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Accelerator mass spectrometry (AMS) [sup.14]C dates of fossiliferous marine mud identify a readvance of the Irish Ice Sheet from the north and central lowlands of Ireland into the northern Irish Sea Basin during the Killard Point Stadial at ca. 16.5 cal k.y. B.P., with subsequent deglaciation occurring by ca. 15.0-15.5 cal k.y. B.P. Killard Point Stadial moraines have been mapped elsewhere in Ireland but have previously remained undated. Here, we report sixteen [sup.10]Be surface exposure dates that constrain the age of retreat of the Killard Point Stadial ice margin from western Ireland. Eight [sup.10]Be dates from the Ox Mountains (13.9-18.1 ka) indicate that final deposition of the moraine occurred at 15.6 [+ or -] 0.5 ka (mean age, standard error). Eight [sup.10]Be dates from Furnace Lough (14.1-17.3 ka, mean age of 15.6 [+ or -] 0.4 ka) are statistically indistinguishable from the Ox Mountain samples, suggesting that the moraines were deposited during the same glacial event. Given the agreement between the two age groups, and their common association with a regionally significant moraine system, we combine them to derive a mean age of 15.6 [+ or -] 0.3 ka (15.6 [+ or -] 1.0 ka with external uncertainty). This age is in excellent agreement with the timing of deglaciation from the Irish Sea Basin (at or older than 15.3 [+ or -] 0.2 cal k.y. B.P.) and suggests the onset of near-contemporaneous retreat of the Irish Ice Sheet from its maximum Killard Point Stadial limit. A reconstruction of the ice surface indicates that the Irish Ice Sheet reached a maximum surface elevation of ~500 m over the central Irish Lowlands during the Killard Point Stadial, suggesting a high sensitivity of the ice sheet to small changes in climate. Keywords: glacial geology, geochronology, cosmogenic dating, Irish Ice Sheet.

Accelerator mass spectrometer [sup.14]C dating of in situ monospecific marine microfaunas and reworked shells records high relative sea level on the western coast of Ireland between ca. 40 and 19 cal (calibrated) ka, requiring substantial isostatic loading by the Irish ice sheet (IIS) during that interval. Glacial and marine deposits also record a rapid fluctuation of the IIS margin onto the continental shelf ca. 28 cal ka. Evidence that the coast was not subsequently overridden by the IIS indicates that, at least for this sector of the ice sheet, the ice margin during the Last Glacial Maximum (LGM) was less extensive than the 28 cal ka event. Our data from western Ireland support [sup.14]C and [sup.36]Cl chronologies from the Irish Sea Basin in identifying an IIS that was as extensive and thick as the LGM IIS for much of the 20 k.y. interval prior to the LGM. Keywords: Irish ice sheet, last glaciation, relative sea level, [sup.14]C dating

Objective: To assess the safety and efficacy of bariatric surgery in patients with cirrhosis. Summary Background Data: Bariatric surgery may be a viable option for patients with cirrhosis and extreme obesity. However, the risk of liver decompensation after surgery is not thoroughly investigated. Methods: We conducted a case-controlled study with 106 obese patients with cirrhosis (cases) and 317 age, sex, body mass index-, and type of surgery-matched obese patients without cirrhosis (controls) who underwent bariatric surgery. Results: Patients with cirrhosis were predominantly Child-Pugh class A (97%) with the diagnosis established prior to surgery in only 46%. In the cirrhosis group, there was no death in the first 30 days compared with 1 patient in the control group. At 90 days there was 1 death in the cirrhosis group but no additional deaths in the control group. In total, 12 months after the surgery, there were 3 deaths in the cirrhosis group and 1 in the control group (2.8% vs 0.6%, P = 0.056). The surgery-related length of stay was significantly longer in patients with cirrhosis (3.7 ± 4.0 vs 2.6 ± 2.4 d, P = 0.001), but the 30-day readmission rate was lower (7.5% vs 11.9%, P = 0.001). The percent of total weight loss at 30 and 90-days was not significantly different between the groups and remained that way even at 1 year (29.1 ± 10.9 vs 31.2 ± 9.4%, P = 0.096). Conclusions: Bariatric surgery in obese cirrhotic patients is not associated with excessive mortality compared with noncirrhotic obese patients. [ABSTRACT FROM AUTHOR]

New research supports the view that the release of icebergs and meltwater during Heinrich event 1 caused changes in the North Atlantic thermohaline circulation. These changes prompted a delay or reversal of deglaciation of the Northern Hemisphere and at least as far south as 40 deg S for between two and three thousand years. Most significantly, discharge of icebergs to the North Atlantic from the Laurentide Ice Sheet would have rapidly reduced formation of North Atlantic Deep Water, bringing about cooling in the North Atlantic region.

Numerical model predictions of low Late Devensian sea levels around Britain are inconsistent with dated sea-level indicators contained in the geological record. Stratigraphies from the western Irish Sea Basin record high sea levels throughout the last deglacial cycle (21-13 ka BP) and onshore ice-marginal glaciomarine and marine sedimentation. Sedimentary evidence emphasizes the role played by delayed isostatic uplift coupled with rapid tidewater evacuation of ice from the basin. Drumlinization and marine downdraw in the northern Irish Sea Basin records subglacial sediment transfer towards tidewater ice margins and headward extension of ice streams deep into the ice sheet around 14 ka BP. Keywords: Irish Sea, changes in level, deglaciation, glaciomarine sedimentation.

In northern Britain glaciotectonically thickened sediment piles represent the sediment flux transferred to ice margins by phases of fast ice flow and drumlin streamlining during the last deglacial cycle. Radiocarbon dating of marine faunas within deglacial muds age-constrain phases of drumlinisation (shaping) to between 19 and 14.5 ka BP. Individual phases of drumlinization can be correlated with millennial time scale discharge events documented from the circum-North Atlantic which are probably climate-driven. The overall deglacial cycle records at least five major millennial time-scale ice-margin oscillations and phases of sediment sequence rhythmicity. Keywords: Great Britain, Ireland, deglaciation, dates, ice-sheets.

A well-preserved moraine on the northern coast of County Donegal, Ireland, has played a critical role in our understanding of the glacial history of this sector of the Irish Ice Sheet (IIS). Because of a lack of numerical dating of the moraine, however, previous interpretations of its age and significance to the glacial history of this region have varied widely. Here we report eight in situ cosmogenic 10Be ages on boulders sampled from the moraine. Two of these ages are outliers, with the remaining six ranging from 18.8±1.0 10Be kyr to 20.9±1.3 10Be kyr, with an uncertainty-weighted mean age of 19.4±0.3 10Be kyr (19.4±1.2 kyr accounting for production rate uncertainty). Our results confirm one previous 10Be age obtained from the moraine, with the combined data ( n=7) constraining the age of initial deglaciation of the IIS from its LGM position on the continental shelf to be 19.3±0.3 10Be kyr (19.3±1.2 kyr accounting for production rate uncertainty). These ages are in excellent agreement with calibrated 14C ages that constrain retreat of the IIS margin from the continental shelf elsewhere in northwestern and western Ireland and the Irish Sea Basin associated with the start of the Cooley Point Interstadial (≥20–≤18.2 cal. kyr BP), suggesting widespread deglaciation of the IIS ∼19.5–20 kyr ago. [ABSTRACT FROM AUTHOR]

Accelerator mass spectrometry (AMS) 14C dates of fossiliferous marine mud identify a re-advance of the Irish Ice Sheet from the north and central lowlands of Ireland into the northern Irish Sea Basin during the Killard Point Stadial at ca. 16.5 cal k.y. B.P., with subsequent deglaciation occurring by ca. 15.0-15.5 cal k.y. B.P. Killard Point Stadial moraines have been mapped elsewhere in Ireland but have previously remained undated. Here, we report sixteen 10Be surface exposure dates that constrain the age of retreat of the Killard Point Stadial ice margin from western Ireland. Eight 10Be dates from the Ox Mountains (13.9-18.1 ka) indicate that final deposition of the moraine occurred at 15.6 ± 0.5 ka (mean age, standard error). Eight 10Be dates from Furnace Lough (14.1-17.3 ka, mean age of 15.6 ± 0.4 ka) are statistically indistinguishable from the Ox Mountain samples, suggesting that the moraines were deposited during the same glacial event. Given the agreement between the two age groups, and their common association with a regionally significant moraine system, we combine them to derive a mean age of 15.6 ± 0.3 ka (15.6 ± 1.0 ka with external uncertainty). This age is in excellent agreement with the timing of deglaciation from the Irish Sea Basin (at or older than 15.3 ± 0.2 cal k.y. B.P.) and suggests the onset of near-contemporaneous retreat of the Irish Ice Sheet from its maximum Killard Point Stadial limit. A reconstruction of the ice surface indicates that the Irish Ice Sheet reached a maximum surface elevation of ∼500 m over the central Irish Lowlands during the Killard Point Stadial, suggesting a high sensitivity of the ice sheet to small changes in climate. [ABSTRACT FROM AUTHOR]

A late Pleistocene morainal bank is sited in a depocentre to the lee of a major rock ridge, near Greystones, in the western Irish Sea Basin. During deglaciation the ridge provided a pinning point during tidewater wastage northwards. Sedimentation patterns and palaeocurrent data show morainal bank growth by discharge from a single basal efflux located to the east or south-east of the ridge during ice marginal re-equilibration. The four lithofacies associations which are recognized from the western part of the formerly more extensive apron are related largely to variable jet and plume sedimentation. At the base of the 1.6 km long exposure. Lithofacies association 1 (massive mud, muddy diamict and laminated mud) was deposited from turbid plumes, variable ice rafting and traction current activity. Lenticular units of gravels within this mud bank record high energy pulses and sediment fluxes from the efflux jet. Lithofacies association 2 (sands, laminated muds and muddy diamict) is discontinuous and occurs within basins along a marked erosion surface cut in Lithofacies association 1. It is associated with a decrease in jet strength, traction currents and suspension sedimenitation. Lithofacies association 3 is a tabular body of interbedded diamicts and gravels which is present along the entire section. 1t documents the decay phase of re-equilibration as the ice margin disintegrated catastrophically and released large volumes of heterogeneous sediment which was resedimented by quasicontinuous mass flow. Lithofacies association 4 consists of stratified and massive gravels within distributary channels cut into underlying facies and represents the last phase of meltwater activity. Sediment geometries, particularly sedimentary contrasts representing erosion surfaces at a variety of scales and abrupt textural contrasts are attributed to jet switching, Lithofacies association 1 (60%) and Lithofacies association 3 (30%) are the dominant facies. In favourable... [ABSTRACT FROM AUTHOR]

Late Pleistocene morainic sequences around Dundalk Bay, eastern Ireland, were deposited in a variety of shallow, glaciomarine environments at the margins of a grounded ice lobe. The deposits are essentially ice-proximal delta-fan and -apron sequences and are divided into two lithofacies associations. Lithofacies association I occurs as a series of morainal banks formed at the southern margin of the ice lobe in a body of water open to influences from the Irish Sea. The morainal banks consist mainly of diamictic muds deposited from turbid plumes and by ice-rafting with minor occurrences of turbidites, cross-bedded gravels (subaqueous outwash) and massive boulder gravels (high-density debris flows). Lithofacies association 2 was deposited in a narrow arm of the sea at the north-eastern margin of the ice lobe. The deposits consist mainly of a series of coalescing, ice-proximal Gilbert-type fan deltas which are interbedded distally with tabular and lens-shaped subaqueous deposits. The latter are mainly ice-rafted diamictons, debris-flow deposits and subaqueous sands and gravels. Both lithofacies associations are draped by diamictons formed by a combination of rain-out, debris flow and traction-current activity. At a few localities the upper parts of the sequence have been sheared by minor oscillations of the ice sheet margin. These sequences form part of an extensive belt of glaciomarine deposits which border the drumlin swarms of east-central Ireland. Lithostratigraphic variability is partially related to the arrival of large volumes of debris at the ice lobe margin when the main lowland ice sheet surged during drumlin formation. Complex depositional continua of this type lack any major erosional breaks and should not be used either as climatic proxies or for stratigraphic correlations. [ABSTRACT FROM AUTHOR]

A thick late Pleistocene sequence comprising multiple beds of massive diamict facies resting on outwash gravels, occurs along the Bow River, near Banff, Alberta. Diamicts have a simple sheet-like geometry which dip downvalley at between 5° and 10°, with largely conformable bedding contacts. The sediments are strongly bimodal in texture, consisting of clasts supported by a silty sand matrix. Prolate clasts show a weak a-axis alignment parallel and transverse to the trend of the Bow Valley with a weak imbrication. Clasts of soft sediment are common. The diamict sequence has a maximum thickness of 30 m, infills the valley floor over an area of approximately 12 km[SUP2] and buries a channeled topography cut on the surface of underlying outwash gravels. Abandoned braided channels, veneered by windblown sand containing volcanic tephra dated at 6600 yr BP, occur on the infill surface. Diamict facies were emplaced as subaerial debris flows derived by the mixing and remobilization of large volumes of outwash and glaciolacustrine sediment. Orientation data from clasts and a few basal grooves indicate that debris was derived upvalley and from adjacent valleyside slopes. A major episode of debris flow sedimentation may have been triggered by the abrupt drainage of lakes in tributary valleys as the Bow Valley glacier retreated. Downslope resedimentation of large volumes of sediment resulted in braided river aggradation downstream along the Bow River and can be dated to between 12 000 and 10 000 yr BP. Similar conditions probably occurred during deglaciation throughout the Canadian Cordillera and many other alpine areas, where poorly-sorted late glacial debris-flow facies have been mistaken for tills deposited directly by glaciers. The late glacial setting identified in this paper provides a basis of comparison with ancient continental glacial facies preserved in area of active tectonism and high relief. [ABSTRACT FROM AUTHOR]

We report 80 10Be ages on 14 moraines from Irish cirques that show a previously unrecognized signal of at least eight millennial-scale fluctuations between 24.5 ± 0.7 ka and 11.0 ± 0.3 ka. Several moraine ages may be correlative with abrupt warming at the onset of the Bølling-Allerød interval (14.7 ka) and the end of the Younger Dryas interval (11.7 ka), suggesting a forced response. Our ages also identify glacier fluctuations that occurred when regional temperatures were relatively stable. This finding is consistent with modeling results showing several hundred-meter-scale glacier fluctuations in response to interannual variability. At the same time, our composite record of cirque-glacier average equilibrium line altitudes (ELAs) shows a response to warming due to increasing greenhouse gases and summer insolation modulated by abrupt climate changes. Our new 10Be chronology thus records both forced and unforced millennial- scale glacier fluctuations superimposed on a lower-frequency ELA signal of forced response to climate change. [ABSTRACT FROM AUTHOR]