Reversing Rapids - 0 to 4600 million years ago - St. John, NB, Canada
Posted by: 
neoc1
N 45° 15.866 W 066° 05.274
19T E 728459 N 5016452
An interpretive sign at Fallsview Park in St. John New Brunswick tells the geological history of the Reversing Rapids. The timeline is that of the earth's geological eras.
Waymark Code: WMP46Y
Location: New Brunswick, Canada
Date Posted: 06/28/2015
Views: 12
The Reversing Rapids is a popular attraction in the Bay of Fundy where huge tides cause the St. John River to reverse its flow over a series of rapids with every high tide. A sign near the parking area gives geological history of this phenomenon. It reads:
About 20,000 years ago the last continental glaciation reached its maximum. Glaciers covered all of the Maritimes. As the glaciers retreated they left a changed landscape. Before the last glaciation the St. John River flowed to the sea through South Bay, past the Irving Nature Park. Retreating glaciers left piles of sand and gravel called moraines that damned that river outlet. When the river found its new route about 14,000 years ago it flowed over ridges at Reversing Rapids to create this gorge.
Thousands of years ago a waterfall existed here, but sea levels rose and the riverbed eroded, the waterfall was drowned. The phenomenon of the Reversing Rapids is only 3,000 years old. A profile of the riverbed shows a series of waterfalls must have existed here starting near the islands at Fallsview Park and ending near the bridges. Just past the islands the river bottom drops to about 25 metres below low water level. it then drops two more times to more than 40 meters below low water level just past the road bridge.
The time line at the left side of the sign gives the earth's geological history. It identifies the eras from the present, O million years = Neogene, to Precambrian = 600 million years ago and continues to the formation of the earth = 4600 million years ago:
GEOLOGICAL AGES
FOR THIS SITE
PRECAMBRIAN
NEOGENE
0 <=
NEOGENE
23
PALEOGENE
65
CRETACEOUS
145
JURASSIC
199
TRIASSIC
251
PERMIAN
299
UPPER CARBONIFEROUS
318
LOWER CARBONIFEROUS
359
DEVONIAN
416
SILURIAN
443
ORDOVICIAN
488
CAMBRIAN
542
PRECAMBRIAN
600 <=
1000
4600
MILLIONS OF YEARS
Visit Instructions:At least one good photo you have personally obtained and a brief story of your visit. Any additions or corrections to the information about the Waymark (for instance, have the hours open to the public changed) will be greatly appreciated.