Geosciences
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 time of Adam and Eve. … Read More
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 a tree or tree-like plants … Read More
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 to wind blowing along a … Read More
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 volcanic neck protrudes high above … Read More
Identify and describe the six major igneous textures. The term igneous exture is used to describe the overall appearance of a rock based on the size, shape, and arrangement of … Read More
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 analyses show that silicon and … Read More
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 nongenetic term (purely descriptive, no … Read More
Chalk is weak, friable, pure limestone; when fresh, UCS = 5–27 MPa; but porosity is 30–50%, so UCS reduces to 50–70% when saturated.It may have solution features, caves and sinkholes, … Read More
