scholarly journals Deglaciation of Nova Scotia: Stratigraphy and chronology of lake sediment cores and buried organic sections

2002 ◽  
Vol 52 (1) ◽  
pp. 3-21 ◽  
Author(s):  
Rudolph R. Stea ◽  
Robert J. Mott
Keyword(s):  
Nova Scotia ◽  
Sediment Cores ◽  
Younger Dryas ◽  
Organic Content ◽  
Sediment Flux ◽  
Coarse Grained ◽  
Glacial Lake ◽  
Bay Of Fundy ◽  
Sediment Layer ◽  
Organic Sediment

Abstract The deglaciation of Nova Scotia is reconstructed using the AMS-dated chronology of lake sediments and buried organic sections exposed in the basins of former glacial lakes. Ice cleared out of the Bay of Fundy around 13.5 ka, punctuated by a brief read- vance ca. 13-12.5 ka (Ice Flow Phase 4). Glacial Lake Shubenacadie (1) formed in central Nova Scotia, impounded by a lobe of ice covering the northern Bay of Fundy outlet. Drainage was re-routed to the Atlantic Ocean until the Fundy outlet became ice free after 12 ka. When this lake drained, bogs and fens formed on the lake plain during climatic warming. Organic sediment (gyttja) began to accumulate in lake basins throughout Nova Scotia. Glacierization during the Younger Dryas period (ca. 10.8 ka) resulted in the inundation of lakes and lake plains with mineral sediment. The nature and intensity of this mineral sediment flux or "oscillation" varies from south to northern regions. Southern lakes simply record changes in total organic content whereas northern lakes, where most buried peat sections are found, feature a thick inorganic sediment layer. Glacial ice or permanent snow cover and seasonal melting are essential in the formation of this mineral sediment layer; both to provide the water source for erosion, and to prevent plant re- colonization and landscape stabilization. Some northern lakes do not appear to record the Younger Dryas event, with organic accumulation starting around 10 ka. During the Younger Dryas, fine and coarse-grained deposits were deposited in Glacial Lake Shubenacadie (2) and other lowland areas at elevations similar to former (12 ka) lake levels, impounded by re-invigorated residual ice caps and permanent snow/aufeis.

A midge-based late-glacial temperature reconstruction from southwestern Nova Scotia

2005 ◽  
Vol 42 (11) ◽  
pp. 2051-2057 ◽  
Author(s):  
Bronwen S Whitney ◽  
Jessie H Vincent ◽  
Les C Cwynar
Keyword(s):  
Nova Scotia ◽  
Younger Dryas ◽  
Temperature Reconstruction ◽  
Late Glacial ◽  
Organic Content ◽  
Eastern North America ◽  
Quantitative Reconstruction ◽  
Late Glacial Period ◽  
Maritime Canada ◽  
Glacial Climate

We present a quantitative reconstruction of the thermal regime spanning the late-glacial period of Nova Scotia (14 700 to 11 600 BP) as inferred by analyzing fossil midges from a small lake (Lac à Magie) in southwestern Nova Scotia. The GS-1 event (equivalent to the Younger Dryas, dating from 12 700 to 11 600 BP in Maritime Canada) was marked by a 5 °C decline in inferred mean July surface-water temperatures and a 15% drop in organic content. Previous pollen and plant macrofossil analyses of this site demonstrate a response of vegetation to GS-1 cooling. These data, coupled with a midge-inferred temperature reconstruction from a nearby site, suggest that late-glacial climate change was less pronounced in southern Nova Scotia than in other sites in Maritime Canada and adjacent eastern North America.

Age of the Five Islands Formation, Nova Scotia, and the Deglaciation of the Bay of Fundy

1987 ◽  
Vol 27 (3) ◽  
pp. 211-219 ◽  
Author(s):  
Rudolph R. Stea ◽  
Daryl M. Wightman
Keyword(s):  
Nova Scotia ◽  
New Brunswick ◽  
Sediment Cores ◽  
Atomic Mass ◽  
Bay Of Fundy ◽  
Shell Material ◽  
Ice Shelf ◽  
Radiocarbon Dates ◽  
Surface Ice ◽  
Ams Dates

AbstractThree atomic mass spectrometry (AMS) dates have been obtained for shell material from the bottomset beds of a glaciomarine delta at Spencers Island, Nova Scotia, near the head of the Bay of Fundy. The sediments in the delta are part of the previously undated Five Islands Formation, and are the first direct indictaion of the age of deglaciation in this region. The dates range from 14,300 to 12,600 yr B.P. and record the duration of deposition of a diamicton under the deltaic deposits and of the delta itself. The diamicton may have formed around 14,000 yr B.P. under ice-shelf or calving-bay conditions, or by a readvance of grounded ice. The Spencers Island delta is part of a prominent ice-marginal stand marked by numerous deltas along the Minas Basin. The time of formation of the deltas and the inferred ice margin is between 13,500 and 12,000 yr B.P. based on the Spencers Island dates and palynologically confirmed dates on the base of lake-sediment cores from the delta surface. Ice-marginal glaciomarine deposits near St. John, New Brunswick, record a range of radiocarbon dates similar to the Spencers Island dates. This implies that the Bay of Fundy became virtually ice free about 14,000 yr B.P.

An Assessment of Environmental Changes in Three Lakes from King's County (Nova Scotia, Canada) Using Diatom-Based Paleolimnological Techniques

2008 ◽  
Vol 43 (2-3) ◽  
pp. 85-98 ◽  
Author(s):  
Joshua R. Thienpont ◽  
Brian K. Ginn ◽  
Brian F. Cumming ◽  
John P. Smol
Keyword(s):  
Nova Scotia ◽  
Environmental Changes ◽  
Sediment Cores ◽  
Lake Management ◽  
River System ◽  
210Pb Dating ◽  
Hydroelectric Power ◽  
Diatom Assemblages ◽  
Shoreline Development ◽  
Before And After

Abstract Paleolimnological approaches using sedimentary diatom assemblages were used to assess water quality changes over the last approximately 200 years in three lakes from King's County, Nova Scotia. In particular, the role of recent shoreline development in accelerating eutrophication in these systems was assessed. Sediment cores collected from each lake were analyzed for their diatom assemblages at approximately 5-year intervals, as determined by 210Pb dating. Analyses showed that each system has changed, but tracked different ecosystem changes. Tupper and George lakes recorded shifts, which are likely primarily related to climatic warming, with diatom assemblages changing from a preindustrial dominance by Aulacoseira spp. to present-day dominance by Cyclotella stelligera. In addition to the recent climatic-related changes, further diatom changes in the Tupper Lake core between approximately 1820 and 1970 were coincident with watershed disturbances (farming, forestry, and construction of hydroelectric power infrastructure). Black River Lake has recorded an increase in diatom-inferred total phosphorus since about 1950, likely due to impoundment of the Black River system for hydroelectric generation and subsequent changes in land runoff. Before-and-after (i.e., top-bottom) sediment analyses of six other lakes from King's County provided further evidence that the region is being influenced by climatic change (decreases in Aulacoseira spp., increases in planktonic diatom taxa), as well as showing other environmental stressors (e.g., acidification). However, we recorded no marked increase in diatom-inferred nutrient levels coincident with shoreline cottage development in any of the nine study lakes. Paleolimnological studies such as these allow lake managers to place the current limnological conditions into a long-term context, and thereby provide important background data for effective lake management.

Autumn Stranding of a Northern Bottlenose Whale (Hyperoodon ampullatus) in the Bay of Fundy, Nova Scotia

1975 ◽  
Vol 32 (7) ◽  
pp. 1019-1040 ◽  
Author(s):  
Edward Mitchell ◽  
V. Michael Kozicki
Keyword(s):  
Nova Scotia ◽  
Rhode Island ◽  
Growth Curve ◽  
North American ◽  
Labrador Sea ◽  
Bay Of Fundy ◽  
Winter Migration ◽  
Hyperoodon Ampullatus

A 615-cm male northern bottlenose whale (Hyperoodon ampullatus) stranded in Cobequid Bay, Bay of Fundy, in early October 1969. The skull, mandible, tympano-periotics, and teeth are described and illustrated. Five growth layers in the lower teeth place the animal below a growth curve based on samples from the Labrador Sea taken in May and June. A summary of nine other North American occurrences of 12 individuals, mainly south of Sable Island, indicates a winter migration to waters offshore of Massachusetts and Rhode Island.

Limnetic Zooplankton Assemblages in Atlantic Canada with Special Reference to Acidification

1986 ◽  
Vol 43 (2) ◽  
pp. 444-456 ◽  
Author(s):  
J. C. H. Carter ◽  
W. D. Taylor ◽  
R. Chengalath ◽  
D. A. Scruton
Keyword(s):  
Nova Scotia ◽  
New Brunswick ◽  
Fish Predation ◽  
Low Ph ◽  
Buffering Capacity ◽  
The Other ◽  
Bay Of Fundy ◽  
Factor Scores ◽  
Multiple Discriminant Analysis ◽  
Biological Factors

Crustacean and rotifer plankton assemblages of 93 lakes in Labrador, 107 in Newfoundland, and 142 in New Brunswick – Nova Scotia were investigated for evidence of correlations with lake morphometric, chemical, or biological factors. Labrador assemblages were almost completely lacking in identifiable structure. Newfoundland species clustered into two groups of different body size, suggesting the influence of fish predation. Only one species in Labrador and Newfoundland was significantly correlated with a derived factor related to lake water buffering capacity. New Brunswick – Nova Scotia species clustered into two groups, one featuring significant positive and the other significant negative correlations with the buffering factor. From this we conclude that acidification is having an impact on the limnetic zooplankton of these two provinces. Multiple discriminant analysis was used to demonstrate that New Brunswick – Nova Scotia lakes differing in their buffering capacity were also distinct in zooplankton composition. Lakes with low factor scores (low pH, alkalinity, and calcium) were mainly located in the Bay of Fundy region; this area has above average fog and precipitation, and lies within the summer air flow carrying pollutants from the south.

scholarly journals The Paths of the Suspended Particulate Inorganic and Organic Matter in a Small Urban Estuary: The Aarhus Harbour Estuary

1986 ◽  
Vol 17 (1) ◽  
pp. 31-46 ◽  
Author(s):  
K. B. Kronvang ◽  
C. Christiansen
Keyword(s):  
Organic Matter ◽  
Particulate Matter ◽  
Organic Content ◽  
Temporal And Spatial Distribution ◽  
Urban Estuary ◽  
Inorganic Matter ◽  
Organic Sediment ◽  
Suspended Particulate ◽  
Good Agreement ◽  
Inorganic And Organic

The nverine supply of suspended inorganic and organic sediment, its temporal and spatial distribution and its exchange with the bay, were estimated for an urban estuary (Aarhus Harbour Estuary, Denmark) during 1983-84. The river supplies high levels of particulate matter to the estuary. Export from the estuary averages one fifth of the river introduced particulate matter resulting in the accumulation of terrigenous material in the estuary. River discharge determines whether the high depletion of particulate matter in the upper estuary follows an exponential(flocculation) or a lineary curve (dilution). Preferential deposition of organic as opposed to inorganic matter in the upper estuary depletes the particulate matter of organic matter and associated pollutants. The estuary is divided into three depositional zones identified on the basis of sediment activity, grain-size and organic content. A sediment budget is precented for the estuary. Good agreement is shown between the actually dredged sediment quantity and the mass to sedimentation from the budget.

scholarly journals Backscatter strength and shaded seafloor relief, Bay of Fundy, sheet 11, offshore Nova Scotia - New Brunswick

2011 ◽  
Author(s):  
B J Todd ◽  
J Shaw ◽  
D R Parrott ◽  
J E Hughes Clarke ◽  
D Cartwright ◽  
...  
Keyword(s):  
Nova Scotia ◽  
New Brunswick ◽  
Bay Of Fundy
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