Glossary


asthenosphere: the geosphere of the Earth that is interior to the lithosphere. Because it is marked by low seismic wave velocities and high seismic attentuation, it is inferred that the asthenosphere is a soft layer, probably partially molten.
benthic: of the sea floor, or pertaining to organisms living on or in the sea floor; (It is now important to differentiate between organisms which live in the bottom water, in the sea floor sediment, or in the crust. Indeed, if the subsurface ecosystem proves to be zonally complex, a new vocabulary with which to specify subsurface biological regions may be warranted. For now, it may do to use "benthic" to describe life living near the sediment-water interface, or above the crust-water contact, and "endolithic" to describe life living beneath the water-crust, in lithified sediments, or entirely within the crust.)
crust/crustal: outermost layer of the lithosphere consisting of relatively low-density, low-melting temperature material; the crust is typically subdivided on the basis of seismic velocity gradients and deep sea drilling data.
endolithic: in the rock; compare with benthic...
lithosphere: the outermost geosphere of the Earth, located external to the asthenosphere and containing the crust.