), cingular displacement (two widths vs. one), and distinct cyst morphology. Incubation experiments (excystment and encystment) show that the resting cyst of Pentaplacodinium saltonense is morphologically most similar to the cyst-defined species Operculodinium israelianum (Rossignol, 1962) Wall (1967) and O. psilatum Wall (1967). Collections of comparative material from around the globe (including Protoceratium reticulatum and the genus Ceratocorys ) and single cell PCR were used to clarify molecular phylogenies. Variable regions in the LSU (three new sequences), SSU (12 new sequences) and intergenic ITS 1–2 (14 new sequences) were obtained. These show that Pentaplacodinium saltonense and Protoceratium reticulatum form two distinct clades. Pentaplacodinium saltonense forms a monophyletic clade with several unidentified strains from Malaysia. LSU and SSU rDNA sequences of three species of Ceratocorys ( C. armata, C. gourreti, C. horrida ) from the Mediterranean and several other unidentified strains from Malaysia form a well-supported sister clade. The unique phylogenetic position of an unidentified strain from Hawaii is also documented and requires further examination. In addition, based on the V9 SSU topology (bootstrap values >80%), specimens from Elands Bay (South Africa), originally described as Gonyaulax grindleyi by Reinecke (1967), cluster with Protoceratium reticulatum . The known range of Pentaplacodinium saltonense is tropical to subtropical, and its cyst is recorded as a fossil in upper Cenozoic sediments. Protoceratium reticulatum and Pentaplacodinium saltonense seem to inhabit different niches: motile stages of these dinoflagellates have not been found in the same plankton sample. [ABSTRACT FROM AUTHOR]

Sediments deposited after the peak of the Messinian Salinity Crisis (MSC) in the Apennine foredeep of Italy embody a topic debated on both chronostratigraphic and palaeoenvironmental grounds. We performed micropalaeontological (calcareous nannofossil and dinoflagellate cyst) analyses on four stratigraphic sections (Monticino, Civitella del Tronto, Fonte dei Pulcini, Fonte la Casa) and reused those previously published from Maccarone. All sections belong to the p-ev 2 Fm. that includes the Colombacci deposits, usually considered emblematic of the Lago Mare in the area. Marine microfossils recorded in previous studies have often been neglected or considered reworked and hence discarded. We propose the occurrence of at least four marine inflows between 5.36 and 5.33 Ma, the first of which is reflected in the Apennine foredeep by marine dinoflagellates that are then replaced by Paratethyan (brackish) ones. Paratethyan species occupied favourable environments during intervals separating marine inflows while the marine species survived elsewhere. From this perspective, the Apennine foredeep was an isolated perched basin during most of the peak of the MSC (5.60–5.36 Ma), and was progressively and repeatedly invaded by marine waters overflowing a palaeo-sill before the beginning of the Zanclean (5.33 Ma) which itself reflects a continuing eustatic rise. The Gargano Peninsula and, offshore, the present-day Pelagosa sill may be regarded as the remnants of this Messinian sill. This interpretation provides new possibilities for ecostratigraphically correlating the sections with Lago Mare biofacies, the deposition of which unquestionably started prior to the deposition of Colombacci sediments and continued into the earliest Zanclean. The results of this study show that the Lago Mare facies cannot be restricted to a single brackish palaeoenvironment but included competing marine and brackish waters controlled by geographic and chronological factors. Deposits overlying the unconformity separating the regional p-ev 1 and p-ev 2 formations are considered to represent the first marine incursion into the Apennine foredeep. These results allow us to refine the palaeogeographic reconstruction of the Apennine foredeep during the peak of the MSC. Although this basin was deep, its history during the peak of the MSC did not parallel that of the central Mediterranean basins. [ABSTRACT FROM AUTHOR]

Major climatic reorganizations, including changes in the nature of glacial–interglacial cycles through the Pleistocene, are a key issue for improving the understanding of Earth's climate system. Highly resolved marine sedimentary records are essential to reconstruct the details of these past climatic changes and investigate the mechanisms responsible for them. The Kazusa Group, located in the central part of the Japanese island chain, is well-exposed and contains a remarkably continuous and thick, deep- and shallow-water marine sedimentary succession. This group also contains well-preserved marine microfossils, pollen, paleomagnetic reversal events, geochemical signatures, and a large number of tephra beds. These features allow us to establish a robust chronological and stratigraphic framework for the Kazusa Group, and provide a rare opportunity to study oceanic and terrestrial climatic and environmental changes at high resolution especially through the Lower and lower Middle Pleistocene. In the Boso Peninsula, Chiba Prefecture, the Kazusa Group is deeply incised, yielding spectacular river-cut exposures. The Matuyama–Brunhes paleomagnetic reversal is observed immediately above the widespread Byakubi-E (Byk-E) tephra in the Chiba composite section within the Kokumoto Formation (Kazusa Group). Because the Matuyama–Brunhes boundary customarily serves as the primary guide for the Lower–Middle Pleistocene Subseries boundary, the Chiba composite section is considered an excellent candidate for its global boundary stratotype section and point (GSSP). This study reviews the published data for the Kazusa Group (hitherto almost exclusively in Japanese) in order to place the Chiba composite section within its broader depositional and chronostratigraphic context. [ABSTRACT FROM AUTHOR]

We present a high-resolution analysis of planktonic foraminifers, calcareous nannofossils, ostracods, dinoflagellate cysts and pollen grains in four sequences from DSDP–ODP holes in the southwestern Mediterranean Alboran and Balearic basins (976B, 977A, 978A and 134B) encompassing the previously defined Messinian–Zanclean boundary. The study focuses on (1) the marine reflooding, which closed the Messinian Salinity Crisis prior to the Zanclean GSSP; (2) the nature of the Lago Mare in the deep basins (indicated by Paratethyan dinoflagellate cysts), which appears to comprise several Paratethyan influxes without climatic control; and (3) the depositional context of the youngest Messinian evaporites which accumulated in a marine environment relatively close to the palaeoshoreline. Isolation of the Aegean Basin during the paroxysmic second step of the crisis is considered to have stored Paratethyan waters, which may then have poured into the Mediterranean central basins after deposition of the evaporitic sequence. [ABSTRACT FROM AUTHOR]

Abstract: In an attempt to document the palaeoecological affinities of individual extant and extinct dinoflagellate cysts, Late Pliocene and Early Pleistocene dinoflagellate cyst assemblages have been compared with geochemical data from the same samples. Mg/Ca ratios of Globigerina bulloides were measured to estimate the spring–summer sea-surface temperatures from four North Atlantic IODP/DSDP sites. Currently, our Pliocene–Pleistocene database contains 204 dinoflagellate cyst samples calibrated to geochemical data. This palaeo-database is compared with modern North Atlantic and global datasets. The focus lies in the quantitative relationship between Mg/Ca-based (i.e. spring–summer) sea-surface temperatures (SSTMg/Ca) and dinoflagellate cyst distributions. In general, extant species are shown to have comparable spring–summer SST ranges in the past (SSTMg/Ca) and today (SST from World Ocean Atlas 2005, Locarnini et al., 2006), demonstrating that our new approach is valid for inferring spring–summer SST ranges for extinct species. For example, Habibacysta tectata represents SSTMg/Ca values between 10 and 15°C when it exceeds 30% of the assemblage, and Invertocysta lacrymosa exceeds 15% when SSTMg/Ca values are between 18.6 and 23.5°C. However, comparing Pliocene and Pleistocene SSTMg/Ca values with present day summer values for the extant Impagidinium pallidum suggests a greater tolerance of higher temperatures in the past. This species occupies more than 5% of the assemblage at SSTMg/Ca values of 11.6–17.9°C in the Pliocene and Pleistocene, whereas present day summer SSTs are around −1.7 to 6.9°C. This observation questions the value of Impagidinium pallidum as reliable indicator of cold waters in older deposits, and may explain its bipolar distribution. [Copyright &y& Elsevier]