Relative sea-level rise and tidal development in the Fundy tidal system

1983 ◽  
Vol 20 (10) ◽  
pp. 1554-1564 ◽  
Author(s):  
David B. Scott ◽  
David A. Greenberg

Previous studies of sea-level and tidal amplification in the Bay of Fundy suggested a linear increase of tidal amplitude as relative sea level rose. New data presented here are used in a numerical tidal model in an effort to reproduce paleotidal regimes over the last 7000 years. Five new sea-level curves covering the last 4000 years and some previously published data extending the record back to 7000 years before present (BP) are used as the data base. These data, when used together with the tidal model, indicate that tidal amplitudes increased much more rapidly between 7000 and 4000 years ago than in the period 4000 years ago to present. It is also shown that changes in depth within the Bay of Fundy produce little effect on the tidal amplitudes, whereas such variations in water depth on Georges Bank account for almost all the change. This calculation of tidal-amplitude changes allows calibration of sea-level curves to be made for the Bay of Fundy using higher high-water (HHW) indicators.

2001 ◽  
Vol 38 (7) ◽  
pp. 1081-1092 ◽  
Author(s):  
Gail L Chmura ◽  
Laurie L Helmer ◽  
C Beth Beecher ◽  
Elsie M Sunderland

We examine rates of salt marsh accumulation in three marshes of the outer Bay of Fundy. At each marsh we selected a site in the high marsh with similar vegetation, and thus similar elevation. Accretion rates were estimated by 137Cs, 210Pb, and pollen stratigraphy to estimate rates of change over periods of 30, 100, and ~170 years, respectively. These rates are compared with records from the two closest tide gauges (Saint John, New Brunswick, and Eastport, Maine) to assess the balance of recent marsh accretion and sea-level change. Averaged marsh accretion rates have ranged from 1.3 ± 0.4 to 4.4 ± 1.6 mm·year–1 over the last two centuries. Recent rates are similar to the rate of sea-level change recorded at Eastport, Maine, suggesting that they are in step with recent sea-level change but very sensitive to short-term variation in relative sea level. Based on the pollen stratigraphy in the marsh sediments, the marsh accretion rate was higher during the late 18th to early 19th century. Higher rates probably were due to local increases in relative sea level as a result of neotectonic activity and may have been enhanced by increased sediment deposition through ice rafting.


2020 ◽  
pp. 1-24
Author(s):  
Shubhra Sharma ◽  
Gaurav Chauhan ◽  
Anil Dutt Shukla ◽  
Romi Nambiar ◽  
Ravi Bhushan ◽  
...  

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.


1999 ◽  
Vol 136 (6) ◽  
pp. 681-696 ◽  
Author(s):  
C. J. UNDERWOOD ◽  
S. F. MITCHELL

The mid-Cretaceous sediments of northeast England were deposited at the western margin of the southern North Sea Basin, with sedimentation occurring in a range of tectonic settings. Detailed analysis of the areal distribution and sedimentary facies of Aptian to earliest Cenomanian sediments has allowed the pattern of onlap onto the Market Weighton structural high and changes in relative sea level to be documented. Successive onlap episodes during the Early Aptian, Late Aptian and Early Albian culminated in the final flooding of the structure during the Late Albian (varicosum Subzone). Sea-level curves generated from coastal onlap patterns are difficult to relate to published ‘global’ sea-level curves due to the high frequency of the fluctuations in relative sea level observed. Despite this, detailed correlation and analysis of sedimentological events suggest that even the most expanded, basinal succession is relatively incomplete. This study has also shown that the change from dominantly syn-tectonic to dominantly post-tectonic sedimentation style occurred in the late Early Albian.


2007 ◽  
Vol 239 (3-4) ◽  
pp. 143-161 ◽  
Author(s):  
Shahin E. Dashtgard ◽  
Richardo O. White ◽  
Karl E. Butler ◽  
Murray K. Gingras

1981 ◽  
Vol 18 (7) ◽  
pp. 1146-1163 ◽  
Author(s):  
Garry Quinlan ◽  
Christopher Beaumont

Two extreme models of late Wisconsinan ice cover in Atlantic Canada and the northeastern U.S.A. are shown to produce postglacial relative sea level curves that bracket existing field observations at six sites throughout the region. This suggests that the true late Wisconsinan ice distribution is probably intermediate to the two contrasting reconstructions proposed. Both ice models predict the existence of four relative sea level zones: an innermost zone closest to the centre of glaciation in which relative sea level falls continuously throughout postglacial time; an outermost zone in which it rises continuously; and two transitional zones in which it first falls and then rises in varying proportions according to the distance from the ice margin. The distinctive forms of the relative sea level curves are probably representative of each of the zones and are unlikely to be significantly perturbed even by large local ice readvances. They, therefore, establish patterns with which future field data are expected to conform. The form that the geological record of relative sea level change is likely to take within each zone is discussed and promising settings for the collection of new data are proposed. The common practice of separating relative sea level into an isostatic and a eustatic component is analysed and shown to be incorrect as usually applied. The practice is also shown to be unnecessary because the models discussed in this paper predict changes in relative sea level that can be compared directly with the observations.


1985 ◽  
Vol 22 (7) ◽  
pp. 1039-1047 ◽  
Author(s):  
I. A. Brookes ◽  
D. B. Scott ◽  
J. H. McAndrews

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.


1990 ◽  
Vol 34 (3) ◽  
pp. 296-305 ◽  
Author(s):  
Peter U. Clark ◽  
William W. Fitzhugh

AbstractThe age of the marine limit and associated deglaciation has been estimated from relative sea-level curves for the Hopedale and Nain areas of the central Labrador coast as approximately 7600 ± 200 and 8500 ± 200 yr ago, respectively. These ages indicate that the ice margin remained on the coast for up to 3000 yr longer than previously estimated. Because the central coast is due east of glacial lakes Naskaupi and McLean, the earliest the lakes could have formed was <8500 ± 200 yr ago, with their largest phases being fully established only after 7600 ± 200 yr ago. This suggests that the age of the lakes, and associated deglaciation of the central Labrador-Ungava region, is younger by at least 1500 yr than previously estimated. A late-glacial marine-based ice mass in Ungava Bay that dammed the lakes collapsed ca. 7000 yr ago. Within this time frame, therefore, the glacial lakes only existed for <500 yr. The persistence of the Laurentide Ice Sheet margin on the central Labrador coast until 7600 yr ago probably restricted the northward movement of early prehistoric people into northern Labrador.


2019 ◽  
Author(s):  
Maren Bender ◽  
Thomas Mann ◽  
Paolo Stocchi ◽  
Dominik Kneer ◽  
Tilo Schöne ◽  
...  

Abstract. Indonesia is a country composed of several thousand islands, many of them small, low-lying and densely inhabited. These are, in particular, subject to high risk of inundation due to future relative sea level changes. The Spermonde Archipelago, off the coast of Southwest Sulawesi, consists of more than 100 small islands. This study presents a dataset of 24 sea-level index points from fossil microatolls, surveyed on five islands in the Spermonde Archipelago and compares these new results with published data from the same region and with relative sea level predictions from different Glacial Isostatic Adjustment (GIA) models. The newly surveyed fossil microatolls are located around the islands of Tambakulu, Suranti (both ~ 60 km offshore of Makassar city), Bone Batang and Kodingareng Keke (both located in the center of the Archipelago) and Sanrobengi (located ~ 20 km south-southwest of Makassar). Results from the near- and mid-shelf islands indicate that relative sea level between 4 to 6 ka BP was less than one meter above present sea level. The only exception to this pattern is the heavily populated island of Barrang Lompo, where we record a significant subsidence when compared to the other islands. These new results support the conclusions from a previous dataset and are relevant to constrain late Holocene ice melting scenarios. Samples from the two outer islands (Tambakulu and Suranti) yielded ages spanning the Common Era that represent, to our knowledge, the first reported for the entire Southeast Asian region.


2007 ◽  
Vol 59 (2-3) ◽  
pp. 155-185 ◽  
Author(s):  
Arthur S. Dyke ◽  
Lynda A. Dredge ◽  
Douglas A. Hodgson

Abstract The deglacial marine-limit surface is a virtual topography that shows the increase of elevation since deglaciation. The currently available set of marine-limit elevations (n = 929), about three times the number available in the most recent synthesis, allows a fairly detailed rendering of the surface across most of glaciated North America and Greenland. Certain large glacial lake-limit surfaces are analogous to marine-limit surfaces, except that their gradients were not dampened by eustatic sea-level rise. Collectively the surfaces reflect both gross ice-sheet geometry and regional to local rates of ice-marginal recession. As such, they are replication targets for glacioisostatic modelling that are supplementary to and more continuously distributed than relative sea-level curves.


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