Ice Core δ18O Record Research Articles

A reconstructed PDO history from an ice core isotope record on the central Tibetan Plateau

Ice core oxygen isotope (δ18O) records from low-latitude regions preserve high-resolution climate records in the past, yet the interpretation of these ice core δ18O records is still facing difficulty due to the uncertainty of ice core dating. Here we present a new established δ18O time series from Qiangtang (QT) No. 1 ice core retrieved from the central Tibetan Plateau. Due to the vague seasonal signals in the QT ice core, we investigated the spectral properties of δ18O record with depth and discussed the implications of significant spectral power peaks in the QT ice core. We employed a variational mode decomposition (VMD) analysis for the upper part of the QT ice core to decompose the δ18O depth series in order to separate the El Niño Southern Oscillation (ENSO) mode, a signal strongly preserved in the QT ice core δ18O record. With this approach, we established a time series of 335 years (1677–2011 CE) for the upper 50 m of the QT ice core. Subsequently, we examined the frequency of the new established δ18O time series and detected strong signals of the bidecadal and multidecadal modes of Pacific Decadal Oscillation (PDO). The PDO consists of two modes with periods of approximately 25–35 years and 50–70 years, and we found that the 50–70 years periodicity has persisted since 1700 CE, succeeded by dominance of the 25–75 years periodicity after 1900 CE. Additionally, we analyzed the δ18O series of the QT ice core during the past century and determined that the increasing frequency of El Niño events is an important factor contributing to the increase in recent ice core δ18O.

Fast response of vegetation in East Asia to abrupt climatic events during the last deglaciation.

Climate changes had major impacts on the vegetation of East Asia during the last deglaciation. However, the rate and pattern of vegetation succession in response to large-scale climatic events during this interval are controversial. Here, we present well-dated decadal-resolution pollen records from annually laminated Maar Lake Xiaolongwan during the last deglaciation. The vegetation changes were rapid and near-synchronous with millennial-scale climatic events, including Greenland Stadial 2.1a (GS-2.1a), Greenland Interstadial 1 (GI-1), Greenland Stadial 1 (GS-1), and the early Holocene (EH). The vegetation responded in different ways to the different rates of climate change. Vegetation change was gradual [∼1 thousand years (kyr) response time] during the transition between GS-2.1a and GI-1, but it was faster (∼0.4 kyr response time) during the transitions between GI-1, GS-1, and the EH, resulting in different patterns of vegetation succession. Additionally, the amplitude and pattern of vegetation changes resembled those in the records of regional climate change based on long-chain n-alkanes δ13C and stalagmite δ18O, as well as in the mid-latitude Northern Hemisphere temperature record and the Greenland ice core δ18O record. Therefore, the rate and pattern of vegetation succession in the Changbai Mountain of Northeast Asia during the last deglaciation were sensitive to the characteristics of changes in the regional hydrothermal conditions and mid-latitude Northern Hemisphere temperature, which were linked to both high- and low-latitude atmospheric-oceanic dynamics. Overall, our findings reveal a close relationship between ecosystem succession and hydrothermal changes during these millennial-scale climatic events in East Asia during the last deglaciation.

Mineralogical, geochemical, and magnetic susceptibility variations in the loess-paleosol sequence from Pattan, Kashmir Valley, India record an enhanced Indian summer monsoon around 35 ka

We present multi-proxy records of bulk chemistry, clay mineralogy, stable isotope composition of soil organic matter (δ13CSOM) and pedogenic carbonate (δ18OSC), and mineral magnetic parameters of a loess-paleosol sequence from Kashmir Valley, India, to infer paleoclimate and paleovegetation during Late Pleistocene. 14C AMS dating brackets the age of paleosols between 40 and 19.6 ka and suggests loess to be > 40 ka. Our study shows that a cold/dry climate prevailed at >40 ka (Late Pleistocene), during which the loess accumulation took place, and a warm/humid climate after that led to the development of soil units, with a prominent warm/humid phase around 35 ka. The range of Chemical Index of Alteration (72–78) and significant amounts of illite and chlorite in the section indicate moderate weathering. High kaolinite content, low chlorite, increased K/C, I/C, K/(I + C) ratio, and presence of poorly crystalline and Al-rich illite by ∼36 ka indicates increasing weathering intensity, likely due to an enhanced Indian Summer Monsoon (ISM). High magnetic susceptibility during 35–32 ka indicates enhanced pedogenesis due to a warm-humid climate. Paleotemperature estimates reveal a relatively warmer (by ∼7 °C) climate during pedogenesis than that at >40 ka. δ13CSOM values (−17‰ to −22.2‰) suggest C3 plants dominated the Kashmir Valley through the Late Pleistocene, however, a short period of enhanced summer monsoon at ∼35 ka favored C4 plant growth. The paleoclimate variability in the loess-paleosol sequence presented here agrees with the Guliya Ice Core δ18O record and high lake water levels in the Tibetan Plateau.

Influence of Recent Climate Shifts on the Relationship Between ENSO and Asian Monsoon Precipitation Oxygen Isotope Ratios

AbstractRecent studies have revealed robust in‐phase relationships between El Niño–Southern Oscillation (ENSO) and Asian Monsoon precipitation δ18O values (i.e., warm ENSO events with high δ18O values), and this relationship has been used in an attempt to reconstruct past ENSO activity. However, whether this relationship holds in the past is unknown. Here we use precipitation δ18O data from Hong Kong (East Asia) and Bangkok (Southeast Asia) and an ice core δ18O record from Dasuopu glacier (South Asia) to examine the δ18O‐ENSO relationship across two recent climate shifts that occurred during the winters of 1976/1977 and 1988/1989. On an annual scale, the δ18O‐ENSO relationship is weak prior to 1977 and strongest after 1988. We show that the changing δ18O‐ENSO relationship mainly originates from changes in the dry season isotope/climate relationship (which is significant only after 1988), whereas the rainy season relationship is relatively stable. We confirm that, consistent with earlier work on the rainy season, the significant δ18O‐ENSO relationship in the dry season post‐1988 is associated with ENSO's influence on regional convection (Bay of Bengal to South China Sea region). We suggest the insignificant dry season relationship prior to 1989 is due to limited ENSO impacts on convection in the Bay of Bengal to South China Sea region, which is supported by the insignificant relationship between ENSO and vertical velocity at 500 hPa. These findings suggest that without additional constraints, systematic variability in isotope/climate relationships will lead to large uncertainties in ENSO reconstructions based on Asian Monsoon region δ18O data.

High-elevation shrub-ring δ18O on the northern slope of the central Himalayas records summer (May–July) temperatures

The potential of shrub-ring oxygen isotopes (SRO) as a paleoclimatic proxy is not well demonstrated. In this study we explored the climate signals embedded in an SRO chronology from Saga, on the northern slope of the central Himalayas by correlation analysis with climate variables and comparison with tree-ring and/or ice-core δ18O records. The Saga SRO had significant and positive correlations with May–July temperatures in both local (r = 0.43) and moisture source areas (r = 0.49) during the period 1955–2015 (CE), while no significant correlations were found with hydroclimatic variables. It is also in good agreement with two tree-ring δ18O series from the southern slope of the central Himalayas, the source of moisture to the site. The temperature signals are further verified by an ice core δ18O record from the Tanggula Mountains on the central Tibetan Plateau. However, it shows little similarity with the nearest Himalayan ice core δ18O record from Dasuopu, demonstrating temperature signals of different seasons. This study suggests that SRO could be used as an acceptable climate proxy, like tree-ring and ice-core δ18O, to broaden the spatial extent of the paleoclimatic records network. However, we should be cautious when combining different proxies with climate signals of different seasons in paleoclimate studies.

Cold air incursions, δ18O variability, and monsoon dynamics associated with snow days at Quelccaya Ice Cap, Peru

AbstractQuelccaya Ice Cap in the Andes of Peru contains an annually resolved δ18O record covering the past 1800 years; yet atmospheric dynamics associated with snow deposition and δ18O variability at this site are poorly understood. Here we make use of 10 years of snow pit and short core δ18O data and hourly snow‐height measurements obtained by an automated weather station deployed at the ice cap's summit to analyze linkages between snowfall, δ18O, and the South American summer monsoon (SASM). Snow accumulation peaks in December and is negative May–September. Snow δ18O values decrease gradually through austral summer from about −17 to −24‰. Surface snow δ18O is altered after deposition during austral winter from about −24 to −15‰. More than 70% of the total snow accumulation is tied to convection along the leading edge of cold air incursions of midlatitude air advected equatorward from southern South America. Snowfall amplitude at Quelccaya Ice Cap varies systematically with regional precipitation, atmospheric dynamics, midtroposphere humidity, and water vapor δD. Strongest snowfall gains correspond with positive precipitation anomalies over the western Amazon Basin, increased humidity, and lowered water vapor δD values, consistent with the “amount effect.” We discuss ventilation of the monsoon, modulated by midlatitude cold air advection, as potentially diagnostic of the relationship between SASM dynamics and Quelccaya snowfall. Results will serve as a basis for development of a comprehensive isotopic forward model to reconstruct past monsoon dynamics using the ice core δ18O record.

A New Record of Holocene Sea Levels from the Northwestern Gulf of Mexico Based on Paleo Algal Mats

A series of cores (box and piston) were collected at 2 key locations in Lancaster Sound (cores 2004-804-009 BC and PC) and Barrow Strait (cores 2005-804-004 BC and PC) in the Canadian Arctic Archipelago to document the evolution of sea-surface conditions in the main axis of the Northwest Passage during the Holocene time period. Reconstruction of sea-surface parameters (summer temperature and salinity, duration of sea-ice cover) were estimated based on transfer functions using dinoflagellate cyst assemblages as proxy indicators. The chronology of these cores is based on calibrated AMS-14C dates, 210Pb analyses, and correlations between paleomagnetic secular variations of the geomagnetic field and a predicted spherical harmonic model of the geomagnetic field (CALS7 K.2). Our age models for both cores indicate that 009 PC spans the last 11,100 cal BP, while 004 PC encompasses the last 10,800 cal BP. Calculated sedimentation rates are in the range of 43–140 cm/kyr for core 009 PC and 15–118 cm/kyr for core 004 PC, allowing for a millennial time scale resolution in each core. Our results indicate relatively harsh conditions in Lancaster Sound between 10,800 and 9000 cal BP (summer temperatures 2 °C cooler than at present), which we associate with the presence of active ice-streams in northernmost Baffin Bay and a weak West Greenland Current. This is followed by a warming trend (up to 3 °C higher than present) that took place between ∼8500 and 5500 cal BP, which we associate with the Holocene thermal maximum and to a large scale atmospheric pattern such as the Arctic Oscillation operating at the millennial time scale. This is concomitant with an increase in the relative abundance of phototrophic dinoflagellate cyst taxa. A gradual cooling of sea-surface temperature and increased sea-ice follow this from 5500 cal BP until the modern period. In Barrow Strait, harsh sea-surface conditions prevailed from 11,100 to 5500 cal BP, with summer temperatures as low as 4 °C cooler than at present. The warming trend occurred later in this region (between 5500 and ∼1000 cal BP), after which a gradual cooling is observed until the modern period. The apparent shift, or opposite warming trends, between Lancaster Sound and Barrow Strait after 5500 cal BP could be the result of a change in atmospheric circulation patterns related to a possible shift in the AO mode (from AO+ to AO−). Comparison of ice core δ18O record from Devon Island ice cap and the reconstructed sea-surface temperature from core 009 PC suggests a strong atmospheric-oceanic coupling throughout the Holocene in this area.

Deglacial variability of Antarctic Intermediate Water penetration into the North Atlantic from authigenic neodymium isotope ratios

Understanding intermediate water circulation across the last deglacial is critical in assessing the role of oceanic heat transport associated with Atlantic Meridional Overturning Circulation variability across abrupt climate events. However, the links between intermediate water circulation and abrupt climate events such as the Younger Dryas (YD) and Heinrich Event 1 (H1) are still poorly constrained. Here, we reconstruct changes in Antarctic Intermediate Water (AAIW) circulation in the subtropical North Atlantic over the past 25 kyr by measuring authigenic neodymium isotope ratios in sediments from two sites in the Florida Straits. Our authigenic Nd isotope records suggest that there was little to no penetration of AAIW into the subtropical North Atlantic during the YD and H1. Variations in the northward penetration of AAIW into the Florida Straits documented in our authigenic Nd isotope record are synchronous with multiple climatic archives, including the Greenland ice core δ18O record, the Cariaco Basin atmosphere Δ14C reconstruction, the Bermuda Rise sedimentary Pa/Th record, and nutrient and stable isotope data from the tropical North Atlantic. The synchroneity of our Nd records with multiple climatic archives suggests a tight connection between AAIW variability and high‐latitude North Atlantic climate change.

Younger Dryas cooling and the Greenland climate response to CO 2

Greenland ice-core δ(18)O-temperature reconstructions suggest a dramatic cooling during the Younger Dryas (YD; 12.9-11.7ka), with temperatures being as cold as the earlier Oldest Dryas (OD; 18.0-14.6ka) despite an approximately 50ppm rise in atmospheric CO(2). Such YD cooling implies a muted Greenland climate response to atmospheric CO(2), contrary to physical predictions of an enhanced high-latitude response to future increases in CO(2). Here we show that North Atlantic sea surface temperature reconstructions as well as transient climate model simulations suggest that the YD over Greenland should be substantially warmer than the OD by approximately 5 °C in response to increased atmospheric CO(2). Additional experiments with an isotope-enabled model suggest that the apparent YD temperature reconstruction derived from the ice-core δ(18)O record is likely an artifact of an altered temperature-δ(18)O relationship due to changing deglacial atmospheric circulation. Our results thus suggest that Greenland climate was warmer during the YD relative to the OD in response to rising atmospheric CO(2), consistent with sea surface temperature reconstructions and physical predictions, and has a sensitivity approximately twice that found in climate models for current climate due to an enhanced albedo feedback during the last deglaciation.

Determining the post-glacial evolution of a northeast Pacific coastal fjord using a multiproxy geochemical approachThis article is one of a series of papers published in this Special Issue on the theme Polar Climate Stability Network.

A 40.32 m piston core recovered from Effingham Inlet, on the west coast of Vancouver Island, provides the basis for a high-resolution geochemical study of the last deglaciation and the Holocene. Glacial retreat, basin isolation, sea-level rise, and productivity variations are determined using proxies for sediment composition (K/Al, Fe/Al, Mg/Al), grain size (Ti/Al, Zr/Al), sedimentary redox conditions (Mo/Al, U/Al), and productivity (wt.% organic carbon, wt.% opal). As local ice retreated and marine waters inundated the basin, coarse-grained glacimarine sediments were replaced by finer grained, laminated, opal-rich sediments. During meltwater pulse-1a, the dominance of local crustal rise over eustatic sea-level rise resulted in the progressive restriction of ocean circulation in Effingham Inlet and the formation of a temporary freshwater lake. The transition into stable Holocene conditions was initiated at ∼12 700 BP, which corresponds to the onset of the Younger Dryas, as identified by the Greenland Ice core Project (GRIP) ice core δ18O record and was completed by 10 700 BP, ∼800 years after the GRIP ice core record stabilized. Holocene Mo/Al and U/Al ratios range between 12–35 (×104) and 1–3.4 (×104), respectively, indicating that although large-amplitude, high-frequency fluctuations occur, the sediments of Effingham Inlet inner basin have remained organic rich and oxygen depleted for the entire Holocene period. The combination of anoxic bottom waters and a Holocene sedimentation rate of 217 cm/ka have preserved a high-resolution record of environmental change in the northeast Pacific over the last 11 000 years.

Recent temperature increase recorded in an ice core in the source region of Yangtze River

Interests on climate change in the source region of Yangtze River have been raised since it is a region with the greatest warming over the Tibetan Plateau (TP). A 70-year history of precipitation δ18O has been recovered using an ice core record retrieved in a plat portion of the firn area in the Guoqu Glacier (33°34′37.8″N, 91°10′35.3″E, 5720 m a.s.l.), Mt. Geladaindong (the source region of Yangtze River), in November, 2005. By using a significant positive relationship between ice core δ18O record and summer air temperature (July to September) from the nearby meteorological stations, a history of summer air temperature has been reconstructed for the last 70 years. Summer temperature was relatively low in 1940s and high in 1950s to the middle of 1960s. The lowest temperature occurred in the middle of 1970s. Temperature was low in 1980s and dramatically increased since 1990s, keeping the trend to the beginning of the 21st century. The warming rate recorded in the ice core with 0.5°C/10 a since 1970s is much higher that that in the central TP and the Northern Hemisphere (NH), and it becomes 1.1 °C/10 a since 1990s which is also higher than these from the central TP and the NH, reflecting an accelerated warming and a more sensitive response to global warming in the high elevation region.

Modeling of the northern hemisphere ice sheets during the last glacial cycle and glaciological sensitivity

We present a new three‐dimensional thermomechanically coupled ice sheet model of the northern hemisphere to reconstruct the Quaternary ice sheets during the last glacial cycle. The model includes basal sliding, internally calculated surface mass balance, glacial isostasy, and a treatment for marine calving. The time dependent forcing consists of temperature and precipitation anomalies from the United Kingdom Meteorological Office (UKMO) General Circulation Model scaled to the Greenland Ice Core Project (GRIP) ice core δ18O record. Model parameters were chosen to best match geomorphological inferences on Last Glacial Maximum extent and global eustatic sea level change. For our standard run we find a maximum ice volume of 57 × 106 km3 at 18.5 ka cal BP. This corresponds to a eustatic sea level lowering of 110 m after correction for hydro‐isostatic displacement and anomalous ice resulting from defects in the specified boundary conditions of the Paleoclimate Model Intercomparison Project (PMIP) for which the UKMO GCM results were generated. Of this 110 m, 82 m was stored in the North American ice sheet and 25 m in the Eurasian ice sheet. We determine the qualitative and quantitative response of the model from a comprehensive sensitivity study in which 11 important parameters were varied over their respective ranges of uncertainty. Model outputs comparable to the observational record were explored in detail as a linear function along the axes of parameter space of the reference model. The method reveals the dominance of climate uncertainty when modeling the Last Glacial Maximum configuration of the northern hemisphere ice sheets, but also highlights the role of ice rheology and basal processes for ice sheet thickness, and glacial isostasy and calving for the timing of maximum ice volume.

AMS14C dating and stable isotope plots of Late Pleistocene ice-wedge ice

Strategy for AMS14C dating of organic micro inclusions from syngenetic ice-wedge ice is considered. AMS14C dates are interpreted in terms of fictitious aging of ice-wedge and permafrost sediments due to high concentration of allochthonous organic material. The dating of organic material from small sample, gives the reliable 14C age. The 14C dates from syngenetic ice-wedges are compared with the dates of the host sediments surrounding syngenetic ice wedges. AMS14C dating of small samples of ice-wedge ice yields to set δ18O plots from ice-wedges to the time scale and to correlate them with ice core δ18O record.

AMS14C dating and stable isotope plots of Late Pleistocene ice-wedge ice

Strategy for AMS14C dating of organic micro inclusions from syngenetic ice-wedge ice is considered. AMS14C dates are interpreted in terms of fictitious aging of ice-wedge and permafrost sediments due to high concentration of allochthonous organic material. The dating of organic material from small sample, gives the reliable 14C age. The 14C dates from syngenetic ice-wedges are compared with the dates of the host sediments surrounding syngenetic ice wedges. AMS14C dating of small samples of ice-wedge ice yields to set δ18O plots from ice-wedges to the time scale and to correlate them with ice core δ18O record.

Possible solar forcing of climate variability in the past 4000 years inferred from a proxy record at the southern margin of Tarim Basin

A ca. 4000a decadal-resolution climate proxy record of the mean grain-size from a lake (or mash) sediment at the southern margin of the Tarim Basin, correlates visually with the atmospheric 14C record from tree ring (residual A14C, solar proxy) and the GISP2 ice core δ18O record (temperature proxy). In general, Δ14C maxima (solar minima) are coincident with cold (wet) periods in the study area and cold periods in the Greenland ice core. Power spectrum analysis revealed statistically significant periodicities of 196a, 121a, 97a, 62a, 45a and 33–30a, which are similar to those principal solaroscillation periods as inferred from the atmospheric radiocarbon and other proxy records. Possible solar forcing is addressed to be the main driving forcing of climate change in the southern margin of Tarim Basin.

Climate variations since the last interglacial recorded in Czech loess

Magnetic susceptibility, organic matter content, and grain size were measured on a loess/palaeosol sequence deposited since the last interglacial at the Dolni Vestonice section in the Czech Republic. High values in magnetic susceptibility and organic matter content in palaeosols PK0, PK2, and PK3 indicate that they were strongly influenced by long‐term pedogenesis and high vegetation density linked to interglacials or interstadials. Grain‐size variations record a series of cold wind‐strengthened events during the last glacial, which we interpret as a record of the distinctive ‘Younger Dryas’ episode and millennial‐scale climate oscillations that correlate with the GRIP ice core δ18O record and North Atlantic Heinrich events. These climate events, as indicated by grain‐size peaks, combined with previous climate records at French Massif Central and Lago Grande di Monticchio in Italy, suggest that the climate over these areas might have undergone synchronous oscillations with the shifts in sea‐surface temperatures of the North Atlantic and air temperature changes above Greenland.

Preliminary results from the chemical records of an 80.4 m ice core recovered from East Rongbuk Glacier, Qomolangma (Mount Everest), Himalaya

AbstractHigh-resolution chemical records from an 80.4m ice core from the central Himalaya demonstrate climatic and environmental changes since 1844. the chronological net accumulation series shows a sharp decrease from the mid-1950s, which is coincident with the widely observed glacier retreat. A negative correlation is found between the ice-core δ18O record and the monsoon precipitation for Indian region 7. the temporal variation of the terrestrial ions (Ca2+ and Mg2+) is controlled by both the monsoon precipitation for Indian regions 3,7 and 8, located directly south and west of the Himalaya, and the dust-storm duration and frequency in the northern arid regions, such as the Taklimakan desert, China. the NH4+ profile is fairly flat until the 1940s, then substantially increases until the end of the 1980s, with a slight decrease during the 1990s which may reflect new agricultural practices. the SO42– and NO3– profiles show an apparent increasing trend, especially during the period 1940s–80s. Moreover, SO42– concentrations for the East Rongbuk Glacier core are roughly double that of the nearby Dasuopu core at Xixabangma, Himalaya, due to local human activity including that of climbing teams who use gasoline for cooking, energy and transport.

A mid-Holocene shift in Arctic sea-ice variability on the East Greenland Shelf

Records of iceberg-rafting and palaeohydrography from two East Greenland shelf cores (JM96-1206/1-GC and JM96-1207/1-GC) are reported. Benthic foraminifera, stable isotopes and IRD fluxes indicate a shift toward colder, lower-salinity ‘polar’ conditions c. 5 cal. ka. A new proxy of iceberg-rafting on the East Greenland Shelf is the flux of calcium carbonate (TIC) thought to be derived from glacial erosion of Cretaceous calcareous mudstones. A change in the regularity and spacing of carbonate flux peaks at c. 4.7 cal. ka in JM96-1207 coincides with the onset of Neoglacial cooling in the Renland ice core δ18O record. We propose that the carbonate flux peaks between 4.7 and 0.4 cal. ka are related to sea-surface coolings associated with increased flux of polar water and sea ice in the East Greenland Current. These peaks are synchronous with sea-surface coolings interpreted from North Atlantic deep-sea cores, but additional peaks centred around 2.4 and 3.8 cal. ka in JM96-1207 suggest that the shelf site captures higher-frequency events. The data indicate that severe Arctic sea-ice events began in the Neoglacial interval, and that earlier-Holocene cool events in deep-sea records are associated with other processes, such as release of meltwater from residual glacier ice and glacial lakes.

Century‐ to millennial‐scale sedimentological–geochemical records of glacial–Holocene sediment variations from the Barra Fan (NE Atlantic)

The Barra Fan, located at the continental margin of NW Scotland, offers a unique possibility to retrieve records of exceptional high resolution to obtain climate records on a century–millennial timescale. We used a sedimentological–geochemical approach to examine the sediment variations that reflect the palaeoceanography and climate history of the area. Inorganic chemistry combined with micropalaeontology reveals trends and changes in NE Atlantic palaeoceanography and northwest European climate at the sub‐Milankovitch frequency. This study builds on results from two British Geological Survey cores and one giant piston core (Core 57/‐11/59, Core 56/‐10/36 and Images Core MD95‐2006) that were obtained during the NEAPACC (NE Atlantic Palaeoceanography, Special Topic NERC) phase. Geochemical records of lithogenic input fluctuate rapidly and their patterns parallel sea surface temperature and particle size records. The cold periods are characterized by increased clay input compared to the warm periods. The Younger Dryas period and other prominent periods such as the equivalent of Heinrich Event 1, show extremely expanded sections up to several metres in thickness. Enhancement of accumulation rates in the glacial section is due to the influence of downslope sedimentation, meltwater deposition; and large‐scale currents redistributing the sediment along the upper slope. The radiochemical tracer (excess 230 Th) shows that major shifts in terrigenous sediment supply were extremely rapid over the last 15 ka. The shifts in terrigenous supply occurred over time‐spans of less than a century. Century‐scale events of lithogenic input can be visually correlated to other North Atlantic climate records such as the GISP2 Greenland ice core δ 18 O record for the last 15 ka, although the resolution of radiocarbon dating of these events in the sediments is not sufficiently precise to verify that the visual correlations are correct. The particle flux and biogenic records show sawtooth‐shaped cycles opposite to the Dansgaard–Oeschger cycles.