myodocope (my-o'-do-cope). Any ostracode belonging to the order Myodocopida, characterized by a shell with subequal valves that may be ornamented or smooth and by a well developed rostrum. Most planktonic marine ostracodes are myodocopes. Range, Ordovician to Holocene.
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.
cirque floor . The nearly flat surface at the bottom of a cirque. Cf: cirque niveau.
wupatkiite . A fibrous silky rose-colored monoclinic mineral of the halotrichite group: (Co,Mg,Ni)Al2(SO4)4•22H2O.
alternative hypothesis . In statistical testing, a hypothesis that is the complement of the null hypothesis. Together, the null and alternative hypotheses must encompass all possible outcomes of the test.
monophyly . Condition of or relating to a monophyletic group.
isothermic temperature regime . A soil temperature regime that has the characteristics of a thermic temperature regime except for a summer-winter variation < 5°C.
Buerger precession method (Buer'-ger). The recording on film of a single level of the reciprocal lattice of an individual crystal by means of X-ray diffractions, for the purpose of determining unit-cell dimensions and space groups. See also: precession camera. Syn: precession method.
protoconodont . Microscopic phosphatic sclerites, usually long and conical, consisting of weakly mineralized (apatitic) and organic layers accreted basally from the inner surface. Many workers do not include the group among the Conodonta, but either as ancestral to the paraconodont structural grade or as a non-related group. Some consider protoconodonts to be Chaetognatha sclerites because of compositional, structural, and morphological similarity. Range: latest Precambrian to Ordovician. See also: conodont . Cf: euconodont; paraconodont .
bilibinskite (bi-li-binsk'-ite). A semi-metallic brown cubic mineral with a crystal structure related to that of gold, and previously referred to as rickardite : Au3Cu2Pb•nTeO2 .
chenite (chen'-ite). A blue triclinic mineral: Pb4Cu(SO4)2(OH)6 .
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