GeoWord of the Day

The GeoWord of the Day is a free service of the American Geosciences Institute. All of the terms and definitions are from the Glossary of Geology, 5th Edition Revised.

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GeoWord of the Daydepositional fabric . Rock fabric or that fabric element or elements that result from deposition during the rock's formation, e.g. sedimentary grains in an unmetamorphosed, current-laid sediment or crystals deposited by crystal settling in a magma chamber; the fabric of a primary tectonite. Cf: deformation fabric.

GeoWord of the Dayparisite-(Ce) . A brownish-yellow rhombohedral secondary mineral: (Ce,La)2Ca(CO3)3F2. It crystallizes in numerous rhombohedral, hexagonal, and monoclinic polytypes. It is related to synchysite.

GeoWord of the Daysporbo (spor'-bo). A term used in the San Joaquin Valley, Calif., for oolite. Pl: sporbo. Etymol: s mooth- po lished- r ound- b lack ( b lue or b rown)- o bject (Galliher, 1931, p.257).

GeoWord of the Dayglade [karst] . (a) A Jamaican term for an elongate depression, having steep sides, in which a generally flat floor is divided into small basins separated by low divides. (b) In Tennessee, limestone pavement having extensive growth of cedar trees. Cf: karst valley.

GeoWord of the Daybiaxial stress . A stress system in which only one of the three principal stresses is zero.

GeoWord of the Dayapical archeopyle . An archeopyle formed in a dinoflagellate cyst by the loss of the entire apical series of plates.

GeoWord of the Daytracheid (tra'-che-id). A pitted, lignified, elongate, cylindrical cell that is the basic water-conducting and support cell in xylem tissue. Tracheids often have tapered end walls and are nonliving at maturity. Cryptogams and gymnosperms generally have only tracheids for conduction; most angiosperms also have vessels.

GeoWord of the DayClerici solution (Cle-ri'-ci). A solution of thallium malonate and thallium formate in water that is used as a heavy liquid; its specific gravity is 4.15. Cf: Sonstadt solution; Klein solution; bromoform; methylene iodide.

GeoWord of the Daygreen beryl . A term applied to the light green or pale green gem variety of beryl, as distinguished from the full green or richly green-colored emerald and the light blue-green aquamarine.

GeoWord of the Dayaspidolite . An olive-green trioctahedral mica: NaMg3(Si3Al)O10(OH)2. Syn: sodium phlogopite; wonesite.