Holocene sea levels, paleoceanography, and late glacial ice configuration near the Northumberland Strait, Maritime Provinces

1987 ◽  
Vol 24 (4) ◽  
pp. 668-675 ◽  
Author(s):  
David B. Scott ◽  
Franco S. Medioli ◽  
Ann A. L. Miller

Work on new cores from old core sites in Baie Verte, New Brunswick, led to the identification of submerged salt-marsh peats, reported earlier as freshwater ones. A comprehensive sea-level curve, between 9 and 15 m below present, is based on marsh foraminiferal assemblages. These data indicate that between 4500 and 5400 BP relative sea-level (RSL) rise was comparatively slow (about 10 cm/100 years); the rate increased dramatically between 4500 and 4000 BP (1 m/100 years) and decreased between 2000 and 4000 BP to its present rate of 15 cm/100 years. We suggest RSL was falling before 5400 BP and that the sequence in our deepest core is similar to some observed in the Bay of Fundy and Nova Scotian Atlantic coast where early RSL fall is documented. To account for this sea-level record and others nearby we suggest that the ice history here is complex, with three separate ice caps thinning towards this area in late glacial times.Earlier work also indicated a number of sediment sequences barren of benthonic foraminifera, suggesting a complex marine–freshwater history for the area. The study of new cores containing the same sequences indicates no barren zones but a simple transgressive sequence with a warm-water calcareous fauna followed by an agglutinated transitional estuarine foraminiferal fauna.

1970 ◽  
Vol 7 (2) ◽  
pp. 676-689 ◽  
Author(s):  
Douglas R. Grant

Hydrographic, archeologic, and geologic evidence indicates that for the last 4000 y the Maritime Provinces have been submerging three to five times faster than the 6 cm/century rate of eustatic rise of sea level. After correcting for the eustatic change, the Bay of Fundy shows an anomalous submergence of 24 cm/century, of which at least 15 cm/century is probably due mainly to rise of high tide, or increase of tidal range, beginning 4000–6000 y ago as eustatic sea-level rise widened and deepened the entrance to the Gulf of Maine. Submergence of the Atlantic coast of Nova Scotia, on the other hand, exceeds the eustatic rate by 9 cm/century, which can be largely explained by new mathematical models as isostatic subsidence of the earth's crust as the sea deepened eustatically over the continental shelf. Only a small part of the residual anomalies of 9 cm and 4 cm/century for the Fundy and Atlantic coasts, respectively, can be attributed to a combination of additional subsidence due to geosynclinal downwarping and relaxation of a possible glacier-margin peripheral bulge, thereby implicating other modes of regional crustal lowering.


1972 ◽  
Vol 2 (1) ◽  
pp. 1-14 ◽  
Author(s):  
R. I. Walcott

Vertical movements of the earth's surface related to postglacial rebound, the eustatic rise in sea level and the elastic deformation of the globe due to melting of late glacial ice sheets are calculated for simplified models of the earth. The movements of the ground are large and require a reevaluation of what is meant by eustatic sea level change. This is defined here as an ocean-wide average change in mean sea level and its measurement requires widely distributed observations weighted according to the areas of oceans they represent. Evidence of a postglacial (6000-0 years BP) relative rise in sea level comes largely from regions affected by ground subsidence related to adjacent upward postglacial rebound movements in deglaciated areas: evidence for a relative fall of sea level comes from coastlines well removed from areas of rebound and which have been affected by a rise of the continental areas through compensation for the eustatic load. It is concluded: (1) no substantial eustatic change of sea level in the past 6,000 years is required to explain postglacial sea levels: (2) in late glacial time the eustatic curve is probably more like the sea level curve of Texas and Mexico than that of the Atlantic seaboard of the United States: (3) that the information of past sea levels, when sufficiently widespread, can provide an important method of studying the deep mechanical structure of the earth.


2011 ◽  
Vol 31 (3-4) ◽  
pp. 203-206 ◽  
Author(s):  
Harold W. Borns ◽  
Terence J. Hughes

Much of the Laurentide ice sheet in Maine, Atlantic Provinces, and southern Quebec was a "marine ice sheet," that is it was grounded below the prevailing sea level. When proper conditions prevailed, calving bays progressed into the ice sheet along ice streams partitioning it, leaving those portions grounded above sea level as residual ice caps. At least by 12,800 yrs. BP a calving bay had progressed up the St. Lawrence Lowland at least to Ottawa while a similar, but less extensive calving bay developed in Central Maine at approximately the same time. Concurrently, ice draining north into the St. Lawrence and south into the Central Maine calving bays rapidly lowered the surface of the intervening ice sheet until it eventually divided over the NE-SW trending Boundary and Longfellow Mountains and probably over other highland areas as well. A major consequence of these nearly simultaneous processes was the separation of an initial large ice cap over part of Maine, New Brunswick, and Québec which was bounded on the west by the calving bay in Central Maine, to the north by the calving bay in the St. Lawrence Lowland, to the south by the Bay of Fundy, and to the east by the Gulf of St. Lawrence. In coastal Maine, east of the calving bay, the margin of the ice cap receded above the marine limit at least 40 km and subsequently read-vanced terminating at Pineo Ridge moraine approximately 12,700 yrs. BP. These events are the stratigraphie and chronologic equivalent of the Cary-Pt. Huron recession/Pt. Huron readvance of the Great Lakes region.


1944 ◽  
Vol 6c (3) ◽  
pp. 281-290 ◽  
Author(s):  
Wilfred Templeman

The relative width of the second abdominal segment was used for comparing onset of sexual maturity of female lobsters in 18 different localities of the Maritime Provinces, after establishing a correlation between them. Judging by the abdominal width, the smallest lobsters to carry eggs range from 17.6 to 22.6 cm. long, and the sizes when approximately half the female lobsters are mature range from 23.5 to 29.2 cm. in the whole southern part of the gulf of St. Lawrence and along the outer Nova Scotian coast at least as far as Jeddore; in southern Nova Scotia and Grand Manan the corresponding ranges in size are higher, being 29 to 32 cm. and 36.7 to 40.4 cm. respectively. Graphs are given showing the relative abdominal width in 189 berried lobsters.


1933 ◽  
Vol 9 (3) ◽  
pp. 265-279 ◽  
Author(s):  
Hugh P. Bell ◽  
Constance MacFarlane

The marine algae of the Atlantic coast of the maritime provinces of Canada were collected at representative places all along the coast. The most intensive collecting was done at St. Andrews, New Brunswick, and at Halifax, Nova Scotia. An entire summer was spent collecting around Prince Edward Island. The report covers the work of more than seven years. The collecting was done chiefly during the summer, but regular collecting was also carried out for two winters. The area is divided into three distinct geographical and ecological regions, namely, the Bay of Fundy, the Atlantic, and the Prince Edward Island regions. In the list of species, their regional distribution and prevalence are given in tabular form. The list includes 120 species, divided into 30 Chlorophyceae, 41 Phaeophyceae, and 49 Rhodophyceae. In addition to critical notes regarding certain forms, the striking differences in the marine flora from region to region are indicated diagramatically by distribution maps for a number of species.


2012 ◽  
Vol 25 (22) ◽  
pp. 7822-7833 ◽  
Author(s):  
Torben Schmith ◽  
Søren Johansen ◽  
Peter Thejll

Abstract Global sea level rise is widely understood as a consequence of thermal expansion and the melting of glaciers and land-based ice caps. Because of the lack of representation of ice-sheet dynamics in present-day physically based climate models, semiempirical models have been applied as an alternative for projecting future sea levels. There are, however, potential pitfalls in this because of the trending nature of the time series. A statistical method called cointegration analysis that is capable of handling such peculiarities is applied to observed global sea level and land–ocean surface temperature. The authors find a relationship between sea level and temperature and find that temperature causally depends on the sea level, which can be understood as a consequence of the large heat capacity of the ocean. They further find that the warming episode in the 1940s is exceptional in the sense that sea level and warming deviate from the expected relationship. This suggests that this warming episode is mainly due to internal dynamics of the ocean rather than external radiative forcing. On the other hand, the present warming follows the expected relationship, suggesting that it is mainly due to radiative forcing. In a second step, the total radiative forcing is used as an explanatory variable, but it is unexpectedly found that the sea level does not depend on the forcing. The authors hypothesize that this is due to a long adjustment time scale of the ocean and show that the number of years of data needed to build statistical models that have the relationship expected from physics exceeds what is currently available by a factor of almost 10.


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