Postglacial relative sea-level change, Port au Port area, west Newfoundland

1985 ◽  
Vol 22 (7) ◽  
pp. 1039-1047 ◽  
Author(s):  
I. A. Brookes ◽  
D. B. Scott ◽  
J. H. McAndrews
Keyword(s):  
Sea Level ◽  
Late Holocene ◽  
High Water ◽  
Relative Sea Level ◽  
Radiocarbon Dates ◽  
Ice Load ◽  
Bay Area ◽  
Port Area ◽  
Minimum Age ◽  
Late Wisconsinan

We first report pollen and foraminifera analyses and radiocarbon dates from two cores taken from salt-marsh deposits bordering Port au Port Bay, southwestern Newfoundland. Results show that relative sea level (RSL) stood at 2.8 m below present higher high-water level (HHWL) at 2770 ± 300 years BP and at −1.8 m at 2365 ± 175 years BP at the core sites. They permit calculation of a rate of late Holocene RSL change from western Newfoundland. We then report other available dates bearing on the earlier RSL record of this area.A date of 5800 ± 200 years BP fixes the age of minimum RSL in Port au Port Bay at 11–14 m below present. A date of 9350 ± 120 years BP from St. George's provides a minimum age for the passage of sea level below present there. A date of 12 600 ± 140 years BP from Stephenville fixes a sea level at 29 m above present, whereas one of 13 600 ± 110 years BP from Abrahams Cove dates the marine limit at 44 m. These geographically restricted data closely constrain a curve of postglacial RSL change in the Port au Port Bay – northern St. George's Bay area. The form of the curve supports a recent model predicting sea-level response to wastage of a limited late Wisconsinan ice load in the wider region.

Holocene delevelling of Devon Island, Arctic Canada: implications for ice sheet geometry and crustal response

1998 ◽  
Vol 35 (8) ◽  
pp. 885-904 ◽  
Author(s):  
Arthur S Dyke
Keyword(s):  
Sea Level ◽  
Ice Sheet ◽  
Bowhead Whale ◽  
Large Set ◽  
Relative Sea Level ◽  
Radiocarbon Dates ◽  
Level Curves ◽  
Devon Island ◽  
Ice Load ◽  
Raised Beaches

The raised beaches and deltas of Devon Island contain an abundance of dateable materials. A large set of radiocarbon dates (228), 154 of which are new, are used to construct relative sea level curves and isobase maps for the island. The best materials for this purpose are driftwood logs (61 dates) and bowhead whale bones (74 dates) from raised beaches and mollusc shells from marine-limit deltas (20 dates) or from altitudes close to marine limit (14 dates). During the last glacial maximum, the island is thought to have lain beneath the southeastern flank of the Innuitian Ice Sheet. The relative sea level history is congruent with that inferred ice configuration. The island spans half the ice sheet width. Relative sea level curves are of simple exponential form, except near the glacial limit where an early Holocene emergence proceeded to a middle Holocene lowstand below present sea level, which was followed by submergence attending the passage of the crustal forebulge. The response times of relative sea level curves and of crustal uplift decrease from the uplift centre toward the limit of loading, but the change appears strongest near the limit. The Innuitian uplift is separated from the Laurentide uplift to the south by a strong isobase embayment over Lancaster Sound. Hence, ice load irregularities with wavelengths of about 100 km were large enough to leave an isostatic thumbprint in this region of the continent. The apparent absence of a similar embayment over Jones Sound probably indicates a greater Late Wisconsinan ice load there, or a thicker crust than in Lancaster Sound.

Evidence for a Postglacial Low Relative Sea-Level Stand in the Drowned Delta of the Merrimack River, Western Gulf of Maine

1983 ◽  
Vol 19 (3) ◽  
pp. 325-336 ◽  
Author(s):  
R. N. Oldale ◽  
L. E. Wommack ◽  
A. B. Whitney
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
New Hampshire ◽  
Gulf Of Maine ◽  
Relative Sea Level ◽  
Radiocarbon Dates ◽  
Late Wisconsinan

AbstractA submerged delta of the Merrimack River, located offshore between Cape Ann, Massachusetts, and the New Hampshire border, indicates a postglacial low relative see-level stand of about −47 m. The low stand is inferred to date to 10,500 yr B.P., but a lack of age control makes this assignment uncertain. A curve based on a late Wisconsinan, high relative sea-level stand of +32m at 13,000 yr B.P., a low stand of −47m at 10,500 yr B.P., and younger radiocarbon dates related to sea-level rise indicates an early postglacial crustal rise of at least 5 m per century.

A reinterpretation of glacial and marine limits around the northwestern Laurentide Ice Sheet

1987 ◽  
Vol 24 (4) ◽  
pp. 591-601 ◽  
Author(s):  
Arthur S. Dyke
Keyword(s):  
Sea Level ◽  
East Coast ◽  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Ice Shelf ◽  
Relative Sea Level ◽  
Radiocarbon Dates ◽  
Banks Island ◽  
History Of ◽  
Late Wisconsinan

Seven new radiocarbon dates pertaining to deglaciation of northern Prince of Wales Island place the margin of the Laurentide Ice Sheet on the island by 11 000 BP. This requires a revision of the proposed age for the Viscount Melville Sound Ice Shelf of 10 300 – 9880 BP. A revised age of 11 300 – 11 000 BP is suggested.The new dates also require revisions of the proposed Wisconsinan and Holocene history of Banks Island. Shells thought to have been thrust onshore to an elevation of 88 m by the ice shelf on northern Banks Island after 10 600 BP are reinterpreted as undisturbed postglacial marine shells recording a relative sea level of 88 m or more. This, in turn, suggests that the East Coast Sea and Jesse Till are of Late Wisconsinan rather than Early Wisconsinan age and that the Late Wisconsinan glacial limit on Banks Island as figured on the 1968 Glacial Map of Canada, rather than on recent revisions, is essentially correct.

Late Holocene sea-level changes and isostasy in western Denmark

2006 ◽  
Vol 66 (2) ◽  
pp. 288-302 ◽  
Author(s):  
W. Roland Gehrels ◽  
Katie Szkornik ◽  
Jesper Bartholdy ◽  
Jason R. Kirby ◽  
Sarah L. Bradley ◽  
...  
Keyword(s):  
Salt Marsh ◽  
Sea Level ◽  
Salt Marshes ◽  
Late Holocene ◽  
Glacial Isostatic Adjustment ◽  
Sea Level Changes ◽  
Relative Sea Level ◽  
Isostatic Adjustment ◽  
Tidal Embayment ◽  
Made In

AbstractCores and exposed cliff sections in salt marshes around Ho Bugt, a tidal embayment in the northernmost part of the Danish Wadden Sea, were subjected to 14C dating and litho- and biostratigraphical analyses to reconstruct paleoenvironmental changes and to establish a late Holocene relative sea-level history. Four stages in the late Holocene development of Ho Bugt can be identified: (1) groundwater-table rise and growth of basal peat (from at least 2300 BC to AD 0); (2) salt-marsh formation (0 to AD 250); (3) a freshening phase (AD 250 to AD 1600?), culminating in the drying out of the marshes and producing a distinct black horizon followed by an aeolian phase with sand deposition; and (4) renewed salt-marsh deposition (AD 1600? to present). From 16 calibrated AMS radiocarbon ages on fossil plant fragments and 4 calibrated conventional radiocarbon ages on peat, we reconstructed a local relative sea-level history that shows a steady sea-level rise of 4 m since 4000 cal yr BP. Contrary to suggestions made in the literature, the relative sea-level record of Ho Bugt does not contain a late Holocene highstand. Relative sea-level changes at Ho Bugt are controlled by glacio-isostatic subsidence and can be duplicated by a glacial isostatic adjustment model in which no water is added to the world's oceans after ca. 5000 cal yr BP.

scholarly journals Rapid inundation of southern Florida coastline despite low relative sea-level rise rates during the late-Holocene

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Miriam C. Jones ◽  
G. Lynn Wingard ◽  
Bethany Stackhouse ◽  
Katherine Keller ◽  
Debra Willard ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Late Holocene ◽  
Relative Sea Level ◽  
Relative Sea Level Rise ◽  
Southern Florida

scholarly journals Postglacial relative sea level change and glacier activity in the early and late Holocene: Wahlenbergfjorden, Nordaustlandet, Svalbard

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Anders Schomacker ◽  
Wesley R. Farnsworth ◽  
Ólafur Ingólfsson ◽  
Lis Allaart ◽  
Lena Håkansson ◽  
...  
Keyword(s):  
Sea Level ◽  
Late Holocene ◽  
Sea Level Change ◽  
Relative Sea Level ◽  
Level Change

Causes and implications of Mid- to Late Holocene relative sea-level change in the Gulf of Kachchh, western India

2020 ◽  
pp. 1-24
Author(s):  
Shubhra Sharma ◽  
Gaurav Chauhan ◽  
Anil Dutt Shukla ◽  
Romi Nambiar ◽  
Ravi Bhushan ◽  
...  
Keyword(s):  
Sea Level ◽  
Late Holocene ◽  
River Estuary ◽  
Western India ◽  
Tidal Amplitude ◽  
Relative Sea Level ◽  
Gulf Of Kachchh ◽  
Level Change ◽  
Isostatic Adjustment ◽  
Positive Tendency

Abstract The relict intertidal deposits from the Kharod River Estuary, Gulf of Kachchh, and the distal end of Kori Creek are used to infer the Mid- to Late Holocene relative sea-level (RSL) change in western India. Employing sedimentology, geochemistry, palynology, ichnology, and optical and radiocarbon dating, the study suggests the dominance of fluvial activity between 16.5 ± 1.6 and 9.9 ± 0.7 ka. After ~7 ka (7.3 ± 0.4, 6.8 ± 0.5 ka), the sea level showed a positive tendency until 4.7 ± 0.2 ka. The tectonically corrected Mid-Holocene RSL change is estimated as 1.45 ± 0.33 m between ~7 and ~5 ka. The study suggests that the Mid-Holocene RSL high was due to the meltwater contribution from the Himalayan cryosphere, with subordinate contribution from glacio-isostatic adjustment and crustal subsidence. The Late Holocene tectonically corrected RSL change at ~1 ka (1.1 ± 0.1 ka and 1045 ± 175 cal yr BP) is estimated as 0.53 ± 0.43 m. This is ascribed to monsoon wind-driven tidal ingression that might have affected the tidal amplitude positively. The study suggests that the Mid-Holocene RSL change did not play a deterministic role in the abandonment of the Harappan coastal settlements.

Trends in Chesapeake Bay Sedimentation Rates during the Late Holocene

1990 ◽  
Vol 34 (1) ◽  
pp. 33-46 ◽  
Author(s):  
Joseph F. Donoghue
Keyword(s):  
Sea Level Rise ◽  
Chesapeake Bay ◽  
Sea Level ◽  
Late Holocene ◽  
Tide Gauge ◽  
Past Century ◽  
Sedimentation Rates ◽  
Relative Sea Level ◽  
The Past ◽  
Relative Sea Level Rise

AbstractTrends are discernible in the estimates of late Holocene rates of sedimentation and sea-level rise for the Chesapeake Bay. During most of the Holocene Epoch sedimentation rates and relative sea-level rise were equal, within the limits of measurement, at approximately 1 mm yr−1. Sedimentation rates measured over the past century, however, are nearly an order of magnitude higher, while the rate of relative sea-level rise for the Chesapeake Bay now averages 3.3 mm yr−1, as measured on long-term tide gauge records. When the acceleration in these rates occurred is uncertain, but it appears to have been confined to the past millennium, and probably to the past few centuries. The rapid sedimentation rates recorded during historic time may be a temporary disequilibrium that has resulted from a recent acceleration in the rate of relative sea-level rise.

scholarly journals Late Quaternary Deglaciation, Glaciomarine Sedimentation and Glacioisostatic Recovery in the Rivière Nastapoka Area, Eastern Hudson Bay, Northern Québec

2005 ◽  
Vol 57 (1) ◽  
pp. 65-83 ◽  
Author(s):  
Patrick Lajeunesse ◽  
Michel Allard
Keyword(s):  
Sea Level ◽  
Late Quaternary ◽  
Phase 1 ◽  
Second Phase ◽  
Hudson Bay ◽  
Silty Clay ◽  
Paleoenvironmental Reconstruction ◽  
Relative Sea Level ◽  
Radiocarbon Dates ◽  
Fluvial Terraces

Abstract This study presents a paleoenvironmental reconstruction of deglaciation dynamics and chronology, glaciomarine and postglacial sedimentation, as well as glacioisostatic recovery in the Rivière Nastapoka area, eastern Hudson Bay. Results indicate that the retreat of Québec-Labrador ice was mainly controlled by topography and was marked by four phases. Radiocarbon dates indicate that deglaciation began about 8.3 ka cal. BP and was characterized by a stillstand of the ice margin in the Nastapoka Hills that lead to the deposition of a drift belt in a high relative sea-level (Phase 1). After this stabilisation, the ice margin retreated rapidly eastward in a region of low relief and deposited a drape of silty clay in a falling relative sea-level (Phase 2). A second phase of stabilization of the ice margin lasted until at least 7.2 ka cal.BP on the higher shield peneplaine east of the limit of the Tyrrell Sea (Phase 3). This lead to the deposition of a belt of glaciofluvial deltas in a lower relative sea-level. Following this stillstand, the eastward retreat and subsequent ablation of the ice in central Québec-Labrador generated meltwater that transported large volumes of glacial sediments by fluvial processes and downcutting of fluvial terraces in previously deposited glaciofluvial and marine sediments (Phase 4). Glacioisostatic rebound reached 0.07 m/yr during the early phase of deglaciation and decreased to 0.04 m/yr between 6 and 5 ka cal. BP and 0.016 m/yr in the last 1000 years.

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