The North of the Wash NSPRMF study area extends from the Scottish border to the northern coast of East Anglia and includes the outer parts of the Humber estuary and The Wash, as well as Dogger Bank. The geological history of the region North of the Wash is dominated by glacial processes as the region has been repeatedly overridden by ice sheets through human history, with the most recent glaciation having the greatest impact on the geology of the seabed and shallow sub-surface as preserved today. As a result, past glaciations have been the focus of many research-driven projects in this region since 2009 (e.g. BRITICE-CHRONO).
The significance of submerged landscapes in the North of the Wash NSPRMF study area was first recognised by the pioneering Mapping Doggerland project when a complex network of palaeochannels was identified across the southern North Sea. Subsequently, development-led and research-driven work has mapped these channel networks across vast areas of the seabed and geomorphological analysis show the systems evolved from high energy braided rivers at the end of the last glaciation to more sinuous and stable rivers as climate warmed; until they became estuaries and, were finally inundated by post-glacial sea-level rise.
A number of projects have focussed on establishing the age, environment and formation history of these complex networks of river channels and the surrounding landscapes to help identify areas suitable for human inhabitation with high potential to preserve archaeological sites or material. Deposits investigated show a transition from a cold, open landscape at the end of the last glaciation, to a freshwater marshland and bog environment surrounded by woodland, as climate warmed. There is also evidence for large proglacial lakes within the region that may have remained prominent features in the landscape long after the ice sheets retreated. A subsequent shift to more brackish/saline environments marks the increasing influence of rising sea-level, and depending on local topography, the region was flooded by the mid-Holocene, between 9,000 cal. BP and 5,000 cal. BP.
There is limited chronological and palaeoenvironmental information from this region, and no archaeological sites have been recorded to date, although a small number of faunal remains have been recovered through trawling and dredging activity suggesting the area was habitable during the Quaternary, contextualised by artefact finds and sites along the current coastal margins (Bicket et al. 2015). One of the key focuses of research in this region should be refining the chronology and stratigraphy of sediments and landscape features to identify the timing and duration of periods suitable for inhabitation in relation to the relatively sparse archaeological record.
A considerable amount of research relevant to submerged prehistory has been undertaken in the region North of The Wash since publication of the NSPRMF 2009, as summarised in Table 6. Funding through the Aggregate Levy Sustainability Fund (ALSF) supported the Seabed Prehistory project (Wessex Archaeology 2008a) and Regional Environmental Characterisation (Tappin et al. 2011) for the Humber region. These projects were the first to acquire geophysical, core, palaeoenvironmental and chronological data for the purpose of archaeological assessment.
A significant proportion of research has been driven by the development of offshore wind, either through the consenting and Environmental Impact Assessment process, or through collaboration with universities through joint funded PhD projects. Academic interest in the region has also increased over the last decade with two key projects, BRITICE-CHRONO and Lost Frontiers, receiving research grant funding.
Collectively, academic and development-led research has led to the acquisition of new geophysical, geotechnical, palaeoenvironmental and chronological data that has been used to refine understanding of glacial history, identify and map palaeolandscape features, reconstruct past environments and provide an improved stratigraphic and chronological framework. Knowledge gained from these projects is highly relevant as it can be used to target landscape features with the greatest potential to contain archaeology, help understand preservation and taphonomy in relation to the sparse archaeological record in this region and provide new palaeoenvironmental records that fill gaps, both spatially and temporally, in environmental history.
Table 6 Publicly available projects and published research since 2009 – North of The Wash
|ALSF Seabed Prehistory Volume VI Humber||Humber||Acquisition and integration of geophysical, core, palaeoenvironmental and chronological data||Palaeolandscape reconstruction and assessment of archaeological potential||Wessex Archaeology (2008a)|
|Lynn and Inner Dowsing OWFs||The Wash||Geoarchaeology, palaeoenvironmental assessment and dating||Palaeoenvironmental reconstruction||Wessex Archaeology (2009a)|
|Dudgeon OWF||The Wash||Interpretation of geophysical data||Identification of palaeolandscape features||Wessex Archaeology (2009b)|
|Race Bank OWF||The Wash||Interpretation of geotechnical data||Lithostratigraphy and assessment of archaeological potential||Wessex Archaeology (2010a; 2010b)|
|Humber REC||Humber||Acquisition and integration of geophysical, core, palaeoenvironmental and chronological data||Palaeolandscape reconstruction and assessment of archaeological potential||Tappin et al. (2011)|
|Academic Research||Dogger Bank and The Wash||Archaeological and landscape modelling||Impact of landscape change on Mesolithic populations in the southern North Sea||Fitch (2011; 2013)|
|Humber Gateway OWF||Humber||Interpretation of geotechnical data||Lithostratigraphy and assessment of archaeological potential||Wessex Archaeology (2013b)|
|Westermost Rough OWF||Humber||Interpretation of geotechnical data||Lithostratigraphy and assessment of archaeological potential||Tetlow (2013)|
|Race Bank OWF||The Wash||Interpretation of geotechnical data||Lithostratigraphy and assessment of archaeological potential||Wessex Archaeology (2014)|
|Teesside A & B OWF||Dogger Bank||Geoarchaeology, palaeoenvironmental assessment and dating||Palaeolandscape reconstruction and assessment of archaeological potential||Wessex Archaeology (2013c; 2013d)|
|Race Bank OWF||The Wash||Geoarchaeology, palaeoenvironmental assessment and dating||Palaeoenvironmental reconstruction||Wessex Archaeology (2015a)|
|Hornsea One OWF||Humber||Interpretation of geotechnical data||Lithostratigraphy and assessment of archaeological potential||Wessex Archaeology (2013e) Krawiec et al. (2011) Maritime Archaeology (2016; 2018)|
|Academic Research||Humber||Interpretation of seabed geomorphology and sub-surface geophysical data||Refined glacial limits||Dove et al. (2017)|
|Academic Research||Dogger Bank||Interpretation of high-resolution geophysical data||Refined lithostratigraphy for Dogger Bank and glacial landscape maps||Cotterill et al. (2017)|
|Historic England Project||Northumberland coast||Acquisition and geomorphological interpretations of nearshore bathymetry||Palaeogeography and sea-level indicators in the nearshore off the coast of Howick||Bicket et al. 2015; Bicket et al. (2017)|
|Academic Research||Humber||Palaeoenvironmental assessment and dating||Palaeoenvironmental reconstruction||Gearey et al. (2017)|
|Hornsea OWF||Humber||Palaeoenvironmental assessment and dating||Palaeoenvironmental reconstruction||Maritime Archaeology (2018)|
|Academic Research||Dogger Bank||Interpretation of high-resolution geophysical data||Glaciotectonic evolution of Dogger Bank, glacial limits and glacial landscape maps||Phillips et al. (2018)|
|BRITICE-CHRONO Academic Research||Southern North Sea||Acquisition and integration of geophysical, core, palaeoenvironmental and chronological data||Refined chronology of glacial history||Roberts et al. (2018)|
|Dudgeon OWF||The Wash||Acquisition and integration of geophysical, core, palaeoenvironmental and chronological data||Palaeoenvironmental reconstruction||Brown et al. (2018)|
|Academic Research||Dogger Bank||Interpretation of high-resolution geophysical and geotechnical data||Palaeolandscape reconstruction – submerged and buried palaeoshoreline||Emery et al. (2019b)|
|Academic Research||Dogger Bank||Interpretation of high-resolution geophysical and geotechnical data||Palaeolandscape reconstruction, glacial limits and glacial history||Emery et al. (2019a)|
|Academic Research||The Wash||Interpretation of high-resolution geophysical and geotechnical data||Lithostratigraphy, glacial limits and glaciotectonism||Mellett et al. (2020)|
|Academic Research||Dogger Bank||Interpretation of high-resolution geophysical and geotechnical data||Palaeolandscape reconstruction – palaeodrainage||Emery et al. (2020)|
|Lost Frontiers Project|
|Southern North Sea||Acquisition and integration of geophysical, core, palaeoenvironmental and chronological data||Characterisation of Storegga Tsunami deposit and palaeogeograhic modelling||Gaffney et al. (2020b); Walker et al. (2020)|
The NSPRMF region North of The Wash was geographically defined considering geological and formation history. The area of seabed extending from the Scottish border to the Wash has been periodically overridden by ice at various times during the Quaternary, most recently during the Devensian period. As a result, glacial processes have left a significant imprint on the stratigraphic and palaeolandscape record (Cotterill et al. 2017; Dove et al. 2017; Roberts et al. 2018; Emery 2019a; 2019b; 2020; Mellett et al. 2020) which must be considered in terms of habitability of landscapes or preservation of archaeological material.
The Quaternary succession of the Central and Southern North Sea is relatively thin (<5 m BGS GeoIndex Offshore) in nearshore areas where bedrock is often exposed at seabed (Bicket et al. 2017) but thickens to ~1000 m at the eastern margin of the NSPRMF (Lamb et al. 2017). The stratigraphic framework can be broadly split into an Early to Middle Pleistocene deltaic sequence (pre-Anglian glaciation) and a Middle Pleistocene to Holocene glaciogenic sequence (post-Anglian glaciation) (Stoker et al. 2011). The majority of seabed and shallow sub-surface investigations undertaken to date in the region have focussed on post-Anglian sediments given they are within the zone of impact for major marine infrastructure (e.g. offshore Wind Turbine Generator foundations) and they have greater potential to preserve archaeological and palaeoenvironmental material.
The Anglian glacial period (MIS 12) is represented in the stratigraphic record by Swarte Bank Formation (Stoker et al. 2011) which is typically constrained to buried tunnel valleys in the Central North Sea and Dogger Bank region (Stewart et al. 2013; Cotterill et al. 2017) but is more widespread to the south, off the coast of Lincolnshire, where it forms a blanket deposit (Wessex Archaeology 2014; Maritime Archaeology 2016) that is, in places, glaciotectonised (Mellett et al. 2020). In support of the Hornsea One Offshore Wind Farm (OWF), palaeoenvironmental assessment of Swarte Bank deposits was attempted but poor preservation and high degrees of reworking meant results were inconclusive (Maritime Archaeology 2018). Swarte Bank Formation is typically not the focus of archaeological assessments as the BGS classify it as a glacial deposit. However, recent investigations of Swarte Bank indicate its formation history is more complex and may include some fluvial and standing freshwater elements, although there are no dates to confirm this and a high degree of reworking may influence the results (Maritime Archaeology 2018). While the formation and initial infill of tunnel valleys may result from glacial activity, it is important to recognise some of these valleys are under- or partially-filled and as climates warm at the end of the glacial period, they can create space for the accumulation of interglacial sediments that may be organic thus preserving a rich palaeoenvironmental record (Cartelle et al. 2021). Therefore, while glacial deposits and processes are often rejected in terms of archaeological assessments, it important to recognise the role they play in antecedence (Emery et al. 2019a).
Interglacial sediments of possible Hoxnian (MIS 11) or later (‘Aveley’; MIS 7 or ‘Purfleet’; MIS 9) date are represented by Sand Hole Formation (locally restricted to the Silver Pit area) and Egmond Ground Formation (Stoker et al. 2011) which are shallow marine deposits that have beds of finer-grained muds that formed in a lagoonal environment suggesting there were periods during these interglacial periods when the North Sea was spatially more restricted and potentially habitable. Sand Hole Formation and Egmond Ground Formation has been identified through offshore wind farm investigations (e.g. Race Bank; Wessex Archaeology 2014; Hornsea One; Maritime Archaeology 2016; Dogger Bank; Cotterill et al. 2017) but very little research has been undertaken to establish a chronology for this interglacial, or to understand palaeoenvironment in relation to archaeological potential.
At a very broad level, the Cold Stages of MIS 10, MIS 8 and MIS 6 are represented by Cleaver Bank Formation (Stoker et al. 2011) which are proglacial clays that have been tentatively recognised in borehole and seismic data in the Dogger Bank region (Cotterill et al. 2017). There is no evidence of a grounded ice sheet in the in the UK sector of the North Sea during these Cold Stages, although there is evidence along the Norfolk coast (Lee et al. 2011) which may suggest any Cold Stage deposits have been subsequently removed by marine and/or glacial erosion. The presence of Cleaver Bank Formation suggests the southern North Sea was a partly flooded basin at some time between MIS 10 and MIS 6 (Cameron et al. 1992). However, there is no chronology for these deposits, and they may have formed during the warmer ‘Purfleet’ (MIS 9) or ‘Aveley’ (MIS 7) interglacial periods.
The Eem Formation correlates to the Ipswichian interglacial (MIS 5e) and comprises shelly or muddy sands of shallow marine to intertidal origin (Stoker et al. 2011) and its distribution is restricted to south of Dogger Bank as it was reworked by glacial processes during the Devensian to the north (Cameron et al. 1992). Distinguishing Eem Formation from underlying Egmond Ground Formation is challenging as they are lithologically similar and there is no chronological data. It may be possible to distinguish between the two formations using biostratigraphic methods, but this will depend on preservation of microfossils and degree of reworking. The presence of Cleaver Bank Formation where present can be used to subdivide the formations (Cotterill et al. 2017) but its distribution is sporadic and poorly mapped. In terms of archaeological potential, resolving the stratigraphy and chronology of Egmond Ground Formation and Eem Formation is important to establish if there are remnants of these deposits that represent shallow intertidal or coastal environments fringing the North Sea during interglacial periods (Hoxnian; MIS 11, Purfleet; MIS 9, Aveley; MIS 7 and Ipswichian; MIS 5e).
Glacial deposits that formed during the Devensian (MIS 5d-MIS 2) period dominate the stratigraphic record North of The Wash. Stratigraphically deposits broadly correlate to the Dogger Bank Formation or Bolders Bank Formation (Stoker et al. 2011) but recent investigations have demonstrated the stratigraphy is much more complex and the existing framework doesn’t capture spatial or temporal variability with the glacial succession (Cotterill et al. 2017; Dove et al. 2017; Roberts et al. 2018; Phillips et al. 2018; Emery et al. 2019a). As a result of glacial processes, earlier deposits have been significantly reworked or eroded and their distribution is patchy and fragmentary. Considering the above, it is not surprising glacial dynamics and ice sheet history have been a key focus of research in the Central and Southern North Sea in recent years.
Building on the data acquired as part of the Humber REC (Tappin et al. 2011), Dove et al. (2017) used seabed geomorphology to identify glacial landform assemblages and redefine ice margins for the North Sea lobe of the British and Irish Ice Sheet (BIIS) indicating several episodes of ice sheet advance and retreat. A dedicated coring and dating programme was undertaken as part of the BRITICE-CHRONO project and the results indicated ice advance into the Central and Southern North Sea between 31.6 and 25.8 ka (MIS 2) which is earlier than previous reconstructions show, with several generations of ice advance and retreat occurring between ~30 and 22 ka (Roberts et al. 2018). The final phase of ice advance in the southern North Sea occurred between 21 and 22 ka but was geographically restricted to the western edge of Dogger Bank (Roberts et al. 2018).
The formation of Dogger Bank is a product of the interplay between climate change, ice dynamics and sea-level change associated with the growth and demise of the BIIS and Fennoscandian ice sheet (FIS) during the last glacial period (MIS2). Recent investigations have demonstrated large-scale glacitectonic deformation across the western parts of Dogger Bank which has created a highly complex stratigraphic record that is not a simple “layer cake” (Phillips et al. 2018; Emery et al. 2019a). Interpretation of seismic data as horizon maps showing the palaeo-topography of the glacial landscape reveal a series of elongate arcuate ridges separated by low lying basins or meltwater channels.
Proglacial lakes are a common landscape feature associated with ice margins, particularly during deglaciation, and there is evidence across Britain for formation of glacial lakes during each of the glacial periods during the last 500 ka (Anglian; MIS 12; MIS 6, MIS 8 and MIS 10; Devensian; MIS 2) (Murton and Murton 2012). In the North Sea, the presence and drainage of a continental-scale glacial lake during the Anglian (MIS 12) and at some point between MIS 10-6 has been linked to major paleogeographic reconfiguration of northern Europe. However, to date there is inconclusive evidence in the sedimentary record in the North Sea of glacial lakes during these periods.
By contrast, there is evidence of proglacial lakes in the Central and Southern North Sea during the Devensian period (Cotterill et al. 2017; Roberts et al. 2018; Emery et al. 2019a) associated with the Devensian ice-sheet margins. Stratigraphically glaciolacustrine sediments form part of the Dogger Bank Formation and Botney Cut Formation (Stoker et al. 2011) and the presence of a large proglacial lake at Dogger Bank has long been hypothesised (Cameron et al. 1992). Seismic mapping by Cotterill et al. (2017) identified a basin up to 35 m deep in the central part of Dogger Bank, infilled with laminated clays. OSL dating of proglacial lake-infill indicates deposition occurred between 31.6 and 25.8 ka before being overridden by ice before 23.1 ka (Roberts et al. 2018). Conceptual palaeogeographic models suggest the proglacial lake at Dogger Bank was a ribbon lake running broadly SW-NE, parallel to the ice sheet margin (Roberts et al. (2018). However, the geometry of the lake basin at Dogger Bank suggest the lake was elongated in a N-S direction (Cotterill et al. 2017; Emery et al. 2019a). At present, the lake basin is completely infilled with fine-grained deposits and there is evidence of desiccation suggesting the lakebed dried out periodically (Emery et al. 2019a).
Proglacial lake deposits are not restricted to the Dogger Bank lake and have been identified elsewhere on Dogger Bank where they infill topographic lows between moraine landforms locally (Phillips et al. 2018; Wessex Archaeology 2013c). In the wider southern North Sea, lacustrine deposits associated with the Botney Cut Formation infill tunnel valleys (Cameron et al. 1992; Tappin et al. 2011; Dove et al. 2017) but recent investigations are showing there is much more complexity in the Botney Cut Formation and not all deposits are glaciolacustrine (Wessex Archaeology 2009b). Palaeoenvironmental assessment of deposits from the Dudgeon OWF show gradual infilling of a proglacial freshwater lake between 12,700 and 9,260 cal. BP (Brown et al. 2018). However, given the age of the deposits and known ice sheet history (Hubbard et al. 2009), the Devensian ice sheet had retreated forming an icecap in the Scottish Highlands hundreds of kilometres to the north at this time. Therefore, the lake deposits more likely reflect localised ponding of water within a formerly glaciated landscape with climate being the key driver of landscape change and arguably have greater archaeological significance when compared with proglacial lake deposits.
A significant amount of research has focused on identifying and mapping palaeochannels as they are important features in the landscape that are known to contain archaeological material, have high potential to preserve palaeoenvironmental records within and along their margins and document the transition from a glacial landscape to a much more habitable more temperate environment before becoming inundated by rising sea levels.
Submerged palaeochannels were first identified in detail as part of the Mapping Doggerland project (Gaffney et al. 2007) revealing an extensive drainage network was buried below the seabed across large parts of the southern North Sea. This palaeochannel network extends into the Humber REC study area and several Botney Cut Formation channels were mapped (Tappin et al. 2011). The channels show different morphology suggesting different formation processes; glacially incised tunnel valleys were identified in the east and a broader anastomosing network, interpreted as part of a glacial outwash plain (Dove et al. 2017), was identified in the west. Detailed mapping of drainage network evolution on Dogger Bank indicates there was an earlier phase of ice-marginal channel formation followed by abandonment of the proglacial system and formation of more sinuous dendritic systems (Emery et al. 2020). This research highlights the importance of understanding formation history in relation to archaeological significance as palaeochannels North of The Wash have greater potential to have been influenced by glacial processes.
Palaeochannels located between the Humber and The Wash have been the target for a number of multi-proxy palaeoenvironmental studies (Tappin et al. 2011; Wessex Archaeology 2015a; Gearey et al. 2017; Maritime Archaeology 2018; Gaffney et al. 2020). Channel infill is often variable, reflecting local processes, and material for radiocarbon dating is not always available (Wessex Archaeology 2015a; Maritime Archaeology 2018). Sediments infilling a palaeochannel located ~80 km off the Lincolnshire coast document an initially freshwater environment with a period of stasis and peat formation between 9-10 ka, followed by a period of channel reactivation between 9-6 ka and an increasing influence of brackish conditions under the influence of rising sea levels with a final shift to fully marine conditions by 6-5 ka (Gearey et al. 2017). This sequence provides a rare palaeoenvironmental record and highlights the importance of channel fill sequences as an environmental archive. This has been reinforced by the recent work of the Lost Frontiers project who identified a Storegga Tsunami deposit within a palaeochannel in the southern North Sea (Gaffney et al. 2020).
Holocene sea-level transgression is recorded within palaeochannels or lake basins by sand, silt and clay deposits that contain microfauna indicative of shallow marine or brackish conditions (Wessex Archaeology 2015a; Gearey et al. 2017; Brown et al. 2018). Stratigraphically, these deposits correlate to Elbow Formation (Stoker et al. 2011). In the Dogger Bank region, Emery et al. (2019b) identified a submerged and buried barrier palaeoshoreline that formed and evolved under the influence of rapid early Holocene sea-level rise. Detailed reconstructions of coastal evolution and paleogeographic mapping provide a landscape context to explore archaeological potential.
Investigating submerged prehistoric landscapes in areas where bedrock is exposed at seabed is challenging which is the case for the shallow water coastal areas fringing the north east coast of England due to persistent erosion by present-day waves and tides. There is however potential to use bathymetric data and seabed geomorphological mapping to identify palaeolandscape features such as submerged palaeochannels or shorelines. This approach was adopted as part of a project to reconstruct the submerged landscapes off the coast of Howick, a key Mesolithic site on the Northumberland coast. Bicket et al. (2017) identified a series of palaeoshorelines that were used to constrain paleogeographic reconstructions of the early Holocene coastal landscape at the time of settlement.
Many of the study areas investigated in the Lost Frontiers Project are located in the North of the Wash NSPRMF study area and following publication in 2022/2023 (Gaffney and Fitch in press), the results are expected to contribute to the understanding of the stratigraphy, chronology, landscapes and palaeogeography of this region.
Palaeoenvironmental datasets obtained from direct sampling of terrestrial sediments located North of The Wash are dominated by environmental impact studies for OWF developments (Table 7). A wide range of paleoenvironmental proxies have been assessed for, with recent research projects including the developing technique of sediment (seda)DNA (Gaffney et al. 2020).
Table 7 Quaternary palaeoenvironmental studies of vibrocore data carried out North of The Wash since 2009
|Project||Location||Publication Year||Age||Paleoenvironmental proxies||Reference|
|Lynn and Inner Dowsing OWF||The Wash||2009||Late Middle/Late Pleistocene (<MIS 7->≥MIS 3)||Pollen Ostracods||Wessex Archaeology (2009a)|
|Teesside A & B OWF||Dogger Bank||2013||Late Pleistocene (Late Glacial)||Plant macrofossils Pollen||Wessex Archaeology (2013b)|
|Teesside A & B OWF ORPAD Peat Samples||Dogger Bank||2013||Early Holocene||Plant macrofossils Insects Molluscs||Wessex Archaeology (2013c)|
|Humber REC||Humber||2011||Late Pleistocene/ Early Holocene||Plant macrofossils Insects Pollen Ostracods Foraminifera||Tappin et al. (2011) Gearey et al. (2017)|
|Hornsea One OWF||Humber||2017||Late Pleistocene/ne Early Holocene||Plant macrofossils Insects Pollen Diatoms Ostracods Foraminifera||Maritime Archaeology (2018)|
|Race Bank OWF||The Wash||2015||Early Holocene||Plant macrofossils Insects Pollen Charcoal Diatoms Ostracods Foraminifera Molluscs||Wessex Archaeology (2015a)|
|Dudgeon OWF||The Wash||2018||Early Holocene||Plant macrofossils Pollen Ostracods Foraminifera Molluscs||Brown et al. (2018)|
|Lost Frontiers Project||Southern North Sea||2020||Early Holocene||Pollen Diatoms Ostracods Foraminifera Molluscs sedaDNA||Gaffney et al. (2020) Walker et al. (2020)|
Most terrestrial palaeoenvironmental records from the region are dated to the early Holocene. However, some Pleistocene datasets, most of which relate to the late Pleistocene (MIS 2; 29–11.7 ka), have been recovered. Potentially the earliest Quaternary record from the region is associated with late Middle or Upper Pleistocene cold stage lacustrine sediments identified east of the Wash (equivalent to Brown Bank Formation) (Wessex Archaeology 2009b). These contained pollen and ostracods faunas indicative of a cold steppe landscape and given the stratigraphy, likely formed during the Devensian (MIS 5d-2).
Late Glacial terrestrial sediments, some of which are fossiliferous, have been identified from Dogger Bank (Wessex Archaeology 2013c) and east of the Humber (Tappin et al. 2011, Wessex Archaeology 2013c, Gearey et al. 2017). These included units of Windermere Interstadial date (associated with radiocarbon dates of 14,890-14,010 cal. BP and 13,810-13,480 cal. BP), which reflect freshwater wet marshland and bog environments, surrounded by drier areas of ground with low growing shrubs (Wessex Archaeology 2013c). Windermere Interstadial deposits in terrestrial British contexts are associated with late Upper Palaeolithic archaeology (Jacobi and Higham 2011).
East of the Humber estuary, late Pleistocene and early Holocene terrestrial sediments have been identified that contained paleoenvironmental evidence reflecting landscape stabilisation, with freshwater and deciduous woodland in the early Holocene (dated to 9,000–10,000 cal. BP), followed by the development of increasingly brackish/saline environments, with final marine inundation occurring between 6,000–5,000 cal. BP (Tappin et al. 2011; Gearey et al. 2017). Palaeoenvironmental evidence from the Dungeon OWF, east of the Wash, recorded a similar transition from wooded landscapes and freshwater environments of the earliest Holocene to increasing brackish and saline influenced conditions from 9,000 cal. BP (Brown et al. 2018). Such early Holocene terrestrial environments have potential to have supported Mesolithic human populations.
Reassessment of terrestrial mammal remains curated in British museums has identified over 11,000 specimens which can be provenanced to the southern North Sea (Bynoe 2014, Bynoe et al. 2016).
For the area North of The Wash, the research identified areas where trawlers operating out of Great Yarmouth recovered Pleistocene mammalian fauna. The biostratigraphically informative component of these collections are dominated by post-Anglian (<MIS 12; <424 ka) species. Woolly mammoth dominates, with smaller numbers of woolly rhinoceros, aurochs, reindeer and giant deer. The collections also include a small number of obligate temperate species, including straight-tusked elephant and hippopotamus. These assemblages likely date to multiple periods of the late Middle and Upper Pleistocene. A mammoth tusk reported as part of the BMAPA protocol from Marine Aggregate Licence Area 408, located east of the Humber estuary, produced a middle Devensian (MIS 3) radio-carbon date of c. 44 ka (Allen et al. 2008), although the reliability of this age is uncertain.
BMAPA data reported since 2009 includes a mammoth jaw fragment from marine aggregate licence Area 102 (Figure 3). Notably, a radius possibly belonging to a hippopotamus was previously identified from Area 102 (Wessex Archaeology 2007), which may be indicative of the presence of last interglacial (MIS 5e; 130–116 ka) deposits.
Recent seabed investigations have reported potential Mesolithic archaeology from a submerged river system located offshore of the Lincolnshire coast (Missiaen et al. 2021). This material is currently under study but has been reported to include a possible fragment of a hammerstone.