A 210Pb sediment budget and granulometric record of sediment fluxes in a subarctic deltaic system: The Great Whale River, Canada

Hülse, Peter; Bentley, Samuel J.

doi:10.1016/j.ecss.2012.05.019

Cited by 19 publications

(14 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A solution was created by adding 2 ml of NaPO 3 and 5 ml of H 2 O 2 , placed in the vortex and then left to sit for 30 min, followed by ca 10 h in a hot bath. This preparation method was modified from that of Hülse & Bentley (). Samples were then analyzed by a Beckman‐Coulter LS 1320W Laser Diffraction Particle Size Analyzer (Beckman Coulter Inc., Brae, CA, USA) at Louisiana State University.…”

Section: Methodsmentioning

confidence: 99%

Grain‐size variability within a mega‐scale point‐bar system, False River, Louisiana

et al. 2018

View full text Add to dashboard Cite

Point bars formed by meandering river systems are an important class of sedimentary deposit and are of significant economic interest as hydrocarbon reservoirs. Standard point‐bar models of how the internal sedimentology varies are based on the structure of small‐scale systems with little information about the largest complexes and how these might differ. Here a very large point bar (>25·0 m thick and 7·5 × 13·0 km across) on the Mississippi River (USA) was examined. The lithology and grain‐size characteristics at different parts of the point bar were determined by using a combination of coring and electrical conductivity logging. The data confirm that there is a general fining up‐section along most parts of the point bar, with a well‐defined transition from massive medium‐grained sands below about 9 to 11 m depth up into interbedded silts and fine–medium sand sediment (inclined heterolithic strata). There is also a poorly defined increase in sorting quality at the transition level. Massive medium sands are especially common in the region of the channel bend apex and regions upstream of that point. Downstream of the meander apex, there is much less evidence for fining up‐section. Finer sediment accumulated more readily after the establishment of a compound bar in the later stages of construction, at the terminal apex and in the bar tail. This work implies that the best reservoir sands are likely to be located in the centre of the point bar, deposited in a simple bar system. Reservoir quality decreases towards the bar edge. The early‐stage channel plug is largely composed of coarsening‐upward cycles of silt to clay and is dominated by clay and clayey silt material with poor reservoir characteristics.

show abstract

Section: Methodsmentioning

confidence: 99%

Grain‐size variability within a mega‐scale point‐bar system, False River, Louisiana

et al. 2018

View full text Add to dashboard Cite

show abstract

“…Many studies using sediment cores, mostly in coastal sectors of the bay, successfully yielded paleo-environmental reconstructions (Jenner and Piper 2002;Ladouceur 2008;Haberzettl et al 2010). More recently, studies have focused on atmospheric and fluvial processes affecting modern sedimentation to better understand the sediment composition and sources (Hare et al 2008;Kuzyk et al 2008Kuzyk et al , 2009Kuzyk et al , 2010Hülse and Bentley 2012). For instances, Kuzyk et al (2008) showed evidences of temporal changes in the composition of terrigenous organic carbon (TOC) in Hudson Bay sediments and linked it to climate and the presence of ice.…”

Section: Introductionmentioning

confidence: 99%

“…During the late Holocene and particularly in recent decades, the coastal region on the eastern side of Hudson Bay has experienced significant variations in air temperature, precipitation, and sea ice cover duration, which have affected environments by increasing their primary production and causing rapid permafrost thaw (Allard and Seguin 1987;Payette et al 2004;Ladouceur 2008;Bhiry et al 2011;Jolivel and Allard 2013). However, sedimentary studies attempting to decipher a marine record of geomorphological and ecological changes in the watershed are almost absent, one exception being research near the mouth of Rivière de la Grande Baleine reported by Hülse and Bentley (2012).…”

Section: Introductionmentioning

confidence: 99%

Climate change and recent sedimentation in Nastapoka Sound, eastern coast of Hudson Bay

2015

View full text Add to dashboard Cite

In an attempt to determine to what extent the impact of recent climate changes that occurred east of Hudson Bay, including important reduction of areas in permafrost, had on the coastal marine environment, a series of shallow cores were extracted from the seabed off the mouth of the Sheldrake River, in Nastapoka Sound. A total of 25 cores were taken in April 2009 from the ice cover. A preliminary seafloor map was first done to help in the selection of the coring sites. Nastapoka Sound has a complex subaqueous relief, formed of asymmetric ridges and deep basins. After preliminary sedimentological analyses, six of the cores were selected for physical and chronological analyses (14 C, 210 Pb, and 137 Cs dating); among them, three were selected for elemental (C, N, OC/TN) and isotopic (␦ 13 C, ␦ 15 N) analyses to identify sedimentary organic matter sources. Sedimentation processes are complex and are primarily driven by bottom currents. This is confirmed by the absence of a clay fraction in several cores, some erosion surfaces in a few cores, and the presence of comet-like mark features on the seafloor. The highest sedimentation rates are found near the coast of the province of Quebec and Gillies Island and the lowest ones occur in the deep depocenters. Isotopic and elemental analyses reveal that Nastapoka Sound is an area of mixing between marine and terrestrial inputs and can be compared to an estuarine system similar to nearby Lac Guillaume-Delisle. Those conditions altogether make it difficult to extract a perfectly clear signal of climate change in the recent sediment record. However, the downcore application of a simple two end-member mixing model to measured ␦ 13 C values strongly suggests that the fraction of sedimentary organic matter from terrestrial sources increased by 30% since about the middle of the Little Ice Age. This trend accelerated at the end of the 20th century. Rapid permafrost decay in adjacent river catchments is likely one source for this terrestrial carbon. However, it cannot be distinguished from other potential sources that are also related to environmental changes such as increase in primary productivity both on land, where peatlands, shrubs, and forest are expanding, and at sea, where sea ice cover duration is diminishing. Résumé : Dans le but de déterminer l'étendue des impacts des changements climatiques récents qui ont eu lieu à l'est de la baie d'Hudson, incluant une réduction significative des secteurs de pergélisol, sur l'environnement marin côtier, une série de carottes peu profondes a été prélevée du lit marin à l'embouchure de la rivière Sheldrake, dans le détroit de Nastapoka. Un total de 25 carottes a été prélevé à partir de la couverture glaciaire en avril 2009. Une carte préliminaire du plancher océanique a été dressée afin d'aider à choisir les sites de prélèvement des carottes. Le détroit de Nastapoka a un relief subaquatique complexe, formé de crêtes asymétriques et de bassins profonds. Après des analyses sédimentologiques préliminaires, six carottes ont été choisies pou...

show abstract

“…Warming has been linked to changes in the type of OC delivered to coastal Arctic and subarctic environments over the last few decades through (i) alteration in river hydrology (e.g., Lammers et al 2001;Roberts et al 2012), (ii) thawing of permafrost (e.g., Goni et al 2005;Mann et al 2015), and (iii) longer open water season that favours greater fetch and storm surges (Lantuit et al 2012), all of which could increase coastal and river bank erosion. In eastern Hudson Bay, an inferred offshore shift in sediment deposition during the past ϳ150 years determined from 210 Pb and 137 Cs sediment radiochemistry was attributed to a more energetic marine environment as a result of decreased sea-ice coverage (Hülse and Bentley 2012). However, in contrast to eastern Hudson Bay, where the ice-free season has already lengthened by several weeks in recent decades, in the Lake Melville area of Labrador, recent seaice timing, duration, and extent are still most strongly connected to climate variability, particularly the North Atlantic Oscillation (Finnis and Smith 2016).…”

Section: Inferences Of Change In the Sources Of Organic Carbon To Thementioning

confidence: 99%

Sources and accumulation of sediment and particulate organic carbon in a subarctic fjard estuary:²¹⁰Pb,¹³⁷Cs, and δ¹³C records from Lake Melville, Labrador

et al. 2017

View full text Add to dashboard Cite

Abstract:The sources and distribution of sediment and particulate organic carbon (OC) to Lake Melville, Labrador, were characterized to better understand impacts from climate and hydrological changes to the system. Mass accumulation rates (MARs) across the Lake Melville System (LMS) were established from 15 sediment cores collected in 2013 and 2014 by fitting excess 210 Pb ( 210 Pb ex ) profiles to a two-layer advection-diffusion model. MARs, validated using 137 Cs, varied between 0.04 and 0.41 g cm −2 a −1 , and overall decreased with increasing distance from the Churchill River, which drains into Goose Bay, a western extension of Lake Melville. The Churchill River is the greatest source of sediment to the system, but surprisingly, MARs were greatest in western Lake Melville rather than Goose Bay, reflecting the contribution of fine material carried eastward in the Churchill River plume and inputs from nearby tributaries. A comparison of 137 Cs and 210 Pb ex inventories to expected atmospheric fallout (1.5 and 23.6 disintegrations per minute (dpm) cm −2 , respectively) in sediment across the LMS suggests particles are largely sourced from the watershed. In eastern Lake Melville, elevated 210 Pb ex inventories and marine OC point to particle scavenging of dissolved 210 Pb from inflowing marine water. A transient tracer mixing model was used to determine the depth in each core where >90% of sediment was deposited before and after hydroelectric development at Churchill Falls (1970) and applied to down-core profiles of OC and organic carbon isotopes (␦ 13 C org ). We observed a significant increase of terrestrial OC to Lake Melville post 1970, which we interpret as change from climate or hydrology of the Churchill River.Résumé : Les sources et la répartition des sédiments et du carbone organique (CO) particulaire du lac Melville, au Labrador, ont été caractérisées pour mieux comprendre les impacts des changements climatiques et hydrologiques sur ce système. Les taux d'accumulation massique (TAM) à l'échelle du système du lac Melville (SLM) ont d'abord été établis à la lumière de 15 carottes de sédiments prélevées en 2013 et 2014, en calant les profils de 210 Pb excédentaire ( 210 Pb ex ) sur un modèle de advection-diffusion à deux couches. Les TAM, validés en utilisant le 137 Cs, vont de 0,04 à 0,41 g cm −2 a −1 , mais diminuent en s'éloignant de la rivière Churchill, qui se déverse dans la baie Goose, un prolongement vers l'ouest du lac Melville et la plus importante source de sédiments entrant dans le système. Étonnement, les TAM sont les plus élevés dans la partie occidentale du lac Melville, reflétant les apports de matériaux fins transportés vers l'est dans le panache de la rivière Churchill et de plus petits affluents situés à proximité. Une comparaison des inventaires de 137 Cs et de 210 Pb ex aux retombées atmosphériques attendues (1,5 et 23,6 désin-tégrations par minute (dpm) cm −2 , respectivement) dans les sédiments à l'échelle du SLM porte à croire que les particules proviennent en majeure partie du ba...

show abstract

A 210Pb sediment budget and granulometric record of sediment fluxes in a subarctic deltaic system: The Great Whale River, Canada

Cited by 19 publications

References 53 publications

Grain‐size variability within a mega‐scale point‐bar system, False River, Louisiana

Grain‐size variability within a mega‐scale point‐bar system, False River, Louisiana

Climate change and recent sedimentation in Nastapoka Sound, eastern coast of Hudson Bay

Sources and accumulation of sediment and particulate organic carbon in a subarctic fjard estuary:²¹⁰Pb,¹³⁷Cs, and δ¹³C records from Lake Melville, Labrador

Contact Info

Product

Resources

About

A 210Pb sediment budget and granulometric record of sediment fluxes in a subarctic deltaic system: The Great Whale River, Canada

Cited by 19 publications

References 53 publications

Grain‐size variability within a mega‐scale point‐bar system, False River, Louisiana

Grain‐size variability within a mega‐scale point‐bar system, False River, Louisiana

Climate change and recent sedimentation in Nastapoka Sound, eastern coast of Hudson Bay

Sources and accumulation of sediment and particulate organic carbon in a subarctic fjard estuary:210Pb,137Cs, and δ13C records from Lake Melville, Labrador

Contact Info

Product

Resources

About

Sources and accumulation of sediment and particulate organic carbon in a subarctic fjard estuary:²¹⁰Pb,¹³⁷Cs, and δ¹³C records from Lake Melville, Labrador