Geological Glossary - Q

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Quaternary	The latest period of geologic time, covering the most-recent 1.6 million years of the Earth's history. It is divided into two epoch: the Pleistocene -- 1.6 million years ago to approximately 10,000 years ago -- and the Holocene -- the period from approximately 10,000 years ago to the present. The Quaternary period is the artificial division of time separating prehuman and human periods. It contains five ice age and four interglaqcial ages, and temperature indicators seem to show sharp abrupt changes by several degrees.
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quantitative stratigraphy	Use of computer-based mathematical methods to calibrate stratigraphic models that with a minimum of information provide maximum predictive potency and include formulation of confidence limits.
quartz	One of the most common mineral in the Earth’s crust (and in some new-age boutiques). Made up of silicon dioxide (SiO2),lso called silica. Commonly in white masses. Crystals are clear, glassy 6-sided prisms.
quartz arenite	"A sandstone containing very little except pure quartz grain and cement. When cemented by a secondary silica it is named quartzite; an orthoquartzite."
quartzite	(1) A very hard, clean, white metamorphic rock formed from a quartz arenite sandstone. (2) A quartz arenite containing so much cement that it resembles ( 1 ). (3) A nonfoliated metamorphic rock formed from pure, dominantly quartz sandstone. (4) Hard, somewhat glassy-looking rock made up almost entirely of quartz. Metamorphosed quartz sandstone and chert are quartzite.
quartzite	(1) A very hard, clean, white metamorphic rock formed from a quartz arenite sandstone. (2) A quartz arenite containing so much cement that it resembles ( 1 ). (3) A nonfoliated metamorphic rock formed from pure, dominantly quartz sandstone. (4) Hard, somewhat glassy-looking rock made up almost entirely of quartz. Metamorphosed quartz sandstone and chert are quartzite.
quartzose sandstone	(1) A quartz arenite. (2) A clean quartz sandstone, less pure than a quartz arehire, that may contain a moderate amount of other detrital mineral and/or calcite cement.