Zenith of the Dinosaurs/Offshore Geology (144-66 mya)
|Global View - Where was Nova Scotia?
Intense continental rifting continued until approximately 140 million years ago, as the Atlantic Ocean grew ever wider. The continents of the eastern hemisphere (present day Africa, Europe and Australia) and the continents of the western hemisphere (present day North and South America) drifted further and further apart. The Bay of Fundy, a rift valley, is a remnant of the rifting process.
Click here to see an animated image of the Atlantic Ocean forming. (127k)
Rocks of Nova Scotia
Offshore, thick Cretaceous deposits record the breakup of Pangea and the development of the Atlantic Ocean margin. The geology beneath Nova Scotia's continental shelf is known from undersea sampling, coring and geophysical techniques.
Early in the Cretaceous Period (140-120 mya) broad deltas developed over the eastern Scotian Shelf, depositing thick sequences of sand and shale that were followed by carbonates and finally by more shales in the Late Cretaceous. This was followed by a gradual drop of the sea level, which resulted in the outbuilding and upbuilding of the shelf that is continuing today.
The whole sedimentary sequence was covered by fine muds during the Late Cretaceous, when seawater once more invaded the shelf and created deepwater conditions in the low lying areas. At that time, erosion on land was very slow, and only very fine sediments were removed from the flat surface.
The later Cretaceous was a period of generally high sea level, with the shoreline occasionally close to present day.
The formation of Nova Scotia's present day landscape began in the Cretaceous Period with the development of a lowland plain. At that time, Nova Scotia may have looked like a relatively uniform, flat plain almost at sea level. This plain extended from New Brunswick to beyond the present coastline and over at least part of today's continental shelf. Erosion occurred in the form of wind abrasion and flash flooding.
The climate was predominantly hot and probably moist. Flowering plants appeared in the Early Cretaceous and included various grains and grasses. Insects continued to evolve and help pollinate the flowers. The earliest evidence of snakes (descended from earlier reptiles) is from this period. Dinosaurs ruled the earth until the end of the Cretaceous Period, when a major extinction event signalled the end of the Mesozoic Era and the rise of mammals.