Category: 

What is Loess?

The Shaanxi area of China has deep loess plateaus.
Loess have been formed by a combination of glaciers and wind.
Loess can be used in agriculture to produce rich soil for planting and growing crops.
Article Details
  • Written By: S. Mithra
  • Edited By: L. S. Wynn
  • Last Modified Date: 11 August 2014
  • Copyright Protected:
    2003-2014
    Conjecture Corporation
  • Print this Article
Free Widgets for your Site/Blog
A chameleon’s tongue is 1.5 times the length of its body.  more...

September 1 ,  1939 :  The Nazis invaded Poland, starting World War II.  more...

Loess is a mineral silt, made by glaciers and wind, forming rare ecosystems. Loess, pronounced "luss," forms hills, mountains, bluffs, and gulleys during the slow process of its deposit and relatively rapid erosion. River valleys and plateaus of loess provide very rich soil, perfect for agriculture, and beautiful, recognizable topographical features.

Loess, meaning "crumbly" in German, is made primarily of particles of quartz, mica, feldspar, and other silicates that make it brown or yellow in color. Loess has a small amount of clay, so it's not sticky like sediment, but rather slippery; that's why it erodes so much more quickly than other types of soil. The central and northwestern areas of the United States, Ukraine, eastern China, and eastern and central Europe all have significant deposits of loess. Agriculture has thrived in these areas since prehistoric humans took advantage of the rich topsoil to grow crops. These rare geographic locations, separated by thousands of miles, all share a similar geologic history.

Ad

Migrating, melting glaciers and high winds formed loess thousands of years ago, after the last Ice Age. First, glaciers scraped along huge beds of rock, dislodging and grinding the rock into particulate minerals. Then, the melting glaciers washed this debris along channels to low-lying areas and flood plains. Eventually, as the earth's temperature continued to rise, these lakes of mud dried. Finally, swift wind carried the light, powdery loess in drifts that layered to form bluffs, hills, and mountains. This is why geologists refer to the formation of loess as eolian, or made by wind.

Loess deposits form striking, remarkable landscapes, such as the Loess Formation of Iowa. There, we see ridged hills, steep mountain drops, deep gullies, jagged crests, and ambling spurs. From the air, the wedge-shaped mountain ranges trace the history of the direction of wind. Different layers, from separate cycles of flooding and blowing, inform geologists about the earth's past. In Iowa, their deposits vary from just 12,000 years ago to 160,000 years ago. The depth of the loess reaches 300 feet (91 m) in some areas. The Shaanxi area of China has much deeper loess plateaus, up to 1,000 feet (305 m) thick, although they exhibit much more erosion.

Ad

More from Wisegeek

You might also Like

Discuss this Article

anon152359
Post 5

Thanks. this site helped me to figure out the answer to a question. I thought I had my answer right and I did,but I checked the information here to make sure my answer was correct. Thank you for the help,it is appreciated!

anon58705
Post 4

what is the chemical equation( balanced equation) for Loess soil? Thanks

anon48206
Post 3

this website gave me an A!

anon47832
Post 2

this website helped me a lot!

anon27016
Post 1

This website is awesomeeeee!!!

Post your comments

Post Anonymously

Login

username
password
forgot password?

Register

username
password
confirm
email