Arkose

Arkose /ˈɑːrkoʊz/ is a detrital sedimentary rock, specifically a type of sandstone containing at least 25% feldspar.Arkosic sand is sand that is similarly rich in feldspar, and thus the potential precursor of arkose.

Quartz is commonly the dominant mineral component, and some mica is often present. Apart from the mineral content, rock fragments may also be a significant component. Arkose usually contains small amounts of calcite cement, which causes it to 'fizz' slightly in dilute hydrochloric acid; sometimes the cement also contains iron oxide. Arkose is typically grey to reddish in colour. The sand grains making up an arkose may range from fine to very coarse, but tend toward the coarser end of the scale. Fossils are rare in arkose, due to the depositional processes that form it, although bedding is frequently visible.

Arkose is generally formed from the weathering of feldspar-rich igneous or metamorphic, most commonly granitic rocks, which are primarily composed of quartz and feldspar (called 'grus' as a sand). These sediments must be deposited rapidly and/or in a cold or arid environment such that the feldspar does not undergo significant chemical weathering and decomposition; therefore arkose is designated a texturally immature sedimentary rock. Arkose is often associated with conglomerate deposits sourced from granitic terrain and is often found above unconformities in the immediate vicinity of granite terrains.

Edubuntu

Edubuntu, also previously known as Ubuntu Education Edition, is an official derivative of the Ubuntu operating system designed for use in classrooms inside schools, homes and communities.

Edubuntu has been developed in collaboration with teachers and technologists in multiple countries. Edubuntu is built on top of the Ubuntu base, incorporates the LTSP thin client architecture and several education-specific applications, and is aimed at users aged 6 to 18. It is designed for easy installation and ongoing system maintenance.

Features

Included with Edubuntu is the Linux Terminal Server Project, a large number of educational applications including GCompris, KDE Edutainment Suite, Sabayon Profile Manager, Pessulus Lockdown Editor, Edubuntu Menueditor, LibreOffice, Gnome Nanny and iTalc as well as many more. Edubuntu CDs were previously available for free through their Shipit service. As of version 8.10 (2008), it is only available as a download in a DVD format.

Edubuntu's default GUI is Unity while GNOME is still available.Unity has been the default GUI since the release of 12.04. Since release 7.10, KDE is also available as Edubuntu KDE. Since Ubuntu 10.04, the Edubuntu community has also worked with the Qimo 4 Kids project to provide a Qimo desktop that is Xfce based.