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Here we reconstruct the last advance to maximum limits and retreat of the Irish Sea Glacier (ISG), the only land‐terminating ice lobe of the western British Irish Ice Sheet. A series of reverse bedrock slopes rendered proglacial lakes endemic, forming time‐transgressive moraine‐ and bedrock‐dammed basins that evolved with ice marginal retreat. Combining, for the first time on glacial sediments, optically stimulated luminescence (OSL) bleaching profiles for cobbles with single grain and small aliquot OSL measurements on sands, has produced a coherent chronology from these heterogeneously bleached samples. This chronology constrains what is globally an early build‐up of ice during late Marine Isotope Stage 3 and Greenland Stadial (GS) 5, with ice margins reaching south Lancashire by 30 ± 1.2 ka, followed by a 120‐km advance at 28.3 ± 1.4 ka reaching its 26.5 ± 1.1 ka maximum extent during GS‐3. Early retreat during GS‐3 reflects piracy of ice sources shared with the Irish‐Sea Ice Stream (ISIS), starving the ISG. With ISG retreat, an opportunistic readvance of Welsh ice during GS‐2 rode over the ISG moraines occupying the space vacated, with ice margins oscillating within a substantial glacial over‐deepening. Our geomorphological chronosequence shows a glacial system forced by climate but mediated by piracy of ice sources shared with the ISIS, changing flow regimes and fronting environments. [ABSTRACT FROM AUTHOR]

A significant advantage of rock surface luminescence dating for determining the burial age of cobbles is that well-bleached samples can be identified according to the variation in calculated luminescence age with depth. A plateau in the luminescence age-depth profile extending from the outer surface into the cobble that also gives a lower value than is seen closer towards the interior of the cobble is conclusive evidence of sufficient daylight exposure. The age of this sub-surface plateau represents the time elapsed since the cobble was last exposed to daylight, prior to burial. But there is speculation regarding whether this age of last exposure represents the true age of the formation of the features / landforms of interest for dating. Over 300 cobbles were investigated in this study, originating from different glacial valleys in Tibet. Samples were taken from a range of depositional settings, including different types of moraines and from glaciofluvial sediments. Independent age control and expected ages were provided by cosmogenic nuclide exposure dating and by collection of modern samples. The Ln/Tn signal or equivalent dose were determined using post-IR IRSL protocols. The diverse shapes of luminescence-depth profiles indicate various bleaching / transport histories for different cobbles. Those considered as well-bleached samples could be found from all sampling sites. However, different sites show different proportions of well-bleached cobbles. We found that some cobbles show sub-surface plateaus that were lower than the values toward the centre of the cobble, but the sub-surface ages are apparently older than the independent or expected ages. One explanation of this is that those cobbles were exposed to sufficient daylight in the past to be wellbleached, but not at the time immediately prior to their last deposition which formed the feature or landform sampled for dating, but instead during a previous event since which time they had not been re-exposed to daylight. This means that the age determined for a feature could be overestimated even though a luminescence-depth profile with a low sub-surface dose plateau was obtained from a cobble indicating that the cobble was well-bleached. Unlike traditional luminescence dating of sediment grains, there are practical and logistical reasons why it is unrealistic, if not impossible, to routinely measure a large number of cobbles from every single site and apply statistical models to extract the true age for the feature of interest for dating. The data show us how confident we are in obtaining the true age for a feature or landform when applying luminescence dating on buried cobbles. Recommendations are provided regarding applying rock surface luminescence dating in environments where conditions mean that not all cobbles will have had any previous luminescence signals (including records of previous bleaching events) removed prior to formation of a feature that is subsequently sampled for dating. In such environments, different levels of low sub-surface age plateau recorded in different cobbles from the same feature demonstrate the potential of tracking the pre-depositional history of these sediments by dating multiple cobbles. [ABSTRACT FROM AUTHOR]

Pluvial lake sediments are frequently luminescence dated using fine sand. Pebbles and cobbles, however, are much less susceptible to post-depositional reworking by wind, pedogenic processes and bioturbation, and thus have the potential to yield more accurate luminescence chronologies for pluvial lake highstands in the Great Basin. This presentation will provide an update on investigations into the dating potential of pebbles from pluvial lake beach ridges in Lincoln County, Nevada. By developing a luminescence protocol to date beach pebbles, we hope to improve upon previous age estimates from sand that severely underestimate the age of the ~16 ka pluvial Lake Coal highstand. In Coal Valley and neighboring valleys, the dominant pebble lithologies sampled include limestone and andesite. Each lithology presents a unique set of challenges regarding sample preparation and measurement; these will be discussed along with preliminary findings as well as proposed future avenues of research. [ABSTRACT FROM AUTHOR]

Landscape at active mountain fronts such as the Himalayas results from climate and/or tectonic interactions. Thus, they are important geomorphic archives that preserve information about such changes/activities in the past. These are a combination of crustal movement and erosion or deposition by surface processes. The Main Frontal Thrust (MFT), which marks the southern end of the Himalayas, has been considered the most active fault in the past. Thus, the landscape in the foothills preserves the signature of deformation events and, at the same time, also records changes in the monsoonal rainfall, controlled by glacial and interglacial events. The present study attempts to understand the evolution of alluvial fan deposits in the Assam- Bhutan Himalayan foothills of the Kokrajhar district of North-East India. The study mainly focuses on the uplifted 30 km long fluvial deposition from the Pinkhua Khola River in the west and Leu Pani in the east. The study is critical because it will help understand the southward propagation of the Himalayan fold and thrust belt. The initiation of the faulting events is marked by the clay layers, which were dated using OSL; the dating of clay layers from the hanging wall of three blocks suggests that the FTB was activated at ~76 ka and experienced three other phases of deformation at ~45 ka, ~27 ka and 12 ka, respectively. [ABSTRACT FROM AUTHOR]

By GERAINT TUDUR (Cardiff: U. of Wales P., 2000; pp. 314. 25 £). AUTOCRATIC, domineering, overbearing, dictatorial, imperious, humourless, stubborn and fallible: these are some of the adjectives used by [...]

Thirty years ago David Williams's masterly study of modern Wales, first published in 1950, was still the only authoritative textbook available for sixth-form students, college students and the lay reader [...]

Class, Community and Culture in Tudor Wales (Cardiff: U. of Wales P., 1989; pp. xxi + 300. £29.50), ed. J. Gwynfor Jones, is a collection of essays, the bulk of [...]