No abstract

An event stratigraphy of dune stability/instability phases has been reconstructed, using 22 radiocarbon and 13 luminescence dates, for six dunefields along the north coast of Northern Ireland. There is no evidence for dune development prior to ċ. 7000 cal. years BP, during the early-Holocene rapid rise in RSL, and only limited evidence for sand accumulation in association with the RSL maximum. Dunefield dates correspond to either the subsequent regressive phase or, later, the gradual transgressive phase of RSL history in the mid-and late Holocene. At these times accommodation space for dune development and sediment supply were maximized. Episodes of climatic deterioration, particularly at 3100–2400 cal. years BP and 650–50 cal. years BP (the‘Little Ice Age’) were marked by widespread dune instability. A similar coincidence in timing has been recorded for dune systems elsewhere in northwestern Europe and is generally attributed to an increased frequency of storms and storm surges associated with the climatic downturns. However, between-site inconsistencies in the event stratigraphy suggest that site-specific factors (e.g., sediment availability) had a modulating influence on dune regional controls.

The recent environmental history of coastal dune systems in Northumberland, northeast England, has been examined using geomorphological, stratigraphical and sedimentological techniques linked to radiocarbon and infrared-stimulated luminescence (IRSL) dating. Stratigraphies were determined from 22 vibracores and three sections, and dune chronology was based on 28 14 C dates, from peat and soil organic horizons, and 26 IRSL dates on K-feldspar grains from within sand layers. Almost all dune systems are associated with regressive shorelines consequent upon a fall in relative sea level (RSL) from its Holocene peak, and indicate RSL functioned as a macroscale control on dune development. Where dunes are anchored on terrestrial sediment, dune expansion may have been either transgressive or regressive in nature. Where near-shore marine sediments form the dune substrate, a regressive (prograding) dune model seems most likely. Most dune building occurred during the ‘Little Ice Age’ (LIA), probably in association with specific climatic and morphosedimentary conditions, principally periods of easterly circulation, a greater frequency of severe North Sea storms, RSL fall, and sediment and accommodation space availability. Dune development in Holocene cool intervals earlier than the LIA was of limited spatial extent, suggesting some differences in prevailing conditions at those times.

Quark nuggets are theoretical objects composed of approximately equal numbers of up, down, and strange quarks and are also called strangelets and nuclearites. They have been proposed as a candidate for dark matter, which constitutes ~85% of the universe’s mass and which has been a mystery for decades. Previous efforts to detect quark nuggets assumed that the nuclear-density core interacts directly with the surrounding matter so the stopping power is minimal. Tatsumi found that quark nuggets could well exist as a ferromagnetic liquid with a ~1012-T magnetic field. We find that the magnetic field produces a magnetopause with surrounding plasma, as the earth’s magnetic field produces a magnetopause with the solar wind, and substantially increases their energy deposition rate in matter. We use the magnetopause model to compute the energy deposition as a function of quark-nugget mass and to analyze testing the quark-nugget hypothesis for dark matter by observations in air, water, and land. We conclude the water option is most promising.

2014. Age and origin of ice-cored moraines In Jotunheimen and Breheimen, Southern Norway: insights from Schmidt-Hammer exposure-age dating.ABSTRACT. High-precision Schmidt-hammer exposureage dating (SHD) is applied to ice-cored moraine-ridge complexes at three high-alpine glaciers in Jotunheimen and Breheimen, southern Norway. Local calibration curves were established using moraine ridges dating from the last 50 years and bedrock surfaces deglaciated ∼9700 years ago. SHD ages, with 95% statistical confidence intervals, ranged from 3920 ± 790 years to a negative (futuristic) age of -890 ± 580 years at Gråsubreen, 420 ± 700 to 260 ± 710 years at Vesle-Juvbreen and 2250 ± 450 to 1605 ± 410 years at Østre Tundradalskyrkjabreen. Negatively skewed R-value distributions were interpreted as the result of weathered boulders from reworked surfaces. This leads to the interpretation of these SHD ages as maximum estimates of moraine-ridge age. Østrem's hypothesis (that the proximal ridges are the oldest and survived being overridden many times) is rejected on the basis of our SHD ages. Although ice-cored moraine ridges resemble the flow structures of rock glaciers, Barsch's hypothesis (that these icecored moraine complexes are rock glaciers) is also rejected. Instead, the ice-cored moraine-ridge complexes are considered to be glaciotectonic structures produced by the interaction of polythermal glaciers and alpine permafrost over the late Holocene. All the individual ridges were essentially formed during the 'Little Ice Age' glacier advance from material deposited earlier by multiple neoglacial events. The considerable size of the moraine complexes is attributed not only to the accumulation of material from these different events over a long period of time but also to their survival in the landscape during phases of glacier retreat when ice cores do not melt and fluvial and other destructive processes remain ineffective in the permafrost environment.

The temporal pattern of rock-slope failures (RSFs) following Late 12Pleistocene deglaciation on tectonically stable terrains is controversial: previous 13 studies variously suggest (1) rapid response due to removal of supporting ice 14 ('debuttressing'), (2) a progressive decline in RSF frequency, (3) a millennial-scale 15 delay before peak RSF activity. We test these competing models through 10 Be Stadial glacial limits, but that runout debris was removed by LLS glaciers. 36Keywords: Rock-slope failure; paraglacial; surface exposure dating; stress release; 37 palaeoseismicity. 2002; Leith et al., 2011; McColl, 2012 Cormier et al., 2005; Agliardi et al., 2009; El Bedoui et al., 2009; Hippolyte et al., 58 2009), to constrain the extent of Pleistocene glacier advances 59 2011), to determine the level of hazard at former landslide sites (Welkner et al., 2010), 60to estimate long-term rates of pre-failure sliding (Hermanns et al., 2012) and to 61 determine the contribution of RSFs to postglacial denudation and landscape evolution 62 (Barnard et al., 2001; Antinao and Gosse, 2009; Seong et al., 2009; Hewitt et al., 63 2011; Shroder et al., 2011). The timing of individual dated RSFs has been variously 64 related to deglacial unloading and stress release (Cossart et al., 2008; Shroder et al., 65 Gosse, 2009; Sanchez et al., 2010; Stock and Uhrhammer, 2010; Hermanns and 67 Niedermann, 2011; Hewitt et al, 2011; Penna et al., 2011) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 that dip ESE at 25-40° and are locally intruded by doleritic dykes (Walker, 1961; 132 Anderton, 1976 132 Anderton, , 1977 132 Anderton, , 1985. 134When the last British-Irish Ice Sheet reached its maximum extent at ~27-26 ka, 135westwards-moving ice crossed Jura and extended to the Atlantic shelf edge, 195 km 136 west of the island (Hubbard et al., 2009; Clark et al., 2012 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 to 7% younger. Where citation of both ages is necessary, the age derived using LL 288LPR is cited first, followed in brackets by the age derived using NWH11.6 LPR. 290An additional advantage of using LPRs is that the variability amongst different 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 1 2 3 4 5 6 7 8 9 ...

We present a new chronology to constrain ice‐margin retreat in the northern Irish Sea Basin. Estimates on the timing of ice thinning derived from surface exposure ages for boulders from the summits of the Isle of Man and south‐west Cumbria suggest that ice thinning was commensurate with the rapid retreat that followed the short‐lived advance of the Irish Sea Ice Stream (ISIS) to maximum limits in the Celtic Sea. This ice retreat in the northern Irish Sea Basin was fastest at 20 ka in response to a wider calving margin, but slowed as ice stabilized and oscillated against the Isle of Man. We provide the first age constraints for the Scottish Readvance (19.2–18.2 ka) and demonstrate that it was a potentially regional event across the Isle of Man and Cumbrian lowlands not linked with Heinrich Event 1. After the Scottish Readvance, the ice front retreated northwards towards the Southern Uplands of Scotland at the same time as climate north of ∼45°N warmed in response to summer insolation. This sequence demonstrates the importance of internal dynamics in controlling ice retreat rates in the Irish Sea, but also that deglaciation of the northern Irish Sea Basin was a response to climate warming.

Relative sea-level (RSL) control on dune initiation during the Holocene is examined in the context of chronostratigraphies established from 43 vibracores through dunes and into sub-dune sediments taken from the Northumberland and Norfolk (UK) coasts. The chronology is based on 23 accelerated mass spectroscopy and conventional 14C dates, and 37 infra-red-stimulated luminescence dates. The oldest dunes in Northumberland are c.4cal, kaBP with phases of dune development at 2.8 and 1.5-1kaBP. Most dune deposition is of last millennium age, with a concentration, especially in Norfolk, around 500-200 a BP. The initiation and survival of coastal dune sequences relate to macroscale RSL changes over the last 4 ka. Northumberland dunes reflect a gradient of RSL change from a northern RSL fall (forced regression) through to a southern RSL rise (normal regression through sediment supply). The north Norfolk coast has been dominated by a rising RSL through the Holocene, though associated with a sediment supply sufficient to offset the transgressive tendency and allow normal regressive deposition at numerous positions along the coast over the last 1 ka. It is suggested that the development of Little Ice Age (LIA) dunes in both Norfolk and Northumberland identifies the onset of specific conditions in which intertidal sediment sources were exposed (falling sea-level) to onshore winds (LIA circulation changes), which reflect a brief west North Sea period in dune initiation and deposition rates. A comparison of this consolidated dune chronology with statements of RSL elevation and climate conditions in the last 2.5 ka leads to some recognition of RSL fall preceding major dune building in two phases post 1.5 ka BP and post 0.6 ka BP.