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The profile of the Lipowo palaeolake (NE Poland) preserves a record of environmental and climate changes from the Last Glacial Termination (16.5k cal ka BP), stretching from the Oldest Dryas to the youngest Allerød warm oscillation. In this interdisciplinary study of the lacustrine succession at Lipowo, we used biological and geochemical indicators and multiproxy analyses to reconstruct environmental changes in the lake ecosystem, such as mollusc, zooplankton and vegetation development, trophic state, water temperature and water level. Four cold and four warm climate oscillations of different durations were identified on this basis: the Older Dryas climate deterioration and two short‐term coolings within the Allerød Interstadial, separated by warm periods in the Bølling and Allerød. The covering of the lake series by diamicton deposits from the melting of dead‐ice blocks is a particularly interesting and rare phenomenon for a postglacial area. The hydrological system of the catchment was generally closed, with a periodically opening and existing flow‐through lake. Over the period of the lake's existence, vegetation changed in general from steppe tundra to forest with birch and pine. For most of this time, the palaeolake was mainly oligotrophic, with increased productivity and a higher trophic level only notable during the middle Bølling. [ABSTRACT FROM AUTHOR]

The analysis of the Late Pleistocene small mammals’ faunas from the three cultural layers of the Late Palaeolithic site Byki 7 (the Seim River basin) consist of a combination of steppe and tundra species. Steppe species definitely prevail and include Ochotona pusilla, Marmota bobac, Spermophilus sp., Spalax microphthalmus, Ellobius talpinus, Lagurus lagurus and Lasiopodomys (Stenocranius) gregalis. Tundra species (collared lemming and Siberian lemming) are only represented by a small amount of remains. The lack of forest dwellers in the Byki 7 small mammal assemblage indicates of the absence of a continuous forest zone on the Central Russian Plain during the end of the Valdai glaciation. The Eurasian geographical distribution of the Rodentia and Lagomorpha species represented in the Byki–7 assemblages, have been reconstructed for the period of deposition of the site. Radiocarbon dates indicate that the multilayer Late Palaeolithic Byki 7 site correlates with the second part of the Valdai Glaciation Maximum cooling (LGM) (22–17 ka BP). Based on the small mammal data the former palaeoenvironmental conditions of the non-analogue periglacial tundra-steppe are reconstructed.

The thick fine‐grained sedimentary rocks in the second member of the Kongdian Formation (Ek2) in the Cangdong sag, Bohai Bay Basin, eastern China, are typical lacustrine source rocks and have recently been regarded as the main target for shale oil exploration. Compared with marine shales, the strong heterogeneity in the mineral composition, structure feature, and vertical association pattern of the Ek2 lacustrine fine‐grained sedimentary rocks in the Cangdong sag is significantly influenced by frequent variations in the sedimentary environment and depositional process. Based on the detailed core and thin‐section description analyses as well as the two‐dimensional X‐ray fluorescence (2D‐XRF) analysis, the Ek2 fine‐grained sedimentary rocks in the Cangdong sag can be classified into six types of lithofacies by employing the content of three main mineral compositions together with structure features, among which five types are mainly deposited, including laminated felsic fine‐grained sedimentary rocks, laminated and massive carbonate fine‐grained sedimentary rocks, and laminated and massive mixed fine‐grained sedimentary rocks. The sedimentary environment during the sedimentary period of the Ek2 in the Cangdong sag was reconstructed by several indexes (including salinity, water depth, redox condition, climate, and detrital input) using the element geochemical parameters. The variations of detrital input and lake physicochemical characteristics driven by climate were vertically divided into four phases, indicating that the lake gradually changed from the transgression to the highstand period. In addition, the water column stratification led to the overall dysoxic–anoxic condition. The depositional process can be interpreted by correlating the lithofacies and the sedimentary environment. The results indicate that the mineral composition is controlled by the detrital input and carbonate production driven by climate and that structural features are mainly affected by the water column stratification. The Ek2 fine‐grained sedimentary rocks in the Cangdong sag present the vertical distribution of lithofacies that matches with the evolution phases of the sedimentary environment. This study's results enhance the understanding of the formation mechanism of lacustrine fine‐grained sedimentary rocks and provide basic geological knowledge for shale oil exploration in the study area. [ABSTRACT FROM AUTHOR]

The flora of the Cianowice 2 borehole (c. 20 km NW of Cracow, Poland), dominated by cycadophytes (mainly bennettitaleans) and conifers, shows high taxonomic diversity relative to the low number of specimens. Twenty species were identified in the 96 determinable plant fragments found in 27 core samples: Cladophlebis sp. (ferns), Pachypteris rhomboidalis (Ettingshausen) Nathorst and Ptilozamites cycadea (Berger) Möller (seed ferns), Anomozamites nilssonii (Phillips) Seward, Nilssoniopteris solitaria (Phillips) Cleal & Rees, Otozamites mimetes Harris, Otozamites parallelus Phillips, Pterophyllum thomasii Harris, Pterophyllum cf. aequale (Brongniart) Nathorst, Ptilophyllum cf. okribense forma ratchiana Doludenko & Svanidze, Ptilophyllum pecten Phillips, Ptilophyllum sirkennethii Watson & Sincock, Cycadolepis sp. (bennettitaleans), Pseudotorellia grojecensis Reymanówna, Pseudotorellia samylinae Nosova & Kiritchkova, Pseudotorellia sp. (Gymnospermae incertae sedis), Bilsdalea dura Harris, Mirovia szaferi Reymanówna, and Brachyphyllum stemonium Kendall (conifers). The floristic composition is supplemented by palynological data. The taxa were connected to five depositional successions distinguished along the core: one, alluvial fans; two, four and five, meandering/ anastomosing river depositional systems with fluvial plain deposits; and three, lacustrine/backswamp environment developed on fluvial plain. The composition of the fossil plant assemblage changes with the depositional setting within the same range of taxa, seen mainly in changed combinations of taxa, which are most diverse in the fluvial plain deposits. Some taxa occur in a single depositional succession; some are present in two or three. The sporomorph assemblages of particular depositional environments differ significantly from the composition of the co-occurring macroflora: ferns occur sporadically in the macroflora of each depositional environment but they strongly dominate the sporomorph assemblage. Our proposed reconstruction of the palaeoenvironment is a slight rise descending into a valley with a depositionary basin, with gymnosperms on the slope and ferns at the base. Some species are shared between Cianowice and nearby Middle Jurassic localities in Grojec and Zabierzów, and the majority of taxa are known from the Middle Jurassic, suggesting that the Cianowice deposits are of that age. [ABSTRACT FROM AUTHOR]

Mammal and bird bone remains from Upper Holocene sediments at the Nizhneirginsky Grotto were studied. Nizhneirginsky Grotto is located in the northern part of the Ufa Plateau in the Middle Fore-Urals. The sequence of deposits contains three layers which have been accumulating during the last 4150 years. Identified mammal elements include 9839 bone remains of 29 species belonging to five orders, i.e., Eulipotyphla (435), Chiroptera (1608), Lagomorpha (52), Rodentia (7688), and Carnivora (56). Recovered bird remains include 1946 bones of 38 species. Most identified species currently inhabit the Nizhneirginsky Grotto area. The analysis of alterations in the first lower molars of arvicoline rodent species caused by the digestion showed that eagle owl (Bubo bubo , Linnaeus, 1758) is the most possible agent responsible for the accumulation of small mammal assemblages in the grotto sediments. An unusually high number of birch mouse fossils was noted over the entire sediment section of the grotto (MNI on average by layers is 8.1–15.4%). This phenomenon, probably, has a taphonomic origin and is associated with the predation activity of mustelids. Palaeoenvironmental analysis of small mammal assemblages based on the habitat weighting method showed the predominance of open landscapes and woodlands around the grotto during the Late Holocene. This landscape did not change in the last 4150 years. The connection of the history of the yellow-necked mouse in the northeast of its modern range with the palaeogeographic events of the second half of the Holocene was established. The material from the sediments of the Nizhneirginsky Grotto shows that the species was common in the northern part of the Ufa Plateau, in the Irgina River valley, in the period of 4150-3100 cal BP, which coincides with the maximum distribution of broad-leaved trees in the Fore-Urals during the mid-Subboreal thermal maximum (SB-2; 4200-3200 BP). Pika's (Ochotona , perhaps O. pusilla , Pallas, 1769) sinister mandible was found among osteological material from the upper part of layer 2 which dates to 710 ± 20 cal BP (1240 ± 20 cal AD). This is the first find of the pika's remains of such late age in the Middle Urals and in adjacent territories. The species was common in the northern part of the Ufa Plateau during Late Pleistocene and Early Holocene. Steppe pika is now disjunct from the Nizhneirginsky Grotto by approximately 200–300 km to the south and to the south-west. O. pusilla probably inhabited the valley of the Irgina River as a relic of the Late Pleistocene and Early Holocene faunas as early as 12th and 13th centuries AD. [ABSTRACT FROM AUTHOR]

Silica is deposited extra- and intracellularly in plants in solid form, as phytoliths. Phytoliths have emerged as accepted taxonomic tools and proxies for reconstructing ancient flora, agricultural economies, environment, and climate. The discovery of silicon transporter genes has aided in the understanding of the mechanism of silicon transport and deposition within the plant body and reconstructing plant phylogeny that is based on the ability of plants to accumulate silica. However, a precise understanding of the process of silica deposition and the formation of phytoliths is still an enigma and the information regarding the proteins that are involved in plant biosilicification is still scarce. With the observation of various shapes and morphologies of phytoliths, it is essential to understand which factors control this mechanism. During the last two decades, significant research has been done in this regard and silicon research has expanded as an Earth-life science superdiscipline. We review and integrate the recent knowledge and concepts on the uptake and transport of silica and its deposition as phytoliths in plants. We also discuss how different factors define the shape, size, and chemistry of the phytoliths and how biosilicification evolved in plants. The role of channel-type and efflux silicon transporters, proline-rich proteins, and siliplant1 protein in transport and deposition of silica is presented. The role of phytoliths against biotic and abiotic stress, as mechanical barriers, and their use as taxonomic tools and proxies, is highlighted.

El creciente desarrollo de la industria cementera ha reactivado la exploración de los yacimientos de calizas en el sur de Argentina. En la zona de Punta Colorada, a 36 km de Sierra Grande, Prov. de Río Negro, se encuentra un depósito de estas rocas pertenecientes a la Formación Arroyo Verde, del Eoceno inferior, originada por una ingresión marina ocurrida el Cretácico superior-Terciario inferior. A través de un estudio técnico se cubicaron 14.806.106 tn de reservas medidas y 1.799.174 tn de reservas indicadas en carbonato de calidad menor al 4 % MgO. Se estudió un área de 800 Ha, dividida en 2 zonas ubicadas al norte y al sur de Punta Colorada, separadas por el Arroyo Las Palmas, en el litoral marítimo atlántico. Se determinó una potencia media de 10 m de calizas por medio de perforaciones y perfiles. El análisis de los perfiles permitió establecer 4 niveles compuestos por calizas masivas a granulares, con estratificación entrecruzada, fosilíferas. Microscópicamente se observan bivalvos, equinodermos, corales, foraminíferos y algas. La fracción clástica terrígena, tamaño arena-limo, está compuesta principalmente por cuarzo, feldespato y concreciones arcillosas verdosas. Se analizaron los tenores de CaO, MgO y se calcularon las relaciones Mg/Ca observándose variaciones verticales con aumento del MgO hacia los niveles superiores del yacimiento. Sobre la base de los porcentajes de estos óxidos se clasifica a las rocas en caliza, caliza dolomítica y dolomita calcítica. Se analizaron además Al, Fe, K, Mg, Mn, Na, P, S y Ti, observándose variaciones geoquímicas laterales y verticales que se relacionarían con cambios morfológicos, paleoambientales y de evolución de la cuenca. Se concluye que las calizas están constituidas principalmente por calcita con cantidades variables de MgO. Estas rocas se habrían formado en lagunas costeras de aguas cálidas, con alto contenido en fósforo. En otros sectores de la cuenca se habrían formado áreas pandas, con alimentación intermitente de aguas marinas, que quedaron aisladas temporalmente del ambiente marino dominante idea apoyada por el aumento en el contenido de Na y K. El contenido de Al, Fe, Mn y Ti estaría relacionado con la presencia de material terrígeno; sin embargo, el escaso aporte a la cuenca indicaría condiciones climáticas de aridez con bajo régimen pluvial. La estratificación entrecruzada en el nivel 2 se asocia a corrientes marinas. La abundancia de fósiles fragmentados revelaría la alta energía del medio. Sobre las planicies de marea las trazas de bioturbación de poco espesor, marcarían condiciones de inestabilidad, además de estadios de energía moderada a relativamente baja con tasa de sedimentación de igual calificación. En la etapa final las condiciones de depositación son marinas costeras, someras, con presencia de conchillas enteras dispersas, estratificación entrecruzada y aumento en el contenido de Fe y Mn. Mientras que en otras áreas el aumento en el contenido de azufre como yeso, señalaría una sostenida regresión del mar en dirección SO-NE.The fast growing cement industry has reactivated the exploration for calcareous materials in southern Argentina.A carbonatic deposit is found in Punta Colorada, located 36 km from the town of Sierra Grande, Río Negro Province. These rocks, deposited during a Late Cretaceous - Early Tertiary marine ingression, belong to Arroyo Verde Formation (Early Eocene). These coastal deposits have been studied since 1927 by Wichmann, Arnolds (1952), de Alba (1964), Weber (1983) and Busteros et al. (1998). Rossi de García and Levy (1982) assigned these rocks to the Eocene; Spalletti et al. (1993) located them within the Roca Formation (Rocanense ingression) and Gelós et al. (1992) correlated these rocks with Arroyo Verde Formation (Malvicini and Llambías, 1974). Arroqui Langer et al. (2006) from sedimentologic, geochemical and lithologic data in carbonatic rocks of the Precordillera Argentina established an exploration and exploitation pattern. Bonuccelli (2006) made a similar technical study in Punta Colorada, where 14,806,106 tn of measured reserves and 1,799,174 tn of indicated reserves were determined in a carbonate of less than 4% MgO grade. The study area comprise 800 Ha divided in two zones separated by Arroyo Las Palmas gully and located at the north and at the south of a basement outcrop denominated Punta Colorada, in the atlantic marine coast (Fig. 1). By means of 12 drills cores and 8 stratigraphic profiles, a thickness of 10 m was determined for the limestone. Major and minor chemical elements were determined by ICP-MA in 100 ml with two replicas in Alex Steward laboratories, Mendoza. The criterion of Tucker (1981) was used to classify the limestones by the dolomite percentage. From stratigraphic profiles four levels composed of cross-bedded massive to granular fosiliferous limestones were determined. Microscopically they are composed of a fossiliferous limestone (bioclastic packstone) with bivalves, equinoderms, corals, foraminifera and algae, being algal buildups more abundant in level three. The clastic sand to silt fraction is mainly composed of quartz, feldspar and green clay concretions. CaO and MgO contents and the relationships Mg/ Ca (Tables 1 and 2) in the stratigraphic profiles and drills cores show vertical variations with increasing MgO values toward the upper levels of the sequence. Based on the percentages of these oxides the rocks are classified as limestone, dolomitic limestone and calcitic dolomite. In drill cores Al, Fe, K, Mg, Mn, Na, P, S and Ti contents, indicate lateral and vertical variations that would be related to geomorphological and paleoenvironmental changes and to the basin evolution as well (Fig. 2, Tables 1-3). It is concluded that the limestones are mainly composed of calcite with variable quantities of MgO. These rocks would have been formed in warm lagoons with high P content. At the same time shallower areas with intermittent influx of marine waters would have been developed in other sectors. The increase in the content of Na and K in these sectors would support the idea that these evaporitic deposits were temporarily isolated from the dominant marine environment. Al, Fe, Mn and Ti concentrations would be related to the presence of terrigenous material; however, the scarce contribution to the basin would indicate climatic conditions of aridity with low pluvial regimen. Crossbedding in level 2 is associated to marine currents. The abundance of broken fossils would indicate a highly energy environment. On the tidal flat, the presence of rather thin bioturbation traces (Thalassinoides) would indicate conditions of instability during the development of this ichnofacies, as well as a rather moderate energy with low sedimentation rates. At the final stage, shallow marine, coastal, sedimentation prevail, marked by the abundance of entire shells, cross-bedding and an increment in the Fe and Mn concentration. At the same time in other sectors, the increase in the sulfur content as gypsum, would indicate a sustained SW-NE sea regression.

The Upper Cretaceous–Paleogene deposits of the Grey Unit, the Lower Red Unit and the Suterranya Limestone of the Tremp Formation (South-Central Pyrenees) preserve sedimentological and palaeontological features that suggest a connection with marine settings and which allow the age of these deposits to be reviewed. The deduced sedimentary environments for the Grey Unit and the Suterranya Limestone – lagoonal and coastal lake environments respectively – agree with those proposed by previous authors. However, a new depositional setting is proposed for the Lower Red Unit, that of a mixed-energy zone in a tide-dominated delta. This new interpretation is based on the presence of inclined heterolithic stratification in point bar deposits, along with flaser and lenticular bedding and the presence of in situ marine fossils – including those of planktonic foraminifera – and glauconite grains. These foraminifera were almost certainly transported, as a suspended load, from the open sea into meandering channels on flood tides. Their associated biostratigraphy suggests a Maastrichtian age for the Grey Unit and Lower Red Unit, and a late Danian age for the Suterranya Limestone. There is a significant hiatus between latter and former units that covers most of the Danian, and presumably includes the Cretaceous/Paleogene boundary. [ABSTRACT FROM AUTHOR]

Abstract: Land snail shell assemblages have been used since the pioneering days of palaeoecology to describe Quaternary environmental changes. Despite the many advantages of this proxy, it has recently been rather overlooked. There are more than 300 mollusc successions from localities throughout the Czech and Slovak Republics, making this a globally unique archive. We selected 91 of these successions for radiocarbon dating and further detailed processing. Based on analyses of 828 mollusc assemblages we found a significant increase in both total species richness and number of forest species since the Lateglacial, with a decrease in both after the Middle Holocene. In contrast, the opposite response was found for open-country species and the proportion of xerophilous species. The proportion of forest and open-country species reversed at the Pleistocene/Holocene transition (approx. 11,500 cal yrs BP). Changes in species richness were rather stable across the study area and at different elevation, contrary to changes in species composition. MDS ordination based on presence/absence data show four main patterns of species composition associated with the number of forest species in a sample, position of site along the west–east direction, the proportion of hygrophilous species and, finally, with the age of the mollusc assemblage. The number of forest species indicates the main pattern of changes in the composition of Central European land snail assemblages from the Lateglacial to the present. We confirmed the application and temporal stability of ecological groups of snails as a useful tool for reconstruction of the terrestrial palaeoenvironment. [Copyright &y& Elsevier]

This paper presents an assessment of Holocene tree cover densities and forest disturbance in European Russia using the best-modern-analogue (BMA) technique of quantitative reconstruction and an innovative approach, which combines modern pollen datasets with remotely sensed data from moderate-resolution imaging spectroradiometer satellite images. The test of the accuracy of the applied method using a database of 450 sets of surface pollen assemblages shows that it can reproduce present day characteristics of woody cover in Europe correctly ( R = 0.57, standard error = 10.8 %), and it is sufficient for reconstruction of major changes of woodland vegetation in the past. Application of the BMA technique to fossil pollen data from two key regions in the central part of European Russia demonstrates that changes in regional woody cover are useful for the reconstruction of prehistoric human disturbance. [ABSTRACT FROM AUTHOR]

Abstract: The Velykyi Glybochok Palaeolithic site near Ternopil town (Podolia Upland) contains a set of cultural layers in a sequence of loess and fossil soils. Beside the archaeological study of stone assemblages, the profile was investigated using lithological, palaeopedological and geochemical methods, including stable carbon and oxygen isotopes composition of pedogenic carbonates, soils micromorphology and TL dating. Remnants of vertebrates'' bones and mollusc shells were also distinguished. The oldest cultural layer III documented the presence of Palaeolithic people during the Penultimate Interglacial represented by fossil soil – cambisol in type, developed under dense vegetation cover. The cultural layer III B is connected with initial cambisol originated in a short period of open landscape vegetation with shrubs development, dated to the climatic amelioration during the time of Penultimate Glaciation. The Last Interglacial is represented by luvisol formation with two stages of illuviation, which shows forest type of vegetation. Materials of the cultural layer III A were dispersed in the soil irregularly and mixed with artifacts of cultural layer II. Artifacts of III, III A and III B cultural layers represent the Middle Palaeolithic “Dniesterian Mousterian culture with Levalloisian technique”. These of assemblage II represent the Upper Palaeolithic. Inside the recent soil at the top of the sequence, the Mesolithic cultural layer I is present. Velykyi Glybochok is the only multilayer site in Podolia with detailed information about geological position of particular cultural layers. [Copyright &y& Elsevier]

n -Alkanes have been widely used to reconstruct palaeoenvironmental variations in lacustrine environments. However, for robust reconstructions, improving the understanding of the origin of n -alkanes and their distribution within the lake is essential. Therefore, we examined the distribution pattern of n -alkanes in the aquatic plants within Lake Lugu (a deep alpine lake on the southeastern margin of the Tibetan Plateau, southwest China), and terrestrial plants and topsoils in the catchment, to unravel the origin of sedimentary n -alkanes and further investigate the spatial distribution of n -alkanes from surface sediments in this lake. The aquatic plants are dominated by mid-chain C 23 and C 25 , terrestrial plants and soils by long-chain C 29 , and 76% of the surface sediment samples show C 29 predominance. The average chain length (ACL) and the aquatic plant proxy (P aq) values of surface sediments are between those of aquatic and terrestrial plants and soils. Thus, n -alkanes from autochthonous (aquatic plants) and allochthonous (terrestrial plants and soils) sources were apparent in the surface sediments. A substantial spatial distribution of n -alkanes exists within Lake Lugu: the n -alkane concentrations of total, aquatic, and terrigenous origins are concentrated in the northwestern portion of the lake's north basin, which may be attributed to the underwater topography and increased human-induced soil erosion in this area. Similarly, the clear spatial heterogeneity of ACL 21 – 33 and P aq may suggest that the sedimentary n -alkanes comprise a mixture contribution of autochthonous and allochthonous production, which might be the major source of n -alkanes in the lakeshore, and a higher proportion of autochthonous n -alkanes is present in deep water. However, there is no significant correlation between the P aq of sediments and water depth in Lake Lugu; thus, the application of P aq as a lake-level indicator should be used with caution in deep-water lakes similar to Lake Lugu. [ABSTRACT FROM AUTHOR]

Studies of the eruptive products from volcanoes with variable ice and snow cover and a long history of activity enable reconstruction of erupted palaeoenvironments, as well as highlighting the hazards associated with meltwater production, such as jökulhlaups and magma-water interaction. Existing difficulties include estimation of ice/snow thicknesses and discrimination between ice- and snow-contact lithofacies. We present field evidence from the Cerro Blanco subcomplex of Nevados de Chillán stratovolcano, central Chile, which has erupted numerous times in glacial and non-glacial periods and most recently produced andesitic lava flows in the 1861–1865 eruption from the Santa Gertrudis cone on the northwest flank of the volcano. The main period of lava effusion occurred during the winter of 1861 when the upper flanks of the volcano were reportedly covered in snow and ice. The bases and margins of the first lava flows produced are cut by arcuate fractures, which are interpreted as snow-contact features formed when steam generated from the melting of snow entered tensional fractures at the flow base. In contrast, the interiors and upper parts of these flows, as well as the overlying flow units, have autobrecciated and blocky textures typical of subaerial conditions, due to insulation by the underlying lava. Similar textures found in a lava flow dated at 90.0±0.6 ka that was emplaced on the northwest flank of Cerro Blanco, are also inferred to be ice and snow-contact features. These textures have been used to infer that a small valley glacier, overlain by snow, existed in the Santa Gertrudis Valley at the time of the eruption. Such reconstructions are important for determining the long-term evolution of the volcano as well as assessing future hazards at seasonally snow-covered volcanoes. [ABSTRACT FROM AUTHOR]

Based on petrography, mineralogy, facies analysis and geochemical data Farias et al. (2019) suggested that syn-depositional hydrothermal fluids generated in part by mantle serpentinisation and seepage of brines through the Walvis Ridge–Rio Grande Rise sourced the South Atlantic basins, which resulted in the deposition of the Barra Velha carbonates in the Santos Basin, focus of their study. However, they seek support for this hypothesis in clumped isotope data, which does not unequivocally provide evidence for this interpretation. Furthermore, they presented significantly radiogenic 87Sr/86Sr data, which in turn do not give support for the inference of significant mantle-derived fluid sources. Therefore, their hypotheses should be carefully reconsidered. • Clumped isotopes of the Barra Velha Fm may require consideration of non-equilibrium isotopic effects or isotopic reordering. • Temperatures estimated from Δ 47 do not necessarily reflect temperatures of the primary surficial depositional environment. • Calculated δ18O VPDB values of 'lake' water more likely reflect superimposed effects, and depend on the premises considered. • 87Sr/86Sr data do not support fluids leaching predominantly basalts or originating from interaction with the mantle. [ABSTRACT FROM AUTHOR]

This paper presents a multiproxy palaeoenvironmental study from Abric del Pastor (Alcoy, Spain), a rock shelter which has yielded evidence for Middle Palaeolithic human occupation. The sedimentary sequence has been analysed for lipid biomarker n -alkane abundances (ACL, CPI), compound specific leaf wax δ2H and δ13C, and bulk organic geochemistry (TOC, %N, %S), providing a record of past climate and local vegetation dynamics. Site formation processes have been reconstructed through the application of soil micromorphology. Analyses of anthracological, microvertebrate and macrofaunal assemblages from selected subunits are also presented here. Our data indicates that a variable climate marked by predominantly cold conditions persisted through most of the sequence and that Neanderthal occupations in stratigraphic unit IVd, assigned to MIS 4 or late MIS 5, occurred in a landscape setting characterised by a mosaic of biotopes. The presence of key resources inside the ravine where the site is located suggests that the occupation of the rock shelter may have been strategically motivated by a subsistence and mobility strategy which focused on zones of localised ecological resilience, such as intra-mountainous valleys or ravines, during periods of global or regional environmental downturn. • New palaeoenvironmental data for Neanderthal site of Abric del Pastor is presented. • Degradation of n -alkanes linked to anthropogenic fire. • Occupations in S.U. IVd occurred in generally cold and dry conditions. • The Barranc del Cinc acted as a vegetation refugium. • Occupation of rock shelter may have been strategically motivated by its location. [ABSTRACT FROM AUTHOR]

Silica is deposited extra- and intracellularly in plants in solid form, as phytoliths. Phytoliths have emerged as accepted taxonomic tools and proxies for reconstructing ancient flora, agricultural economies, environment, and climate. The discovery of silicon transporter genes has aided in the understanding of the mechanism of silicon transport and deposition within the plant body and reconstructing plant phylogeny that is based on the ability of plants to accumulate silica. However, a precise understanding of the process of silica deposition and the formation of phytoliths is still an enigma and the information regarding the proteins that are involved in plant biosilicification is still scarce. With the observation of various shapes and morphologies of phytoliths, it is essential to understand which factors control this mechanism. During the last two decades, significant research has been done in this regard and silicon research has expanded as an Earth-life science superdiscipline. We review and integrate the recent knowledge and concepts on the uptake and transport of silica and its deposition as phytoliths in plants. We also discuss how different factors define the shape, size, and chemistry of the phytoliths and how biosilicification evolved in plants. The role of channel-type and efflux silicon transporters, proline-rich proteins, and siliplant1 protein in transport and deposition of silica is presented. The role of phytoliths against biotic and abiotic stress, as mechanical barriers, and their use as taxonomic tools and proxies, is highlighted. [ABSTRACT FROM AUTHOR]