Jan Mangerud

University of Bergen | UiB · Departement of Earth Science and Bjerknes Centre for Climate Research

The extent of the Scandinavian Ice Sheet in southwestern Norway is precisely located during the well-characterized Younger Dryas re-advance. However, the thickness of the ice sheet is less well constrained inland from the terminal position. Some exceptions include lateral moraines traced inland and up to 1000 m a.s.l. along Hardangerfjorden. Here,...

At the start of the Holocene, the Fennoscandian Ice Sheet was still a sizable ice mass, comparable to the present-day Greenland Ice Sheet, and covered most of the modern terrestrial area of Norway, Sweden and Finland, as well as the Gulf of Bothnia. Such a large ice sheet quickly became out of equilibrium with the rapidly warming Early Holocene cli...

We describe glaci-lacustrine sediments buried under thick tills in Folldalen, south-east Norway, a site located close to the former centre of the Scandinavian Ice Sheet. Thus, the location implies that the ice sheet had melted when the sediments were deposited. The exposed ground was occupied by arctic vegetation. The best age estimate from 20 quar...

During the Younger Dryas (YD) many cirque- and valley glaciers, as well as some ice caps, existed in mountains west of the margin of the Fennoscandian ice sheet in Norway. Some formed spectacular horseshoe-formed moraines, in some places they were down to sea level. The Kråkenes cirque glacier was formed at the onset of the YD, whereas many others...

The Younger Dryas (YD) moraines have been mapped almost continuously around the Fennoscandian ice sheet. Segments of the moraine have individual names, best known are the Salpausselkä in Finland, the Middle Swedish moraines in Sweden and the Ra and the Herdla-Halsnøy moraines in Norway. The outline of the ice margin was very different around the ic...

We here outline the deglaciation history in the Polar Ural Mountains from the Last Glacial Maximum (LGM) until the mountain range was completely ice-free during the early Holocene. Our reconstruction of the course of deglaciation is based on cosmogenic exposure dating (¹⁰Be) of erratic boulders combined with stratigraphic results from sediment core...

Because global sea level during the last interglacial (LIG; 130–115 ka) was higher than today, the LIG is a useful approximate analogue for improving predictions of future sea-level rise. Here, we synthesize sea-level proxies for the LIG in the glaciated Northern Hemisphere for inclusion in the World Atlas of Last Interglacial Shorelines (WALIS) da...

There have been large uncertainties about the glacial history in the Ural Mountains during Marine Isotope Stage 2 (MIS 2). New field-based studies have now provided a better basis to constrain the dimensions of the glaciers. ¹⁰Be exposure dating of glacier transported boulders from moraines indicates that some were only slightly larger during the L...

Our knowledge of the glacial history of the Ural Mountains is largely based on geomorphological mapping supported by cosmogenic nuclide ¹⁰Be exposure dating, and descriptions of exposed sections dated with optically stimulated luminescence and ¹⁴C methods. Additionally, we have gained new insight into the glacial chronology from seismic surveys and...

We provide a brief description of the glacial landscapes in the Ural Mountains. It is primarily north of 63°45′ latitude that one finds distinctive glacial landforms such as glacially eroded cirques, U-shaped valley, and overdeepened mountain lakes. These landforms are a result of both locally formed glaciers and large shelf-centred ice sheets. Tod...

Understanding past responses of ice sheets to climate change provides an important long-term context for observations of present day, and projected future, ice-sheet change. In this work, we reconstruct the deglaciation of the marine-terminating western margin of the Scandinavian Ice Sheet in the outer Hardangerfjorden area of southwestern Norway,...

Based on radiocarbon dating, a tephra horizon, varve counts and palaeomagnetism, detailed age models covering the last~24 k cal a BP, have been developed for the stratigraphy in the lakes Bolshoye Shchuchye and Maloye Shchuchye in the Polar Ural Mountains, Russia. The inclination curves from these lakes show nearly identical palaeomagnetic secular...

The Russian Arctic is an extensive region, with relatively few long-duration paleoclimate reconstructions compared to other terrestrial Arctic regions. We present a 24 000-year reconstruction of climate in the Polar Ural Mountains using n-alkanoic acid hydrogen isotopes from Lake Bolshoye Shchuchye. Major last deglaciation climate changes in the No...

Because global sea level during the last interglacial (LIG; 130-115 ka) was higher than today, the LIG is a useful analogue for improving predictions of future sea level rise. Here, we synthesize sea level proxies for the LIG in the glaciated Northern Hemisphere for inclusion in the World Atlas of Last Interglacial Shorelines (WALIS) database. We d...

During the last glacial–interglacial cycle, Arctic biotas experienced substantial climatic changes, yet the nature, extent and rate of their responses are not fully understood1–8. Here we report a large-scale environmental DNA metagenomic study of ancient plant and mammal communities, analysing 535 permafrost and lake sediment samples from across t...

A detailed, well‐dated record of pollen and sedimentary ancient DNA (sedaDNA) for the period 15 000–9500 cal a bp describes changes at Lake Bolshoye Shchuchye in the Polar Ural Mountains, located far east of the classical Lateglacial sites in western Europe. Arctic tundra rapidly changed to lusher vegetation, possibly including both dwarf (Betula n...

Here we present the use of ice-dammed lake-related landforms and sediments for reconstructing the final phases of decay of the Scandinavian Ice Sheet. In the late stages of the deglaciation, extensive glacial lakes were dammed between the easterly retreating Scandinavian Ice Sheet and the water divide within the mountains to the west. Using high-r...

The evolution of past global ice sheets is highly uncertain. One example is the missing ice problem during the Last Glacial Maximum (LGM, 26 000-19 000 years before present) – an apparent 8-28 m discrepancy between far-field sea level indicators and modelled sea level from ice sheet reconstructions. In the absence of ice sheet reconstructions, rese...

Marine outlet glaciers on Greenland are retreating, yet it is unclear if the recent fast retreat will persist, and how atmosphere and ocean warming will impact future retreat. We show how a marine outlet glacier in Hardangerfjorden retreated rapidly in response to the abrupt warming following the Younger Dryas cold period (approximately 11,600 year...

The Younger Dryas (YD) cold event was discovered in Denmark by Hartz and Mithers in 1904 and the term coined by Hartz in 1912. It was identified as a lacustrine clay bed containing plant macrofossils of an Arctic flora, including Dryas octopetala, and lying between Allerød and Holocene gyttjas containing a warmer flora with birch trees. The YD is u...

A 24,000-year record of plant community dynamics, based on pollen and ancient DNA from the sediments (sedaDNA) of Lake Bolshoye Shchuchye in the Polar Ural Mountains, provides detailed information on the flora of the Last Glacial Maximum (LGM) and also changes in plant community composition and dominance. It greatly improves on incomplete records f...

Plain Language Summary The end of the last glacial maximum (~22,000 to 11,600 years ago) in northern Europe contains two particularly abrupt warming events that occurred around 14,600 and 11,600 years ago. These past warming events provide an opportunity to study changes in precipitation and other aspects of hydrology during abrupt temperature incr...

The Barents Sea Ice Sheet was part of an interconnected complex of ice sheets, collectively referred to as the Eurasian Ice Sheet, which covered north-westernmost Europe, Russia and the Barents Sea during the Last Glacial Maximum (around 21 ky BP). Due to common geological features, the Barents Sea component of this ice complex is seen as a paleo-a...

Plants adapted to extreme conditions can be at high risk from climate change; arctic-alpine plants, in particular, could "run out of space" as they are out-competed by expansion of woody vegetation. Mountain regions could potentially provide safe sites for arctic-alpine plants in a warmer climate, but empirical evidence is fragmentary. Here we pres...

We present geomorphological evidence of large, previously undocumented, early Holocene ice-dammed lakes in the Scandinavian Mountains of northwestern Sweden. The lakes extents indicate that the last remnants of the Scandinavian Ice Sheet were located east of the mountain range. Some early pioneering works have presented similar reconstructions, whe...

Abstract: This study presents geomorphological evidence indicating final deglaciation of the last Scandinavian Ice Sheet remnants east of the Scandinavian mountain range, northwestern Sweden, in contrast with the prevailing view of final deglaciation in the higher mountains of Sarek. High resolution (LiDAR) terrain models was used to map out a larg...

Abstract: Here we present new results constraining the ice-sheet thinning during deglaciation and the formation of a local ice-cap during the Younger Dryas at the mouth of Hardangerfjorden, southwest Norway. We base our interpretations on a combination of geomorphological mapping, using high resolution (LiDAR) terrain models, together with 10Be-dat...

Based on six consistent radiocarbon dates from the isolation basins Grødheimsvatnet and Kringlemyr, we estimate a minimum deglaciation age for southern Karmøy, an island in outer Boknafjorden (south‐west Norway), of around 18 000 calibrated years before present (18k cal a bp). We use microscopic phytoplankton, macrofossils, lithostratigraphic evide...

We reconstruct patterns of ice flow and retreat of the southwestern Scandinavian Ice Sheet, from 2900 field observations of glacial striae and elevation measurements of 60 ice-marginal-deltas from a high-resolution LiDAR DEM. During the Last Glacial Maximum, ice flow was towards the west across the entire area, including across several-hundred mete...

Here we present new results constraining the ice-sheet thinning during deglaciation and extent of the Younger Dryas re-advance in the outer Hardangerfjord area. We base our interpretations on a combination of geomorphological mapping, using high resolution (LiDAR) terrain models, together with Terrestrial Cosmogenic Nuclide (TCN) dating of glacial...

We present a well‐dated, high‐resolution and continuous sediment record spanning the last c. 24 000 years from lake Bolshoye Shchuchye located in the Polar Ural Mountains, Arctic Russia. This is the first continuous sediment succession reaching back into the Last Glacial Maximum (LGM) ever retrieved from this region. We reconstruct the glacial and...

While there are extensive macro- and microfossil records of a range of plants and animals from the Quaternary, earthworms and their close relatives amongst annelids are not preserved as fossils and therefore the knowledge of their past distributions is limited. This lack of fossils means that clitellate worms (Annelida) are currently underused in p...

Our knowledge about the glaciation history in the Russian Arctic has to a large extent been based on geomorphological mapping supplemented by studies of short stratigraphical sequences found in exposed sections. Here we present new geochronological data from the Polar Ural Mountains along with a high‐resolution sediment record from Bolshoye Shchuch...

Marine-terminating glaciers and ice streams are important controls of ice sheet mass balance. However, understanding of their long-term response to external forcing is limited by relatively short observational records of present-day glaciers and sparse geologic evidence for paleo-glaciers. Here we use a high-resolution ice sheet model with an accur...

Here we present a partly varved and exceptionally well dated continuous sediment record spanning the last ca. 24,000 years from lake Bolshoye Shchuchye in the Polar Ural mountains of Arctic Russia. In addition, we present some preliminary results from the adjacent and seemingly also varved sediment record in lake Malshoye Shchuchye. The varved part...

Here we present an exceptionally well dated, high resolution and continuous 24 m long sediment core spanning the last ca. 24 000 years from the Polar Ural mountains, Arctic Russia. The bottom half of the retrieved sediment sequence is composed of rhythmic silt-clay couplets interpreted as annual varves. The varves are composed of coarser basal lami...

We describe a sediment sequence comprising a thick till covered by thin beds of lacustrine sediments containing pollen and plant macrofossils derived from pioneer vegetation. Four consistent radiocarbon dates on terrestrial plant remains from the lacustrine sediments yielded an age of 10,500 calibrated years BP (cal years BP). This is the first acc...

Shallow marine molluscs that are today extinct close to Svalbard, because of the cold climate, are found in deposits there dating to the early Holocene. The most warmth-demanding species found, Zirfaea crispata, currently has a northern limit 1000 km farther south, indicating that August temperatures on Svalbard were 6°C warmer at around 10.2–9.2 c...

Counting of more than 5000 rhythmically laminated sediment layers in two cores from lake Bol. Schuchye in the Polar Urals display striking concordance to the AMS 14C-chronology, suggesting that they represent annual layers or i.e. varves. The potentially varved sequence spans a time period from c. 19 – 24 ka and thus hold the potential to construct...

Understanding the response and resilience of the Arctic flora to past environmental change is an essential component informing ecosystem models and anticipating how plant communities may respond to future climate change. Reconstructing Arctic vegetation histories has often proved challenging due to poor taxonomic resolution and often low concentrat...

We present 30 10Be ages from glacial erratic boulders to constrain the deglaciation of the Scandinavian Ice Sheet in the Boknafjorden region, south-western Norway. The southern part of the island Karmøy, located at the mouth of this fjord system, became free of glacier ice before 16 ka, probably because of the sudden break up of the Norwegian Chann...

Blomvåg, on the western coast of Norway north of Bergen, is a classical site in Norwegian Quaternary science. Foreshore marine sediments, named the Blomvåg Beds and now dated to the Bølling-Allerød from 14.8 to 13.3 cal. ka BP, contain the richest Lateglacial bone fauna in Norway, numerous mollusc shells, driftwood, and flint that some archaeologis...

Cosmogenic nuclide exposure dating is a widely used method for constraining past ice sheet histories. We scrutinize a recently published dataset of cosmogenic 10Be data from erratic boulders in Norway used to constrain the deglaciation of the western Scandinavian Ice Sheet to 20 ka. Our model of the 10Be inventory in glacial surfaces leads us to co...

Distinct Younger Dryas (YD) moraines are mapped more-or-less continuously around the Scandinavian Ice Sheet. In most areas there is no evidence to suggest that a glacial re-advance took place during the YD, either because it did not happen or because older deposits have been removed by glacial erosion. In contrast we here present 90 radiocarbon dat...

The response of ice sheets to climate change can be examined by generating reconstructions of ice sheet change during the climatic turbulence that characterized the last deglaciation. Building on our previous published ¹⁰Be chronologies of southwestern Scandinavian Ice Sheet history, we present new data that complete our reconstruction of the ice s...

We present a new time-slice reconstruction of the Eurasian ice sheets (British–Irish, Svalbard–Barents–Kara Seas and Scandinavian) documenting the spatial evolution of these interconnected ice sheets every 1000 years from 25 to 10 ka, and at four selected time periods back to 40 ka. The time-slice maps of ice-sheet extent are based on a new Geograp...

DATED-1 comprises a compilation of dates related to the build-up and retreat of the Eurasian (British-Irish, Scandinavian, Svalbard-Barents-Kara Seas) Ice Sheets, and time-slice maps of the Eurasian Ice sheet margins. Dates are sourced from the published literature. Ice margins are based on published geological and chronological data and include un...

From Kråkenes Lake in western Norway there exist 118 accelerator mass spectrometry 14C dates for the time interval 12 000–8000 14C a BP that we earlier calibrated using the IntCal09 data set. These yielded the most accurate and precise ages available for the Younger Dryas boundaries and the Vedde and Saksunarvatn ashes. Here we present a new calibr...

To better understand Pleistocene climatic changes in the Arctic, integrated palaeoenvironmental and palaeoclimatic signals from a variety of marine and terrestrial geological records as well as geochronologic age control are required, not least for correlation to extra-Arctic records. In this paper we discuss, from an Arctic perspective, methods an...

We present 34 new cosmogenic 10Be exposure ages that constrain the Lateglacial (Bølling–Preboreal) history of the Scandinavian Ice Sheet in the Lysefjorden region, south-western Norway. We find that the classical Lysefjorden moraines, earlier thought to be entirely of Younger Dryas age, encompass three adjacent moraines attributed to at least two i...

New luminescence dates and lithostratigraphic information from key section Bolshoi Shar on the Lower Yenissei shed light on the history of terrestrial sedimentation between 100 and 40 ka BP and change the chronostratigraphic position of two major ice advances of the Late Pleistocene.

a b s t r a c t We describe and discuss the glacial and climate variations in the Polar Ural Mountains in northern Russia over the last 100 000 years. A series of optically stimulated luminescence (OSL) and radio-carbon ages from sediment cores demonstrate that there has been continuous deposition of lacustrine sediments throughout the last 65 ka i...

In recent decades, knowledge of the glacial history of the last Pleistocene glaciation in Eurasia has changed tremendously. According to recent investigations, a major ice advance first entered the Russian mainland as early as 80–100 ka, blocking all drainage and damming huge lakes in West Siberia and European Russia. Drainage was diverted southwar...

In the middle Pleistocene, Eurasia was affected by three major glaciations. The extent of the largest glaciation, the Don glaciation, is still incompletely known. For the Elsterian glaciation as well, the eastern limits are only roughly estimated. The ice sheet probably covered the West Siberian Plain and may have been the most extensive glaciation...

The Greenland ice cores with the GICC05 chronology represent a standard for late Quaternary climate events and their ages, whereas many other palaeoclimatic archives are dependent on 14 C dates. It is therefore critical to know if the ice-core and the calibrated 14 C chronologies are identical, and if not to quantify the offset between them. We pre...