from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A mass of igneous rock intruded between layers of sedimentary rock, resulting in uplift.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. a mass of igneous or volcanic rock found within strata which forces the overlaying strata upwards and forms domes.
- n. mass similar to lopolith but concave up.
from The Century Dictionary and Cyclopedia
- n. A name given by G. K. Gilbert to masses of lava which, when rising from below, have not found their way to the surface, but have spread out laterally, and formed a lenticular aggregation, thereby lifting the rocks above into dome-shaped forms.
Wikipedia has an interesting blurb about it: "Whilst he was in fact describing an actual geological feature - a laccolith which he saw as resembling a cactus 1 - he was also, tongue-in-cheek, commenting on what he saw as an absurd number of "-lith" words in the field of Geology."
The laccolith (Greek laccos, cistern; lithos, stone) is a variety of intrusive masses in which molten rock has spread between the strata, and, lifting the strata above it to a dome - shaped form, has collected beneath them in a lens-shaped body with
The large shear zones may converge and are the hosts for the mineralization, but finer grained porphyritic dikes and sills that are located near mineralization are emplaced as laccolith type fillings parallel to the shear zone with north south structural boundaries.