Background Info

The Minas Basin, part of the Bay of Fundy in Nova Scotia, Canada, is home to the most dramatic tidal range in the world. Tides, moving as fast as a person can walk, rise and fall as much as 14-16 meters (46-52 feet) every day.

This photograph was taken at low tide, exposing the wide, extensive mudflats of the Minas tidal basin.

The Minas Basin is an estuary. It forms at the mouth of the Cornwallis River, where it empties into the Bay of Fundy and the Atlantic Ocean. Like many estuaries around the world, the mudflats of the Minas Basin are blanketed by thick layers of bay mud.

Bay mud has many unique characteristics. It is often saturated with moving water, creating extremely fine-grained sand particles. It has a high concentration of clay, mostly from silty river deposits. Bay mud also contains sediments carried by glaciers during the last ice age. This all combines to create very soft, flexible mud.

Layers of bay mud are classified according to their age. Quaternary older bay mud—layers from the Ice Age and earlier is abbreviated QoBM. Quaternary younger bay mud is abbreviated QyBM. Layers of QyBM can be as thick as 8 meters (25 feet), while layers of QoBM can be more than 55 meters (180 feet).



Do you think these mudflats are good places to farm?

Show Answer

Answers will vary.

No: The extreme tides and lack of dry soil make it impossible to farm on the Minas Basin mudflats.

Yes: Dikes have been used throughout the coastline of the Bay of Fundy. These levees block the tides and "reclaim" low-lying mudflats for agriculture and development. Similar land reclamation is common in places such as the Netherlands (where levees block the North Sea) and along the Mississippi River basin in the United States.


Do you think mudflats are good places for industry?

Show Answer

Answers will vary.

No: Bay mud is far too soft and flexible to provide a stable foundation for most large, heavy buildings. Structures built on bay mud in seismically active areas, such as the San Francisco Bay Area, are especially vulnerable.

Yes: Engineers can secure a building's foundation to harder, more stable rock beneath the layers of bay mud. Sometimes, these features, called pilings, can reach more than 30 meters (100 feet) below ground.


Bay mud is divided into Quaternary old bay mud (QoBM) and Quaternary younger bay mud (QyBM). Which layer do you think lies deeper underground?

Show Answer

QoBM was deposited hundreds and even thousands of years before QyBM. It is a much deeper layer of sediment, found underneath QyBM.


Term Part of Speech Definition Encyclopedic Entry

bay mud


thick deposits of soft rocks (mostly clay, silt, and sand) that form around some bays and estuaries.



physical, cultural, or psychological feature of an organism, place, or object.



type of sedimentary rock that is able to be shaped when wet.



mouth of a river where the river's current meets the sea's tide.

Encyclopedic Entry: estuary



mass of ice that moves slowly over land.

Encyclopedic Entry: glacier

ice age


long period of cold climate where glaciers cover large parts of the Earth. The last ice age peaked about 20,000 years ago. Also called glacial age.

low tide


water level that has dropped as a result of the moon's gravitational pull on the Earth.



place where a river empties its water. Usually rivers enter another body of water at their mouths.

Encyclopedic Entry: mouth



coastal wetland formed as rivers or tides deposit sediment.



small, loose grains of disintegrated rocks.



to fill one substance with as much of another substance as it can take.



solid material transported and deposited by water, ice, and wind.

Encyclopedic Entry: sediment



small sediment particles.

Encyclopedic Entry: silt

tidal basin


depression in the earth that fills with water at high tide.

tidal plain


large, flat area where mud and sediment are deposited by ocean tides. Also called tidal flat or mudflat.

tidal range


the difference in height between an area's high tide and low tide.



rise and fall of the ocean's waters, caused by the gravitational pull of the moon and sun.

Encyclopedic Entry: tide


Media Credits

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Ben Farmer


Caryl-Sue, National Geographic Society

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