Keywords

[trench] (c) Any long, narrow cut or excavation produced naturally in the Earth’s surface by erosion or tectonic movements.  Also, a similar feature produced artificially, such as a ditch.

Geological keywords, such as “granite”, “lake”.  The definitions are generally taken from the AGI Glossary of Geology.  Keywords with a geographic context (e.g. Cape Smith Fold Belt, Selwyn Basin, Grenville Province) are assigned to a separate category.