Fig 1 - uploaded by F. Muschitiello
Content may be subject to copyright.
Paleoenvironment of the LGM (20 ka B.P.) with the location of core 31-PC (red star; SWERUS-C3 expedition 2014). Bathymetry of the Arctic and Northern Pacific Ocean are from GEBCO 2014. The beige shade marks the additional-to-present permafrost-covered land surface during the LGM, purple marks the area flooded during the EH (11 to 7.6 ka B.P.; based on shelf bathymetry and global sea-level rise) (5, 31), and dark gray marks the modern land surface. The orange color indicates the distribution of ICDs in periglacial regions of Siberia and Alaska (10). LIS, Laurentide Ice Sheet; BS, Bering Sea; CS, Chukchi Sea; ESS, East Siberian Sea; LS, Laptev Sea; BKIS, Barents-Kara Sea Ice Sheet; OS, Sea of Okhotsk; NSI, New Siberian Islands. Red triangles indicate the location of cores described in previous studies on the Arctic shelves, the 4-PC (13), GC-58 (17), and PC-23 (11). Yellow triangles indicate the location of cores located in the Pacific realm; the cores SO202-18-3/6, SO201-2-114KL, and SO201-2-12KL in the Bering Sea (18); as well as the cores SO178-13-6 and LV28-4-4 in the Sea of Okhotsk (14).
Source publication
Carbon cycle models suggest that past warming events in the Arctic may have caused large-scale permafrost thaw and carbon remobilization, thus affecting atmospheric CO 2 levels. However, observational records are sparse, preventing spatially extensive and time-continuous reconstructions of permafrost carbon release during the late Pleistocene and e...
Contexts in source publication
Context 1
... Siberia likely over large areas that now make up the world's largest conventional shelf-the East Siberian Arctic Shelf (ESAS) (8). The postglacial sea-level rise and flooding of what became the ESAS is thought to have removed about 220 to 260 Pg of OC (8,10), leaving 400 Pg of total above-sea ICD-OC in near-coastal areas in Siberia and Alaska ( Fig. 1) ...
Context 2
... and noncontinuous observational studies have confirmed with radiocarbon dating that the deglacial sea-level rise remobilized old OC, likely due to coastal retreat of permafrost (13,17). Two studies from the northeast Pacific suggest that this also happened outside the Arctic Ocean during shelf inundation in the Bering Sea and the Sea of Okhotsk ( Fig. 1) (14,18). There is, however, no single continuous archive that explores the remobilization of OC from Arctic permafrost during the last deglaciation, leaving both the magnitude and the onset and end of this hypothetically massive permafrost OC remobilization largely ...
Context 3
... during the SWERUS-C3 expedition (Swedish-Russian-U.S. East Siberian Arctic Ocean Investigation of Climate-Cryosphere-Carbon Interactions) onboard the Swedish icebreaker Oden. The 8-m-long core, with a basal age of 27.3 + 2.3/−1.4 ka B.P. (19), was recovered from the Southern Lomonosov Ridge in the Arctic Ocean north of the New Siberian Islands (Fig. 1). In contrast to the previous studies in the Arctic Ocean, this archive is uniquely located to record inputs from seaward-transported carbon from a broad catchment area in the East Siberian region and provides a record across the full deglaciation period. To distinguish between the two dominating thaw and permafrost-carbon ...
Context 4
... to a combination of (i) the lack of recovered core material to document also the onset of the DO-3 event in the 31-PC record, (ii) uncertainty in the 31-PC age-depth model for the core base of 27.3 + 2.3/−1.4 ka B.P. (90% uncertainty range; fig. S1) (19), and (iii) the possible delay between inland permafrost thaw and peak signal arrival at the 31-PC location. This represents, to our knowledge, the first support for permafrost OC release related to DO events during one of the main periods of ICD formation in Siberia (10, 23). Hence, permafrost might have been more vulnerable to ...
Context 5
... flux of permafrost carbon from ICD to 31-PC more than tripled from the LGM and HS-1 baseline (0.3 ± 0.1 g m −2 year −1 ) to the BA (1.1 ± 0.1 g m −2 year −1 ). This is in line with reconstructed fluxes of ICD-OC to the Chukchi Sea (Figs. 1 and 4), which were three times higher during the late BA (13.1 to 12.9 ka B.P.) than in the Holocene (13). The synchronous observational records in the Chukchi Sea and on the southern Lomonosov Ridge (31-PC) together represent a wide drainage footprint (ESAS) and suggest that thawing and remobilization of OC from ICD was a large-scale phenomenon across the entire ESAS coastline and drainage basin. ...
Context 6
... ESAS during the BA (5, 31). Irrespective of the exact mobilization mechanism, the (i) highly enhanced liberation of old OC from ICD permafrost and (ii) molecular evidence for extensive degradation support the hypothesis that ICD thawing during the BA contributed to the concurrent rise of atmospheric CO 2 and its isotopic changes ( 13 C, 14 C) (Fig. 4) (14, 15). However, the exact amount of OC that was stored as ICD on exposed Arctic shelves is still challenging to estimate (8), and it is not yet possible to quantitatively constrain the magnitude of the fraction that got converted to CO 2 after thaw. In summary, the BA warming at 14.7 ka B.P. activated the thawing and degradation of old ...
Context 7
... the Younger Dryas (YD)-EH warming expands upon an earlier report on this (11). Tesi and coworkers (11) showed that the dominant source of the large OC input to their sampling location in the Laptev Sea was fluvially transported material from the permafrost active layer (Fig. 4). This previous study built on source apportionments in core PC-23 ( Fig. 1), which is located near the mouth of the paleo-Lena river. It is likely that OC transported to this location showed a particularly strong contribution of river-transported material from inland Siberia that may not be representative for most of the ESAS. An increasing number of studies with a broader regional footprint (East Siberian ...
Context 8
... comparison of the travel distance for terrigenous OC with modern cross-shelf degradation trends in the Laptev Sea (33) shows that the 3,5-Bd/V ratio in 31-PC for the EH interval between 10 and 7.6 ka B.P. (0.4 to 0.5) agrees with the 3,5-Bd/V ratio of ~0.5 at a crossshelf transport distance of about 400 km or more (33). The modern system relationship between transport distance and the 3,5-Bd/V degradation status is consistent with the EH period observations as the offshore distance of the core site increased from about 200 to 400 km between 11 and 7.6 ka B.P. (5, 31). However, other degradation status proxies such as the ratio of HMW n-alkanoic acids over HMW n-alkanes (0.7 ± 0.3) are even somewhat lower than expected based on the comparison above (acids/alkanes > 1.9) (33). ...
Context 9
... Siberian continental margin is the northern margin of the Eurasian continent and recipient of large terrestrial export of sediments and OC (Fig. 1). Taken together, the shelf area of the Laptev, East Siberian, and Russian Chukchi Seas constitutes the world's largest continental shelf area, i.e., the ESAS, where about half of the area is shallower than 50 m depth (31). This region today receives terrigenous OC both from erosion of permafrost coastlines and from riverine transport ...
Context 10
... sedimentation history of the 8-m-long core 31-PC encompasses the last 27 ka ( fig. S1) and builds on stratigraphic correlation to Greenland ice-core records within the constraints of radiocarbon dating, using a novel Bayesian probabilistic alignment method (19). Accordingly, this environmental record starts at the onset of early Marine Isotope Stage (MIS-2), which includes the entire LGM (26.5 to 20 ka B.P.) (5), the ...
Similar publications
Siberian wildfire is of paramount importance in the carbon cycle and climate change as it is a major disturbance in the pan‐Arctic ecosystems. In recent decades, the Siberian wildfire regime has been shifting; however, less is known about its process‐based feedback mechanisms. By integrating in‐situ and satellite observational data sets as well as...
Permafrost carbon represents a potentially powerful amplifier of climate change, but little is known about permafrost sensitivity and associated carbon cycling during past warm intervals. We reconstruct permafrost history in western Canada during Pleistocene interglacials from 130 uranium-thorium ages on 72 speleothems, cave deposits that only accu...
Citations
... Previous studies have explored the concentrations and spatiotemporal dynamics of dissolved organic carbon (DOC) and major ions in Arctic river basins [20][21][22][23][24], for example, emerging solute-induced mineralization with significant increases in annual flux of total dissolved solids from the Ob, Kolyma and Yukon Rivers [25][26][27], along with significant rises in alkalinity fluxes in major Arctic rivers such as the Ob and Yenisei [28]. In contrast, other research indicates that the total concentration of major ions in certain regions, like northern West Siberia, might remain relatively stable in the coming decades, despite seasonal variability [29,30]. ...
The Arctic river basins, among the most sensitive regions to climate warming, are experiencing rapid temperature rise and permafrost thawing that profoundly affect their hydrological and hydrochemical systems. However, our understanding of chemical export from Arctic basins to oceans remains limited due to scarce data, particularly in permafrost-dominated regions. This study examines the spatiotemporal variations and seasonal dynamics of major ions (Na+, K+, Mg2+, Ca2+, Cl−, SO42−) and dissolved organic carbon (DOC) concentrations across three river basins with varying permafrost extents: the Severnaya Dvina (2006–2008, 2012–2014), the Pechora (2016–2019) and the Taz Rivers (2016–2020). All the data were sourced from published Chemical Geological researches and were taken from Mendeley and PANGAEA datasets. Our results showed that DOC concentrations ranged from 1.75 to 26.40 mg/L, with the Severnaya Dvina River exhibiting the highest levels of DOC concentrations, alongside significantly elevated ion concentrations compared to the other two basins. A positive correlation was observed between DOC concentrations and river discharge, with peaks during the spring flood and summer baseflow due to leaching processes. The Severnaya Dvina and Pechora Rivers exhibited the highest DOC values during the spring flood, reaching 26.40 mg/L and 8.07 mg/L, respectively. In contrast, the Taz River had the highest runoff during the spring flood season, but the DOC concentration reached its highest value of 11.69 mg/L in the summer. Specifically, a 1% increase in river discharge corresponded to a 1.25% rise in DOC concentrations in the Severnaya Dvina River and a 1.04% increase in the Pechora River, while there was no significant correlation between runoff and DOC concentrations in the Taz River. Major ion concentrations demonstrated a negative correlation with river discharge, remaining relatively high during winter low-flow period. A robust power-law relationship between river discharge and concentration of DOC and major ions was observed, with distinct variations across the three river basins depending on permafrost extent. The Pechora and Taz Rivers, characterized by extensive permafrost, exhibited increasing trends in river discharge and DOC concentrations, accompanied by decreasing major ion concentrations, whereas the non-permafrost-dominated Severnaya Dvina River basin showed the opposite pattern. The Taz River, with the most extensive permafrost, also displayed a delayed DOC peak and more complex seasonal ion concentration patterns. These findings highlight the importance of varying permafrost extents and their implications for water quality and environmental protection in these vulnerable regions.
... Estimates from models suggest that deglacial warming caused massive release of terrestrial OC from Arctic permafrost (up to 1,000 Pg C; Pg = 10 15 g; Ciais et al., 2012;Lindgren et al., 2018) through various reactivation pathways (e.g., Jones et al., 2023). For instance, erosion of coastal permafrost has remobilized deep and ancient carbon pools (Martens et al., 2019(Martens et al., , 2020Meyer et al., 2019;Winterfeld et al., 2018). However, not only ancient carbon pools were remobilized. ...
... Marine sediments used in this study are from the 4.02 m-long PC23 previously described in detail by Tesi, Muschitiello, et al. (2016). The core was retrieved in 2014 in the mid/outer-shelf of the Laptev Sea (Lat 76°F igure 1. Map created using Ocean Data View (Schlitzer, 2023) showing the location of Piston Core 23 (PC23; Tesi, Muschitello, et al., 2016) and other sediment cores discussed for comparison in this study (31-PC: Martens et al., 2020;4-PC: Martens et al., 2019;18-3 and -6, 114KL, 12KL: Meyer et al., 2019;13-6, 4-4: Winterfeld et al., 2018). Paleo-drainage above and below 70°N according to Martens et al. (2019Martens et al. ( , 2020 and Meyer et al. (2019), respectively. ...
... The core was retrieved in 2014 in the mid/outer-shelf of the Laptev Sea (Lat 76°F igure 1. Map created using Ocean Data View (Schlitzer, 2023) showing the location of Piston Core 23 (PC23; Tesi, Muschitello, et al., 2016) and other sediment cores discussed for comparison in this study (31-PC: Martens et al., 2020;4-PC: Martens et al., 2019;18-3 and -6, 114KL, 12KL: Meyer et al., 2019;13-6, 4-4: Winterfeld et al., 2018). Paleo-drainage above and below 70°N according to Martens et al. (2019Martens et al. ( , 2020 and Meyer et al. (2019), respectively. 10.26′N, Long 129°20.22′E, ...
The abrupt warming events punctuating the Termination 1 (about 11.7–18 ka Before Present, BP) were marked by sharp rises in the concentration of atmospheric methane (CH4). The role of permafrost organic carbon (OC) in these rises is still debated, with studies based on top‐down measurements of radiocarbon (¹⁴C) content of CH4 trapped in ice cores suggesting minimum contributions from old and strongly ¹⁴C‐depleted permafrost OC. However, organic matter from permafrost can exhibit a continuum of ¹⁴C ages (contemporaneous to >50 ky). Here, we investigate the large‐scale permafrost remobilization at the Younger Dryas‐Preboreal transition (ca. 11.6 ka BP) using the sedimentary record deposited at the Lena River paleo‐outlet (Arctic Ocean) to reflect permafrost destabilization in this vast drainage basin. Terrestrial OC was isolated from sediments and characterized geochemically measuring δ¹³C, Δ¹⁴C, and lignin phenol molecular fossils. Results indicate massive remobilization of relatively young (about 2,600 years) permafrost OC from inland Siberia after abrupt warming triggered severe active layer deepening. Methane emissions from this young fraction of permafrost OC contributed to the deglacial CH4 rise. This study stresses that underestimating permafrost complexities may affect our comprehension of the deglacial permafrost OC‐climate feedback and helps understand how modern permafrost systems may react to rapid warming events, including enhanced CH4 emissions that would amplify anthropogenic climate change.
... Marine sedimentary archives from the Laptev Sea covering the early period of the last deglaciation (>14 ka BP) are scarce, and existing records often have low temporal resolution and are discontinuous (Martens et al., 2020;Tesi et al., 2016a;Keskitalo et al., 2017;Martens et al., 2019). Here, we present two high-resolution sediment core records that have continuously covered the last 17.8 kyr. ...
Arctic permafrost stores vast amounts of terrestrial organic matter (terrOM). Under warming climate conditions, Arctic permafrost thaws, releasing aged carbon and potentially impacting the modern carbon cycle. We investigated the characteristics of terrestrial biomarkers, including n-alkanes, fatty acids, and lignin phenols, in marine sediment cores to understand how the sources of terrOM transported to the ocean change in response to varying environmental conditions such as sea-level rise, sea ice coverage, inland climate warming, and freshwater input. We examined two sediment records from the western Laptev Sea (PS51/154 and PS51/159) covering the past 17.8 kyr. Our analyses reveal three periods with high mass accumulation rates (MARs) of terrestrial biomarkers, from 14.1 to 13.2, 11.6 to 10.9, and 10.9 to 9.5 kyr BP. These MAR peaks revealed distinct terrOM sources, likely in response to changes in shelf topography, rates of sea-level rise, and inland warming. By comparing periods of high terrOM MAR in the Laptev Sea with published records from other Arctic marginal seas, we suggest that enhanced coastal erosion driven by rapid sea-level rise during meltwater pulse 1A (mwp-1A) triggered elevated terrOM MAR across the Arctic. Additional terrOM MAR peaks coincided with periods of enhanced inland warming, prolonged ice-free conditions, and freshwater flooding, which varied between regions. Our results highlight regional environmental controls on terrOM sources, which can either facilitate or preclude regional terrOM fluxes in addition to global controls.
... Our approach builds on a series of studies primarily conducted on the Siberian Shelf, aiming to quantify OC source fractions originating from permafrost soils, particularly the seasonally thawed active layer, and OC mobilized from the erosion of coastal ice-rich and old ICD. This approach follows a method initially introduced in this region by Vonk et al. (2010), and was further refined by Andersson et al. (2015) and applied in a series of studies across various regions (e.g., Bröder et al., 2018;Karlsson et al., 2016;Vonk et al., 2012;Wild et al., 2019) and time scales (Martens et al., 2019(Martens et al., , 2020. More recently, the method was further advanced by correcting for terrOC aging during cross-shelf transport , which was quantitatively described by Bröder et al. (2018). ...
Continental margins receive, process and sequester most of the terrestrial organic carbon (terrOC) released into the ocean. In the Arctic, increasing fluvial discharge and collapsing permafrost are expected to enhance terrOC release and degradation, leading to ocean acidification and translocated CO2 release to the atmosphere. However, the processes controlling terrOC transport beyond the continental shelf, and the amount of terrOC that reaches the slope and the rise are poorly described. Here we study terrOC transport to the Laptev Sea continental slope and rise by probing surface sediments with dual‐isotope (δ¹³C/Δ¹⁴C) source apportionment, degradation‐diagnostic terrestrial biomarkers (n‐alkanes, n‐alkanoic acids, lignin phenols) and ²¹⁰Pbxs‐based mass accumulation rates (MAR). The MAR‐terrOC (g m⁻² yr⁻¹) decrease from 14.7 ± 12.2 on the shelf, to 7.0 ± 5.8 over the slope, to 2.3 ± 0.3 for the rise. Scaling this to the respective regimes yields that 80% of the terrOC accumulates on the shelf, while 11% and 9% of the accumulation occurs in slope and rise sediments, respectively. TerrOC remineralization is evidenced by biomarker degradation proxies (CPI of n‐alkanes and 3,5Bd/V) indicating 40% and 60% more terrOC degradation from slope to rise, consistent with a decline in terrOC concentrations by 57%. TerrOC degradation only partially explains this decline. An updated Laptev Sea terrOC budget suggests that sediment transport dynamics such as turbidity currents may drive terrOC shelf‐basin export, contributing to the observed accumulation pattern. This study quantitatively demonstrates that Arctic shelf seas are key receptor systems for remobilized terrOC, emphasizing their importance in the carbon cycle of the rapidly changing Arctic.
... 10,31-33 . Coastal erosion driven by sea-level rise during this Early Holocene warming has frequently been documented as a significant trigger for remobilization of old dormant OC from high-latitude Arctic and subarctic permafrost 8,[34][35][36] . Likewise, remobilization of dormant terrestrial or petrogenic OC beneath the Greenland ice sheet should be expected during the Early Holocene temperature rise. ...
... The marine OC end member is based on literature values for high-latitude marine phytoplankton (δ 13 C mar = −21.0 ± 2.6‰; Δ 14 C mar = −50 ± 12‰) 34 . For the petrogenic OC end member, the δ 13 C org value of the East Greenland Permian-Triassic strata was adopted (δ 13 C petr = −28.86 ...
Marine sediments in glacially-carved fjords at high latitudes feature high organic carbon (OC) burial rates, but there are fewer data on the role of glacial activity on high-latitude OC burial rates outside of fjords. Here, we investigate the relationship between sediment OC burial rates in the deep troughs and basins of the southwest Greenland shelf and Holocene glacial dynamics. Since the onset of prominent Neoglacial advances ~2500 years ago, the nature of the OC buried in the deep troughs and basins of the shelf was influenced by the glacier-driven increase in sediment accumulation rates (SAR), reactive iron (oxyhydr)oxide concentrations and fine-grain sediment, while OC burial rates were primarily enhanced by increasing SAR. Peak OC burial rates (~18.5 ± 5.7 g m⁻² a⁻¹) in the deep troughs and basins of the shelf during the past ~1300 years are comparable to those of many high-latitude fjords, and the inferred total annual OC burial in these trough and basin areas is equivalent to ~5% of the annual CO2 uptake by the Labrador Sea deep convection.
... The functioning and evolution of this system is determined by geological, geophysical, and lithological-geochemical environmental factors (Opyt…, 2001;Stein and Macdonald, 2004;Vetrov and Romankevich, 2004;Grosse et al., 2007;Pavlidis and Nikiforov, 2007;Sistema…, 2009;Laverov et al., 2013;Pease et al., 2014;Kanao et al., 2015;Dudarev et al., 2016;Romankevich and Vetrov, 2021). The importance of studying this system is dictated by current climate changes that contribute to the degradation of permafrost, thermal abrasion of the coast, degassing and exaration of the seabed, increased discharge of river and groundwater runoff, ancient organic carbon, as well as the necessity to predict dangerous natural and anthropogenic phenomena on the shelf (Batchelor and Dowdeswell, 2015;Gunther et al., 2015;Lobkovskiy et al., 2015;Schuur et al., 2015;Nikiforov et al., 2016;Semiletov et al., 2016;Shakhova et al., 2017;Winterfeld et al., 2018;Turetsky et al., 2019;Martens et al., 2020). The planned exploitation of the Northern Sea Route, the development of the resource-exploration and transport logistics industries, as well as the industrial development of biological resources, focus on comprehensive studies of the seabed on the shelf of the Arctic seas of Russia as the most important transit and logistics element in the system of relationships and communications. ...
The paper summarizes data on the lithological and elemental composition of bottom sediments and permafrost from boreholes 1D-14, 3D-14, and 1D-15 drilled from shore ice in Buor-Khaya Bay in 2014-2015. Based on the determined percentage content of SiO in sediments, the values of lithochemical mod-uli were calculated, and a comparative analysis of the lithological and geochemical composition was performed. Differences in the lithochemical composition between the coastal (1D-14 and 3D-14) and relatively distant (1D-15) strata were shown, explained by the spatiotemporal variability of sedimentary fluxes and the weathering crust activity in the studied area of the Laptev Sea. Based on the geological structure, the obtained data on the lithochemical composition of thawed and permafrost deposits indicated that sedimentary rocks in the Kharaulakh Ridge of the Verkhoyansk mountain system, corresponding to sandstones, siltstones, and mudstones, were probably the basis of the petrofund. The contribution of igneous and metamorphic rocks to the supply of sedimentary matter in the strata uncovered by drilling was insignificant and of a subordinate nature.
... The recorded trend of a decrease in the mass fraction of sand during the transition from the oxidized to the reduced layer, accompanied by a mutual increase in the contribution of finer-grained fractions and a decrease in the average particle diameter, indicates activation in modern conditions of terrigenous (river and thermal abrasion) fluxes carrying large quantities of sandy material. The results obtained in this study agree with previously obtained data [4] and confirm the currently observed trends in the variability of the natural environment of the Arctic, most often associated with climate fluctuations [18,[20][21][22]24]. Taking into account the insignificant bioproductivity of Chaun Bay's water area [11,12], analysis of the calculated grain size parameters allows us to conclude that the studied sediments are characterized by pronounced polymictity and detrital origin. ...
Based on the results of an analysis of 174 samples of bottom sediments collected at 48 stations in the Chaun Bay during the cruise 60 of the R/V Akademik Oparin (October 2020), it was found that their grain size distribution varies from poorly sorted silty clay to well sorted sand. The results of the study led to conclusion that the main sedimentation mechanisms in Chaun Bay are thermal abrasion, river runoff, and abrasion, as well as ice rafting and aeolian transport. The zoning of grain size types of bottom sediments is related to the bottom topography and consistent with areas affected by riverine runoff, abrasion, and thermal coastal abrasion , as well as with the direction of currents. The high occurrence of coarse clastic matter in sediments is evidence of abrasion of the coastal zone and active ice rafting of large (up to 15 cm) rock fragments. The vertical variability of the grain size parameters of the studied bottom sediments within the upper 20 cm layer reflects gradual Late Holocene intensification of terrigenous (fluvial and thermal abrasion) fluxes with the current effects of climate change in the Arctic.
... The relevance of studying the coastal-shelf zone of the Arctic, which is a complex natural system, is governed by the scale of problems facing the Russian Federation, which is strengthening the development of resources and space in the Arctic in complex and actively changing natural and climatic conditions. The most significant climate-mediated processes include degradation of coastal and subsea permafrost, thermal abrasion of the coastal zone, degassing of the seabed, increased unloading of river and groundwater runoff, contributing to an imbalance in the bioproductivity of water areas and the carbon cycle in the Arctic [6,18,22,[29][30][31][32][33][34][35]. The planned exploitation of the Northern Sea Route and the development of the resource extraction industry in the Arctic focus on comprehensive studies of the seabed on the shelf of the Arctic seas of Russia as the most important logistical element. ...
According to the results of an analysis of 99 samples of bottom sediments and submarine perma-frost from boreholes 1D-14, 3D-14, and 1D-15 drilled in Buor-Khaya Bay, differences in their mineral composition due to paleogeographic factors, namely, Late Quaternary changes in climate and sea level, as well as regional hydrodynamics are shown. The basis of the light fraction of minerals was quartz and feldspar (mainly plagioclase), found as grains of various dimensions and degree of sorting, as well as fine grains. To a lesser extent, chlorite, kaolinite, and serpentine have been noted; illite and smectite are rare. Forty-two accessory minerals were identified in the heavy fraction (average yield 0.95%) concentrated in fine-grained sands. It mainly consists of pyroxene, amphibole, carbonatite, epidote, zoisite, magnetite, mica, garnet, limonite, titanite, leucoxene, and ilmenite. Rutile, kyanite, sillimanite, zircon, tourmaline, apatite, and staurolite were found in smaller quantities. In the studied strata, plant remnants and carbonlike particles (kerogen) have been found, the contribution of which exceeds 5% by weight in a number of samples. The results of the study allowed the conclusion that the basis of the petrofund of the studied deposits are most likely sedimentary rocks of the Kharaulakh ridge of the Verkhoyansk Mountain system (sandstone, siltstone, and mudstone). The presence of characteristic accessory minerals in the sediments marks the unloading of igneous and met-amorphic rocks, but their contribution is subordinate. They probably also include rocks of the Verkhoyansk Complex, common near Tiksi.
... These regions comprise the southern edge of the LGM permafrost area and, according to Köhler et al. (2014), are likely to have experienced a rapid loss of massive amounts of ancient C as a result of thawing during the last deglaciation. However, while direct evidence for the deglacial remobilization of ancient C from permafrost has been reported for the Arctic (Tesi et al., 2016;Keskitalo et al., 2017;Martens et al., 2019Martens et al., , 2020Wu et al., 2022) and subarctic (Winterfeld et al., 2018;Meyer et al., 2019), similar data are still lacking for the European realm, where the phenomenon has been suggested on the basis of enhanced terrigenous biomarker concentrations in sediment cores (Ménot et al., 2006;Rostek and Bard, 2013;Soulet et al., 2013). ...
The last deglaciation is the most recent relatively well-documented period of pronounced and fast climate warming, and, as such, it holds important information for our understanding of the climate system. Notably, while research into terrestrial organic carbon reservoirs has been instrumental in exploring the possible sources of atmospheric carbon dioxide during periods of rapid change, the underlying mechanisms are not fully understood. Here we investigate the mobilization of organic matter to the Bay of Biscay, located in the north-eastern Atlantic Ocean off the coasts of France and Spain. Specifically, we focus on the area that was the mouth of the Channel River during the last deglaciation, where an enhanced terrigenous input has been reported for the last glacial–interglacial transition. We conducted a comprehensive suite of biomarker analyses (e.g. n-alkanes, hopanes and n-alkanoic acids) and isotopic investigations (radiocarbon dating and δ13C measurements) on a high-resolution sedimentary archive. The present study provides the first direct evidence for the fluvial supply of immature and ancient terrestrial organic matter to the core location. Moreover, our results reveal the possibility of permafrost carbon export to the ocean, driven by processes such as deglacial warming and glacial erosion. These findings are consistent with observations from other regions characterized by present or past permafrost conditions on land, which have shown that permafrost thaw and glacial erosion can lead to carbon remobilization, potentially influencing atmospheric carbon dioxide levels.
... Between Marine Isotopic Stage (MIS) 5 and MIS 2 (ca. 120-18 kyr BP), the large sea level drop and the subsequent exposure of large portions of the Laptev Sea, East Siberian Sea and Chukchi Sea continental shelves caused the expansion of Ice Complex deposits [20][21][22] , also referred to as Yedoma deposits, formed by fine-grained material with high amounts of OC and ice (up to 5% and 80%, respectively 23 ). Today, the Yedoma domain represents approximately one third of the total OC stored in the Circumpolar Arctic permafrost region (327-466 Pg C), with Yedoma deposits accounting for 83-129 Pg C 17,24 . ...
... Our final objective was to elucidate permafrost carbon reactivation mechanisms driven by abrupt climate warming and rapid sea level rise during MWP-1A. We also compared our dataset with other previously obtained records from the Eurasian Arctic, most notably from cores PS2138-1 33 and 31-PC 22 (Fig. 1). Specifically, the former, retrieved in the deeper part of the slope 80 km east of HH11-09GC, allows us to demonstrate that our record is not confined to a local effect, while the latter represents a valuable record from the Eurasian Arctic that covers the entirety of the last Termination and for which terrestrial biomarkers have also been analysed at high resolution. ...
... The radiocarbon dates include 13 foraminiferal tests and one bivalve shell (Supplementary Table 1), of which 5 have been analysed in the current study and 9 published previously by Chauhan et al. 30 . The near surface ΔR values used here for reservoir correction were obtained from the work of Brendryen et al. 5 (see section "Radiocarbon dating and age-depth model" in Materials and Methods for details) in the Norwegian Sea, which affects surface waters entering the Arctic Ocean 22 . e Cutin-derived products MAR (green line and dots) from core HH11-09GC. ...
The Bølling-Allerød interstadial (14,700–12,900 years before present), during the last deglaciation, was characterized by rapid warming and sea level rise. Yet, the response of the Arctic terrestrial cryosphere during this abrupt climate change remains thus far elusive. Here we present a multi-proxy analysis of a sediment record from the northern Svalbard continental margin, an area strongly influenced by sea ice export from the Arctic, to elucidate sea level - permafrost erosion connections. We show that permafrost-derived material rich in biospheric carbon became the dominant source of sediments at the onset of the Bølling-Allerød, despite the lack of direct connections with permafrost deposits. Our results suggest that the abrupt temperature and sea level rise triggered massive erosion of coastal ice-rich Yedoma permafrost, possibly from Siberian and Alaskan coasts, followed by long-range sea ice transport towards the Fram Strait and the Arctic Ocean gateway. Overall, we show how coastal permafrost is susceptible to large-scale remobilization in a scenario of rapid climate variability.
