Atlantic Coast

.............................................................. PAGE 181 Atlantic Coast I 0 81o 0 820 I§ 830 Iii 840 [j]jJ] 850 IIIIJ 860 ~ 870 • 880 • 890 I Figure 26: Region 800, Atlantic Coast, and its component Districts. Theme Regions: Natural History of Nova Scotia, Volume II PAGE .............................................................. 182 800 ATLANTIC COAST The Atlantic Coast Region is divided into nine Dis GEOLOGY tricts based upon major geomorphological charac teristics: The Atlantic Coast Region of Nova Scotia cuts across 810 Basalt Peninsula a great variety of rock types. 820 Cliffs and Beaches The Western Shore, South Shore, and Eastern 830 Beaches and Islands Shore (Districts 820, 830, and 840) are dominated by 840 Quartzite Headlands the old and generally very hard rocks of the Meguma 850 Granite Barrens Group. These are interfolded slates and greywackes, 860 Sedimentary Lowland with local outcroppings of metamorphosed volcanic 870 Till Plain ash and lava (Yarmouth area). Areas of very resistant 880 CUffed Island granite (District 850) also occur. In contrast, Cheda 890 Sandy Island bucto Bay has been eroded from weakly metamor phosed Carboniferous sandstones (District 860). Districts 830, 840, and 850 are further divided into Southeastern Cape Breton (District 870) is underlain Units based upon geomorphological, soil, and veg- by metamorphosed Precambrian volcanic ash de etation characteristics. · posits, sandstone, and granite. At the entrance to the Bay of Fundy, Digby Neck REGIONAL CHARACTERISTICS (District 810) is a low-lying basalt ridge. St. Paul Island (District 880) consists of very ancient Pre Exposure to winds from the Atlantic Ocean domi cambrian rocks similar to those found in the Cape nates coastal environments from Digby Neck to Breton massif. Scatarie Island. The Region includes Isle Haute and The coastal bedrock is low-lying and exhibits low 800 St. Paul Island. The coastal forest is found through relief. Elevations rarely exceed 100 m, except on the Atlantic Coast out, and its inland extension marks the regional granite promontories and knolls at Pennant Barrens boundary. Headlands, especially in granite and (Unit 851) and Canso Barrens (Unit 852), where the 1 quartzite areas, are frequently barren. Almost every maximum elevation is 250 m. major rock type in Nova Scotia is found in this re gion, but the soils are often dominated by hardpans LANDSCAPE DEVELOPMENT that result from excessive moisture. Coastal erosion is rapidly reshaping coastal areas containing drum The coastline can be divided into two sections based lins; there beaches, marshes, and waterfowl habitat upon classic features of emergence and submer are found. Seabird nesting colonies and marine gence. Post -glacial readjustment north of a pivot line mammals are common on coastal islands. that lies parallel to the length of the province from The Atlantic Coast Region is much influenced by Yarmouth to Truro resulted in the emergence of Bay the adjacent Offshore/Continental Shelf (Region of Fundy coasts. From Yarmouth to Scatarie Island, 900). There is _a transition zone where the marine and the Atlantic coast has been continuously submerged terrestrial conditions interact, and it is sometimes as sea levels have risen. The emergent shore has difficult to make a distinction between coastal and raised beaches, raised wave-cut platforms, and a offshore waters. In general, Region 800 extends to the smooth shoreline. The submerged shore is highly ir low tide mark, and marine conditions are described regular, with drowned estuaries and headlands pro in Region 900. However, in some bays, such as St. ducing an indented coast fringed by islands. The Margarets and Mahone bays (District 460), the ma post-glacial rise in sea levels recorded over the past rine characteristics are more typically coastal and the 10,000 years or so has affected all coastal areas. District encompasses subtidal waters. Drowned forests, eroding headlands, tidal marshes, and beaches driven inland are all evidence of the continuing transgression of the sea. The shape of the coastline is also strongly influ enced by faults, especially along the Eastern Shore Natural History of Nova Scotia, Volume II: Theme Regions .............................................................. PAGE 183 and the southern boundary of Chedabucto Bay. • The median extent of sea ice just reaches the east Many of the long inlets in Guysborough County have em limit of this region. In heavier-than-average ice formed along fault lines. The straight shore west of years, ice fields may extend as far southwest as Hali Cape Canso marks the position of the Chedabucto faxCounty. Fault. The smooth eastern shoreline of the Louis The background features of the ocean climate are b~urg lowlands (and Gabarus Bay) may also be fault controlled by the southwest-flowing Nova Scotia controlled. The orientation of St. Marys Bay, North Current, which is relatively low in salinity; superim Mountain, and the Parrsboro shore also owe much to posed upon this are meteorological events which can fault movements within the Bay of Fundy area. bring large runoffs of fresh water or upwellings of saltier deeper waters. In general, the Region is a cool GLACIAL DEPOSITS water coast. In summer the coldest temperatures are found around Cape Sable and in the Bay of Fundy, as The last major flood of ice across Nova Scotia during a result of a strong mixing of surface waters. by tidal the Wisconsin Period left a predominantly north currents. south to northwest-southeast imprint upon the land The ocean is the dominant influence on the Re scape. Pre-existing drainage channels and any faults gion's climate. The main features are moderated sea lying parallel to the flow were deepened. Interfolded sonal and daily temperatures, high precipitation and strata oriented parallel to the direction of ice flow humidity, strong winds, fog, and salt spray. were differentially eroded, leaving ridges and valleys The winters are comparatively mild, an~ the sum (Tusket area); ridges perpendicular to the ice flow mers are short and cool. The mean annual tempera were smoothed off. The whole area was then blan ture range is 15-20°C and is least in the southwest, keted with glacial till derived mainly from local increasing towards Cape Breton. This can be con sources but also carried from one geological district trasted to a mean annual temperature range of 20- to another and deposited as drumlins. 250C throughout the rest of the province. Along the Along the coast the amount of sediment available coast, spring starts early but is long and cool. Mean for redistribution depends largely upon the nature of daily temperatures rise above the freezing point the glacial deposits. Areas with drumlin headlands about the second week of March in the south, and and islands tend to have adequate sediment supply about two to three weeks later along the Eastern derived from coastal erosion. Another very limited Shore and in Cape Breton. Because of frequent fogs, 800 Atlantic source of coastal sediment, quartz sand, is washed and the cooling influence of ocean waters, the mean Coast from the surface of coastal granite bodies by sub daily temperature in July stays below 15°C near the aerial erosion. A more important source of coastal coast, increasing somewhat inland. Mean daily freez I sediment is silt and sand that was carried landward ing temperatures return to northern inland areas be from glacial deposits on the Scotian Shelf by the sea fore the end of November, but in the Atlantic Coast as it rose during the post-glacial period. Many of the Region this does not usually happen until after the present sand beaches owe their origins to material second week in December, or even as late as the end driven landward in this manner. of December in the southwest. Mean daily January temperatures stay above -5°C and, in some areas, re CLIMATE main above OOC. Like most of the province, the Atlantic Coast Re Although the Atlantic Coast Region is generally an gion receives fairly high total precipitation, generally exposed, high-energy environment, the many inden between 1200 and 1400 mm, but between 1400 and tations along the coast provide sheltered bays and 1600 mm in Queens and Lunenburg counties and in estuaries. The average tidal range is small: at Guys the northern half of Halifax County. Only about 15 borough Harbour it is 1.4 m, at Halifax 1.4 m, at per cent falls as snow because of the mild winter Lunenburg 1.6 m, and at Barrington Passage 1.9 m. temperatures. Most of the Region receives less than In the Gulf of Maine, however, the tidal range in 200 em of snow annually, and Guysborough County creases sharply. At Woods Harbour, 10 km west of and Cape Breton receive less than 150 em. The snow Barrington Passage, the average tidal range is 2.6 m, cover season starts late and finishes early, ranging which becomes 3. 7 m at Yarmouth and 4. 7 m in St. from less than 100 days near Cape Sable to more Marys Bay. Ocean swells move in from the south and than 130 days in Cape Breton. Snow accumulations east, though their erosive power is somewhat re are usually low. duced by refraction and by northerly offshore winds, Fog and high humidities are common along the particularly in winter. Atlantic coast. Summer and fall are the main seasons Theme Regions: Natural History of Nova Scotia, Volume II PAGE 184• for fog, when warm, moist air moving in from the verely stunted. Continuous high winds increase tran south comes into contact with cool Atlantic coastal spiration, and trees may actually become "desic waters. On av€rage, fog occurs 15-25 per cent of the cated" in spite of high rainfall. Salt spray can kill part year. The southwestern section of the coast is the fog or all of a tree, but its effects are limited to a fairly giest, with Yarmouth registering an average of 120 narrow band along the coast.

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