scholarly journals The Geology of the Bras d'Or Lakes, Nova Scotia

2002 ◽  
Vol 42 (1) ◽  
Author(s):  
J. Shaw ◽  
D.J.W. Piper ◽  
R.B. Taylor
Keyword(s):  
Sea Level ◽  
Sediment Cores ◽  
Early Holocene ◽  
Multibeam Bathymetry ◽  
Eastern Cape ◽  
River Channels ◽  
Relative Sea Level ◽  
Il Y A ◽  
Ice Retreat ◽  
Seismic Reflection Profiles

The evolution of the Bras d’Or Lakes since the retreat of the last ice sheets c. 15 ka (thousands of radiocarbon years before present, where present is defined as 1950) is inferred from multibeam bathymetry, seismic reflection profiles, and sediment cores. The thickness of stratified sediment in the Lakes overlying glacial till shows that there was a step-like retreat of ice towards a late ice centre in the western part of the Bras d’Or Lakes. As ice retreated, a lake formed in the area of the modern Bras d’Or Lakes and probably drained through Little Bras d’Or Channel. Ice retreat and sea level change on the continental shelf off south-eastern Cape Breton are inferred from multibeam bathymetry that shows proglacial subaerial river channels and suggests that sea level was perhaps 50 m lower than present about 15 ka. Relative sea level appears to have risen subsequently, so that marine conditions existed in Bras d’Or Lakes basin at 10 to 9 ka. Sea level may have risen to -15 m (below modern sea level)before falling again in the early Holocene. This falling early Holocene relative sea level resulted in the creation of freshwater lakes, with a prominent erosion surface at -25 m marking the lake level in some areas. Rising sea level then resulted in a return to marine conditions in the Lakes by 4 to 5 ka. L’évolution des lacs Bras d’Or depuis le retrait des dernières nappes glaciaires il y a 15 000 ans se révèle par la bathymétrie multifaisceaux, les profils de réflexion sismique et les carottes de sédiments. L’épaisseur des sédiments stratifiés dans le till sus-jacent des lacs démontre qu’il y a eu un retrait en escaliers des glaces vers un centre fini-glaciaire situé dans la partie occidentale des lacs Bras d’Or. Les eaux, libérées lors du retrait des glaces, s’échappèrent probablement via le canal du Little Bras d’Or pour former un lac dans le lit actuel des lacs Bras d’Or. Le retrait des glaces et les changements du niveau de la mer sur la plateforme continentale au sud-est de Cap-Breton sont mis en évidence par la bathymétrie multifaisceaux, qui montre des lits de rivière sub-aériens proglaciaires et indiqueque le niveau de la mer se trouvait peut-être à 50 m plus bas qu’aujourd’hui il y a environ 15 milles d’années. La hausse du niveau de la mer depuis cette époque a provoqué l’inondation des lacs Bras d’Or ancestraux il y a de 9 à 10 milles d’années, et le niveau des eaux aurait atteint -15 m avant de chuter au début de l’Holocène. Cette chute relative du début de l’Holocène a résulté en la création de lacs pour une seconde fois, avec une importante surface d’érosion à -25 m qui marque le niveau des eaux dans certaines zones. Ces lacs ont été finalement inondés par la mer il y a de 4 à 5 milles d’années.

scholarly journals Early Holocene sea-level changes in Øresund, southern Scandinavia

1969 ◽  
Vol 26 ◽  
pp. 29-32
Author(s):  
Ole Bennike ◽  
Martin Skov Andreasen ◽  
Jørn Bo Jensen ◽  
Matthias Moros ◽  
Nanna Noe-Nygaard
Keyword(s):  
Sea Level ◽  
Sediment Cores ◽  
Early Holocene ◽  
Sea Level Changes ◽  
Relative Sea Level ◽  
Data Set ◽  
The North ◽  
Global Sea Level ◽  
The Baltic ◽  
Water Depths

The Baltic Sea and Kattegat are connected via three straits: Storebælt, Lillebælt and Øresund (Fig. 1). Øresund is the shallowest with a threshold around 7 m deep and increasing water depths to the north (Fig. 2). In the early Holocene, global sea-level rise led to reflooding of Øresund. It started in northern Øresund which was transformed into a fjord. However, so far the timing of the transgression has not been well determined, but sediment cores collected north of the threshold, at water depths of 12 to 20 m, and a new series of radiocarbon ages help to constrain this. As the relative sea level continued to rise, the threshold in Øresund was also flooded, and Øresund became a strait. In mid-Holocene time, the relative sea level rose until it was 4–5 m higher than at present, and low-lying areas around Øresund became small fjords. During the late Holocene, the relative sea level fell again. Part of the data set discussed here was presented by Andreasen (2005).

scholarly journals Neoglacial change of ice cover and the related response of the Earth's crust in West Greenland

1993 ◽  
Vol 159 ◽  
pp. 121-126
Author(s):  
A Weidick
Keyword(s):  
Spatial Distribution ◽  
Sea Level ◽  
Early Holocene ◽  
Relative Sea Level ◽  
West Greenland ◽  
Exact Data ◽  
Present Information ◽  
Long Time ◽  
Related Response ◽  
Inland Ice

The cooling trends of Neoglacial time caused re-formation of minor local glaciers and expansion of the Inland Ice margin. A consequence of this glacial reactivation in West Greenland was the conversion of an early Holocene glacio-isostatic emergence to Neoglacial submergence. Although the major trends of fluctuations of ice margins and relative sea level have been studied over a long time, exact data on the spatial distribution of Neoglacial changes of glacier load and relative sea level are still sparse. Present information points to a major conversion from emergence to submergence between 1000 and 3000 B.P., depending on location and the effect of superimposed secondary oscillations.

Holocene relative sea levels and coastal changes in the lower Cree valley and estuary, SW Scotland, U.K.

2002 ◽  
Vol 93 (4) ◽  
pp. 301-331 ◽  
Author(s):  
D. E. Smith ◽  
J. M. Wells ◽  
T. M. Mighall ◽  
R. A. Cullingford ◽  
L. K. Holloway ◽  
...  
Keyword(s):  
Sea Level ◽  
Early Holocene ◽  
Coastal Geomorphology ◽  
Sea Level Changes ◽  
Relative Sea Level ◽  
Sea Levels ◽  
Coastal Changes

ABSTRACTChanges in Holocene (Flandrian) relative sea levels and coastal geomorphology in the lower Cree valley and estuary, SW Scotland, are inferred from detailed morphological and stratigraphical investigations. A graph of relative sea level changes is proposed for the area. Rising relative sea levels during the early Holocene were interrupted at c. 8300–8600 14C years B.P.(c. 9400–9900 calibrated years B.P.), when an extensive estuarine surface was reached at c. −1 m O.D., after which a fluctuating rise culminated at c. 6100–6500 14C B.P. (c. 7000–7500 calibrated years B.P.) in a prominent shoreline and associated estuarine surface measured at 7·7–10·3 m O.D. A subsequent fall in relative sea level was followed by a rise to a shoreline at 7·8–10·1 m O.D., exceeding or reoccupying the earlier shoreline over much of the area after c. 5000 14C B.P. (c. 5,800 calibrated years B.P.), before relative sea level fell to a later shoreline, reached after c. 2900 14C B.P. (c. 3100 calibrated years B.P.) at 5·5–8·0 m O.D., following which relative sea levels fell, ultimately reaching present levels. During these changes, a particular feature of the coastline was the development of a number of barrier systems. The relative sea level changes identified are compared with changes elsewhere in SW Scotland and their wider context is briefly considered.

scholarly journals Developing detailed records of relative sea-level change using a foraminiferal transfer function: an example from North Norfolk, UK

2006 ◽  
Vol 364 (1841) ◽  
pp. 973-991 ◽  
Author(s):  
Robin J Edwards ◽  
B.P Horton
Keyword(s):  
Transfer Function ◽  
Sea Level ◽  
Transfer Functions ◽  
Sediment Cores ◽  
Sea Level Change ◽  
Relative Sea Level ◽  
Level Change ◽  
The North ◽  
Level Information ◽  
Coastal Deposits

This paper provides a brief overview of the transfer function approach to sea-level reconstruction. Using the example of two overlapping sediment cores from the North Norfolk coast, UK, the advantages and limitations of the transfer function methodology are examined. While the selected cores are taken from different sites, and display contrasting patterns of sedimentation, the foraminiferal transfer function distils comparable records of relative sea-level change from both sequences. These reconstructions are consistent with existing sea-level index points from the region but produce a more detailed record of relative sea-level change. Transfer functions can extract sea-level information from a wider range of sedimentary sub-environments. This increases the amount of data that can be collected from coastal deposits and improves record resolution. The replicability of the transfer function methodology, coupled with the sequential nature of the data it produces, assists in the compilation and analysis of sea-level records from different sites. This technique has the potential to bridge the gap between short-term (instrumental) and long-term (geological or geophysical) records of sea-level change.

Relative sea-level history from the Lambert Glacier region, East Antarctica, and its relation to deglaciation and Holocene glacier readvance

2005 ◽  
Vol 63 (1) ◽  
pp. 45-52 ◽  
Author(s):  
Elie Verleyen ◽  
Dominic A. Hodgson ◽  
Glenn A. Milne ◽  
Koen Sabbe ◽  
Wim Vyverman
Keyword(s):  
Sea Level ◽  
Late Holocene ◽  
East Antarctica ◽  
Relative Sea Level ◽  
Larsemann Hills ◽  
Melting Event ◽  
Ice Retreat ◽  
Vestfold Hills ◽  
A Site ◽  
Lambert Glacier

We present a relative sea-level (RSL) history, constrained by AMS radiocarbon-dated marine–freshwater transitions in isolation basins from a site adjacent to the Lambert Glacier, East Antarctica. The RSL data suggest an initial ice retreat between c. 15,370 and 12,660 cal yr B.P Within this period, meltwater pulse IA (mwp IA, between c. 14,600–14,200 and 14,100–13,700 cal yr B.P.) occurred; an exceptionally large ice melting event, inferred from far-field sea-level records. The RSL curve shows a pronounced highstand of approximately 8 m between c. 7570–7270 and 7250–6950 cal yr B.P. that is consistent with the timing of the RSL highstand in the nearby Vestfold Hills. This is followed by a fall in RSL to the present. In contrast to previous findings, the isolation of the lakes in the Larsemann Hills postdates the isolation of lakes with similar sill heights in the Vestfold Hills. An increase in RSL fall during the late Holocene may record a decline in the rate of isostatic uplift in the Larsemann Hills between c. 7250–6950 and 2847–2509 cal yr B.P., that occurred in response to a documented mid-Holocene glacier readvance followed by a late-Holocene retreat.

Intertidal peat deposits and early Holocene relative sea-level changes, Traigh Eileraig, Isle of Coll, Scottish Hebrides

2001 ◽  
Vol 37 (1) ◽  
pp. 11-18 ◽  
Author(s):  
A. G. Dawson ◽  
S. Dawson ◽  
T. M. Mighall ◽  
G. Waldmann ◽  
A. Brown ◽  
...  
Keyword(s):  
Sea Level ◽  
Early Holocene ◽  
Sea Level Changes ◽  
Relative Sea Level ◽  
Peat Deposits

Late Weichselian Glacier Retreat in Kongsfjorden, West Spitsbergen, Svalbard

1992 ◽  
Vol 37 (2) ◽  
pp. 139-154 ◽  
Author(s):  
Scott J. Lehman ◽  
Steven L. Forman
Keyword(s):  
Sea Level ◽  
Ice Sheet ◽  
Younger Dryas ◽  
Atlantic Region ◽  
Relative Sea Level ◽  
Stratigraphic Record ◽  
Ice Retreat ◽  
Late Weichselian ◽  
West Spitsbergen ◽  
Rule Out

AbstractThe chronology of Late Weichselian to Holocene deglaciation of Kongsfjorden, west Spitsbergen has been reconstructed based on the geomorphic and stratigraphic record of ice retreat, relative sea-level relationships, and 14C dating of associated marine organic materials. The seaward extent of glacial drift and fjord bathymetry constrain a secure reconstruction for the ice sheet near the mouth of the fjord at ca. 13,000 yr B.P., but do not rule out the possibility that more extensive glaciation was achieved earlier during the Late Weichselian. Regional shoreline relations, rates of emergence, and radiocarbon dating of foraminifera deposited just above till indicate that deglaciation occurred in two steps: one beginning during or just prior to the Late Weichselian Marine Limit phase at 13,000–12,000 yr B.P. and another beginning at 10,000–9500 yr B.P. The fjord was completely deglaciated by 9440 ± 130 yr B.P. A period of stable relative sea level began 10,700 yr B.P. and ended between 10,000 and 9500 yr B.P., which we take to indicate renewed glacial loading during the Younger Dryas. Glacier readvance within Kongsfjorden at this time was diminutive, suggesting that most of the Younger Dryas ice-sheet growth was confined to the eastern part of the archipelago and/or to the Barents Shelf. The two-step deglaciation of Kongsfjorden occurred during intervals of accelerated global ice-sheet melting and rapid oceanic and atmospheric warming in more temperate latitudes of the circum-Atlantic region. This coincidence most likely resulted from contemporaneous increases in the poleward transport of oceanic heat.

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