The Late-Devensian proglacial Lake Humber: new evidence from littoral deposits at Ferrybridge, Yorkshire, England

Proglacial Lake Humber is of UK national significance in terms of landscape drainage and development of the British Ice Sheet (BIS) during Marine Isotope Stage 2 (MIS 2), yet it is poorly understood in terms of its dynamics and timing. Sands and gravels exposed at Ferrybridge, West Yorkshire, UK, are interpreted as part of the Upper Littoral sands and gravels related to a high-level Lake Humber, which inundated the Humber Basin to ∼30 m OD during MIS 2. Excavations exposed well-rounded gravels of local origin extending downslope from the 27.5 m OD contour and interbedded sands and fine gravels, which are interpreted as the coarse littoral deposits and nearshore associated deposits. A sample from the distal sands returned an Optically Stimulated Luminescence age of 16.6±1.2 kyr, providing the first direct age for the high-level lake and for when North Sea Basin ice must have blocked the Humber Gap. An underlying sequence included a diamicton dated to after 23.3 ±1.5 kyr and before 20.5±1.2 kyr, indicating that the Late Devensian ice reached at least 15 km south of the Escrick Moraine prior to the high-level lake. Previous to both the high-level lake and this ice advance, loess found at the two sites investigated indicates a long period of loess deposition earlier in MIS 2. These new data for the history of Lake Humber are discussed in the context of ice-marginal oscillations in both the Vale of York and the North Sea Basin.     

Developing KaNgwane: geographies of segregation and integration in the new South Africa

This paper examines social, political and economic processes within the former KaNgwane bantustan to understand the changing relationships between society and space in the post-apartheid era. Research on rural development and reconstruction in South Africa attest to the spatial legacy of apartheid while suggesting that dynamic transformations are occurring within the former bantustans. A central concern of this paper is the ways the apartheid government constructed and presented KaNgwane as a development project in order to justify racial segregation and control. While the bantustans have been effectively erased from the popular imagination, these spaces continue to be framed developmentally in ways that provide limited attention to local context and change. In order to consider the shifts in environment and development discourses within these territories, a case study is employed to evaluate livelihood production systems, environmental change, and governance institutions. It is argued that these patterns reveal the simultaneously static and dynamic nature of the bantustans while demonstrating that their reincorporation will remain an ongoing process in the post-apartheid era.     

Interstadial and last interglacial deposits covered by till in Scotland: a reply

Caseldine & Edwards ( Boreas , Vol. 11, pp. 119–122) have misrepresented assessments of published evidence in the paper by Sissons 1981 ( Boreas , Vol. 10, No. 1). They have not used radiocarbon dates objectively and argue illogically. A different interpretation for the Teindland site is suggested.     

Hurricane control on shelf-edge-reef architecture around Grand Cayman

Rimming the outer shelf of Grand Cayman is a submerged, 87 km long shelf-edge reef that rises to within 12 m of mean sea level. It consists of an array of coral-armoured buttresses aligned perpendicular to shore and separated by steep-sided sediment-floored canyons. Individual buttresses have a diverse coral-dominated biota and consist of three architectural elements: a shield-like front wall colonized by platy corals, a dome-shaped crown colonized by head corals, and a shoreward-projecting spur covered by varying amounts of branching coral. Buttresses are commonly fronted by coral pinnacles that, in some areas, have amalgamated with buttress walls to produce pinnacle-and-arch structures. As margin orientation changes, shelf-edge-reef architecture shows systematic variations that are consistent with changes in fetch and height of hurricane waves. Along margins exposed to fully developed storm waves, shelf-edge-reef buttresses are deep, have large amplitudes, and are dominated by robust head corals. These characteristics are consistent with hurricane-induced pruning of branching corals and the flushing of significant quantities of sand from buttress canyons by return flows. Along margins impacted by fetch-limited storm waves, reef buttresses are shallower, have intermediate-amplitudes, and have a significantly higher proportion of branching corals. These characteristics are consistent with less coral pruning and sand flushing by weaker hurricane waves. Along margins fully protected from storm waves, the buttresses-canyon architecture of the shelf-edge reef breaks down producing a series of shallow, undulating, branching-coral-dominated ridges that merge laterally into an unbroken belt of coral. These characteristics correspond with negligible amounts of pruning and flushing during hurricanes. In addition to differences between margins, local intra-marginal changes in shelf-edge reef architecture are consistent with changes in the angle of hurricane-wave approach. Open sections of the shelf-edge reef, which face directly into storm waves, are pruned of branching corals and the fragments swept back onto the shelf producing extensive spurs. By contrast, on more sheltered, obliquely orientated sections, storm-waves sweep debris along and off shelf producing little or no spur development. Instead, the debris shed seawards accumulates in front of the buttress walls and initiates the development of coral pinnacles. Over time, repeated buttress pruning and canyon flushing during hurricanes not only controls reef architecture but may also influence accretion patterns. Vertical accretion is limited by the effective depth of storm-wave fragmentation. Once this hurricane-accretion threshold is reached the reef moves into a shedding phase and accretes laterally via pinnacle growth, amalgamation, and infilling. Consequently, the reef steps out over its own debris in a kind of balancing act between lateral growth and slope failure — a pattern widely recognized in ancient reefs.