An examination of the Geochemical properties of late devensian glacigenic sediments in Eastern England

Onshore advance of the North Sea lobe of the Late Devensian British Ice Sheet the last glaciation resulted in the deposition of thick multiple till sequences along the coasts of east Yorkshire and north Lincolnshire. Despite an abundance of sedimentological and stratigraphical data, the origin of these tills remains controversial, and their correlation along the coast is poorly understood. These multiple till sequences provide an excellent opportunity to test models of large-scale subglacial sediment transport and deposition beneath soft-bed ice sheets using geochemistry. Such geochemical analysis has been used extensively in other formerly glaciated areas, notably Canada, to identify till characteristics and dispersal patterns. However, to date it has not been applied in any detail to glacial sediments in the UK and its potential as a tool for till correlation and understanding till genesis remains relatively undeveloped. A detailed sampling method was employed at seven sites in eastern England; Filey, Skipsea, Dimlington, South Ferriby, Kirmington, Welton-Le-Wold and Morston; to investigate vertical and lateral changes in till geochemistry in this region. Particle size analysis of the till matrix was used as an additional tool to provide extra sedimentological data. Complete linkage and Ward's method cluster analysis was used to establish groups of geochemically similar diamicton samples. Geochemical results suggest that there are vertical changes in till geochemistry, which are likely to be related to a change in provenance from local to more distal sources. Geochemistry and particle size results were also unable to precisely differentiate between the Basement, Skipsea and Withernsea till types. Instead, the repeated nature of the geochemical signature at larger sites, such as Dimlington, and the lateral discontinuity of some geochemical groups suggests that the till sequences at Filey, Dimlington, and Skipsea are comprised of a number of lithologically distinct rafts which have been tectonically stacked or elevated to higher levels in the sediment pile. At Dimlington the production of a glacitectonically folded and stacked moraine is proposed as a mechanism to explain the remarkably thick sequence of Withemsea Till and the repeated nature of the geochemical signature at this site. This research therefore provides new evidence for our understanding of glacial stratigraphy and former ice dynamics in eastern England, suggesting that till composition and the mechanics behind its production are more complex than the traditional stratigraphic division allows

Guide for third and fourth year students

Advice complied by Boston University School of Medicine students for incoming first year students and third or fourth year students preparing for clinical rotations

A Younger Dryas plateau icefield in the Monadhliath, Scotland, and implications for regional palaeoclimate

A record of Younger Dryas glaciation in Scotland is well established. However, the role of the Monadhliath, a significant plateau area extending over 840 km2 in central Scotland, has never been investigated systematically. We present the first systematic glacial geomorphological mapping across the whole region, which has led to the identification of hitherto-unrecorded glacial and associated landforms. The spatial distribution of these landforms indicates that the last phase of glaciation in the area was that of a local plateau icefield. In addition, a clear morphostratigraphical signature provides a strong indication that the icefield dates to the Younger Dryas (12.9–11.7 ka), which is supported by numerical ages in the southeast of the study area. Based on the geomorphological evidence and 2D glacier surface profile modelling, a 280 km2 icefield is reconstructed. A novel approach is introduced to quantify plateau icefield thickness for equilibrium line altitude (ELA) and palaeoprecipitation calculations, resulting in greater overall data confidence compared to traditional reconstruction methods. The ELA for the whole icefield is calculated to be 714 ± 25 m, whilst the ELAs of individual outlet glaciers range from 560 m in the west to 816 m in the east, demonstrating a significant W–E precipitation gradient across the region during the Younger Dryas. These ELAs compare well with those calculated for Younger Dryas ice masses reconstructed in neighbouring regions and are in good agreement with overall precipitation patterns suggested for Scotland during this time. Whilst the total amount of precipitation calculated from these ELAs is highly dependent on the method used, irrespective of this, the study suggests a more arid Younger Dryas climate in the region compared to the present day

A Lateglacial Plateau Icefield in the Monadhliath Mountains, Scotland: reconstruction, dynamics and palaeoclimatic implications

PhDThe complex record of glaciogenic landforms and sediments in Britain relating to the last British-Irish Ice Sheet provides the opportunity to reconstruct former ice extents, ice dynamics, retreat patterns and examine their links to climate change. Yet in Scotland, as in the rest of Britain, a previously fragmentary approach to palaeoglaciological research has limited our understanding of glacier dynamics and their relationship to climate, particularly during the Last Glacial-Interglacial Transition. The Monadhliath Mountains in the Central Scottish Highlands are dominated by an extensive plateau area that has received little research attention in the past. The few examples of research include work by British Geological Survey officers in the early 1900s and J.R. Young in the 1970s. These studies focussed primarily on the geomorphology and sedimentology of isolated valleys and therefore this PhD research provides the first systematic mapping of the region as a whole. Results of remote and field mapping demonstrate that two coalescent plateau icefields, together covering an area of c. 280 km2, occurred over the southwest and central sector of the Monadhliath Mountains during the Younger Dryas. Equilibrium line altitudes calculated for the icefield are of comparable magnitude to those reconstructed for nearby Younger Dryas ice masses, such as in Drumochter and Creag Meagaidh, but indicate slightly lower precipitation in the Monadhliath Mountains. ELAs of individual outlet glaciers rise steeply from west to east across the plateau, indicating a strong local precipitation gradient. Significant variations in the geomorphology on the plateau and within outlet valleys allowed an examination of former thermal regime and differences in ice dynamics during retreat. In-depth analysis of moraine retreat patterns enabled a detailed insight into palaeoglaciological controls on deglaciation for the first time, concluding that valley morphology and gradient were the most influential factors on the retreat dynamics of the plateau icefield.Natural Environment Research Council Algorithm Studentshi

A spatially-restricted Younger Dryas plateau icefield in the Gaick, Scotland: reconstruction and palaeoclimatic implications

Considerable research has been conducted in Scotland to reconstruct Younger Dryas glaciers and palaeoclimatic conditions, but our understanding remains incomplete. In this contribution, we examine the Gaick, a dissected plateau that extends over ∼520 km 2 in the Central Grampians, Scotland. The extent and style of Younger Dryas glaciation in the Gaick has been repeatedly contested, although a model of extensive plateau icefield glaciation has become generally accepted. This is despite well-documented issues with key elements of the plateau icefield reconstruction. We synthesise the results of recent geomorphological mapping in the Gaick and recognise a distinct morphostratigraphic signature in the upper parts of the western catchments. This differs markedly from sediment-landform associations in other parts of the area, and we argue this provides a strong indication of spatially-restricted Younger Dryas (∼12.9–11.7 ka) glaciation in the Gaick. Our interpretation is independently supported by glacierisation threshold analysis, which implies that the eastern Gaick was unable to nourish Younger Dryas ice. We therefore contest the accepted paradigm of extensive Younger Dryas glaciation in this area. Based on the geomorphological evidence and glacier surface profile modelling, we reconstruct a ∼42 km 2 plateau icefield that yields an equilibrium line altitude of 751 ± 46 m. Using this value, a sea-level precipitation value of 826 ± 331 mm a −1 is inferred for the Younger Dryas, which suggests considerably drier conditions than at present. Using recalculated glacier-derived precipitation estimates from Scotland, we present regional climate analysis that corroborates arguments for a strong west-east precipitation gradient across Scotland

Beyond summative evaluation: The Instructional Quality Assessment as a professional development tool

In order to improve students' opportunities to learn, educators need tools that can assist them to reflect on and analyze their own and others' teaching practice. Many available observation tools and protocols for studying student work are inadequate because they do not directly engage educators in core issues about rigorous content and pedagogy. In this conceptual paper, we argue that the Instructional Quality Assessment (IQA)--a formal toolkit for rating instructional quality that is based primarily on classroom observations and student assignments--has strong potential to support professional development within schools at multiple levels. We argue that the IQA could be useful to "teachers" for analyzing their own and their colleagues' practice; additionally, the IQA could aid the efforts of "principals" in their work as instructional leaders, identifying effective practitioners to help lead professional development within a school and targeting professional development needs that would require external support. Although the IQA was designed for summative, external evaluation, we argue that the steps taken to improve the reliability of the instrument--particularly the efforts to make the rubric descriptors for gradations of instructional quality as transparent as possible--also serve to make the tool a resource for professional growth among educators. The following are appended: (1) Abridged Version of the Principles of Learning; (2) Relationship between Checklist Ratings and Rubric Scores; and (3) Accountable Talk Function Checklist. (Contains 3 notes, 1 table, and 1 figure.

Glacial geomorphology of the Gaick, Central Grampians, Scotland

The Gaick is an enigmatic glaciated landscape in the Central Grampians, Scotland, dominated by an expansive dissected plateau. Previous studies have postulated widely differing interpretations of the glacial landforms and current understanding of the glacial events in this area is partly restricted by the absence of detailed glacial geomorphological mapping. To address this issue, we present a comprehensive 1: 46,000-scale glacial geomorphological map, covering an area of ∼520 km2. A combination of detailed field mapping and interpretation of aerial photographs and Digital Surface Models (DSMs) has revealed a variety of glacial, periglacial and fluvial landforms, including an abundance of moraines and meltwater channels within valleys. We also identify a glacial sediment-landform assemblage, dissected glaciogenic material, that has not previously been reported in the Scottish Highlands. The geomorphological map provides the necessary foundation for elucidating the extent, dynamics and timing of former glaciation in the area