tree ring Layer of wood in a tree that forms in one year. You can determine the age of a
tree by counting its rings.
varve Thin layer of sediment deposited on a lakebed over the course of one year usually
found at the bottom of glacial lakes.
Points to Consider
- Why are techniques like tree rings, ice cores, and varves only useful for events that
occurred in the last few thousand years? - Why was it so important for Darwin and his followers to prove that the Earth was very
old? - Why is it important to use more than one method to find the age of a rock or other
object?
Image Sources
(1) griffin Arimaspus Louvre CA491.jpg,http:
//commons.wikimedia.org/wiki/Image:Protoceratops-skeleton.jpgGriffin
(left) andProtoceratops(right).. Public Domain,GNU-FDL.(2) Tribal,Eli Hodapp. teeth in stone.jpg,http://www.flickr.com/photos/io
burn/1805341269/ Fossil Shark Tooth (left) and Modern Shark Tooth (right)..
GNU-FDL,CC-A 2.0.(3) Lawrence Murray.
http://www.flickr.com/photos/22699083@N04/2284340556/sizes/o/. CC-A.(4) wiki/Image:Coprolite.jpg Coprolite (fossilized waste or feces) from a meat-eating
dinosaur.. Public Domain.(5) http://esp.cr.usgs.gov/info/kt/stop2b.html. Public Domain / USGS.(6) Tobias Alt. Canyon NP-Arizona-USA.jpg Grand Canyon, with the Kaibab Limestone
marked with arrows.. GNU-FDL.(7) Eric Cravens, Assistant Curator, National Ice Core Laboratory. crop.jpg Ice core
section showing annual layers.. Public Domain.(8) Pyrit.jpg,http://de.wikipedia.org/wiki/Benutzer:GD
Berlin,http://commons.wikimedia.org/wiki/Image:Pecopterisarborescens.jpg.
Public Domain,GNU-FDL.