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).

Questions

1. 

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.

2. 

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.

3. 

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.

Vocabulary

Term Part of Speech Definition Encyclopedic Entry

bay mud

Noun

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

characteristic

Noun

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

clay

Noun

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

estuary

Noun

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

Encyclopedic Entry: estuary

glacier

Noun

mass of ice that moves slowly over land.

Encyclopedic Entry: glacier

ice age

Noun

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

Noun

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

mouth

Noun

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

Encyclopedic Entry: mouth

mudflat

Noun

coastal wetland formed as rivers or tides deposit sediment.

sand

Noun

small, loose grains of disintegrated rocks.

saturate

Verb

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

sediment

Noun

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

Encyclopedic Entry: sediment

silt

Noun

small sediment particles.

Encyclopedic Entry: silt

tidal basin

Noun

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

tidal plain

Noun

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

tidal range

Noun

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

tide

Noun

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

Encyclopedic Entry: tide

Credits

Media Credits

The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit. The Rights Holder for media is the person or group credited.

Photographer

Ben Farmer

Producer

Caryl-Sue, National Geographic Society

User Permissions

For information on user permissions, please read our Terms of Service.

If you have questions about licensing content on this page, please contact natgeocreative@ngs.org for more information and to obtain a license.

If you have questions about how to cite anything on our website in your project or classroom presentation, please visit our FAQ page.

Media

Some media assets (videos, photos, audio recordings and PDFs) can be downloaded and used outside the National Geographic website according to the Terms of Service. If a media asset is downloadable, a download button appears in the lower right hand corner (download) of the media viewer. If no button appears, you cannot download or save the media.

Text

Text on this page is printable and can be used according to our Terms of Service.

Interactives

Any interactives on this page can only be played while you are visiting our website. You cannot download interactives.