JK by rudi.fisika


									Geology & Geophysics Dictionary By Rudi

Jade: A translucent gemstone consisting of either jadeite or nephrite that is typically green in color. Jade is a very durable stone and is used for a variety of jewelry and ornamental objects. Typically cut in the cabochon shape or carved. Jadeite: A high pressure clinopyroxene that is frequently carved and polished as a gemstone. Jasper: A variety of colored chert, typically red or green and often found in association with iron ores. Jasper is frequently used as a gemstone or in the production of ornaments. Jet: A variety of coal that is frequently cut and polished for jewelry or ornaments. Jetty: A human made structure built at right angles to a coastline and extending into the water. Jetties are built to protect an area of shoreline from the effects of currents, erosion or deposition. Joint: A fracture in rock along which there has been no displacement. Joint Set: A group of joints that are parallel or nearly parallel. They are frequently formed at the same time interval from a common process. Jolly Balance: A spring balance used in the determination of specific gravity. Juvenile Water: Water that is new to the hydrologic cycle. Brought to Earth's surface through volcanic eruptions.

Karst: A landscape that is characterized by the features of solution weathering and erosion in the subsurface. These features include caves, sinkholes, disappearing streams and subsurface drainage. Kerogen: Solid organic substances frequently found in shales. The organic component of an oil shale. Kettle: A depression formed in glacial deposits when a buried block of ice, left behind by a retreating glacier, melts. Kettle Lake: A lake that forms in a kettle. K-feldspar: A potassium feldspar such as orthoclase, microcline, sanidine or adularia. Also referred to as potash feldspar. Kilobar: A unit of pressure equal to 1000 bars (the mean Kimberlite: A variety of peridotite that is found in volcanic pipes which are thought to be intrusions from the upper mantle. Many diamond deposits are found in kimberlite pipes. Knickpoint: An abrupt change in slope. A point on a stream profile where a change in gradient occurs. This could be caused by a change in underlying bedrock or bedrock structure. Knob: A small hilltop that is round in shape.

atmospheric pressure at 100 meters above sea level is one bar).

- 13 -

To top