(ËlÉk tÉrn) n. 1. a reading desk in a church from which the Bible lessons are read during the service. 2. a stand with a slanted top, used to hold a book, speech, etc., at the proper height for a standing reader or speaker.
How a Diamond is Formed. In order for diamond to form there must be an available source of carbon and relatively narrow ranges of temperates and pressures must align. This happens around 100 miles below the crust. Once crystalized the diamonds must be rapidly transported to the surface without undergoing substantial change.
This carbon probably was pulled during plate subduction, since eclogitic diamonds were formed mainly in old subduction regions. These diamonds have been carried to the surface in a few places by violent eruptions caused by the release of active fluids, probably mainly water, in the hot rocks of the upper mantle.