Holocene sediment budget for wave-dominated Moruya coastline, southeastern Australia: sediment sources, transport and embayment interconnectivity

2021 ◽  
Author(s):  
Thomas Oliver ◽  
Toru Tamura ◽  
Brendan Brooke ◽  
Andrew Short ◽  
Michael Kinsela ◽  
...  
Keyword(s):  
Late Holocene ◽  
Accumulation Rate ◽  
Average Rate ◽  
Sediment Budget ◽  
Carbonate Content ◽  
Sediment Sources ◽  
Sediment Budgets ◽  
Sand Drift ◽  
Length Changes ◽  
Shoreline Progradation

<p>Sediment budgets on wave-dominated coastlines are important in understanding shoreline behaviour. Coastal sediment compartments provide a means to investigate sediment budgets over a range of time and space scales. This study reconstructs the sediment budget over the mid- to late- Holocene for a secondary coastal compartment on the New South Wales (NSW) south coast ~26 km in length and containing five adjacent but discrete barriers: Barlings Beach, Broulee Beach, Bengello Beach, Moruya Heads Beach and Pedro Beach. Building upon existing morphostratigraphic studies in this region, a new set of Optically Stimulated Luminescence (OSL) ages are reported for foredune ridge successions at previously un-dated sites. Additional Ground Penetrating Radar (GPR) transects complement earlier stratigraphic data, and topographic and bathymetric LiDAR datasets capture the morphology of subaerial coastal deposits and the inner shelf. The results demonstrate two different sediment sources promoting shoreline progradation and coastal barrier construction. A quartz-rich sand, transported onshore from the shoreface as it evolved towards equilibrium, dominates the barrier sequences. Skeletal carbonate sand augmented the quartz sand supply for the northern Barlings and Broulee beaches after ~3000 years ago. Shoreline progradation at Bengello Beach was steady throughout the mid-to late- Holocene. Bengello Beach contains the largest volume of Holocene sand and accreted at an average rate of 3.1 m<sup>3</sup>/m/yr (for the current shoreline length). Changes in sediment accumulation rate has occurred for the other barrier systems as their shorelines prograded resulting in changes to their alongshore interconnectivity. Rapid infilling of the Pedro Beach embayment by ~4000 years ago initiated headland bypassing northwards to Moruya Heads Beach which only then commenced progradation. In contrast, as Broulee and Bengello Beaches prograded, a tombolo formed in the lee of Broulee Headland which restricted northward sand drift into the Broulee embayment. As these once continuous shorelines became two, a marked increase in skeletal carbonate content at Broulee occurred attesting to shoreline separation and independence of sediment budget. This study emphasises the importance of quantifying the long-term temporal variability in sediment budget and embayment interconnectivity in order to better understand shoreline response to contemporary anthropogenic influences and changing boundary conditions such as sea level and wave climate.</p>

Tree line shifts, changing vegetation assemblages and permafrost dynamics on Galdhøpiggen (Jotunheimen, Norway) over the past ~4400 years

The Holocene ◽  
2021 ◽  
pp. 095968362110665
Author(s):  
Helen Hallang ◽  
Cynthia A Froyd ◽  
John F Hiemstra ◽  
Sietse O Los
Keyword(s):  
Scots Pine ◽  
Late Holocene ◽  
Accumulation Rate ◽  
Climatic Changes ◽  
Climatic Conditions ◽  
Tree Line ◽  
Peat Core ◽  
Modern Pollen ◽  
Modern Analogue ◽  
Downy Birch

An environmental reconstruction based on palynological evidence preserved in peat was carried out to examine late-Holocene alpine tree line dynamics in the context of past climatic changes on Galdhøpiggen (Jotunheimen, southern Norway). We analysed a peat core taken from a mire at the present-day tree line (1000 m a.s.l.), c. 450 m downslope from the lower limit of sporadic permafrost. We adopted a combination of commonly used indicators of species’ local presence to reconstruct past vegetation assemblages, such as the relative pollen abundance (%), pollen accumulation rate (PAR), and presence of indicator species. Additionally, fossil pollen from the peat sequence was compared to modern pollen from a surface moss polster to establish a modern analogue. The results were compared with studies covering the late-Holocene climatic changes in the area. The reconstruction demonstrates that a pine-dominated woodland reached above the present-day tree line at c. 4300 cal. yr BP, suggesting a warmer climate suitable for Scots pine ( Pinus sylvestris) growth at this altitude. Scots pine retreated to lower altitudes between c. 3400 and 1700 cal. yr BP, accompanied by the descent of the low-alpine shrub-dominated belt, in response to cooling climatic conditions. The colder period covered c. 1700–170 cal. yr BP, and an open downy birch ( Betula pubescens) woodland became widespread at 1000 m a.s.l., whilst pine remained sparse at this altitude. From c. 170 cal. yr BP onwards, warming allowed pine to re-establish its local presence alongside downy birch at 1000 m a.s.l.

scholarly journals Erosion assessment in the middle Kali Gandaki (Nepal): A sediment budget approach

2013 ◽  
Vol 46 ◽  
Author(s):  
Monique Fort ◽  
Etienne Cossart
Keyword(s):  
Drainage Basin ◽  
Sediment Budget ◽  
Mountain Range ◽  
Primary Concern ◽  
Stream Power ◽  
Sediment Budgets ◽  
Relative Chronology ◽  
Wide Range ◽  
History Of

Active mountains supply the largest sediment fluxes experienced on earth. At mountain range scale, remote sensing approaches, sediments provenance or stream power law analyses, collectively provide rough long-term estimates of total erosion. Erosion is indeed controlled by rock uplift and climate, hence by a wide range of processes (detachment, transport and deposition), all operating within drainage basin units, yet with time and spatial patterns that are quite complex at local scale. We focus on the Kali Gandaki valley, along the gorge section across the Higher Himalaya (e.g. from Kagbeni down to Tatopani). Along this reach, we identify sediment sources, stores and sinks, and consider hillslope int eractions with valley floor, in particular valley damming at short and longer time scales, and their impact on sediment budgets and fluxes. A detailed sediment budget is presented, constrained by available dates and/or relative chronology, ranging from several 10 kyr to a few decades. Obtained results span over two orders of magnitude that can best be explained by the type and magnitude of erosional processes involved. We show that if large landslides contribute significantly to the denudation history of active mountain range, more frequent medium to small scales landslides are in fact of primary concern for Himalayan population.

Recent Dynamics of Subarctic Dunes as Determined by Tree-Ring Analysis of White Spruce, Hudson Bay, Québec

1992 ◽  
Vol 38 (3) ◽  
pp. 316-330 ◽  
Author(s):  
Pierre Marin ◽  
Louise Filion
Keyword(s):  
Tree Ring ◽  
Migration Rate ◽  
Accumulation Rate ◽  
Average Rate ◽  
Sand Dunes ◽  
White Spruce ◽  
Growth Patterns ◽  
Cold Climate ◽  
Eastern Coast ◽  
Hudson Bay

AbstractThe radial-growth patterns of white spruce were studied on a number of trees growing in subarctic dunes along the eastern coast of Hudson Bay to calculate the rates of accumulation, erosion, and migration of cold-climate sand dunes. The average rate of sand accumulation in sheltered dunes (forest sites) was 2.5 to 3.3 cm/yr, which is two to three times lower than in highly exposed dunes with a rate of sedimentation of 7.65 cm/yr. The average erosion rate was 1.4–1.7 cm/yr, about two times lower than the accumulation rate. The migration rate of sheltered dunes was 18 to 30 cm/yr, three to five times lower than for an exposed dune which advanced at a speed of 74 cm/yr. This migration rate established for highly exposed dunes in the Subarctic with tree-ring methods is about 10 times lower than that established for a barchan in the Sahara with other methods.

Unstable Climate Oscillations during the Late Holocene in the Eastern Bransfield Basin, Antarctic Peninsula

2002 ◽  
Vol 58 (3) ◽  
pp. 234-245 ◽  
Author(s):  
Boo-Keun Khim ◽  
Ho Il Yoon ◽  
Cheon Yun Kang ◽  
Jang Jun Bahk
Keyword(s):  
Antarctic Peninsula ◽  
Late Holocene ◽  
Accumulation Rate ◽  
Silica Content ◽  
Climatic Conditions ◽  
Ice Age ◽  
Geochemical Data ◽  
Sediment Properties ◽  
Bransfield Basin ◽  
Distinct Features

AbstractCore A9-EB2 from the eastern Bransfield Basin, Antarctic Peninsula, consists of pelagic (diatom ooze-clay couplets and bioturbated diatom ooze) and hemipelagic (bioturbated mud) sediments interbedded with turbidites (homogeneous mud and silt–clay couplets). The cyclic and laminated nature of these pelagic sediments represents alternation between the deposition of diatom-rich biogenic sediments and of terrigenous sediments. Sediment properties and geochemical data explain the contrasting lamination, with light layers being finer-grained and relatively rich in total organic carbon and biogenic silica content. Also, the high-resolution magnetic susceptibility (MS) variations highlight distinct features: high MS values coincide with clastic-rich sections and low MS values correspond to biogenic sections. The chronology developed for core A9-EB2 accounts for anomalous ages associated with turbidites and shows a linear sedimentation rate of approximately 87 cm/103 yr, which is supported by an accumulation rate of 80 cm/103 yr calculated from 210Pb activity. The late Holocene records clearly identify Neoglacial events of the Little Ice Age (LIA) and Medieval Warm Period (MWP). Other unexplained climatic events comparable in duration and amplitude to the LIA and MWP events also appear in the MS record, suggesting intrinsically unstable climatic conditions during the late Holocene in the Bransfield Basin of Antarctic Peninsula.

scholarly journals Late-Holocene climate evolution at the WAIS Divide site, West Antarctica: bubble number-density estimates

2011 ◽  
Vol 57 (204) ◽  
pp. 629-638 ◽  
Author(s):  
J.M. Fegyveresi ◽  
R.B. Alley ◽  
M.K. Spencer ◽  
J.J. Fitzpatrick ◽  
E.J. Steig ◽  
...  
Keyword(s):  
Late Holocene ◽  
Accumulation Rate ◽  
Ice Core ◽  
Temperature History ◽  
Flow Density ◽  
Number Density ◽  
West Antarctica ◽  
Surface Cooling ◽  
Bubble Number ◽  
Bubble Number Density

AbstractA surface cooling of ∼1.7°C occurred over the ∼two millennia prior to ∼1700 CE at the West Antarctic ice sheet (WAIS) Divide site, based on trends in observed bubble number-density of samples from the WDC06A ice core, and on an independently constructed accumulation-rate history using annual-layer dating corrected for density variations and thinning from ice flow. Density increase and grain growth in polar firn are both controlled by temperature and accumulation rate, and the integrated effects are recorded in the number-density of bubbles as the firn changes to ice. Number-density is conserved in bubbly ice following pore close-off, allowing reconstruction of either paleotemperature or paleo-accumulation rate if the other is known. A quantitative late-Holocene paleoclimate reconstruction is presented for West Antarctica using data obtained from the WAIS Divide WDC06A ice core and a steady-state bubble number-density model. The resultant temperature history agrees closely with independent reconstructions based on stable-isotopic ratios of ice. The ∼1.7°C cooling trend observed is consistent with a decrease in Antarctic summer duration from changing orbital obliquity, although it remains possible that elevation change at the site contributed part of the signal. Accumulation rate and temperature dropped together, broadly consistent with control by saturation vapor pressure.

Late-Holocene evolution of a coastal lagoon in the Gulf of Lions (South of France)

2010 ◽  
Vol 181 (1) ◽  
pp. 27-36 ◽  
Author(s):  
Pierre Sabatier ◽  
Laurent Dezileau ◽  
Mickaël Barbier ◽  
Olivier Raynal ◽  
Johanna Lofi ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Coastal Lagoon ◽  
Late Holocene ◽  
Accumulation Rate ◽  
Sediment Cores ◽  
Coastal System ◽  
Gulf Of Lions ◽  
Marine Sand ◽  
Radiocarbon Data

Abstract The central part of the Gulf of Lions shoreline is characterized by many coastal wetlands that resulted from the interaction between a process of shoreline regularization by migrations of littoral barriers and a slow filling of the back-barrier areas by the riverine and marine inputs. Analyses of Late-Holocene deposits with a very high-resolution multi-proxy study of two sediment cores, allow us to reconstruct the evolution of this coastal system. Two main Holocene sediment units are identified overlying a Pliocene carbonate continental formation. The lower unit consists of sandy and pebbly marine sediments deposited around 7800 B.P., during the final stand of the last sea level rise. Just above, the upper unit displays lagoonal grey clay silts with shells and some intercalated layers of silty sands related to paleostorm events. The age model was established from radiocarbon dating, for the oldest part of the core. Over the last century, sedimentation rates were calculated using the CFCS 210Pb model, together with 137Cs data. Radiocarbon data show an increase in the accumulation rate from the base to the top of cores. Marine sand units related to the last transgressive deposit allow to refine the curve of Holocene post-glacial sea level rise. Sedimentological and faunal analyses associated with chronological data provide a means for reconstructing the Late-Holocene paleoenvironments along this part of the coast and suggest that the final closure of the coastal lagoon by the sandy barrier occurred at around 730 ± 120 yr cal B.P. The beginning of this closure, together with the progradation of the coastal plain, could be responsible for the decline in economic activity of the Lattara harbour during the Roman period.

Holocene history of forest trees in southern Ontario

1987 ◽  
Vol 65 (9) ◽  
pp. 1792-1801 ◽  
Author(s):  
K. D. Bennett
Keyword(s):  
Acer Saccharum ◽  
Pinus Banksiana ◽  
Late Holocene ◽  
Accumulation Rate ◽  
Pinus Strobus ◽  
Fagus Grandifolia ◽  
Forest Trees ◽  
Southern Ontario ◽  
History Of ◽  
Available Information

Three new Holocene pollen percentage and accumulation rate diagrams for southern Ontario are presented. They greatly increase the available information on the history of the area's forest trees and permit a discussion of the competitive interactions that have brought about the forest pattern seen today. In the earliest Holocene, the forests were dominated by Picea, which was replaced by first Pinus banksiana–resinosa and then Pinus strobus. In extreme southern Ontario, Pinus strobus was replaced by Acer saccharum and Fagus grandifolia, but in the area east of Georgian Bay, Tsuga canadensis became the dominant, and near Mattawa, Betula (probably lutea). Late Holocene stability of forests is considered to be a function of the lack of taxa better able to compete than those already present.

scholarly journals Linking the Variation of Sediment Accumulation Rate to Short Term Sea-Level Change Using Cyclostratigraphy: Case Study of the Lower Berriasian Hemipelagic Sediments in Central Tunisia (Southern Tethys)

2021 ◽  
Vol 9 ◽  
Author(s):  
Hamdi Omar ◽  
Anne-Christine Da Silva ◽  
Chokri Yaich
Keyword(s):  
Magnetic Susceptibility ◽  
Accumulation Rate ◽  
Sediment Accumulation ◽  
Sediment Accumulation Rate ◽  
Carbonate Content ◽  
Milankovitch Cycles ◽  
Central Tunisia ◽  
Level Change ◽  
Two Samples ◽  
Lower Berriasian

High-resolution magnetic susceptibility and % CaCO3 records (5 to 10 cm sampling interval) are used to track astronomical cycles from a Lower Berriasian record from central Tunisia. Six hundred and twenty two samples were measured for magnetic susceptibility and carbonate content as paleoclimate proxies for the detection of potential Milankovitch cycles. Elemental data using X-Ray fluorescence analyses was acquired from 19 samples to prove the reliability of the MS signal on recording the past paleoclimatic changes. We performed multiple spectral analyses and statistical techniques on the magnetic susceptibility signal, such as Multi-taper Method, Evolutive Harmonic Analysis, Correlation Coefficient, Time-optimization, and Average Spectral Misfit to obtain an optimal astronomical model. The application of these spectral analysis techniques revealed a pervasive dominance of E405-kyr and e100-kyr cycles showing that the climate turnover across the early Berriasian—middle Berriasian seems to had been governed by the long and short orbital eccentricity cycles. The identification of Milankovitch cycles in the record also allowed to propose a floating astronomical timescale of the studied section, with ~4 long eccentricity cycles (E405) extracted, which points to a duration estimate of ~1.6 Myr with an average sediment accumulation rate (SAR, after compaction) of 2.77 cm/kyr. The inferred floating ATS was tuned to the La2004 astronomical solution. In addition, we applied the DYNOT and ρ1 methods for seal-level change modeling to reconstruct a local eustatic profile which matches the previously published local and global eustatic charts.

scholarly journals Sediment Budget and Geomorphological Evolution of the Estuarine Dune-Beach System on Three Nourished Beaches, Delaware Bay, New Jersey

Geosciences ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 16 ◽  
Author(s):  
Norbert Psuty ◽  
Katherine Ames ◽  
Andrea Habeck ◽  
Glenn Liu
Keyword(s):  
New Jersey ◽  
Temporal Evolution ◽  
Sediment Budget ◽  
Delaware Bay ◽  
Volumetric Change ◽  
Sediment Budgets ◽  
Digital Elevation ◽  
Seasonal Monitoring ◽  
Geomorphological Evolution ◽  
Dune Crest

Beach nourishment was applied at three fetch-restricted sites along the estuarine margin of Delaware Bay, New Jersey. Evaluation of geomorphological performance of the nourishment project was conducted through seasonal monitoring to track linear features (shoreline, dune crest, peat edge) and to create digital elevation models (DEMs). Comparisons of the DEMs yielded sediment budgets of the updrift, fill area, and downdrift zones as well as the spatial and temporal evolution of the tidal flat, beach, and dune features within the zones. Through four years, Moore’s Beach lost all of the emplaced fill as well as an additional −5446 m3 from the fill area. The shoreline position shifted inland −12.78 m, and the foredune crest shifted inland −9.23 m. The fill area at Pierce’s Point lost all of the fill and an additional −3810 m3. The shoreline and dune crest shifted inland −7.35 m and −1.17 m, respectively. The Reed’s Beach study area benefited from beach fill updrift that more than offset the losses in the fill area, a net gain of 2107 m3. There was a major contrast in volumetric change between the updrift and downdrift portions. Sediment budget calculations established alongshore transport was an important factor in the fetch-restricted estuarine environment driving the variable geomorphological responses in the updrift, fill, and downdrift zones.

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