Sticky stuff : redefining bedform prediction in modern and ancient environments

This work was funded by the UK Natural Environment Research Council (NERC) under the COHBED project (NE/1027223/1). Paterson was funded by the Marine Alliance for Science and Technology for Scotland (MASTS).The dimensions and dynamics of subaqueous bedforms are well known for cohesionless sediments. However, the effect of physical cohesion imparted by cohesive clay within mixed sand-mud substrates has not been examined, despite its recognized influence on sediment stability. Here we present a series of controlled laboratory experiments to establish the influence of substrate clay content on subaqueous bedform dynamics within mixtures of sand and clay exposed to unidirectional flow. The results show that bedform dimensions and steepness decrease linearly with clay content, and comparison with existing predictors of bedform dimensions, established within cohesionless sediments, reveals significant over-prediction of bedform size for all but the lowermost clay contents examined. The profound effect substrate clay content has on bedform dimensions has a number of important implications for interpretation in a range of modern and ancient environments, including reduced roughness and bedform heights in estuarine systems and the often cited lack of large dune cross-sets in turbidites. The results therefore offer a step change in our understanding of bedform formation and dynamics in these, and many other, sedimentary environments.Publisher PDFPeer reviewe

Geology of the Llanidloes district : British Geological Survey Sheet 164

This Sheet Explanation provides a summary of the geology of the district covered by Geological 1:50 000 Series Map Sheet 164 (Llanidloes), published in 2010 as a Bedrock and Superficial Deposits edition. The district mostly lies within the county of Powys, but includes small parts of Ceredigion in the extreme west and south-west. Much of the western part of the district is occupied by the deeply dissected uplands of the Cambrian Mountains, a designated Area of Outstanding Natural Beauty. In this area the land rises to 740 m on the flanks of Plynlimon (Pumlumon Fawr), the highest summit in the range. It falls away towards the eastern part of the district into rolling countryside that includes the important catchment of the River Severn (Afon Hafren) and its tributaries, the largest of which are the rivers Carno, Trannon, Cerist, Clywedog and Dulas. A major reservoir (Llyn Clywedog) occupies the upper reaches of the Clywedog valley, its purpose being to regulate river discharge and groundwater levels within the catchment. The south-western part of the district is drained by the River Wye (Afon Gwy) and its tributaries, that flow south-eastwards via Llangurig. The sources of both the Severn and Wye are situated on the eastern flanks of Plynlimon within the western part of the district. The town of Llanidloes is the main centre of population, with smaller settlements at Llangurig, Carno, Trefeglwys, Caersws and Staylittle; the Newtown conurbation impinges on the eastern part of the district. Much of the district is given over to beef and dairy farming, although sheep are reared in the remote upland areas in the west and extensive forestry plantations have been developed in places. The Ordovician and Silurian rocks of the district have been exploited locally, in the past, as a source of building material and, recently, commercial quantities of sandstone aggregate have been excavated at Penstrowed Quarry [SO 0680 9100]. The district includes part of the Central Wales Mining Field from which substantial volumes of lead and zinc ore were extracted during the 19th and early 20th centuries. A number of former mine sites are still visible, notably along the Van, Nant-y-ricket, Dylife, Dyfngwm and Llanerchyraur lodes (Jones, 1922[1]; IGS, 1974), and the historic Bryntail Mine, below the Clywedog Dam has been restored as a site of industrial archaeological interest. The district is underlain by a succession of Late Ordovician (Ashgill) to Silurian sedimentary rocks, over 5 km thick, deposited between 450 and 420 million years ago in the Early Palaeozoic Welsh Basin (Figure P930911). The basin developed on a fragment of the ancient supercontinent of Gondwana, known as Eastern Avalonia (e.g. Pickering et al., 1988[2]), that drifted northwards to collide with the continents of Baltica and Laurentia during the Late Ordovician and Silurian (Soper and Hutton, 1984[3]; Soper and Woodcock, 1990[4]; Woodcock and Strachan, 2000[5]). To the east and the south of the basin lay the Midland Platform, a relatively stable shallow marine shelf that was subject to periodic emergence. The basinal sediments are predominantly deep marine turbiditic facies that were introduced into the district by density currents from southerly, south-easterly and north-westerly quadrants. Coeval shallower-water ‘shelfal’ sediments were deposited north and east of the district, and locally impinge on its northern margins. Thickness variations within the major sedimentary units suggest that, at times, syndepositional fault movements were an important control on their distribution. During late Silurian (Ludlow) times, shallowing of the basin occurred, and sandstones, variably interpreted as a turbiditic (Cave and Hains, 2001[6]) or storm-generated facies (Tyler and Woodcock, 1987[7]), were laid down over the eastern part of the district and adjacent areas. The shallowing was a result of tectonic reconfiguration of the basin, a precursor to the late Caledonian (Acadian) Orogeny that affected the region during the late Early Devonian, around 400 million years ag

Biochar versus hydrochar as growth media constituents for ornamental plant cultivation

[EN] Biochar and hydrochar have been proposed as novel materials for providing soilless growth media. However, much more knowledge is required before reliable advice can be given on the use of these materials for this purpose. Depending on the material and the technology applied (pyrolysis or hydrothermal carbonization), phytotoxicity and greenhouse gas emissions have been found for certain chars. In this study, our aim was to assess the feasibility of three chars as substrate constituents. We compared two biochars, one from forest waste and the other from olive mill waste, and a hydrochar from forest waste. We studied how chars affected substrate characteristics, plant performance, water economy and respiratory CO2 emission. Substrates containing biochar from forest waste showed the best characteristics, with good air/water relationships and adequate electrical conductivity. Those with biochar from olive mill waste were highly saline and, consequently, low quality. The substrates with hydrochar retained too much water and were poorly aerated, presenting high CO2 concentrations due to high respiratory activity. Plants performed well only when grown in substrates containing a maximum of 25 % biochar from forest waste or hydrochar. After analyzing the char characteristics, we concluded that biochar from forest waste could be safely used as a substrate constituent and is environmentally friendly when applied due to its low salinity and low CO2 emission. However, biochar from olive mill waste and hydrochar need to be improved before they can be used as substrate constituents.This study was funded by the Polytechnic University of Valencia (Projects on New Multidisciplinary Research; PAID-05-12). We thank Molly Marcus-McBride for supervising the English.Fornes Sebastiá, F.; Belda Navarro, RM. (2018). Biochar versus hydrochar as growth media constituents for ornamental plant cultivation. Scientia Agricola (Online). 75(4):304-312. https://doi.org/10.1590/1678-992X-2017-0062S304312754Abad, M., Noguera, P., & Burés, S. (2001). National inventory of organic wastes for use as growing media for ornamental potted plant production: case study in Spain. Bioresource Technology, 77(2), 197-200. doi:10.1016/s0960-8524(00)00152-8Bargmann, I., Martens, R., Rillig, M. C., Kruse, A., & Kücke, M. (2013). Hydrochar amendment promotes microbial immobilization of mineral nitrogen. Journal of Plant Nutrition and Soil Science, 177(1), 59-67. doi:10.1002/jpln.201300154Bargmann, I., Rillig, M. C., Buss, W., Kruse, A., & Kuecke, M. (2013). Hydrochar and Biochar Effects on Germination of Spring Barley. Journal of Agronomy and Crop Science, 199(5), 360-373. doi:10.1111/jac.12024Bedussi, F., Zaccheo, P., & Crippa, L. (2015). Pattern of pore water nutrients in planted and non-planted soilless substrates as affected by the addition of biochars from wood gasification. Biology and Fertility of Soils, 51(5), 625-635. doi:10.1007/s00374-015-1011-6Belda, R. M., Lidón, A., & Fornes, F. (2016). Biochars and hydrochars as substrate constituents for soilless growth of myrtle and mastic. Industrial Crops and Products, 94, 132-142. doi:10.1016/j.indcrop.2016.08.024Costello, R. C., & Sullivan, D. M. (2013). Determining the pH Buffering Capacity of Compost Via Titration with Dilute Sulfuric Acid. Waste and Biomass Valorization, 5(3), 505-513. doi:10.1007/s12649-013-9279-yFernandes, C., & Corá, J. E. (2004). Bulk density and relationship air/water of horticultural substrate. Scientia Agricola, 61(4), 446-450. doi:10.1590/s0103-90162004000400015Fornes, F., Belda, R. M., Carrión, C., Noguera, V., García-Agustín, P., & Abad, M. (2007). Pre-conditioning ornamental plants to drought by means of saline water irrigation as related to salinity tolerance. Scientia Horticulturae, 113(1), 52-59. doi:10.1016/j.scienta.2007.01.008Fornes, F., Belda, R. M., & Lidón, A. (2015). Analysis of two biochars and one hydrochar from different feedstock: focus set on environmental, nutritional and horticultural considerations. Journal of Cleaner Production, 86, 40-48. doi:10.1016/j.jclepro.2014.08.057Fornes, F., & Belda, R. M. (2017). Acidification with nitric acid improves chemical characteristics and reduces phytotoxicity of alkaline chars. Journal of Environmental Management, 191, 237-243. doi:10.1016/j.jenvman.2017.01.026Fornes, F., Belda, R. M., Fernández de Córdova, P., & Cebolla-Cornejo, J. (2017). Assessment of biochar and hydrochar as minor to major constituents of growing media for containerized tomato production. Journal of the Science of Food and Agriculture, 97(11), 3675-3684. doi:10.1002/jsfa.8227Fornes, F., Carrión, C., García-de-la-Fuente, R., Puchades, R., & Abad, M. (2010). Leaching composted lignocellulosic wastes to prepare container media: Feasibility and environmental concerns. Journal of Environmental Management, 91(8), 1747-1755. doi:10.1016/j.jenvman.2010.03.017GARCIADELAFUENTE, R., CARRION, C., BOTELLA, S., FORNES, F., NOGUERA, V., & ABAD, M. (2007). Biological oxidation of elemental sulphur added to three composts from different feedstocks to reduce their pH for horticultural purposes. Bioresource Technology, 98(18), 3561-3569. doi:10.1016/j.biortech.2006.11.008Genty, B., Briantais, J.-M., & Baker, N. R. (1989). The relationship between the quantum yield of photosynthetic electron transport and quenching of chlorophyll fluorescence. Biochimica et Biophysica Acta (BBA) - General Subjects, 990(1), 87-92. doi:10.1016/s0304-4165(89)80016-9Hoitink, H. A. J., Stone, A. G., & Han, D. Y. (1997). Suppression of Plant Diseases by Composts. HortScience, 32(2), 184-187. doi:10.21273/hortsci.32.2.184Libra, J. A., Ro, K. S., Kammann, C., Funke, A., Berge, N. D., Neubauer, Y., … Emmerich, K.-H. (2011). Hydrothermal carbonization of biomass residuals: a comparative review of the chemistry, processes and applications of wet and dry pyrolysis. Biofuels, 2(1), 71-106. doi:10.4155/bfs.10.81Mazuela, P., Salas, M. del C., & Urrestarazu, M. (2005). Vegetable Waste Compost as Substrate for Melon. Communications in Soil Science and Plant Analysis, 36(11-12), 1557-1572. doi:10.1081/css-200059054Méndez, A., Paz-Ferreiro, J., Gil, E., & Gascó, G. (2015). The effect of paper sludge and biochar addition on brown peat and coir based growing media properties. Scientia Horticulturae, 193, 225-230. doi:10.1016/j.scienta.2015.07.032Nieto, A., Gascó, G., Paz-Ferreiro, J., Fernández, J. M., Plaza, C., & Méndez, A. (2016). The effect of pruning waste and biochar addition on brown peat based growing media properties. Scientia Horticulturae, 199, 142-148. doi:10.1016/j.scienta.2015.12.012Sáez, J. A., Belda, R. M., Bernal, M. P., & Fornes, F. (2016). Biochar improves agro-environmental aspects of pig slurry compost as a substrate for crops with energy and remediation uses. Industrial Crops and Products, 94, 97-106. doi:10.1016/j.indcrop.2016.08.035Smith, B. R., Fisher, P. R., & Argo, W. R. (2004). Growth and Pigment Content of Container-grown Impatiens and Petunia in Relation to Root Substrate pH and Applied Micronutrient Concentration. HortScience, 39(6), 1421-1425. doi:10.21273/hortsci.39.6.1421Solaiman, Z. M., Murphy, D. V., & Abbott, L. K. (2011). Biochars influence seed germination and early growth of seedlings. Plant and Soil, 353(1-2), 273-287. doi:10.1007/s11104-011-1031-4Steiner, C., & Harttung, T. (2014). Biochar as a growing media additive and peat substitute. Solid Earth, 5(2), 995-999. doi:10.5194/se-5-995-2014Tian, Y., Sun, X., Li, S., Wang, H., Wang, L., Cao, J., & Zhang, L. (2012). Biochar made from green waste as peat substitute in growth media for Calathea rotundifola cv. Fasciata. Scientia Horticulturae, 143, 15-18. doi:10.1016/j.scienta.2012.05.018Vaughn, S. F., Eller, F. J., Evangelista, R. L., Moser, B. R., Lee, E., Wagner, R. E., & Peterson, S. C. (2015). Evaluation of biochar-anaerobic potato digestate mixtures as renewable components of horticultural potting media. Industrial Crops and Products, 65, 467-471. doi:10.1016/j.indcrop.2014.10.04

The use of artificial roughness in movable-bed models

Tests have been done in a laboratory flume, to evaluate the influence of vertical rods of 3 mm dia on the hydraulic and sedimentological characteristics of the flow. The first two tests have been done with some 10 cm waterdepth. In both tests the s ame flow rate and sediment transport was used, the only difference between the tests being the artificial roughness, which was applied during the second test. The following two tests were done in a similar way with a waterdepth of about ~ and with a reduqed flow rate and sediment transport. For both 10 em and 5 om waterdepths, the bar resistance was then measured in the flume without bakelite. The influence of the rods on the ripple factor, ~, thus on the bottom roughness, could be evaluated, after e1imination of the bar resistance. In the case of 10 em depth, the artificial roughness caused a reduction "of bottom roughness, while with a depth of 5 cm an increased bottom roughness with the bars was found. By calculating the bed load from the product of the mean ripple celerity and half the meru1 ripple height a very good agreement was found with the actually measured quantities

New U–Pb and Rb–Sr constraints on pre-Acadian tectonism in North Wales

<p>A new U–Pb date of 615.2 ± 1.3 (2σ) Ma for the Twt Hill Granite, North Wales, contrasts with an Rb–Sr isochron age of 491 ± 12 (2σ) Ma from the same body. The latter age is thought to result from isotope resetting during regional low-grade metamorphism or fault reactivation. The Rb–Sr age also coincides with the onset of latest Cambrian to Early Tremadoc regression and is taken to reflect tectonic uplift prior to the Arenig overstep at around 478 Ma. It is proposed that this in turn reflects plate-scale processes along the contemporary peri-Gondwanan continental margin. </p

Geology of the Fishguard district : a brief explanation of the geological map Sheet 210 Fishguard

This Sheet Explanation provides a summary of the geology of the area covered by geological 1:50 000 Sheet 210 Fishguard. The map was published as a single combined bedrock and superficial deposits edition in 2010. The greater part of the district lies within the county of Pembrokeshire, with a small area in the south-east within Carmarthenshire. It is bordered to the north by the picturesque coast of Cardigan Bay and includes the scenic uplands of the Mynydd Preseli with their distinctive rock tors or ‘carns’, which rise to a maximum height of 536 m OD at Foel Cwmcerwyn [SN 094 311]. The main rivers are the Afon Nyfer and Afon Gwaun, which drain the northern flanks of the Preselis into Cardigan Bay, and the Eastern and Western Afon Cleddau which, together with the Afon Syfynwi and Afon Taf, drain the southern flanks of the range into the Daugleddau estuary. Livestock-based agriculture remains a significant part of the local economy, although tourism is increasingly important for the principal towns of Fishguard and Newport. Both were important 19th Century ports, and the former is now a major terminal for passenger ferries to Eire. In 1952, the Pembrokeshire Coast National Park was established to conserve the county’s spectacular scenery. About half of the district, including the coast and the Preseli Hills, lies within its limits