Merle Muru | University of Tartu (original) (raw)

Papers by Merle Muru

Coastline Changes of the Baltic Sea from South to East

This paper reviews Estonian relative sea level, land uplift and coastal floods data and provides ... more This paper reviews Estonian relative sea level, land uplift and coastal floods data and provides sealevel scenarios and risk assessment of coastal flooding in urban areas for the 21st century. Considering the present post-glacial land uplift rates of Estonian coastal areas and the global ocean level rise projections, the long-existing trend of relative sea-level lowering may very probably be replaced by a relative sea-level rising trend during the 21st century. By the end of the 21st century we project the relative sea level to be c. 20 to 40 cm or c. 40 to 60 cm higher in the case of the International Panel for Climate Change Representative Concentration Pathways (RCP) 4.5 or RCP 8.5 scenario, respectively. The sea level rise together with the increased storm frequency and decreased winter ice cover period will very probably increase the extent of floods during the 21st century. A significant coastal flooding risk affects four cities, Pärnu, Kuressaare, Haapsalu and Tallinn and eight smaller towns. The largest coastal flooding in Estonia is recorded in Pärnu, with the highest sea level 275 cm in 2005. Calculations show that due to the impact of predicted climate change and in the case of certain weather conditions, coastal floods in Pärnu may affect areas up to 400 cm above the present sea level by the end of the 21st century. The scenarious of future flood limits are needed for sustainable planning of the coastal zone and for development of rescue strategies.There are already several land use and urban planning instruments and laws for climate adaptation, such as environmental impact assessment, risk assessment and restriction zones for construction in certain buffer and flood areas. Flooding risk measures consist of risk mapping and a national emergency plan. However, further integration of climate issues into existing laws, strategies and land use plans is essential to have a targeted approach in reducing the vulnerability of populated areas and strengthening the adaptive capacity of the urban system against climate change.

Journal of Coastal Research

ABSTRACT Tõnisson, H.; Suursaar, Ü.; Kont, A.; Muru, M.; Rivis, R.; Rosentau, A.; Tamura, T., and... more ABSTRACT Tõnisson, H.; Suursaar, Ü.; Kont, A.; Muru, M.; Rivis, R.; Rosentau, A.; Tamura, T., and Vilumaa, K., 2018. Rhythmic patterns of coastal formations as signs of past climate fluctuations on uplifting coasts of Estonia, the Baltic Sea. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 611–615. Coconut Creek (Florida), ISSN 0749-0208. On uplifting and tideless Baltic Sea Coasts in Estonia, a number of elevated mid to late Holocene beach ridge systems with rhythmic patterns are identified. Such uplifted coastal formations serve as archives of past variations in sea level and climate, as well as extreme events. Luminescence dating and interpretation of airborne LiDAR elevation data were used to identify the main formation mechanisms of such beach ridge systems. More extensive (up to 100–150 ridges) and clearer ridge patterns were found on faster emerging (uplift rates around 3 mm/yr) and well-exposed western and northern coasts, where they were located on the heights of up to 18 m. The average temporal periodicity (30–40 years) in such ridge systems is in good agreement with 25–40 year cyclicity, which is detectable in Estonian tide-gauge records, wave hindcasts, regional storminess and the NAO indices. However, typical average ridge spacing was 2–3 times longer in the study areas with lower (0.5–2 mm/yr) uplift rates. It suggests that the cyclicity in ridges depends on uplift rate and is additionally enhanced or modified by decadal-scale variations in forcing conditions that is locally available.

Remote Sensing

Freely available global digital elevation models (DEMs) are important inputs for many research fi... more Freely available global digital elevation models (DEMs) are important inputs for many research fields and applications. During the last decade, several global DEMs have been released based on satellite data. ASTER and SRTM are the most widely used DEMs, but the more recently released, AW3D30, TanDEM-X and MERIT, are being increasingly used. Many researchers have studied the quality of these DEM products in recent years. However, there has been no comprehensive and systematic evaluation of their quality over areas with variable topography and land cover conditions. To provide this comparison, we examined the accuracy of six freely available global DEMs (ASTER, AW3D30, MERIT, TanDEM-X, SRTM, and NASADEM) in four geographic regions with different topographic and land use conditions. We used local high-precision elevation models (Light Detection and Ranging (LiDAR), Pleiades-1A) as reference models and all global models were resampled to reference model resolution (1m). In total, 608 mi...

<p&amp... more <p>During the late glacial and early Holocene, vast areas of dry land stretched from the British Isles to continental Europe over what is now the southern part of the North Sea. Whilst it is known that this landscape was inhabited, little is known about the cultures that lived there and the surrounding environment. This study focuses on the Brown Bank area, between the UK and Dutch coasts, with its significant 25 km long and 10-15 m high ridge on the seabed which has provided many Mesolithic ex-situ finds. However, all of these finds have been recovered serendipitously due to commercial fishing and dredging, and thus the landscape and sedimentary context of these archaeological finds is unclear.<br>The goal of this study is to map the terrestrial features in the Brown Bank area and reconstruct the palaeolandscape and its inundation to determine the potential locations from which this archaeological material derives, and potentially locate Mesolithic settlement sites. The project uses high-resolution parametric echosounder surveys in a dense survey network to record the area and facilitate later targeted dredging and vibro-core sampling.<br>The seismic surveys revealed a pre-marine inundation landscape with fluvial channels eroded into post glacial sediments. A peat layer was located on the top of the banks of the channels where it continues laterally hundreds of metres. Radiocarbon dating of the top part of the peat layer, just below the transgressive deposits gave ages around 10.2-9.9 cal ka BP. Palaeogeographic reconstructions based on the mapped terrestrial features and the available relative sea level change data suggest that the final inundation of the area happened c. 1000 years later. Where dredging was carried out in areas of interest, primarily where the early Holocene surface outcropped onto the seabed, a large number of blocks of peat with pieces of wood and other macrofossils were recovered, suggesting a good potential for preservation of possible archaeological material and possible locations of origin for the serendipitous finds made by fishermen.<br>We conclude that this study provides new insights into the palaeogeography and the timing of the inundation of the Brown Bank area and gives the landscape context to the potential Mesolithic habitation of this part of the southern North Sea.</p>

Journal of Coastal Research, 2016

Journal of Coastal Research, 2016

Doggerland was a land mass occupying an area currently covered by the North Sea until marine inun... more Doggerland was a land mass occupying an area currently covered by the North Sea until marine inundation took place during the mid-Holocene, ultimately separating the British land mass from the rest of Europe. The Storegga Slide, which triggered a tsunami reflected in sediment deposits in the Northern North Sea, North East coastlines of the British Isles and across the North Atlantic, was a major event during this transgressive phase. The spatial extent of the Storegga tsunami however remains unconfirmed because to date no direct evidence for the event has been recovered from the southern North Sea. We present evidence that Storegga associated deposits occur in the southern North Sea. Palaeo-river systems have been identified using seismic survey in the southwestern North Sea and sedimentary cores extracted to track the Mid Holocene inundation. At the head of one palaeo-river system near the Outer Dowsing Deep, the Southern River, we observed an abrupt and catastrophic inundation str...

A great wave: the Storegga tsunami and the end of Doggerland?, 2020

Around 8150 BP, the Storegga tsunami struck Northwest Europe. The size of this wave has led many ... more Around 8150 BP, the Storegga tsunami struck Northwest Europe. The size of this wave has led many to assume that it had a devastating impact upon contemporaneous Mesolithic communities, including the final inundation of Doggerland, the now submerged Mesolithic North Sea landscape. Here, the authors present the first evidence of the tsunami from the southern North Sea, and suggest that traditionalnotions of a catastrophically destructive event may need rethinking. In providing a more nuanced interpretation by incorporating the role of local topographic variation within the study of the Storegga event, we are better placed to understand the impact of such dramatic occurrences and their larger significance in settlement studies.

Geosciences, 2020

Doggerland was a landmass occupying an area currently covered by the North Sea until marine inund... more Doggerland was a landmass occupying an area currently covered by the North Sea until marine inundation took place during the mid-Holocene, ultimately separating the British landmass from the rest of Europe. The Storegga Event, which triggered a tsunami reflected in sediment deposits in the northern North Sea, northeast coastlines of the British Isles and across the North Atlantic, was a major event during this transgressive phase. The spatial extent of the Storegga tsunami however remains unconfirmed as, to date, no direct evidence for the event has been recovered from the southern North Sea. We present evidence of a tsunami deposit in the southern North Sea at the head of a palaeo-river system that has been identified using seismic survey. The evidence, based on lithostratigraphy, geochemical signatures, macro and microfossils and sedimentary ancient DNA (sedaDNA), supported by optical stimulated luminescence (OSL) and radiocarbon dating, suggests that these deposits were a result of the tsunami. Seismic identification of this stratum and analysis of adjacent cores showed diminished traces of the tsunami which was largely removed by subsequent erosional processes. Our results confirm previous modelling of the impact of the tsunami within this area of the southern North Sea, and also indicate that these effects were temporary, localized, and mitigated by the dense woodland and topography of the area. We conclude that clear physical remnants of the wave in these areas are likely to be restricted to now buried, palaeo-inland basins and incised river valley systems.

EGU General Assembly, 2020

During the late glacial and early Holocene, vast areas of dry land stretched from the British Isl... more During the late glacial and early Holocene, vast areas of dry land stretched from the British Isles to continental Europe over what is now the southern part of the North Sea. Whilst it is known that this landscape was inhabited, little is known about the cultures that lived there and the surrounding environment. This study focuses on the Brown Bank area, between the UK and Dutch coasts, with its significant 25 km long and 10-15 m high ridge on the seabed which has provided many Mesolithic ex-situ finds. However, all of these finds have been recovered serendipitously due to commercial fishing and dredging, and thus the landscape and sedimentary context of these archaeological finds is unclear.
The goal of this study is to map the terrestrial features in the Brown Bank area and reconstruct the palaeolandscape and its inundation to determine the potential locations from which this archaeological material derives, and potentially locate Mesolithic settlement sites. The project uses high-resolution parametric echosounder surveys in a dense survey network to record the area and facilitate later targeted dredging and vibro-core sampling.
The seismic surveys revealed a pre-marine inundation landscape with fluvial channels eroded into post glacial sediments. A peat layer was located on the top of the banks of the channels where it continues laterally hundreds of metres. Radiocarbon dating of the top part of the peat layer, just below the transgressive deposits gave ages around 10.2-9.9 cal ka BP. Palaeogeographic reconstructions based on the mapped terrestrial features and the available relative sea level change data suggest that the final inundation of the area happened c. 1000 years later. Where dredging was carried out in areas of interest, primarily where the early Holocene surface outcropped onto the seabed, a large number of blocks of peat with pieces of wood and other macrofossils were recovered, suggesting a good potential for preservation of possible archaeological material and possible locations of origin for the serendipitous finds made by fishermen.
We conclude that this study provides new insights into the palaeogeography and the timing of the inundation of the Brown Bank area and gives the landscape context to the potential Mesolithic habitation of this part of the southern North Sea.

Geomorphology, 2018

Holocene shore displacement and the palaeogeography of Late Mesolithic and Late Neolithic settlem... more Holocene shore displacement and the palaeogeography of Late Mesolithic and Late Neolithic settlements on Ruhnu Island, Gulf of Riga, were reconstructed using foredune sequence luminescence dating, sedimentological data supported by ground-penetrating radar analysis, and GIS-based landscape modelling. The foredune ridges consist of very well to well sorted fine- to medium-grained aeolian sand and are underlain by seaward dipping foreshore sediments. The studied sequence of 38 ridges was formed between 6.91±0.58 ka and 2.54±0.19 ka ago, and represents a period of falling relative sea level. Foredune plain progradation, with average rates of 0.3–0.6 m per year, was controlled by isostatic land uplift, which caused a continuous withdrawal of shorelines to lower elevations. The dated foredune succession was used to reconstruct the coastal palaeogeography of the island. Palaeogeographical reconstructions show that during two phases of Late Mesolithic habitation, at ca. 7.2 cal. ka BP and 6.2 cal. ka BP, seal hunters settled the coastal zone of Ruhnu Island. Based on tool material and pottery type they could have originated from Saaremaa Island, which according to palaeoreconstruction of the Gulf of Riga, was located approximately 70 km northwest of Ruhnu Island during the Late Mesolithic. Later signs of human occupation, radiocarbon dated to ca. 4.7 cal. ka BP, were from the centre of the island, hundreds of metres away from the shore at about 8 m above its contemporary sea level. This Late Neolithic habitation shows a clearly different pattern than earlier coastal settlement, and suggests a shift in subsistence strategy towards agriculture and animal husbandry.

Relative sea level changes and the palaeogeography of a Neolithic hunter-fisher-gatherer settleme... more Relative sea level changes and the palaeogeography of a Neolithic hunter-fisher-gatherer settlement site on the former shore of the Gulf of Finland in the city centre of Tallinn were reconstructed by implementing GIS in landscape modelling based on archaeological, sedimentary and relative shore level (RSL) data. AMS radiocarbon dating of mammal bones from the cultural layer suggests the existence of the hunter-fisher-gatherer settlement around 5.1–4.8 cal. ka BP on a seaward inclining sandy beach of Tallinn palaeo-bay c. 100 m from the Litorina Sea shoreline and at about 2.4 m above the coeval sea level. The shoreline passed the study site at about 5.8 cal. ka BP and retreated towards northeast with an average speed of 13 m per century, while the RSL lowered by c. 2.5 mm annually. Combining radiocarbon dates of terrestrial and marine mammal bones from the Neolithic cultural layer a marine reservoir effect of 350 14C years for the brackish-water Baltic Sea was calculated. By using high-resolution archaeological data in combination with RSL and other geological proxies we demonstrate new possibilities to reconstruct the palaeoenvironment of deeply buried coastal settlement sites and to predict a possible continuation of the cultural layer in heavily built-up areas.

Boreas 42(4), 2013

N. 2013: Stone Age settlement and Holocene shore displacement in the Narva-Luga Klint Bay area, e... more N. 2013: Stone Age settlement and Holocene shore displacement in the Narva-Luga Klint Bay area, eastern Gulf of Finland. Boreas. 10.1111/ bor.12004. ISSN 0300-9483.

Boreas, 2013

Based on geological and archaeological proxies from NW Russia and NE Estonia and on GIS-based mod... more Based on geological and archaeological proxies from NW Russia and NE Estonia and on GIS-based modelling, shore displacement during the Stone Age in the Narva-Luga Klint Bay area in the eastern Gulf of Finland was reconstructed. The reconstructed shore displacement curve displays three regressive phases in the Baltic Sea history, interrupted by the rapid Ancylus Lake and Litorina Sea transgressions c. 10.9-10.2 cal. ka BP and c. 8.5-7.3 cal. ka BP, respectively. During the Ancylus transgression the lake level rose 9 m at an average rate of about 13 mm per year, while during the Litorina transgression the sea level rose 8 m at an average rate of about 7 mm per year. The results show that the highest shoreline of Ancylus Lake at an altitude of 8-17 m a.s.l. was formed c. 10.2 cal. ka BP and that of the Litorina Sea at an altitude of 6-14 m a.s.l., c. 7.3 cal. ka BP. The oldest traces of human activity dated to 8.5-7.9 cal. ka BP are associated with the palaeo-Narva River in the period of low water level in the Baltic basin at the beginning of the Litorina Sea transgression. The coastal settlement associated with the Litorina Sea lagoon, presently represented by 33 Stone Age sites, developed in the area c. 7.1 cal. ka BP and existed there for more than 2000 years. Transformation from the coastal settlement back to the river settlement indicates a change from a fishing-and-hunting economy to farming and animal husbandry c. 4.4 cal. ka BP, coinciding with the time of the overgrowing of the lagoon in the Narva-Luga Klint Bay area.

Different post-IR Infrared Stimulated Luminescence (IRSL) approaches are applied to sed-iments fr... more Different post-IR Infrared Stimulated Luminescence (IRSL) approaches are applied to sed-iments from a Holocene coastal foredune sequence on Ruhnu Island in the eastern Baltic Sea. The comparison of De-values and ages determined by the different approaches is complimented by fading and bleaching experiments. The fading experiments imply strong fading of IRSL (50°C) signals and no fading of any of the post-IR IRSL signals, but this is not confirmed by the determined De-values. In fact, post-IR IRSL (150°C) De-values agree within errors with those calculated for IRSL (50°C). From the bleaching experiments it is inferred that the higher values observed for post-IR IRSL at more elevated stimulation temperatures (225°C/290°C) are likely related to either thermal transfer and/or slow-to-bleach components within the signal. For the dating of the Holocene foredune se-quence of Ruhnu Island, the post-IR IRSL (150°C) approach is preferred and these agree with the limited independent age control available from radiocarbon dating. Accordingly, the sequence formed between ca. 7.0 ka and 2.5 ka ago.

Boreas, Jan 17, 2013

Based on geological and archaeological proxies from NW Russia and NE Estonia and on GIS-based mod... more Based on geological and archaeological proxies from NW Russia and NE Estonia and on GIS-based modelling, shore displacement during the Stone Age in the Narva-Luga Klint Bay area in the eastern Gulf of Finland was reconstructed. The reconstructed shore displacement curve displays three regressive phases in the Baltic Sea history, interrupted by the rapid Ancylus Lake and Litorina Sea transgressions c. 10.9–10.2 cal. ka BP and c. 8.5–7.3 cal. ka BP, respectively. During the Ancylus transgression the lake level rose 9 m at an average rate of about 13 mm per year, while during the Litorina transgression the sea level rose 8 m at an average rate of about 7 mm per year. The results show that the highest shoreline of Ancylus Lake at an altitude of 8–17 m a.s.l. was formed c. 10.2 cal. ka BP and that of the Litorina Sea at an altitude of 6–14 m a.s.l., c. 7.3 cal. ka BP. The oldest traces of human activity dated to 8.5–7.9 cal. ka BP are associated with the palaeo-Narva River in the period of low water level in the Baltic basin at the beginning of the Litorina Sea transgression. The coastal settlement associated with the Litorina Sea lagoon, presently represented by 33 Stone Age sites, developed in the area c. 7.1 cal. ka BP and existed there for more than 2000 years. Transformation from the coastal settlement back to the river settlement indicates a change from a fishing-and-hunting economy to farming and animal husbandry c. 4.4 cal. ka BP, coinciding with the time of the overgrowing of the lagoon in the Narva-Luga Klint Bay area.

2 In sti tute of His tory and Ar chae ol ogy, Uni ver sity of Tartu, Lossi 3, 51003 Tartu, Es to ... more 2 In sti tute of His tory and Ar chae ol ogy, Uni ver sity of Tartu, Lossi 3, 51003 Tartu, Es to nia 3 De part ment of Ge og ra phy, Uni ver sity of Tartu, Vanemuise 46, 51014 Tartu, Es to nia 4 Finn ish Mu seum of Nat u ral His tory, Uni ver sity of Hel sinki, Gustaf Hällströmin katu 2, 00014 Hel sinki, Fin land Rosentau A., Joeleht A., Plado J., Aunap R., Muru M. and Eskola K.O. (2013) De vel op ment of the Ho lo cene foredune plain in the Narva-Joesuu area, east ern Gulf of Fin land. Geo log i cal Quar terly, 57 (1): 89-100, doi: 10.7306/gq.1077

GEOLOGICAL SURVEY OF FINLAND Guide 57

Coastline Changes of the Baltic Sea from South to East

This paper reviews Estonian relative sea level, land uplift and coastal floods data and provides ... more This paper reviews Estonian relative sea level, land uplift and coastal floods data and provides sealevel scenarios and risk assessment of coastal flooding in urban areas for the 21st century. Considering the present post-glacial land uplift rates of Estonian coastal areas and the global ocean level rise projections, the long-existing trend of relative sea-level lowering may very probably be replaced by a relative sea-level rising trend during the 21st century. By the end of the 21st century we project the relative sea level to be c. 20 to 40 cm or c. 40 to 60 cm higher in the case of the International Panel for Climate Change Representative Concentration Pathways (RCP) 4.5 or RCP 8.5 scenario, respectively. The sea level rise together with the increased storm frequency and decreased winter ice cover period will very probably increase the extent of floods during the 21st century. A significant coastal flooding risk affects four cities, Pärnu, Kuressaare, Haapsalu and Tallinn and eight smaller towns. The largest coastal flooding in Estonia is recorded in Pärnu, with the highest sea level 275 cm in 2005. Calculations show that due to the impact of predicted climate change and in the case of certain weather conditions, coastal floods in Pärnu may affect areas up to 400 cm above the present sea level by the end of the 21st century. The scenarious of future flood limits are needed for sustainable planning of the coastal zone and for development of rescue strategies.There are already several land use and urban planning instruments and laws for climate adaptation, such as environmental impact assessment, risk assessment and restriction zones for construction in certain buffer and flood areas. Flooding risk measures consist of risk mapping and a national emergency plan. However, further integration of climate issues into existing laws, strategies and land use plans is essential to have a targeted approach in reducing the vulnerability of populated areas and strengthening the adaptive capacity of the urban system against climate change.

Journal of Coastal Research

ABSTRACT Tõnisson, H.; Suursaar, Ü.; Kont, A.; Muru, M.; Rivis, R.; Rosentau, A.; Tamura, T., and... more ABSTRACT Tõnisson, H.; Suursaar, Ü.; Kont, A.; Muru, M.; Rivis, R.; Rosentau, A.; Tamura, T., and Vilumaa, K., 2018. Rhythmic patterns of coastal formations as signs of past climate fluctuations on uplifting coasts of Estonia, the Baltic Sea. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 611–615. Coconut Creek (Florida), ISSN 0749-0208. On uplifting and tideless Baltic Sea Coasts in Estonia, a number of elevated mid to late Holocene beach ridge systems with rhythmic patterns are identified. Such uplifted coastal formations serve as archives of past variations in sea level and climate, as well as extreme events. Luminescence dating and interpretation of airborne LiDAR elevation data were used to identify the main formation mechanisms of such beach ridge systems. More extensive (up to 100–150 ridges) and clearer ridge patterns were found on faster emerging (uplift rates around 3 mm/yr) and well-exposed western and northern coasts, where they were located on the heights of up to 18 m. The average temporal periodicity (30–40 years) in such ridge systems is in good agreement with 25–40 year cyclicity, which is detectable in Estonian tide-gauge records, wave hindcasts, regional storminess and the NAO indices. However, typical average ridge spacing was 2–3 times longer in the study areas with lower (0.5–2 mm/yr) uplift rates. It suggests that the cyclicity in ridges depends on uplift rate and is additionally enhanced or modified by decadal-scale variations in forcing conditions that is locally available.

Remote Sensing

Freely available global digital elevation models (DEMs) are important inputs for many research fi... more Freely available global digital elevation models (DEMs) are important inputs for many research fields and applications. During the last decade, several global DEMs have been released based on satellite data. ASTER and SRTM are the most widely used DEMs, but the more recently released, AW3D30, TanDEM-X and MERIT, are being increasingly used. Many researchers have studied the quality of these DEM products in recent years. However, there has been no comprehensive and systematic evaluation of their quality over areas with variable topography and land cover conditions. To provide this comparison, we examined the accuracy of six freely available global DEMs (ASTER, AW3D30, MERIT, TanDEM-X, SRTM, and NASADEM) in four geographic regions with different topographic and land use conditions. We used local high-precision elevation models (Light Detection and Ranging (LiDAR), Pleiades-1A) as reference models and all global models were resampled to reference model resolution (1m). In total, 608 mi...

<p&amp... more <p>During the late glacial and early Holocene, vast areas of dry land stretched from the British Isles to continental Europe over what is now the southern part of the North Sea. Whilst it is known that this landscape was inhabited, little is known about the cultures that lived there and the surrounding environment. This study focuses on the Brown Bank area, between the UK and Dutch coasts, with its significant 25 km long and 10-15 m high ridge on the seabed which has provided many Mesolithic ex-situ finds. However, all of these finds have been recovered serendipitously due to commercial fishing and dredging, and thus the landscape and sedimentary context of these archaeological finds is unclear.<br>The goal of this study is to map the terrestrial features in the Brown Bank area and reconstruct the palaeolandscape and its inundation to determine the potential locations from which this archaeological material derives, and potentially locate Mesolithic settlement sites. The project uses high-resolution parametric echosounder surveys in a dense survey network to record the area and facilitate later targeted dredging and vibro-core sampling.<br>The seismic surveys revealed a pre-marine inundation landscape with fluvial channels eroded into post glacial sediments. A peat layer was located on the top of the banks of the channels where it continues laterally hundreds of metres. Radiocarbon dating of the top part of the peat layer, just below the transgressive deposits gave ages around 10.2-9.9 cal ka BP. Palaeogeographic reconstructions based on the mapped terrestrial features and the available relative sea level change data suggest that the final inundation of the area happened c. 1000 years later. Where dredging was carried out in areas of interest, primarily where the early Holocene surface outcropped onto the seabed, a large number of blocks of peat with pieces of wood and other macrofossils were recovered, suggesting a good potential for preservation of possible archaeological material and possible locations of origin for the serendipitous finds made by fishermen.<br>We conclude that this study provides new insights into the palaeogeography and the timing of the inundation of the Brown Bank area and gives the landscape context to the potential Mesolithic habitation of this part of the southern North Sea.</p>

Journal of Coastal Research, 2016

Journal of Coastal Research, 2016

Doggerland was a land mass occupying an area currently covered by the North Sea until marine inun... more Doggerland was a land mass occupying an area currently covered by the North Sea until marine inundation took place during the mid-Holocene, ultimately separating the British land mass from the rest of Europe. The Storegga Slide, which triggered a tsunami reflected in sediment deposits in the Northern North Sea, North East coastlines of the British Isles and across the North Atlantic, was a major event during this transgressive phase. The spatial extent of the Storegga tsunami however remains unconfirmed because to date no direct evidence for the event has been recovered from the southern North Sea. We present evidence that Storegga associated deposits occur in the southern North Sea. Palaeo-river systems have been identified using seismic survey in the southwestern North Sea and sedimentary cores extracted to track the Mid Holocene inundation. At the head of one palaeo-river system near the Outer Dowsing Deep, the Southern River, we observed an abrupt and catastrophic inundation str...

A great wave: the Storegga tsunami and the end of Doggerland?, 2020

Around 8150 BP, the Storegga tsunami struck Northwest Europe. The size of this wave has led many ... more Around 8150 BP, the Storegga tsunami struck Northwest Europe. The size of this wave has led many to assume that it had a devastating impact upon contemporaneous Mesolithic communities, including the final inundation of Doggerland, the now submerged Mesolithic North Sea landscape. Here, the authors present the first evidence of the tsunami from the southern North Sea, and suggest that traditionalnotions of a catastrophically destructive event may need rethinking. In providing a more nuanced interpretation by incorporating the role of local topographic variation within the study of the Storegga event, we are better placed to understand the impact of such dramatic occurrences and their larger significance in settlement studies.

Geosciences, 2020

Doggerland was a landmass occupying an area currently covered by the North Sea until marine inund... more Doggerland was a landmass occupying an area currently covered by the North Sea until marine inundation took place during the mid-Holocene, ultimately separating the British landmass from the rest of Europe. The Storegga Event, which triggered a tsunami reflected in sediment deposits in the northern North Sea, northeast coastlines of the British Isles and across the North Atlantic, was a major event during this transgressive phase. The spatial extent of the Storegga tsunami however remains unconfirmed as, to date, no direct evidence for the event has been recovered from the southern North Sea. We present evidence of a tsunami deposit in the southern North Sea at the head of a palaeo-river system that has been identified using seismic survey. The evidence, based on lithostratigraphy, geochemical signatures, macro and microfossils and sedimentary ancient DNA (sedaDNA), supported by optical stimulated luminescence (OSL) and radiocarbon dating, suggests that these deposits were a result of the tsunami. Seismic identification of this stratum and analysis of adjacent cores showed diminished traces of the tsunami which was largely removed by subsequent erosional processes. Our results confirm previous modelling of the impact of the tsunami within this area of the southern North Sea, and also indicate that these effects were temporary, localized, and mitigated by the dense woodland and topography of the area. We conclude that clear physical remnants of the wave in these areas are likely to be restricted to now buried, palaeo-inland basins and incised river valley systems.

EGU General Assembly, 2020

During the late glacial and early Holocene, vast areas of dry land stretched from the British Isl... more During the late glacial and early Holocene, vast areas of dry land stretched from the British Isles to continental Europe over what is now the southern part of the North Sea. Whilst it is known that this landscape was inhabited, little is known about the cultures that lived there and the surrounding environment. This study focuses on the Brown Bank area, between the UK and Dutch coasts, with its significant 25 km long and 10-15 m high ridge on the seabed which has provided many Mesolithic ex-situ finds. However, all of these finds have been recovered serendipitously due to commercial fishing and dredging, and thus the landscape and sedimentary context of these archaeological finds is unclear.
The goal of this study is to map the terrestrial features in the Brown Bank area and reconstruct the palaeolandscape and its inundation to determine the potential locations from which this archaeological material derives, and potentially locate Mesolithic settlement sites. The project uses high-resolution parametric echosounder surveys in a dense survey network to record the area and facilitate later targeted dredging and vibro-core sampling.
The seismic surveys revealed a pre-marine inundation landscape with fluvial channels eroded into post glacial sediments. A peat layer was located on the top of the banks of the channels where it continues laterally hundreds of metres. Radiocarbon dating of the top part of the peat layer, just below the transgressive deposits gave ages around 10.2-9.9 cal ka BP. Palaeogeographic reconstructions based on the mapped terrestrial features and the available relative sea level change data suggest that the final inundation of the area happened c. 1000 years later. Where dredging was carried out in areas of interest, primarily where the early Holocene surface outcropped onto the seabed, a large number of blocks of peat with pieces of wood and other macrofossils were recovered, suggesting a good potential for preservation of possible archaeological material and possible locations of origin for the serendipitous finds made by fishermen.
We conclude that this study provides new insights into the palaeogeography and the timing of the inundation of the Brown Bank area and gives the landscape context to the potential Mesolithic habitation of this part of the southern North Sea.

Geomorphology, 2018

Holocene shore displacement and the palaeogeography of Late Mesolithic and Late Neolithic settlem... more Holocene shore displacement and the palaeogeography of Late Mesolithic and Late Neolithic settlements on Ruhnu Island, Gulf of Riga, were reconstructed using foredune sequence luminescence dating, sedimentological data supported by ground-penetrating radar analysis, and GIS-based landscape modelling. The foredune ridges consist of very well to well sorted fine- to medium-grained aeolian sand and are underlain by seaward dipping foreshore sediments. The studied sequence of 38 ridges was formed between 6.91±0.58 ka and 2.54±0.19 ka ago, and represents a period of falling relative sea level. Foredune plain progradation, with average rates of 0.3–0.6 m per year, was controlled by isostatic land uplift, which caused a continuous withdrawal of shorelines to lower elevations. The dated foredune succession was used to reconstruct the coastal palaeogeography of the island. Palaeogeographical reconstructions show that during two phases of Late Mesolithic habitation, at ca. 7.2 cal. ka BP and 6.2 cal. ka BP, seal hunters settled the coastal zone of Ruhnu Island. Based on tool material and pottery type they could have originated from Saaremaa Island, which according to palaeoreconstruction of the Gulf of Riga, was located approximately 70 km northwest of Ruhnu Island during the Late Mesolithic. Later signs of human occupation, radiocarbon dated to ca. 4.7 cal. ka BP, were from the centre of the island, hundreds of metres away from the shore at about 8 m above its contemporary sea level. This Late Neolithic habitation shows a clearly different pattern than earlier coastal settlement, and suggests a shift in subsistence strategy towards agriculture and animal husbandry.

Relative sea level changes and the palaeogeography of a Neolithic hunter-fisher-gatherer settleme... more Relative sea level changes and the palaeogeography of a Neolithic hunter-fisher-gatherer settlement site on the former shore of the Gulf of Finland in the city centre of Tallinn were reconstructed by implementing GIS in landscape modelling based on archaeological, sedimentary and relative shore level (RSL) data. AMS radiocarbon dating of mammal bones from the cultural layer suggests the existence of the hunter-fisher-gatherer settlement around 5.1–4.8 cal. ka BP on a seaward inclining sandy beach of Tallinn palaeo-bay c. 100 m from the Litorina Sea shoreline and at about 2.4 m above the coeval sea level. The shoreline passed the study site at about 5.8 cal. ka BP and retreated towards northeast with an average speed of 13 m per century, while the RSL lowered by c. 2.5 mm annually. Combining radiocarbon dates of terrestrial and marine mammal bones from the Neolithic cultural layer a marine reservoir effect of 350 14C years for the brackish-water Baltic Sea was calculated. By using high-resolution archaeological data in combination with RSL and other geological proxies we demonstrate new possibilities to reconstruct the palaeoenvironment of deeply buried coastal settlement sites and to predict a possible continuation of the cultural layer in heavily built-up areas.

Boreas 42(4), 2013

N. 2013: Stone Age settlement and Holocene shore displacement in the Narva-Luga Klint Bay area, e... more N. 2013: Stone Age settlement and Holocene shore displacement in the Narva-Luga Klint Bay area, eastern Gulf of Finland. Boreas. 10.1111/ bor.12004. ISSN 0300-9483.

Boreas, 2013

Based on geological and archaeological proxies from NW Russia and NE Estonia and on GIS-based mod... more Based on geological and archaeological proxies from NW Russia and NE Estonia and on GIS-based modelling, shore displacement during the Stone Age in the Narva-Luga Klint Bay area in the eastern Gulf of Finland was reconstructed. The reconstructed shore displacement curve displays three regressive phases in the Baltic Sea history, interrupted by the rapid Ancylus Lake and Litorina Sea transgressions c. 10.9-10.2 cal. ka BP and c. 8.5-7.3 cal. ka BP, respectively. During the Ancylus transgression the lake level rose 9 m at an average rate of about 13 mm per year, while during the Litorina transgression the sea level rose 8 m at an average rate of about 7 mm per year. The results show that the highest shoreline of Ancylus Lake at an altitude of 8-17 m a.s.l. was formed c. 10.2 cal. ka BP and that of the Litorina Sea at an altitude of 6-14 m a.s.l., c. 7.3 cal. ka BP. The oldest traces of human activity dated to 8.5-7.9 cal. ka BP are associated with the palaeo-Narva River in the period of low water level in the Baltic basin at the beginning of the Litorina Sea transgression. The coastal settlement associated with the Litorina Sea lagoon, presently represented by 33 Stone Age sites, developed in the area c. 7.1 cal. ka BP and existed there for more than 2000 years. Transformation from the coastal settlement back to the river settlement indicates a change from a fishing-and-hunting economy to farming and animal husbandry c. 4.4 cal. ka BP, coinciding with the time of the overgrowing of the lagoon in the Narva-Luga Klint Bay area.

Different post-IR Infrared Stimulated Luminescence (IRSL) approaches are applied to sed-iments fr... more Different post-IR Infrared Stimulated Luminescence (IRSL) approaches are applied to sed-iments from a Holocene coastal foredune sequence on Ruhnu Island in the eastern Baltic Sea. The comparison of De-values and ages determined by the different approaches is complimented by fading and bleaching experiments. The fading experiments imply strong fading of IRSL (50°C) signals and no fading of any of the post-IR IRSL signals, but this is not confirmed by the determined De-values. In fact, post-IR IRSL (150°C) De-values agree within errors with those calculated for IRSL (50°C). From the bleaching experiments it is inferred that the higher values observed for post-IR IRSL at more elevated stimulation temperatures (225°C/290°C) are likely related to either thermal transfer and/or slow-to-bleach components within the signal. For the dating of the Holocene foredune se-quence of Ruhnu Island, the post-IR IRSL (150°C) approach is preferred and these agree with the limited independent age control available from radiocarbon dating. Accordingly, the sequence formed between ca. 7.0 ka and 2.5 ka ago.

Boreas, Jan 17, 2013

Based on geological and archaeological proxies from NW Russia and NE Estonia and on GIS-based mod... more Based on geological and archaeological proxies from NW Russia and NE Estonia and on GIS-based modelling, shore displacement during the Stone Age in the Narva-Luga Klint Bay area in the eastern Gulf of Finland was reconstructed. The reconstructed shore displacement curve displays three regressive phases in the Baltic Sea history, interrupted by the rapid Ancylus Lake and Litorina Sea transgressions c. 10.9–10.2 cal. ka BP and c. 8.5–7.3 cal. ka BP, respectively. During the Ancylus transgression the lake level rose 9 m at an average rate of about 13 mm per year, while during the Litorina transgression the sea level rose 8 m at an average rate of about 7 mm per year. The results show that the highest shoreline of Ancylus Lake at an altitude of 8–17 m a.s.l. was formed c. 10.2 cal. ka BP and that of the Litorina Sea at an altitude of 6–14 m a.s.l., c. 7.3 cal. ka BP. The oldest traces of human activity dated to 8.5–7.9 cal. ka BP are associated with the palaeo-Narva River in the period of low water level in the Baltic basin at the beginning of the Litorina Sea transgression. The coastal settlement associated with the Litorina Sea lagoon, presently represented by 33 Stone Age sites, developed in the area c. 7.1 cal. ka BP and existed there for more than 2000 years. Transformation from the coastal settlement back to the river settlement indicates a change from a fishing-and-hunting economy to farming and animal husbandry c. 4.4 cal. ka BP, coinciding with the time of the overgrowing of the lagoon in the Narva-Luga Klint Bay area.

2 In sti tute of His tory and Ar chae ol ogy, Uni ver sity of Tartu, Lossi 3, 51003 Tartu, Es to ... more 2 In sti tute of His tory and Ar chae ol ogy, Uni ver sity of Tartu, Lossi 3, 51003 Tartu, Es to nia 3 De part ment of Ge og ra phy, Uni ver sity of Tartu, Vanemuise 46, 51014 Tartu, Es to nia 4 Finn ish Mu seum of Nat u ral His tory, Uni ver sity of Hel sinki, Gustaf Hällströmin katu 2, 00014 Hel sinki, Fin land Rosentau A., Joeleht A., Plado J., Aunap R., Muru M. and Eskola K.O. (2013) De vel op ment of the Ho lo cene foredune plain in the Narva-Joesuu area, east ern Gulf of Fin land. Geo log i cal Quar terly, 57 (1): 89-100, doi: 10.7306/gq.1077

GEOLOGICAL SURVEY OF FINLAND Guide 57