GEES

Flutes are widespread across the forefield of polythermal valley glacier Midre Lovenbreen, Svalbard, where they consistently form on the downglacier face of cobble to boulder-sized subglacially-transported clasts ploughed into proglacial till. The width of flutes at Midre Lovenbreen is constant along their long-axes and proportional to the size of their associated subglacially-transported boulders. Frozen flutes are observed subglacially where they protrude into the debris-rich basal ice layer of the glacier. Particle-size analysis shows that flutes are depleted in gravel-sized particles relative to adjacent subglacial till. Ice sampled from flutes is enriched in delta18O relative to overlying glacier ice and debris-rich basal ice. These properties are interpreted to reflect the formation of flutes by the squeezing of till into basal cavities associated with boulders beneath warm-based ice in the interior of the glacier. It is hypothesized that localized freeze-on of flute sediments, within a broader zone of warm-based ice, occurs within cavities due to either (i) a 'heat-pump' effect operating across these boulders leading to the development of a cold patch within the cavity, and/or (ii) fluctuations in cavity length caused by slip-stick glacial motion. Once incorporated into the basal ice layer, the frozen flute sediment would then be transported away from the boulder by ice flow, allowing the cavity to remain continuously open and the flute to propagate down flow.

Surface sediments, water samples and environmental data from 37 lakes, ponds and streams in Israel were analysed to determine the main variables controlling ostracod species distributions. Multivariate statistical analysis revealed that the greatest amounts of variation in the distribution of the ostracod taxa among the 37 water bodies were explained by the host water δD value (12.9%), water temperature (11.0%), mean January air temperature (10.5%), electrical conductivity (9.5%), and the Mg and NO3 concentrations (7.8 and 7.1%, ion concentrations as % of the anions or cations). A supplementary data set comprising ostracod species composition and electrical conductivity readings for 24 water bodies was available from previous research and was merged with the 37 samples data set to develop an ostracod-based transfer function for the reconstruction of electrical conductivities. A weighted averaging partial least squares regression (WA-PLS) provided the best results with a relatively high coefficient of determination (r 2) between measured and inferred electrical conductivity values of 0.73, a root mean square error of prediction of 0.13 (13.4% of gradient length) and a maximum bias of 0.24 (23.9% of gradient length), as assessed by leave-one-out cross-validation based on 56 water bodies. The application of the EC transfer function onto (sub)fossil ostracod assemblages from Holocene and early to mid Pleistocene lake sediments provided EC values consistent with other proxies and demonstrated that Quaternary ostracod assemblages from subaqueous sediments can now be used to trace the hydrological history of water bodies in the Near East. A better understanding of past hydrological conditions in response to the natural climate variability is crucial in regions that face restricted water resources and rising demands in times of rapid climate and environmental change.

The Iron Age hill fort at Burrough Hill, Leicestershire, eastern England, lies in a lowland landscape of Mesozoic sedimentary  ocks comprising mudstones with thin limestone units, sandstones and ironstones, which are blanketed by Pleistocene till. During the late Iron Age the hill fort was an important central place; permanent occupation probably began in Early-Middle Iron Age and continued into the Roman period. A  variety of materials in archaeological contexts from the site, including clay rampart bonding and the clay linings of storage pits and floors, are found to yield characteristically mixed microfossil assemblages of Early to Late Jurassic ostracods and foraminifera, together with foraminifera from the Late  Cretaceous. These provide a unique microfossil signature that indicate provenance from the local till. Microfossils can also be recovered from Middle to Late Iron Age potsherds at Burrough Hill, and these too suggest a local glacial source for the clay. Our analysis demonstrates the power of microfossils to provenance clay materials used for construction and manufactures at an Iron Age site, where a detailed baseline understanding of the local geology is firmly established.

Annual, monthly and daily analyses of stable isotopes in precipitation are commonly made worldwide, yet only a few studies have explored the variations occurring on short timescales within individual precipitation events, particularly at mid-latitude locations. This study examines hydrogen isotope data from sequential, intra-event samples from sixteen precipitation events during different seasons and a range of synoptic conditions over an 18-month period in Birmingham, UK. Precipitation events were observed simultaneously using a vertically-pointing micro rain radar (MRR), which, for the first time at a mid-latitude location, allowed high resolution examination of the microphysical characteristics (e.g. rain rate, fall velocity, drop size distributions) that may influence the local isotopic composition of rainwater. The range in δD from 242 samples from 16 events was -87.0‰ to +9.2‰, whilst the largest variation observed in a single event was 55.4‰. In contrast to previous work, the results indicate that some mid-latitude precipitation events do indeed show significant intra-event trends that are strongly influenced by precipitation processes and parameters such as rain rate, melting level height and droplet sizes. Inverse relationships between rain rate and isotopic composition are observed, representing an example of a local type of ‘amount effect’, a still poorly-understood process occurring at different scales. For these particular events the mean δ value may therefore not provide all the relevant information. This work has significance for the testing and development of isotope-enabled cloud resolving models and land surface models at higher resolutions, and provides improved insights into a range of environmental processes that are influenced by sub-sampled precipitation events.

... The HPI fraction from treated effluent displays a small peak at about 6 min, attributable to the very high molecular weight compounds that could be colloidal polysac-charides and proteins due to the negligible corre-sponding UVA peaks (Croué 2004; Nam and Amy 2008). ...

Hilary H. Birks1,3, Sylvia M. Peglar1, Ian Boomer2, RJ Flower3 and M. Ramdani4, with contributions from PG Appleby5, AE Bjune1, ST Patrick3, MM Kraïem6, AA Fathi7 and HMA Abdelzaher7 1Botanical Institute, University of Bergen, Allégaten 41, N-5007 Bergen, Norway (Fax: +47 ...

This article discusses the potential value of geoarchaeological and paleoenvironmental data for the contextualization of human activity at the site of Domuztepe, southeast Turkey. The data come from cores excavated on a series of transects centered on the höyük and from samples collected for paleoenvironmental assessment and radiocarbon dating. The results indicate that the site is situated on an alluvial plain of some stratigraphic complexity. Deep (up to 9 m) sediment sequences consisting of peats, marls, silts, clays, ...

ABSTRACT Subsurface flow pathways of groundwater-fed streams were characterized on a floodplain terrace of the Toklat River, Alaska, in summer 2008, to establish the influence of local physicochemical variability upon macroinvertebrate communities. Streams proximal to the valley side (A sites) and to the main meltwater channel (B sites) were studied. Chloride and natural isotopic tracers (δ18O and δ2H) were used to identify water sources and flow pathways. Results indicated that flow in B sites was dominated by seepage of glacial meltwater through the alluvial aquifer. Streamflow at sites situated at higher elevations was ephemeral, and commenced with the seasonal rise in the groundwater table. In contrast, the physicochemistry of A sites was characteristic of seepage from valley-side debris fans, which maintained perennial flow to streams at lower elevations. Macroinvertebrate diversity was lower in ephemeral streams, likely due to colonization constraints. In June macroinvertebrate abundance was significantly positively correlated with the percentage contribution to streamflow from debris-fan seepage (p < 0.05) and with fine particulate organic matter concentration (FPOM) (p < 0.05); FPOM was correlated with debris fan seepage (p < 0.05). These relationships were not evident in July and August, when organic matter availability increased. Our study demonstrates that flow pathways and organic matter availability significantly influence macroinvertebrate communities in these groundwater-fed streams.