A 7000-year record of coastal evolution, Vejers, SW Jutland, Denmark

The Holocene coastal lowland at Vejers in western Jutland has formed during the last 7000 years. The lowland is composed of a large, NNE-SSW trending spit system associated with minor and only locally developed strandplain or beach ridge systems. The main spit and back-barrier system is bounded to the north and east (inland) by old moraine landscapes (Varde Bakkeø). Most of the coastal system and also large parts of the adjacent moraine landscape is covered by aeolian sand. In this study one of the minor strandplain systems is investigated. This system is developed at the south-western margin of the old moraine landscape at Grovsø, a lake near Vejers. The Holocene sedimentary evolution of this latter system is evaluated on the basis of data from two closely situated cores and Ground-Penetrating Radar (GPR) mapping. Both cores consist of a lowermost unit with marine sediment, a middle unit with lake-aeolian sand and an uppermost unit with aeolian sandplain deposits. Peat layers and peat-rich paleosols are common. These peat-rich horizons are dated by the Accelerator Mass Spectrometry (AMS) radiocarbon technique, while the intervening sand layers are dated by Optically Stimulated Luminescence (OSL). Combined evidence from the sedimentological and chronological studies of the cores and the GPR survey, indicate that the area was first transgressed at about 5100 BC. During the subsequent period (5100–2700 BC) relative sea level rose about 5 meters, the strandplain prograded, and small coastal dunes formed. During this progradational event a large strandplain lake formed behind the frontal dune ridge and this lake was filled primarily by aeolian sand. Aeolian sand drift may have been most intense around 3000 BC. This first period of large-scale aeolian activity ended some time before 2300 BC with formation of a peat-rich paleosol. Aeolian activity, however, was soon re-established and resulted in the formation of a large sandplain with small dunes. Aeolian sand movement and accumulation, however, was punctuated by periods of landscape stabilisation and peat-rich paleosol formation. Changes from landscape stabilisation to dune field activity took place at about 2300 BC, 1450 BC, 800 BC, and 650 BC. Aeolian accumulation at the study site terminated at about AD 0, but other evidence indicates renewed aeolian activity in the dune field after AD 300 and between AD 1100 and 1900. The chronology of some of these aeolian activity phases are synchronous with cooling events in the North Atlantic region suggesting that climatic change strongly influenced dune field dynamics.

Download Full-text

Lake and inland dunes as interconnected Systems: The story of Lake Tresssee and an adjacent dune field (Schleswig-Holstein, North Germany)

The Holocene ◽

10.1177/0959683620981684 ◽

2020 ◽

pp. 095968362098168

Author(s):

Christian Stolz ◽

Magdalena Suchora ◽

Irena A Pidek ◽

Alexander Fülling

Keyword(s):

Water Level ◽

Bronze Age ◽

Environmental Changes ◽

High Water ◽

Alluvial Fan ◽

Water Levels ◽

Lake Area ◽

Dune Field ◽

The North ◽

Sand Drift

The specific aim of the study was to investigate how four adjacent geomorphological systems – a lake, a dune field, a small alluvial fan and a slope system – responded to the same impacts. Lake Tresssee is a shallow lake in the North of Germany (Schleswig-Holstein). During the Holocene, the lake’s water surface declined drastically, predominately as a consequence of human impact. The adjacent inland dune field shows several traces of former sand drift events. Using 30 new radiocarbon ages and the results of 16 OSL samples, this study aims to create a new timeline tracing the interaction between lake and dunes, as well, as how both the lake and the dunes reacted to environmental changes. The water level of the lake is presumed to have peaked during the period before the Younger Dryas (YD; start at 10.73 ka BC). After the Boreal period (OSL age 8050 ± 690 BC) the level must have undergone fluctuations triggered by climatic events and the first human influences. The last demonstrable high water level was during the Late Bronze Age (1003–844 cal. BC). The first to the 9th century AD saw slightly shrinking water levels, and more significant ones thereafter. In the 19th century, the lake area was artificially reduced to a minimum by the human population. In the dunes, a total of seven different phases of sand drift were demonstrated for the last 13,000 years. It is one of the most precisely dated inland-dune chronologies of Central Europe. The small alluvial fan took shape mainly between the 13th and 17th centuries AD. After 1700 cal. BC (Middle Bronze Age), and again during the sixth and seventh centuries AD, we find enhanced slope activity with the formation of Holocene colluvia.

Download Full-text

Records of climate changes and anthropogenic actions over dune fields in historical times

10.5194/egusphere-egu2020-19359 ◽

2020 ◽

Author(s):

Mihaela Tudor ◽

Ana Ramos-Pereira ◽

Joana Gaspar de Freitas

Keyword(s):

Climatic Variability ◽

Coastal Dunes ◽

Coastal Dune ◽

Environmental Data ◽

Dune System ◽

Climatic Fluctuations ◽

Dune Systems ◽

Sand Drift ◽

Aeolian Activity ◽

Historical Times

Coastal dunes are very complex systems and very sensitive to climatic variability and human actions. In Portugal, coastal dune fields have undergone major changes over historical times. The aim of the paper is focused on the coastal dune systems evolution over the last five centuries, natural and man induced (namely by deforestation and afforestation) and their transformation under the present global changes (sea level rise and coastal storms). The analysis of historical records and environmental data using a set of proxies recorded over the last 1,000 yrs, show intense aeolian activity and sand drift episodes during Little Age Period, causing serious problems for human settlements and agriculture. Coastal society have responded to the wind-blown sands fixing the dunes through afforestation. The process is well documented in the historical sources and many management measures, including abundant legislation, projects and reports were carried out by Portuguese authorities to avoid sand incursion inland. &#160;According to the main report of the General Forest Administration, in the final of 18th century, was estimated an area of about 72 000 ha of free aeolian sands in need of afforestation. Thus, along Portuguese coastline, the dunes experienced a period of stability during the 20th century, due to planting of grasses and pine forest. This paper examines the pathways of the transgressive dune fields of the Central Western Portuguese coast, over various stages of coastal evolution. Mapping the morphological features between Mondego river mouth and Nazar&#233;, using a combination of satellite images, aerial photographs and Lidar data we identified distinct phases of aeolian activity and landforms modification that were associated to climatic fluctuations. This coastal dune system is composed by a succession of different aeolian phases, including a littoral foredune, which lies inland with a complexity of morphologies with transverse and crescentic ridges, and also parabolic dunes. The results show that the dunes building and sand migration inland appears to be linked to the conditions of predominantly negative winter North Atlantic Oscillation index (NAOi), driven by climatic variability during Holocene/Antrhopocene. The consistency of intense sand drift episodes with abrupt cold events during Little Age Period, drastically reduced the area occupied by vegetation, causing changes in aeolian sedimentary processes. Thus, it seems that coastal dunes evolution over the past centuries have been controlled by the two-way interactions between natural conditions and human activities, shaping the Portuguese coastline. Placing historical evidence in a geographical perspective, we hope to fill the gaps in coastal zone dynamics, providing new insights of the human-landscape relationships to predict the future response of the coastal dune systems to human pressure and climate change. Key-words: coastal dunes evolution, geomorphological features, sand drift, anthropogenic impacts, climatic fluctuation, Western Portugal.

Download Full-text

Aeolian-fluvial sediments as palaeoenvironmental records in the eastern Qaidam Basin, NE Tibetan Plateau, since MIS6

10.5194/egusphere-egu2020-21453 ◽

2020 ◽

Author(s):

Lupeng Yu ◽

Noam Greenbaum ◽

Joel Roskin

Keyword(s):

Tibetan Plateau ◽

Large Scale ◽

Asian Summer Monsoon ◽

Qaidam Basin ◽

Sedimentary Facies ◽

Fluvial Sediments ◽

Last Deglaciation ◽

Aeolian Sand ◽

The Holocene ◽

New Interpretation

Aeolian sediments sensitively respond to climatic changes. Continuous Quaternary loess deposits plays important roles in palaeoclimatic reconstructions. However, application of aeolian sand for such reconstructions is limited by its discontinuous depositional nature. Aeolian-fluvial sediments are widely distributed in arid and semi-arid regions where dunefields interact with watercourses. These palaeoenvironmental archives have been sparsely studied mainly due to their mixed character that requires new interpretation approaches.We have found that climate fluctuations lead good preservation of aeolian sand deposits that underlay fluvial sediments, making the sedimentary records more continuous. In this study, aeolian and fluvial sediments (elevation of 3400-3500 m a.s.l.) were studied in the eastern margin of Qaidam Basin (QB), northeastern Tibetan Plateau to reconstruct palaeoenvironmental and palaeoclimatic changes since the MIS6, based on sedimentary facies, 120 OSL ages (with age range of 143-1 ka), grain size distribution, MS, TOC, and carbonates.Within a deeply (10-65 m) incised 1.5-km-long valley, aeolian-fluvial cycles displayed frequent dune-damming of a stream since MIS6. Dune sands were dated to MIS's 6, 5d, 4, 3c, 3a, and the last deglaciation, while fluvial and dune-dammed lake sediments were dated to MIS's 5c, 3c, 3a, and deglaciation.Large-scale A-F interactions mainly occurred during MIS3 and deglaciation, when the QB dunefields were still mobile after LGM and MIS4 and precipitation started to increase. No ages fall within LGM, suggesting an extremely arid and windy environment in which the dune sand kept reworking and cannot record OSL ages. This further confirms that only with the covering of fluvial sediments, aeolian sand can be well preserved. On the other hand, OSL ages of aeolian sand might only present periods when aeolian activities were not too strong.During the Holocene, loess-paleosol accumulated in the QB margins, with loess accumulation since 10 ka and development of paleosols during ca. 8.5-3 ka, the Holocene optimum. These results demonstrate that aeolian-fluvial sediments are important palaeoenvironmental records in arid region and indicate that the climate of the eastern QB was mainly controlled by the temperature (solar insolation) and precipitation (Asian Summer Monsoon) changes since MIS6. &#160;

Download Full-text

Lithostratigraphy, sedimentary evolution and sequence stratigraphy of the Upper Proterozoic Lyell Land Group (Eleonore Bay Supergroup) of East and North-East Greenland

Geological Survey of Denmark and Greenland Bulletin ◽

10.34194/ggub.v179.5076 ◽

1997 ◽

pp. 1-60

Author(s):

Henrik Tirsgaard ◽

Martin Sønderholm

Keyword(s):

Sequence Stratigraphy ◽

Large Scale ◽

Middle Part ◽

East Greenland ◽

North East ◽

The North ◽

Upper Proterozoic ◽

Sedimentary Evolution ◽

Facies Associations ◽

Cyclic Changes

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Tirsgaard, H., & Sønderholm, M. (1997). Lithostratigraphy, sedimentary evolution and sequence stratigraphy of the Upper Proterozoic Lyell Land Group (Eleonore Bay Supergroup) of East and North-East Greenland. Geology of Greenland Survey Bulletin, 178, 1-60. https://doi.org/10.34194/ggub.v179.5076 _______________ The Late Proterozoic Lyell Land Group is an approximately 3 km thick succession of siliciclastic shelf deposits, within the upper part of the Eleonore Bay Supergroup. It is widely exposed in the region between Ardencaple Fjord in the north and Canning Land in the south. In this paper the seven formations named by Sønderholm & Tirsgaard (1993) are formally described. These are from base to top: the Kempe Fjord Formation (400-600 m thick), the Sandertop Formation (200-405 m thick), the Berzelius Bjerg Formation (250-450 m thick), the Kap Alfred Formation (500-640 m thick), the Vibeke Sø Formation (290-325 m thick), the Skjoldungebrae Formation (205-240 m thick) and the Teufelsschloss Formation (35-110 m thick). Five facies associations have been recognised. Outer shelf deposits dominated by dark green, brown to dark red mudstones with thin sandstone lenses are mainly found in the Sandertop, Kap Alfred and Skjoldungebræ Formations. Storm- and wave-dominated inner shelf deposits comprising fine-grained sandstones and dark heterolithic mudstones are common in the Sandertop, Kap Alfred, Vibeke Sø and Skjoldungebrae Formations and are also found in southern outcrops of the Teufelsschloss Formation. Tidally influenced shoreface deposits form stacks of laterally extensive sandstone bodies separated by heterolithic mudstones and are only found in the middle part of the Kap Alfred Formation. Storm- and wave-dominated shoreface deposits comprise highly mature, thick and laterally very extensive sandstone bodies of which a few may be traced for distances exceeding 150 km. This association is present in several intervals within all formations of the Lyell Land Group. Tidally dominated coastal plain deposits consist of stacked sandstone sheets forming laterally extensive, multistorey units separated by heterolithic mudstones and sandstones. These sediments form part of the Kempe Fjord and Berzelius Bjerg Formations and are also found in northern outcrops of the Teufelsschloss Formation. Evidence from palaeocurrent data combined with regional lithological variations suggest a consistent general N-S coastline with the basin deepening in an eastward direction. Deflection of geostrophic currents suggest a palaeolatitude on the southern hemisphere. The deposits of the Lyell Land Group are subdivided into four, large-scale sequences which overall show the same general sedimentary evolution through time reflecting large-scale, cyclic changes in relative sea-level. The sequences vary in thickness from 400-1000 m and are all readily traceable 300 km parallel and 100 km perpendicular to inferred palaeocoastline. The development of all sequences indicates that major regional translation of facies are related to large-scale forced regressions. Sequence stratigraphic considerations suggest that correlation of formations of the Lyell Land Group with units of the Petermann Bjerg Group some 75 km to the west may be very difficult to carry out. Citation: Tirsgaard, H. & Sønderholm, M. 1997: Lithostratigraphy, sedimentary evolution and sequence stratigraphy of the Upper Proterozoic Lyell Land Group (Eleonore Bay Supergroup) of East and North-East Greenland. Geology of Greenland Survey Bulletin 178, 60 pp.

Download Full-text

An n-alkane-based Holocene climate reconstruction in the Altai Mountains, northern Xinjiang, China

10.5194/egusphere-egu2020-3185 ◽

2020 ◽

Author(s):

Min Ran

Keyword(s):

North Atlantic ◽

Large Scale ◽

Time Lag ◽

Geographic Location ◽

Early Holocene ◽

Altai Mountains ◽

Temperature Changes ◽

The Holocene ◽

The North ◽

Highly Sensitive

The climate in the Altai Mountains is highly sensitive to large-scale forcing factors because of its special geographic location. Based on n-alkane data of 150 samples and with a chronologic support of 15 accelerator mass spectrometry (AMS) dates from a 600-cm core at GHZ Peat, the Holocene climatic changes in the Altai Mountains were reconstructed. The reconstruction revealed a warming and drying early Holocene (~10,750-~8500 cal. yr BP), a cooling and persistent dry middle Holocene (~8500-~4500 cal. yr BP), and a cooling and wetting late Holocene (~4500-~700 cal. yr BP). The Holocene temperature changes were primarily controlled by the summer solar radiation with a certain time lag in the early Holocene and also modulated by solar activity, and the time lag in the early Holocene was probably resulted from ice and permafrost melting. The Holocene moisture in the southern Altai Mountains was likely modulated by the North Atlantic Oscillations (NAO) or by the Atlantic Multi-centennial Oscillations (i.e., AMO-like) or by temperature, and or by any combination of the three (NAO, AMO-like, and temperature).

Download Full-text

Western Mediterranean hydro-climatic consequences of Holocene iceberg advances (Bond events)

10.5194/cp-2018-97 ◽

2018 ◽

Cited By ~ 2

Author(s):

Christoph Zielhofer ◽

Anne Köhler ◽

Steffen Mischke ◽

Abdelfattah Benkaddour ◽

Abdeslam Mikdad ◽

...

Keyword(s):

North Atlantic ◽

Large Scale ◽

Thermohaline Circulation ◽

Winter Precipitation ◽

Western Mediterranean ◽

Coupled Processes ◽

Opposite Pattern ◽

The Holocene ◽

The North ◽

Winter Rain

Abstract. Gerald C. Bond established a Holocene series of North Atlantic ice rafted debris events based on quartz and hematite stained grains recovered from subpolar North Atlantic marine cores. These so-called ‘Bond events’ document nine large-scale and multi-centennial North-Atlantic cooling phases that might be linked to a reduced thermohaline circulation. Regardless of the high prominence of the Holocene North Atlantic ice rafted debris record, there are critical scientific comments on the study: the Holocene Bond curve has not yet been replicated in other marine archives of the North Atlantic and there exist only very few palaeo-climatic studies that indicate all individual Bond events in their own record. Therefore, evidence for consistent hydro-climatic teleconnections between the subpolar North Atlantic and distant regions is not clear. In this context, the Western Mediterranean region reveals key hydro-climatic sites for the reconstruction of a teleconnection with the subpolar North Atlantic. In particular, variability of Western Mediterranean winter precipitation might be the result of atmosphere-ocean coupled processes in the outer-tropical North Atlantic realm. Based on an improved Holocene δ18O record from Lake Sidi Ali (Middle Atlas, Morocco) we correlate Western Mediterranean precipitation anomalies with North Atlantic Bond events to identify a probable teleconnection between Western Mediterranean winter rains and subpolar North Atlantic cooling phases. Our data show a noticeable positive correlation between Western Mediterranean winter rain minima and Bond events during the Early Holocene and an opposite pattern during the Late Holocene. There is evidence for an enduring hydro-climatic change in the overall Atlantic atmosphere-ocean system and the response to external forcing during the Mid-Holocene. Regarding a potential climatic anomaly around 4.2 ka (Bond event 3) in the Western Mediterranean, a centennial-scale winter rain maximum is generally in phase with the overall pattern of alternating ‘wet and cool’ and ‘dry and warm’ intervals during the last 5,000 years.

Download Full-text

Interannual evolution of (sub)mesoscale dynamics in the Bay of Biscay

Ocean Science ◽

10.5194/os-13-777-2017 ◽

2017 ◽

Vol 13 (5) ◽

pp. 777-797 ◽

Cited By ~ 5

Author(s):

Guillaume Charria ◽

Sébastien Theetten ◽

Frédéric Vandermeirsch ◽

Özge Yelekçi ◽

Nicole Audiffren

Keyword(s):

Mixed Layer ◽

Large Scale ◽

Mixed Layer Depth ◽

Relative Vorticity ◽

Circulation System ◽

Western Boundary ◽

Bay Of Biscay ◽

Coastal System ◽

North East ◽

The North

Abstract. In the north-east Atlantic Ocean, the Bay of Biscay is an intersection between a coastal constrained dynamics (wide continental shelf and shelf break regions) and an eastern boundary circulation system. In this framework, the eddy kinetic energy is 1 order of magnitude lower than in western boundary systems. To explore this coastal complex system, a high-resolution (1 km, 100 vertical sigma layers) model experiment including tidal dynamics over a period of 10 years (2001–2010) has been implemented. The ability of the numerical environment to reproduce main patterns over interannual scales is demonstrated. Based on this experiment, the features of the (sub)mesoscale processes are described in the deep part of the region (i.e. abyssal plain and continental slope). A system with the development of mixed layer instabilities at the end of winter is highlighted. Beyond confirming an observed behaviour of seasonal (sub)mesoscale activity in other regions, the simulated period allows exploring the interannual variability of these structures. A relationship between the winter maximum of mixed layer depth and the intensity of (sub)mesoscale related activity (vertical velocity, relative vorticity) is revealed and can be explained by large-scale atmospheric forcings (e.g. the cold winter in 2005). The first submesoscale-permitting exploration of this 3-D coastal system shows the importance of (sub)mesoscale activity in this region with its evolution implying a potentially significant impact on vertical and horizontal mixing.

Download Full-text

Holocene Chronology of the Brattforsheden Delta and Inland Dune Field, Sw Sweden

Geochronometria ◽

10.1515/geochr-2015-0001 ◽

2015 ◽

Vol 42 (1) ◽

Cited By ~ 1

Author(s):

Helena Alexanderson ◽

Derek Fabel

Keyword(s):

Previous Exposure ◽

Sedi Ments ◽

Dose Distributions ◽

Dune Field ◽

The Holocene ◽

Aeolian Activity ◽

Dating Methods ◽

Aeolian Dunes ◽

Depositional Age ◽

Sand Sheets

Abstract Brattforsheden is a large glacifluvial deposit in southwestern Sweden and associated with it is one of Sweden’s largest inland dune fields. Although the relative ages of the Brattforsheden depos-its are well known, absolute ages from the area are few. In this study we have used optically stimulat-ed luminescence (OSL), surface exposure (10Be) and radiocarbon (14C) dating to provide an absolute chronology for the deglaciation and for the Holocene development of the aeolian dunes. Our data show that the deglaciation took place just before 11 ka (11.5 ± 0.6 ka OSL, 11.3 ± 0.8 ka 10Be), in line with the 14C-based regional deglaciation age. Aeolian dunes started forming immediately after degla-ciation and were active for at least 2000 years, well after vegetation had established. Renewed aeolian activity occurred 270-180 years ago, resulting in the deposition of sand sheets. Comparison between dating methods and studies of OSL dose distributions show that glacial, glacifluvial and littoral sedi-ments suffer from incomplete bleaching and thus that mean OSL ages from such deposits overesti-mate the true depositional age. By using small aliquots and statistical age models, this effect can part-ly be countered. Also, some of the 10Be ages appear too old, which may be due to previous exposure.

Download Full-text

The Valley-Fill Deposits of the Kłodnica River (Southern Poland): Environmental Drivers of Facies Changes from the Late Vistulian Through the Holocene

Geochronometria ◽

10.2478/v10003-010-0005-5 ◽

2010 ◽

Vol 35 (-1) ◽

pp. 49-66 ◽

Cited By ~ 5

Author(s):

Krzysztof Wójcicki

Keyword(s):

Middle Ages ◽

Large Scale ◽

Accumulation Rate ◽

Late Quaternary ◽

Environmental Drivers ◽

The Holocene ◽

Southern Poland ◽

Valley Fill ◽

Sedimentary Evolution ◽

Late Vistulian

The Valley-Fill Deposits of the Kłodnica River (Southern Poland): Environmental Drivers of Facies Changes from the Late Vistulian Through the HoloceneLithological analyses and radiocarbon dating were used to elucidate the patterns and controls of Late Quaternary valley floor development of the Kłodnica River, the Upper Odra Basin. The research results were discussed with data obtained from valleys of rivers draining piedmont basins and highlands of southern Poland. In consequence, five stages of morpho-sedimentary evolution of the Kłodnica valley were distinguished. In the Late Vistulian a large-scale deposition of channel alluvium took place in the conditions of high river discharges. This sedimentary style probably still existed in the Early Pre-Boreal as long as open grass communities survived in the Kłodnica catchment. The next phase, in the Late Pre-Boreal and Boreal, is characterized by a significant increase in accumulation rate of biochemical facies. The considerable restriction of minerogenic deposition was connected with widespread of forest and gradual limitation of the river discharges. The third stage began at the decline of the Boreal and was defined by decrease of accumulation rate or even biogenic accumulation break. Synchronously, periodic increases of fluvial activity were noticed in the form of cutoffs of meander loops and overbank deposition in oxbows. The beginning of the fourth period took place not earlier than in the Early Sub-Boreal. This stage was distinguished by renewed peat growth/increase in biochemical accumulation rate and periodic increase in alluviation, generally taking place in the conditions of low channel-forming flows. The latest phase (from the Middle Sub-Atlantic till now) is characterized by common initiation of slope deposition and a rapid increase in fluvial sedimentation, especially overbank and tributary fan facies. An increase in minerogenic deposition occurred in response to human impact, which became more significant from the Roman Period and occurred on a large scale from the early Middle Ages. Older settlement phases, including intense settlement from the Hallstatt Period, were not clearly recorded in the Kłodnica valley fill.

Download Full-text

Western Mediterranean hydro-climatic consequences of Holocene ice-rafted debris (Bond) events

Climate of the Past ◽

10.5194/cp-15-463-2019 ◽

2019 ◽

Vol 15 (2) ◽

pp. 463-475 ◽

Cited By ~ 9

Author(s):

Christoph Zielhofer ◽

Anne Köhler ◽

Steffen Mischke ◽

Abdelfattah Benkaddour ◽

Abdeslam Mikdad ◽

...

Keyword(s):

North Atlantic ◽

Large Scale ◽

Thermohaline Circulation ◽

Winter Precipitation ◽

Western Mediterranean ◽

Coupled Processes ◽

Opposite Pattern ◽

The Holocene ◽

The North ◽

Winter Rain

Abstract. Gerard C. Bond established a Holocene series of North Atlantic ice-rafted debris events based on quartz and haematite-stained grains recovered from subpolar North Atlantic marine cores. These so-called “Bond events” document nine large-scale and multi-centennial North Atlantic cooling phases that might be linked to a reduced thermohaline circulation. Regardless of the high prominence of the Holocene North Atlantic ice-rafted debris record, there are critical scientific comments on the study: the Holocene Bond curve has not yet been replicated in other marine archives of the North Atlantic and there exist only very few palaeoclimatic studies that indicate all individual Bond events in their own record. Therefore, evidence of consistent hydro-climatic teleconnections between the subpolar North Atlantic and distant regions is not clear. In this context, the Western Mediterranean region presents key hydro-climatic sites for the reconstruction of a teleconnection with the subpolar North Atlantic. In particular, variability in Western Mediterranean winter precipitation might be the result of atmosphere–ocean coupled processes in the outer-tropical North Atlantic realm. Based on an improved Holocene δ18O record from Lake Sidi Ali (Middle Atlas, Morocco), we correlate Western Mediterranean precipitation anomalies with North Atlantic Bond events to identify a probable teleconnection between Western Mediterranean winter rains and subpolar North Atlantic cooling phases. Our data show a noticeable similarity between Western Mediterranean winter rain minima and Bond events during the Early Holocene and an opposite pattern during the Late Holocene. There is evidence of an enduring hydro-climatic change in the overall Atlantic atmosphere–ocean system and the response to external forcing during the Middle Holocene. Regarding a potential climatic anomaly around 4.2 ka (Bond event 3) in the Western Mediterranean, a centennial-scale winter rain maximum is generally in-phase with the overall pattern of alternating “wet and cool” and “dry and warm” intervals during the last 5000 years.

Download Full-text