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.

Subscribe via EMail to the GeoWord of the Day.

belonosphaerite (bel''-o-no-sphae'-rite). An obsolete term for a spherulite whose minerals are in radial arrangement.

stratiform nickel-copper deposit . A mineral-deposit type characterized by stratiform nickel and copper sulfide minerals in the basal portion of layered mafic-ultramafic intrusive complexes. Syn: Stillwater-type nickel-copper deposit.

rutheniridosmine (ru''-then-ir''-id-os'-mine). A metallic white hexagonal mineral: (Ir,Os,Ru) .

initial ratio [radioactivity] . The atomic ratio of two isotopes of an element at the time of crystallization of a mineral containing one or more radioactive elements.

cork cambium . In woody plants, a cambium or lateral meristem in the outer bark that produces cork (phellem) to the outside and phelloderm toward the inside. Syn: phellogen. Cf: periderm [bot]; vascular cambium.

flat-on-flat geometry . The situation where a flat in the hanging-wall template of a fault is juxtaposed against a flat in the footwall template of the fault.

flinkite (flink'-ite). A greenish-brown or green orthorhombic mineral: Mn2+2Mn3+(AsO4)(OH)4 .

permafrost island . A small, shallow, isolated patch of permafrost surrounded by unfrozen ground; occurs on protected north-facing slopes in regions of sporadic permafrost.

flat [lake] . (a) The low-lying, exposed, flat land of a lake delta or of a lake bottom. (b) The flat bottom of a desiccated lake in the arid parts of western U.S. Commonly used in the plural.

calcite bubble . A nonattached hollow sphere, usually of calcite, that has formed around a gas bubble on the surface of a cave pool. Syn: cave bubble .


Subscribe to GeoWord of the Day