Petrology Archives - Page 5 of 11

Gneiss

June 26, 2020 admin 0

Gneiss is a banded coarse-grained metamorphic rock that formed deep in the crust beneath forming mountain ranges. The chemical composition may be highly variable, although […]

Bauxite

June 25, 2020 admin 0

Bauxite is an aluminum-rich sedimentary rock. It is a principal ore of aluminum. Aluminum in bauxite is hosted by aluminum hydroxide minerals, mostly gibbsite. The […]

What is the Black Stone of Mecca? What is the type of Black Stone?

June 24, 2020 admin 0

The Black Stone of Mecca, Al-Ḥajaru al-Aswad, “Black Stone”, or Kaaba Stone, is a Muslim relic, which according to Islamic tradition dates back to the […]

What is Petrified Wood? How Does it Form?

June 22, 2020 admin 0

What is Petrified Wood? Petrified wood is the name given to a special type of fossilized remains of terrestrial vegetation. It is the result of […]

What are Ripple Marks?

June 21, 2020 admin 0

Ripple marks are sedimentary structures and indicate agitation by water (current or waves) or wind. Ripple marks are ridges of sediment that form in response […]

Shale

June 10, 2020 admin 0

Shale is by far the most abundant sedimentary rock. Although strictly speaking shale is a rock, it is relatively weak and soft, and engineers consider […]

Differential Weathering

June 9, 2020 admin 1

Masses of rock do not weather uniformly. Take a moment to look back at the photo of Shiprock, New Mexico, in Figure 1. The durable […]

Arkose

June 9, 2020 admin 0

Arkose is a feldspar-rich (25%) sandstone. Arkose is usually coarse-grained and composed of angular grains. These properties are characteristic of relatively immature sediments. Arkose is […]

Compare and contrast the four basic igneous compositions: basaltic (mafic), granitic (felsic), andesitic (intermediate), and ultramafic. Igneous rocks are composed mainly of silicate minerals. Chemical […]

Diamictite

June 6, 2020 admin 0

Diamictite is a poorly sorted or non-sorted terrigenous non-calcareous sedimentary rock. Diamictite is composed of widely variable clast sizes from clay to boulders.Diamictite is a […]