Abstract:The stratigraphic sequence at North Cave, on the eastern margins of the Lake Humber basin, records the deposition of a fluvioperiglacial fan (LFs 1-4), with early sedimentation (LF1) dating to Marine Isotope Stage (MIS) 3 (optically stimulated luminescence date range 41.8-38.6 ka and 14 C dates 41.6-49 ka BP). Three phases of permafrost and ice wedge development during MIS 3 are evident and indicate possible fan abandonment and hence periods of reduced nival runoff. Involution structures dated to 11.1 ka with … Show more
“…Detailed information included primary sedimentary structures, bed contacts, sediment body geometry, sorting and texture and secondary structures, as well as data on clast form and lithology and palaeocurrents where appropriate. Further details in terms of site‐specific analyses are available in Evans et al (2017, 2018, 2019), Bateman et al (2018) and Roberts et al (2018, 2019). The sediment–landform associations identified both onshore and offshore were placed in a glacial land‐systems context established for the region by earlier research (Eyles et al 1982; Evans et al 1995; Bradwell et al 2008; Davies et al 2009; Boston et al 2010; Evans & Thomson 2010; Roberts et al 2013; Sejrup et al 2015; Dove et al 2017) as well as a regional lithostratigraphic context (cf.…”
Section: Methodsmentioning
confidence: 99%
“…Consequently, a potentially deeper lake (cf. Straw 1979) is regarded as an ephemeral feature during MIS 2 by Evans et al (2018), likely because it was difficult to maintain by the NSL plugging the Humber Gap, and hence highstand Lake Humber was repeatedly terminated by catastrophic drainage in response to ice margin floatation.…”
Section: Glacial Land Systems Of the North Sea Regionmentioning
confidence: 99%
“…The findings of Transect 2 are summarised here based upon new data from a number of localised case studies that were designed to further interrogate the existing glacial geomorphology, Late Quaternary stratigraphy and geochronology in key locations around the British sector of the North Sea Basin (Evans et al 2017, 2018, 2019; Bateman et al 2018; Roberts et al 2018, 2019), as well as concurrent reports on glacial reconstructions prepared outwith, but at the same time complementary to, the BRITICE‐CHRONO project (e.g. Murton et al 2009; Bateman et al 2008, 2015; Fairburn & Bateman 2016; Dove et al 2017; Fig.…”
The findings of BRITICE‐CHRONO Transect 2 through the North Sea Basin and eastern England are reported. We define ice‐sheet marginal oscillation between ~31 and 16 ka, with seven distinctive former ice‐sheet limits (L1–7) constrained by Bayesian statistical analysis. The southernmost limit of the North Sea Lobe is recorded by the Bolders Bank Formation (L1; 25.8–24.6 ka). L2 represents ice‐sheet oscillation and early retreat to the northern edge of the Dogger Bank (23.5–22.2 ka), with the Garret Hill Moraine in north Norfolk recording a significant regional readvance to L3 at 21.5–20.8 ka. Ice‐marginal oscillations at ~26–21 ka resulted in L1, L2 and L3 being partially to totally overprinted. Ice‐dammed lakes related to L1–3, including Lake Humber, are dated at 24.1–22.3 ka. Ice‐sheet oscillation and retreat from L4 to L5 occurred between 19.7 and 17.3 ka, with grounding zone wedges marking an important transition from terrestrial to marine tidewater conditions, triggered by the opening of the Dogger Lake spillway between 19.9 and 17.5 ka. L6 relates to ice retreat under glacimarine conditions and final ice retreat into the Firth of Forth by 15.8 ka. L7 (~15 ka) represents an ice retreat from Bosies Bank into the Moray Firth.
“…Detailed information included primary sedimentary structures, bed contacts, sediment body geometry, sorting and texture and secondary structures, as well as data on clast form and lithology and palaeocurrents where appropriate. Further details in terms of site‐specific analyses are available in Evans et al (2017, 2018, 2019), Bateman et al (2018) and Roberts et al (2018, 2019). The sediment–landform associations identified both onshore and offshore were placed in a glacial land‐systems context established for the region by earlier research (Eyles et al 1982; Evans et al 1995; Bradwell et al 2008; Davies et al 2009; Boston et al 2010; Evans & Thomson 2010; Roberts et al 2013; Sejrup et al 2015; Dove et al 2017) as well as a regional lithostratigraphic context (cf.…”
Section: Methodsmentioning
confidence: 99%
“…Consequently, a potentially deeper lake (cf. Straw 1979) is regarded as an ephemeral feature during MIS 2 by Evans et al (2018), likely because it was difficult to maintain by the NSL plugging the Humber Gap, and hence highstand Lake Humber was repeatedly terminated by catastrophic drainage in response to ice margin floatation.…”
Section: Glacial Land Systems Of the North Sea Regionmentioning
confidence: 99%
“…The findings of Transect 2 are summarised here based upon new data from a number of localised case studies that were designed to further interrogate the existing glacial geomorphology, Late Quaternary stratigraphy and geochronology in key locations around the British sector of the North Sea Basin (Evans et al 2017, 2018, 2019; Bateman et al 2018; Roberts et al 2018, 2019), as well as concurrent reports on glacial reconstructions prepared outwith, but at the same time complementary to, the BRITICE‐CHRONO project (e.g. Murton et al 2009; Bateman et al 2008, 2015; Fairburn & Bateman 2016; Dove et al 2017; Fig.…”
The findings of BRITICE‐CHRONO Transect 2 through the North Sea Basin and eastern England are reported. We define ice‐sheet marginal oscillation between ~31 and 16 ka, with seven distinctive former ice‐sheet limits (L1–7) constrained by Bayesian statistical analysis. The southernmost limit of the North Sea Lobe is recorded by the Bolders Bank Formation (L1; 25.8–24.6 ka). L2 represents ice‐sheet oscillation and early retreat to the northern edge of the Dogger Bank (23.5–22.2 ka), with the Garret Hill Moraine in north Norfolk recording a significant regional readvance to L3 at 21.5–20.8 ka. Ice‐marginal oscillations at ~26–21 ka resulted in L1, L2 and L3 being partially to totally overprinted. Ice‐dammed lakes related to L1–3, including Lake Humber, are dated at 24.1–22.3 ka. Ice‐sheet oscillation and retreat from L4 to L5 occurred between 19.7 and 17.3 ka, with grounding zone wedges marking an important transition from terrestrial to marine tidewater conditions, triggered by the opening of the Dogger Lake spillway between 19.9 and 17.5 ka. L6 relates to ice retreat under glacimarine conditions and final ice retreat into the Firth of Forth by 15.8 ka. L7 (~15 ka) represents an ice retreat from Bosies Bank into the Moray Firth.
“…Proglacial lakes are a common feature of ice-sheet margins during deglaciation, with several lake-fills preserved in the Quaternary geological record (Carrivick and Tweed, 2013), and have been identified in many locations around the margin of the British-Irish Ice Sheet (Livingstone et al, 2010;Clark et al, 2012;Murton and Murton, 2012;Evans et al, 2016aEvans et al, , 2018. A large proglacial lake has been previously interpreted at Dogger Bank, with three phases of infill (Cotterill et al, 2017a).…”
Reconstructions of palaeo-ice sheet retreat in response to climate warming using offshore archives can provide vital analogs for future ice-sheet behavior. At the Last Glacial Maximum, Dogger Bank, in the southern North Sea, was covered by the Eurasian Ice Sheet. However, the maximum extent and behavior of the ice sheet in the North Sea basin is poorly constrained. We reveal ice-marginal dynamics and maximum ice extent at Dogger Bank through sedimentological and stratigraphic investigation of glacial and proglacial lake sediments. We use a large, integrated subsurface dataset of shallow seismic reflection and geotechnical data collected during windfarm site investigation. For the first time, an ice stream is identified at Dogger Bank, based on preserved subglacial bedforms, eskers and meltwater channels. During ice-sheet advance, a terminal thrustblock moraine complex formed, whose crest runs approximately north-northeast to south-southwest. Subsequent ice stream shutdown caused stagnation of ice, and rapid retreat of the ice-sheet margin. The moraine complex, and outwash head from an adjacent ice-sheet lobe to the west, dammed a large (approximately 750 km 2) proglacial lake. Subsequent sedimentation infilled the lake with 30 m of glacial outwash sediments. A lobate subaqueous fan formed at the ice-sheet margin, which thins toward the southeast with iceberg scours and ice-rafted debris at the base, and is onlapped by lake sediments calibrated to core as alternating clay and silt laminae, interpreted to be varves. The lake became isolated from the retreating ice-sheet margin, and ice-sheet retreat slowed. Sediment-laden meltwater was supplied to the ice-distal proglacial lake for c. 1500-2000 years. Subsequent ice-sheet retreat off Dogger Bank was more rapid due to the negative subglacial slope. The stepped retreat of rapid downwasting, slow retreat, and a final rapid phase off Dogger Bank occurred after the LGM at around 27 ka and before formation of a ribbon lake, dated previously to 23 ka and approximately 60 m lower in elevation, formed to the north of Dogger Bank. The complicated stratigraphic architecture revealed through these data improves forecasting of ground conditions for turbine footings at Dogger Bank, an important step in the provision of clean, sustainable energy.
“…A number of vertical sections were cleaned back, recorded and scaled photomontages prepared in 2001 (figures 5 and 6; electronic supplementary material figures S1 and S2). Included on these were sediment texture and colour (using Munsell colours), primary and secondary sedimentary structures, bed contacts, sediment body geometry as well as observations on clast form and lithology, as per Gale & Hoare [42] and Evans et al [10]. Figure 5.Vertical face through units 3–5 in the south section at the Finningley Quarry.…”
While there is extensive evidence for the Late Devensian, less is known about Early and Middle Devensian (approx. 110–30 ka) climates and environments in the UK. The Greenland ice-core record suggests the UK should have endured multiple changes, but the terrestrial palaeo-record lacks sufficient detail for confirmation from sites in the British Isles. Data from deposits at Finningley, South Yorkshire, can help redress this. A channel with organic silts, dated 40 314–39 552 cal a BP, contained plant macrofossil and insect remains showing tundra with dwarf-shrub heath and bare ground. Soil moisture conditions varied from free draining to riparian, with ponds and wetter vegetated areas. The climate was probably low arctic with snow cover during the winter. Mutual climatic range (MCR), based on Coleoptera, shows the mean monthly winter temperatures of −22 to −2°C and summer ones of 8–14°C. Periglacial structures within the basal gravel deposits and beyond the glacial limits indicate cold-climate conditions, including permafrost. A compilation of MCR reconstructions for other Middle Devensian English sites shows that marine isotope stage 3—between 59 and 28 ka—experienced substantial variation in climate consistent with the Greenland ice-core record. The exact correlation is hampered by temporal resolution, but the Finningley site stadial at approximately 40 ka may correlate with the one of the Greenland stadials 7–11.
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