Geothermal gradient

Geothermal gradient is the rate of increasing temperature with respect to increasing depth in the Earth's interior. Away from tectonic plate boundaries, it is about 25 °C per km of depth (1 °F per 70 feet of depth) near the surface in most of the world. Strictly speaking, geo-thermal necessarily refers to the Earth but the concept may be applied to other planets. A line tracing the gradient through the planetary body is called a geotherm on Earth and other terrestrial planets. On the Moon it is called a selenotherm.

The Earth's internal heat comes from a combination of residual heat from planetary accretion, heat produced through radioactive decay, and possibly heat from other sources. The major heat-producing isotopes in the Earth are potassium-40, uranium-238, uranium-235, and thorium-232. At the center of the planet, the temperature may be up to 7,000 K and the pressure could reach 360 GPa(3.6 million atm). Because much of the heat is provided by radioactive decay, scientists believe that early in Earth history, before isotopes with short half-lives had been depleted, Earth's heat production would have been much higher. Heat production was twice that of present-day at approximately 3 billion years ago, resulting in larger temperature gradients within the Earth, larger rates of mantle convection and plate tectonics, allowing the production of igneous rocks such as komatiites that are not formed anymore today.

Geothermal (disambiguation)

Geothermal is related to energy and may refer to:

Renewable technology

Zone

Zone or The Zone or In the Zone may refer to:

Geography

Place names

Zones

Zone (play)

Zone is a French-language three-act play written by French-Canadian author Marcel Dubé. Written when Dubé was 21 and based on memories of his childhood,Zone revolves around a gang of teenaged Québécois criminals who sell contraband cigarettes, and the internal conflicts that ultimately tear the group apart. The title "Zone" refers to the fact that each of the smugglers are stuck in a zone of society from which it is almost impossible to escape.

Cast

The original production of Zone was directed by Robert Rivard.

Characters

Zone (band)

Zone was an all-female pop rock band started in Sapporo, Japan in 1999. Although it initially started as a dance group, they turned to an all-female band. Zone has been categorized in a new genre called "bandol" (a portmanteau of the words band and idol). The band was started and managed by Studio RunTime and released their first single, "Good Days", under the major record label Sony Records, on February 7, 2001. The group has officially ended on March 2, 2013.

Their most famous song is "Secret Base (Kimi ga Kureta Mono)", released on August 8, 2001. The single sold about 744,000 copies on Japanese Oricon charts.

History

Zone started off with eight members in 1997, then reduced to six and finally to four – Miyu Nagase, Mizuho Saito, Maiko Sakae, and Takayo Ookoshi – by the time they released their first indie disc in 1999.

Tadayuki Ominami, a representative of Sony Records, noticed that the crowd reaction to the group's debut concert was particularly enthusiastic. Initially, Zone was solely focused on singing and dancing. Ominami watched a live video of the band playing with instruments at the KomeKome Klub and felt that, due to the overabundance of dance groups, Zone had the makings of a breakthrough act, provided they could play their instruments as well as sing and dance.