Skip to page content |

Tiscali Quicklinks. Please visit our Accessibility Page for a list of the Access Keys you can use to find your way around the site, skip directly to the main navigation, to the page content, or to more links within reference.

Advertisement starts

Advertisement ends

Content Starts Here

chalk (rock)

encyclopaedia header
Encyclopaedia Search
Click a letter for the index
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Or search the encyclopaedia:
 
 
 
all results tagged with the © symbol denotes content that is relevant to the national curriculum

Chalk (rock)

chalk cliffs on the Isle of Purbeck, Dorset - Click to enlarge chalk soil - Click to enlarge

Click images to enlarge

Soft, fine-grained, whitish sedimentary rock composed of calcium carbonate, CaCO3, extensively quarried for use in cement, lime, and mortar, and in the manufacture of cosmetics and toothpaste. Blackboard chalk in fact consists of gypsum (calcium sulphate, CaSO4.2H2O).

Chalk was once thought to derive from the remains of microscopic animals or foraminifera. In 1953, however, it was seen under the electron microscope to be composed chiefly of coccolithophores, unicellular lime-secreting algae, and hence primarily of plant origin. It is formed from deposits of deep-sea sediments called oozes.

© Research Machines plc 2008. All rights reserved. Helicon Publishing is a division of Research Machines plc.


 
Back
 

Advertisement starts

Advertisement ends



atmosphere (earth science)
basalt
calcium carbonate
calcium hydroxide
carbon cycle
carbon dioxide
carbonate
cementation
chalk (rock)
chemical weathering
coastal erosion
conglomerate (geology)
continental drift
core (earth science)
crust
earthquake
erosion
evaporation
exfoliation
extrusive rock
fault
fertilizer
fold
fossil
freeze–thaw
global warming
gneiss
granite
gravel
greenhouse effect
helium
igneous rock
intrusive rock
krypton
lava
limestone
lithosphere
magma
mantle
marble
metamorphic rock
metamorphism
mineral
neon
nitrate
nitrogen
nitrogen cycle
ocean
oxygen
physical weathering
plate
plate tectonics
plutonic rock
pollution
Precambrian era
rock
rock cycle
sandstone
schist
seafloor spreading
seawater
sediment
sedimentary rock
shale
silica
slate
soil
volcano
water
water cycle
water pollution
weathering

Related Links

St Vincent and the Grenadines Flag
St Vincent and the Grenadines Flag Green stands for agriculture, the lush vegetation, and the enduring vitality of the population. Gold symbolizes warmth, the bright spirit of the people, and the golden sands. Blue represents the sky and sea. Effective date: 24 October 1985. >>

Advertorial

AdvertorialFind out how to buy the things you've always wanted and sell the things you don't on ebay.

Advertisement starts

Advertisement ends

More Links Within This Section

-->
encylopaedia

Page Footer

print now Print now send to a friend Send to a friend related articles Related articles related products Related products

Check shares

Check shares
Look up latest prices
more...

Best Loans

Best Loans
Search for the best rate.
more...

Dating

Dating
Find the love of your life
more...

TV guide

TV Guide
What's on the box?
more...
| Advertise | Press | Work at Tiscali | Site Map | Service Status | Help | Contact Us
© Tiscali 2008
IT | NET | SERVICES

Access keys


You will need to use different key combinations in order to use access keys depending on your internet browser, find out which on our accessibility page.
  • (0) Navigate to Accessibility page.
  • (1) Navigate to Home page.
  • (2) Navigate to My email.
  • (3) Navigate to My Account.
  • (4) Navigate to Site Map page.
  • (5) Navigate to Contact us page.
  • (6) Navigate to Members channel.
  • (7) Navigate to Services channel.
  • (8) Navigate to News & Info channel.
  • (9) Navigate to Entertainment channel.
  • ([) Skip down to the Primary navigation block.
  • (]) Skip down to the more links within this section block.
  • (=) Bypass all navigation and jump to the content.