Glacial Processes Research Articles

Characteristics and formation of natural fractures in a silica-rich chalk, Coniacian Arnager Limestone Formation, Bornholm, Denmark.

Natural fractures are abundant and important components in many carbonate sedimentary rocks globally. In hydrocarbon and groundwater reservoirs of carbonate rocks they can form connected networks and thereby influence the permeability and f luid flow significantly. Outcrop studies of fractured carbonate rocks can provide an essential understanding of 3-dimensional fracture networks, thereby aiding in understanding fracture patterns and connectivity in subsurface carbonate reservoirs. The Arnager Limestone Formation is a naturally fractured silica-rich chalk of Coniacian age exposed in a coastal cliff on the island of Bornholm in the Baltic Sea (Denmark). This study examines the natural fractures in the Arnager Limestone Formation from a structural and geomechanical perspective. The Arnager Limestone Formation forms one, 12–20 m thick, main rock mechanical unit; bedding planes acts as weak interfaces and divides it into near-identical, cm- to dm-thick rock mechanical subuits. Flat-lying (horizontal) or low-angle dipping bedding-parallel fractures are intersected by two near-vertical or steeply dipping fracture systems, a major N–S-trending system and a less prominent W–E-trending fracture system. Rock mechanical analysis of the tensile strength and elastic moduli provides the foundation for discussing maximum burial depth of the Arnager Limestone Formation. The tensile strength gives information on the bedding-parallel fractures, which can have formed due to stress relief during uplift and erosion, possible accentuated by glacial processes. The near-vertical fracture sets are interpreted to have formed in response to tectonic movements.

An inception framework hypothesis for karst development in the Burren, Ireland

The Inception Horizon Hypothesis (IHH) postulates that certain stratigraphic horizons in a limestone sequence, combined with structural surfaces such as joints, provide a framework for cave development. Although subsurface and surface karst landforms are fundamentally linked, the IHH has not yet been extended to surface karstification. We tested this extension of the IHH in the world-renowned Burren karst due to its stratigraphic and structural simplicity. We used very high-resolution remote sensing datasets and detailed fieldwork to develop an updated map of the Burren's surface karst features, combined with a 3D geological model containing over 60 km of mapped cave passages.Our analysis shows that karstic connectivity between the surface and subsurface is primarily provided by a suite of vertically-persistent calcite and silica-rich veins, which form a non-stratabound fracture system across the Burren. The flow pathways provided by these veins then intersect the following inception horizons: (i) boundaries between distinct lithological units in the limestone sequence; (ii) crinoidal cycle tops, and more sporadically chert lenses, within one of those units (the Slievenaglasha Formation); (iii) thin horizons of non‑carbonates (‘clay wayboards’) within another unit (the Aillwee member). At the surface, the same horizons have been preferentially exploited by glacial processes, creating surfaces from which meteoric waters now recharge the subsurface and form new surface karst depressions and other karst landforms. Our new inception framework for karstification thus provides a new basis for understanding surface and subsurface connectivity in the karst critical zone in the Burren landscape, and it provides new geological insight into the functioning of carbonate critical zones more generally.

Constraining the origin of the Norwegian strandflat – The influence of isostatic and dynamic surface changes

The Norwegian strandflat is a prominent low-relief bedrock surface found near sea level along most of the west coast of Norway. Its origin has been discussed throughout the last 130 years but is yet to be resolved. Some studies suggest that the strandflat represent a tropical weathering front of Mesozoic age that has since been buried and re-exhumed, while others relate its origin to Pleistocene periglacial and glacial processes and/or wave-induced weathering and erosion. Previous interpretations of the strandflat have considered postglacial isostatic uplift, but the impacts of isostatic changes due to glacial erosion and deposition, as well as dynamic surface changes driven by mantle convection, have been largely overlooked. Here we examine how geomorphological-driven isostatic changes and dynamic surface changes have influenced the land-surface elevation along the Norwegian coast during late Pliocene-Quaternary (the last ca. 3 million years). We employ quantitative estimates of glacial erosion and deposition to assess the flexural isostatic response from the resulting load changes. Our analyses show that patterns of geomorphic isostatic adjustments and dynamic surface changes are generally not reflected in the present elevation of the strandflat. Only the loading effect from the deposition of the North Sea Fan can clearly be correlated with the submerged strandflat found near Stad (~62 °N). Our results imply that if the strandflat formed synchronously along the Norwegian coast as a flat surface at sea level, the strandflat we observe today must have developed after the majority of late Pliocene-Quaternary glacial erosion took place, but prior to the main deposition of the North Sea Fan. This would place strandflat formation within the last few glacial cycles, but before the Last Glacial Maximum (LGM). This inferred pre-LGM age of the strandflat is generally consistent with cosmogenic nuclide exposure ages and observed striations on the strandflat. Finally, we examine ice cover and land-surface changes relative to sea level during the last 80,000 years and find no extended periods favorable for synchronous strandflat formation across all regions along the Norwegian coast. This implies that either the strandflat is diachronous, or that the processes of formation have either been extremely fast under certain conditions or are independent of sea level, for instance related to glacial erosion.

Evaluating possible glacial modification in the Martian tropics near Gale crater using a new U-shaped valley metric

Growing evidence supports the case for glacial processes within the equatorial regions of Mars. However, few examples of modeling or numerical analysis exist to support this hypothesis. Here we apply an automated method on valleys near Gale crater to extract morphometric data and analyze formative processes responsible for their current expression. The V-index utilized is a new robust method that is an alternative to traditional valley parabolic curve fits. This approach more easily characterizes irregular valley cross sections and thus aids in distinguishing between glacial and nonglacial forms. We applied this method along with standard power law and quadratic curve fits on valley cross sections along a 2300 km extent of the Martian tropics near Gale crater. Both V-index and power law b fit values suggest that the majority of the valleys are U-shaped and possibly created through glacial erosive processes. Further, V-index and power law b values plotted against elevation show a positive trend with higher V-index (glaciated) values associated with higher elevation. This suggests that an equilibrium-line altitude (ELA) may have existed at the time of valley formation. The timing of the formation of these U-shaped valleys is poorly defined. However, our initial crater statistics conducted within the study area suggest a young ∼1.05 (±0.25) Ga relative ages of the valley floors. Equatorial glaciers that produced these and other related glacial forms may be as old as the Hesperian to Amazonian transition (∼3 Ga) but more intriguingly may be associated with Amazonian equatorward migration of the Martian cryosphere during more recent periods of high obliquity oscillations.

Worked examples for peer interaction: a feedback and learning resource

Abstract Feedback penetrates many walks of our lives, and its importance in L2 teaching and assessment is well recognised. However, while corrective feedback and writing feedback have been the focus of much L2 research and classroom practice, there seems relatively little attention to feedback on spoken interactional skills. Concomitantly, translating research on interactional competence (IC) to classroom practice has been a glacial process. Aiming at supporting teachers in providing assessment feedback and teaching IC in the classroom, this article introduces worked examples of peer interactions as a feedback and learning resource. Adopting a procedure used in conversation analytic (CA) research, the worked examples are designed to guide learners to notice and understand IC features in context, at a less cognitively demanding pace for processing, and promote learners’ active engagement with the feedback or teaching focus. The article concludes with suggestions for teachers to develop similar resources for their local contexts.

Evaluating marine dust records as templates for optical dating of Oldest Ice

Abstract. The continuous ice core record extends 800 000 years into the past, covering the period of 100 000-year glacial cycles but not the transition from 40 000-year glacial cycles (the mid-Pleistocene transition, 1.2–0.7 million years ago). A primary goal of the International Partnerships in Ice Core Sciences is therefore to retrieve a 1.5-million-year-old continuous ice core, increasing our understanding of this major change in the climate system and thus of fundamental climate forcings and feedbacks. However, complex glacial processes, limited bedrock data, and young basal ice in previous cores necessitate careful reconnaissance studies before extracting a full core. Ice borehole optical logging reflects the ice dust content and may be used to date ice quickly and inexpensively if a reference record is known. Here we explore the relationship between ice dust records and well-dated marine dust records from sediment cores in the southern Atlantic and Pacific oceans, which lie along paths of dust sources to Antarctica. We evaluate how representative these records are of Antarctic dust both through the existing ice core record and during the older target age range, suggesting that a newly published 1.5-million-year record from Site U1537 near South America is likely the most robust predictor of the Oldest Ice dust signal. We then assess procedures for rapid dating of potential Oldest Ice sites, noting that the ability to detect dating errors is an essential feature. We emphasize that ongoing efforts to identify, recover, date, and interpret an Oldest Ice core should use care to avoid unfounded assumptions about the 40 kyr world based on the 100 kyr world.

Phase-sensitive radar measurements of glacial processes

Phase-sensitive radar measurements of glacial processes

Isotope Hydrograph Separation Reveals Rainfall on the Glaciers Will Enhance Ice Meltwater Discharge to the Himalayan Rivers

AbstractThe Indian Summer Monsoon (ISM) and meltwater from the Himalayan are the two most important sources of water in the Indian subcontinent. However, the impact of ISM on Himalayan glaciers and subsequent stream hydrology remains largely unknown. To provide new insight into the impact of rainfall on glacial hydrology, here we present hydro‐meteorological and time‐series observations of meltwater stable water isotope compositions from the snout of the Chorabari glacier in the Upper Ganga Basin, Central Himalayas across the ablation season corresponding to 2019. We observe that rainfall events (>2 mm d−1) on the glacier enhance discharge driven by ice meltwater in River Mandakini. Energy balance calculations reveal that one of the drivers behind enhanced ice meltwater contribution could be rain‐induced melting of the glacier where rainfall on the ice surface melts the glacier producing up to 13% of the total discharge at the glacier snout. Further, rainfall on glacier surface have other control on glacial processes—for example, snow metamorphism, ice flow dynamics such as short‐term acceleration in ice speed flow, and reorganization of the englacial and subglacial drainage network—that are poorly studied and needs further investigation. We conclude rainfall events on the glacier have a complex control on mountain hydrology. This study, therefore, provides an interpretative framework that calls for additional assessments of the direct and indirect impact of rainfall in glacial hydrology.

Hydrologic evolution of two Martian deltas in the Ismenius Cavus system

Ismenius Cavus (33.76° N, 17.05° W) is a large Martian basin that has been interpreted as an ancient paleolake. It is situated in the middle of the path Mamers Valles traces from the Cerulli Crater to the Borealis Basin. This ancient lake served as a key deposition area (or depocenter) for multiple lake chains originating in the southern highlands. The collected water was then transported downstream to the Borealis Basin. The ancient hydrologic activity of this zone is evidenced in the widespread appearance of valley networks and fretted channels, but especially in the presence of deltaic deposits converging in Ismenius Cavus. We made a hydrological and geomorphological analysis of two of these deltas, which compose a three-crater lake chain system. It was interpreted that both deltas, although being close to each other, were created by different processes and at different times. The Aracataca Delta was deposited during the Noachian by a valley network system. The Ariguani Delta, in turn, was the result of the discharge of a fretted channel carved by groundwater sapping. The transformations of the hydrologic systems in the Ismenius Cavus region were established by analyzing the change in the deltaic pulses over time. It was determined that the first hydrologic stage was dominated by widespread valley networks that probably represent subglacial hydrologic systems, a second stage started when these systems were replaced by groundwater activity; and finally, when the water sources were exhausted, a final stage of glacial processes prevailed until the present.

Insights into glacial processes from micromorphology of silt-sized sediment

Abstract. Silt-rich meltwater plume deposits (MPDs) analyzed from marine sediment cores have elucidated relationships that are clearly connected, yet difficult to constrain, between subglacial hydrology, ice-marginal landforms, and grounding-zone retreat patterns for several glacial catchments. Few attempts have been made to infer details of subglacial hydrology, such as flow regime, geometry of drainage pathways, and mode(s) of sediment transport through time, from grain-scale characteristics of MPDs. Using sediment samples from MPD, till, and grounding-zone proximal diamicton collected offshore of six modern and relict glacial catchments in both hemispheres, we examine grain shape distributions and microtextures (collectively, grain micromorphology) of the silt fraction to explore whether grains are measurably altered from their subglacial sources via meltwater action. We find that 75 % of all imaged grains (n = 9400) can be described by 25 % of the full range of measured shape morphometrics, indicating grain shape homogenization through widespread and efficient abrasive processes in subglacial environments. Although silt grains from MPDs exhibit edge rounding more often than silt grains from tills, grain surface textures indicative of fluvial transport (e.g., v-shaped percussions) occur in only a modest number of grains. Furthermore, MPD grain surfaces retain several textures consistent with transport beneath glacial ice (e.g., straight or arcuate steps, (sub)linear fractures) in comparable abundances to till grains. Significant grain shape alteration in MPDs compared to their till sources is observed in sediments from glacial regions where (1) high-magnitude, potentially catastrophic meltwater drainage events are inferred from marine sediment records and (2) submarine landforms suggest supraglacial melt contributed to the subglacial hydrological budget. This implies that quantifiable grain shape alteration in MPDs could reflect a combination of high-energy flow of subglacial meltwater, persistent sediment entrainment, and/or long sediment transport distances through subglacial drainage pathways. Integrating grain micromorphology into analysis of MPDs in site-specific studies could therefore aid in distinguishing periods of persistent, well-connected subglacial discharge from periods of sluggish or disorganized drainage. In the wider context of deglacial marine sedimentary and bathymetric records, a grain micromorphological approach may bolster our ability to characterize ice response to subglacial meltwater transmission through time. This work additionally demonstrates that glacial and fluvial surface textures are retained on silt-sized quartz grains in adequate amounts for microtexture analysis, which has heretofore been conducted exclusively on the sand fraction. Therefore, grain microtextures can be examined on silt-rich glaciogenic deposits that contain little to no sand as a means to evaluate sediment transport processes.

Glacial and volcanic landforms in the upper catchment of Claro River, Central Chile (35.5°S): A Late Quaternary geomorphological case study

AbstractThe upper catchment of the Claro river is located within the Transitional Southern Volcanic Zone in the Maule Region of Chile (35.5°S), at the foothills of Manantial Pelado volcano, a Pleistocene stratovolcano whose morphology suggests the occurrence of important glacial processes in the area. The observed glacial landforms can be sequenced and associated with episodes of volcanic activity. Different units of volcanic and glacial origin were identified based on field observations, detailed mapping, and digital elevation model and satellite image analysis. The contact relations between them made it possible to discern four events that can be linked to Marine Isotope Stages 8, 6, 4‐2, and to the Neoglacial. We propose seven stages in the geomorphological evolution from the late Pleistocene to the late Holocene, where there is coexistence between volcanic and glacial episodes, such as the emplacement of the Manantial Pelado volcano overlying the Abanico and Cola de Zorro formations; a subsequent debris avalanche; the enlargement of the Del Indio valley during the Penultimate Glaciation; the construction of Cerro Redondo (a minor eruptive center at the head of Del Indio valley); ongoing fluvial incision; and Neoglacial advances. The relative chronology proposed in this work contributes to clarifying the Pleistocene–Holocene geomorphological history in this catchment and to further understand the interplay between volcanic and glacial processes in the central Chilean Andes during the Quaternary.

Geomorphological study of the origin of Mongolian Altai Mountains Lake depressions: implications for the relationships between tectonic and glacial processes

The lake depressions in the Mongolian Altai Mountains, and the issues related to their formation have yet to be thoroughly examined in previous research. Previous studies primarily focused on the paleogeographical evolution and glaciation dynamics of the Altai Mountains. This study presents relationships between tectonic and glacial processes that have formed the lake depressions, such asKhoton, Khurgan, Dayan, Khar (western), and Khar (eastern) in the Mongolian Altai Mountains. The depressions of Khoton, Khurgan, and Dayan lakes are situated along regional fault zones, extending in an northwest-southeast direction, forming intermontane depressions directly connected to the Mongolian Altai Mountains. However, the depressions of Dayan, Khar (western), and Khar (eastern) lakes have been dammed by moraine deposits in the near portion of the depression. The compliance matrix of tectonic geomorphological criteria indicates that the Khoton, Khurgan, Dayan Lake, and Khar (western) Lake depressions are more than 50% compatible. Similarly, the compliance matrix for glacial eomorphological criteria indicates more than 60% compliance for all lake depressions. The Mongolian Altai intermontane depressions are thus of tectonic origin, whereas the lakes have a glacial origin, resulting from dammed moraine sediments. The significanceof this work lies in demonstrating how geomorphological research can be employed to provide a detailed understanding of the pattern of lake depressions.

Geospatial analysis of groundwater arsenic and fluoride in Quaternary aquifers of southern Ontario, Canada

The geological setting of an area plays a critical role in the transfer and ultimate distribution of hydrochemical constituents present in groundwater. In southern Ontario, Canada, the present physiography was significantly influenced by glacial processes during the Quaternary period. The heterogeneous nature and complex pattern of shallow subsurface glacial overburden sediments, likely affect the fate of different groundwater constituents. In this study, arsenic (As) and fluoride (F−) concentrations from 515 water wells, that are constructed within overburden sediment, were analyzed with the physiographic map of southern Ontario along with other related variables. Geospatial mapping and several spatial statistical analyses were performed to examine the possible geological influence on As and F− distribution and water-well susceptibility at a regional scale. Key findings suggest four physiographic settings were significant variables influencing the distribution of As and F− in differently constructed bored/dug and drilled wells. Bored/dug wells in Bevelled Till Plains and bored/dug wells in Undrumlinized and Bevelled Till Plains were found to be relatively susceptible to As and F− contamination respectively. In contrast, bored/dug and drilled wells in Drumlinized Till Plains and Drumlins and drilled wells in Sand Plains seemed to be relatively safe from F− and As respectively. The statistical regression analyses suggested that other variables, such as the application of phosphate fertilizer and the textures of till, influenced the spatial distribution of As and F− as well as which types of wells (bored/dug or drilled) were impacted. The geospatial mapping and statistical cluster analysis indicated that the possible sources of elevated As and F− in drilled wells are the clasts of underlying bedrock. The relationship between physiographic settings and impacted overburden wells in southern Ontario provides planners with an approach to water-well susceptibility assessments at the regional scale, which in turn can guide further local analysis for water resource management.

Greater than the sum of its parts: optical remote sensing and sediment core data provide a holistic perspective on glacial processes

Abstract In this letter we make the case that closer integration of sediment core and passive optical remote sensing data would provide new insights into past and contemporary glacio-sedimentary processes. Sediment cores are frequently used to study past glacial processes and environments as they contain a lengthy geochemical and sedimentological record of changing conditions. In contrast, optical remote sensing imagery is used extensively to examine contemporary glacial processes, including meltwater dynamics, glacial retreat, calving, and ice accumulation. While paleoenvironmental data from sediment cores and optical remote sensing imagery are rarely used in tandem, they are complementary. Sediment core records are spatially discrete, providing long-term paleoenvironmental proxy data which require assumptions about environment-sediment linkages. Optical imagery offers precise, spatially extensive data to visualize contemporary processes often limited in their temporal extent. We suggest that methodologies which integrate optical remotely sensing with sediment core data allow direct observation of processes interpolated from sedimentological analysis and achieve a more holistic perspective on glacial processes. This integration addresses the limitations of both data sources and can achieve a stronger understanding of glacier dynamics by expanding the spatiotemporal extent of data, reducing the uncertainty of interpretations, and broadening the local analyses to regional and global scales.

Tracing earthquakes through lake sediments for better prediction

<p>Intensive climatic extremes and frequent earthquakes, both in China and other regions, have captured public attention recently. The Tibetan Plateau at middle northern latitudes boasts large glacier and snow coverage, coupled with frequent tectonic activities, exerting profound yet poorly understood influences on zonal atmospheric motion and energy flux during interhemispheric coupling. This study proposes a comprehensive process-based approach involving multi-proxies focused on alpine lakes to illuminate the intricate interactions among tectonics, glacial processes and hydro-climatic variations. This perspective can enhance our understanding of the spatiotemporal diversity of the local-to-global hydro-climatic change pattern, particularly forced by Tibetan Plateau, and suggests to consider its combined summer thermal and tectonic forcing. Additionally, the approach provides unbiased geological data extracted from lakes, contributing to the optimization of hazard and climate models for better predictions of tectonics, abrupt and irreversible climate tipping points with confidence.</p>

Potential of pine forest in controlling soil erosion in Himalayan region - Investigation using fallout radionuclide (137Cs) measurements

The Himalayas possess a distinctive topography owe to the dynamic interplay of tectonic activity, geological erosion and sedimentation, glacial processes, and climatic influences over the millions of years. The rugged, steep terrain and poor land management make it more prone to water erosion, negatively impacts the soil, affecting the goods and services supported by the soil ecosystems. Traditional methods used in soil erosion assessment face limitations when dealing with topographically complex hillslopes. The use of Fallout Radionuclide (FRN) -137Cs provides a feasible alternative for measurement of soil erosion in the region with such topography. However, there is lack of 137Cs-based soil erosion studies in the north-west Himalayas. Pine (Pinus roxburghii) is the predominant forest type in the Himalayas, offering numerous benefits to both natural ecosystems and human beings. In this study, we selected a typical steep hillslope covered with pine forest in the Himalayas for soil erosion assessment. The study measured 137Cs reference inventory of 1409 Bq m−2 in the landscape. Importantly, the concentration of 137Cs along the hillslope positions showed a significant variation attributed to topographic variability. Topographic factors, such as the slope shape and gradient, were identified as the major governing parameters of soil erosion in the hilly and mountainous region. The net soil erosion rate over hillslope positions revealed highest at upper hillslope followed by ridge, middle and valley hillslope positions. The net soil erosion rate under the pine forest ranged from 8.0 to 14.6 t ha−1 yr−1, with an average rate of 9.9 t ha−1 yr−1. Erosion rate over the hillslope positions were found in accordance to the soil loss tolerance limit (SLTL) except for the upper hillslope, indicating it as critical slope position requires to adopt suitable conservation measures. The study signifies the role of the forest in mitigating soil erosion and, in turn, conserving soil resources. The findings provide crucial insights and guidance to land managers and decision-makers, emphasizing the necessity of conserving and restoring forests in the Himalayas.

Differential surface uplift and knickpoint evolution along the transient Teesta river in the eastern Himalayas

Tectonic and erosional processes that contribute to the gradual process of topographic uplift and erosion have shaped the Himalayan terrain. We used geomorphic proxies and previous published rates of erosion and exhumation across the Teesta River catchment to model the presence of transient segments. This helped us understand how the regional landscape has been changing over time due to surface uplift and channel incision. The Celerity model has been used to evaluate the knickpoint distribution and headward migration along the river system. Based on the river profile and Chi-(χ) analysis, the observed major knickpoints at about ∼ 2500–4000 m elevation comprise the fluvial erosion process, while higher elevation knickpoints suggest the glacial process. The strong significance of the model is shown by the observed correlation coefficient of 0.94 between the predicted and observed horizontal knickpoints. The analysis of relict reach for the paleo-channel reconstruction across the transient drainage channels shows a differential surface uplift of 3823 ± 252 m and 2372 ± 48 m with a corresponding relief gain. The rates of erosion and exhumation were spatially correlated with topographic metrics, precipitation intensity, knickpoint distribution, and surface uplift. The observation suggests that the rate of erosion tends to be more significant and spatially more varied than the long-term rate of exhumation. The rate of exhumation has been found to decline through topographic timescales from south to north, with rates as high as ∼ 1.0 mm/y in the southwest and as low as ∼ 0.4 mm/y in the northernmost Tessta catchment.

Margin processes sculpting a land-detached canyon-channel system: the Gollum Channel System in the Porcupine Seabight

The land-detached Gollum Channel System (GCS) is one of very few large-scale canyon-channel systems on the Northwest European margin and thought to be of high importance in both along-slope and downslope sediment transport processes in the Porcupine Seabight basin. It is, however, unknown when this system was formed and how active it has been throughout its evolution, making it difficult to assess its regional impact. Here, using well data integrated with airgun seismic reflection data, a seismic stratigraphy (Cretaceous to present) is built for the GCS for the first time. We find that, contrary to what was thought before, the GCS was formed before Quaternary glaciations occupied the continental shelf and its origin is tentatively associated to a phase of Northeast Atlantic margin tilting in the early Pliocene. Each of the channels that make up the GCS was initiated by incision from erosive downslope gravity flows originating on the Celtic Sea Shelf. Gravity flows from Quaternary glacial processes reused the channels and mostly bypassed the upper slope or contributed to the channel fill, though some flows were capable of erosion of existing channel flanks and incision of several smaller channels. Additionally, we show that this margin was incised by erosive gravity flows on several occasions through time and that these incisions seem to follow preferential pathways. Interaction with along-slope bottom currents from the start of the Quaternary onwards was crucial to distribute sediments and nutrients to sediment drifts and cold-water coral mounds further north (downstream) along the Irish margin.

Impacts of anthropogenic activities and glacial processes on the distribution of chemical elements in Billefjord, Svalbard, Arctic

The Arctic region is undergoing rapid and extensive transformations due to global climate change. This study investigated the spatial distribution of 31 chemical elements in eight locations in Billefjord, Svalbard, Arctic, with varying degrees of anthropogenic and glacial influences. The west coast of Billefjord has experienced a greater historical anthropogenic impact, while the east coast has larger glaciers and shows less visible evidence of direct human impact. Over 450 topsoil samples collected in the west (abandoned mining town Pyramiden, and glacial valleys of Elsa, Ferdinand, Sven) and east coast of the fjord (glacial valleys of Ebba, Pollock, Ragnar and nearby the Nordenskiöld glacier). These samples were extracted and analyzed by ICP-OES. The results revealed complex distributions of elements among the locations. Nordenskiöld glacier area, along with other locations in the eastern part of the Billefjord, had significantly higher levels of most elements (20 out of 31; As, B, Ca, Cd, Co, Cr, Cu, K, Li, Mg, Mo, Sb, Se, Sn, Sr, Ti, Tl, U, V, Zr). In contrast, Ferdinand Valley and other locations on the western side of the fjord had the lowest mean concentrations of most elements (18 out of 31; B, Ca, Cu, Cd, K, Li, P, Mg, Mo, Sb, Se, Sn, Sr, Ti, Tl, U, V, Zr). These findings highlight the significant influence of glacial processes on the elemental composition of soils within the region. The meltwater flow originating from glaciers in the sampled valleys contributes to the local element load, while the loss of glacier mass is associated with decreased element concentrations within these valleys. These results underscore the complexity of element distribution in the study area and emphasize the necessity for continuous monitoring efforts in this unique and environmentally sensitive region.

The Cenozoic spatiotemporal exhumation of the SE Tibetan Plateau: insight from the data mining and modeling of low-temperature thermochronology

Introduction: The SE Tibetan Plateau is distinct from other margins due to its high elevation, long wavelength, and low relief. A clear understanding of the Cenozoic exhumation history of this region is the key to understanding the special geomorphological process and the associated mechanisms. Previous thermochronological studies have either focused on vertical sections or horizontal variations in the local regions. However, the spatiotemporal exhumation pattern of the entire SE Tibetan Plateau is enigmatic.Methods: In this article, we have compiled 1,202 thermochronological data using joint kernel density estimation (KDE) and linear inversion approaches to address the exhumation process.Results: The results reveal that at least six episodes of rapid cooling have occurred since the Cenozoic, which include ∼61–58 Ma, 38–35 Ma, 32–23 Ma, 18–13 Ma, 11–6 Ma, and 4–3 Ma. Furthermore, the entire SE Tibetan Plateau underwent spatially inhomogeneous exhumation throughout the main episodes.Discussion: We infer that all cooling episodes may be attributed to the lateral extrusion and continuous convergence between the Indian and Eurasian continents. Meanwhile, climate changes (e.g., intensified Asian summer monsoon and glacial processes) have also played a non-negligible role in shaping the landscape since the Miocene. Our results will provide new insights into geodynamic mechanisms of the exhumation processes throughout the whole SE Tibetan Plateau since the Cenozoic.