Genesis and provenance of a new Middle Pleistocene diamicton unit at Happisburgh, NE Norfolk, UK

Abstract

Glacigenic deposits at Happisburgh, NE Norfolk, record the earliest known expansion of glaciers into lowland eastern England during the Quaternary. The sequence comprises two regionally extensive till units, the Happisburgh Till and Corton Diamicton members of the Happisburgh Glacigenic Formation, deposited during separate ice advances, and intervening glacilacustrine and outwash deposits laid down during ice-marginal retreat. During 2012, a new diamicton unit was discovered within the intervening sorted sediments and its significance is outlined here. Sedimentological and structural evidence suggests, tentatively, that the diamicton forms a small debris fan generated subaerially by a series of water-saturated hyperconcentrated or debris flows. The precise trigger mechanism for these flow deposits remains unclear, but may relate to seasonal melting of surface or buried ice followed by mass-movement, or to more abrupt geological events including periods of intense rainfall, moraine dam failure or a glacier outburst flood

Orientation of gravels and soft-sediment clasts in subaqueous debrites – implications for palaeodirection reconstruction: case study from Puck Bay, northern Poland

“…Sedimentation took place during a recession of Middle Weichselian ice sheet, probably between ice blocks, which is deduced from (1) the lack of typical terminoglacial lacustrine sequences (cf. Brodzikowski & Van Loon, 1991;Bennett et al, 2002;Lajeunesse & Allard, 2002;Gruszka, 2007;Tripsanas & Piper, 2008;Hodkin et al, 2016), (2) the lack of ice-rafted debris and (3) the proximal part of the fan occurring opposite to the presumed ice-sheet margin position in this area (north). Debrites were deposited by subaquatic debris flows of material derived from the remobilisation of unstable sediments deposited on the slope of small glaciolacustrine basin and from dead ice blocks south of this lake .…”

The forensic utility of reworked geological materials in soil

“…In the case of the latter, Lower and Upper Jurassic black, bituminous shales such as Mulgrave Shale Member (Lower Toarcian) and the Kimmeridge Clay Formation (Kimmeridgian) regularly provided stratigraphically recycled palynomorphs into tills in the UK (e.g. Busfield et al, 2015;Hodkin et al, 2016). This is due to the relative mechanical robustness and the resistance to oxidation during weathering of these relatively hard and physically strong lithotypes.…”

“…Of these, the glaciolacustrine clays and till are the most consistent in yielding palynomorphs. Both these sediments commonly yield palynofloras (Riding et al, 2003;Hodkin et al, 2016). In the case of till, the content of these assemblages is dependent on the sedimentary rocks entrained into the ice on route taken by the glacier.…”