isograd (  s -gr d ) A line on a map connecting points on the Earth where metamorphism of rocks occurred under the same pressure and temperature conditions. These lines are established on the basis of the distribution of index minerals and are useful in reconstructing the tectonic history of a given region. |
Want to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit the webmaster's page for free fun content.
| ?Page tools | ||
|---|---|---|
|