Cours de Géologie

Gagner Du Temps, Trouvez Ce Que Vous Voulez En Remplissant Ce Formulaire

Geyser



A geyser is a vent in Earth's surface that periodically ejects a column of hot water and steam. Even a small geyser is an amazing phenomenon; however some geysers have eruptions that blast thousands of gallons of boiling hot water up to a few hundred feet in the air.
  

Volcanoes & Magma



Magma is molten rock and the other materials contained within: gases, liquids, solids. Magma reaching the earth's surface is expelled through a volcano. It is a vent from lower regions of the earth.

Lava is a river of molten magma. Magma may also be explosively expelled and be in the form of super heated gases and tiny hot particles.

  

The Geology of Egypt



The three layers

A layer of limestone covers most of the surface of modern Egypt.

Beneath this lies a bed of sandstone, and this earlier sandstone is the surface rock in Nubia and southern Upper Egypt, as far north as the area between Edfu and Luxor.

The oldest ground of modern Egypt comprises outcrops of metamorphic and igneous rocks.

  

Kyanite



Kyanite is a metamorphic mineral that most often forms from the high pressure alteration of clay-rich sedimentary rocks. It is found in the schists and gneisses of regionally metamorphosed areas and less often in quartzite or eclogite.

Kyanite's typical habit is a bladed crystal although it sometimes occurs as radiating masses of crystals. Kyanite is often associated with other metamorphic minerals such as garnet, staurolite and corundum.

  

Theoretical Basis for Medical Geology (Part 2)

THE MEDICAL GEOLOGY APPROACH TOWARDS STEWARDSHIP

Human existence is embedded in the Earth System along with its composition and workings. The vast array of processes and transformations among solid, aqueous and gas phases with the participation of living organisms encompassing the Earth System forms the milieu for human interaction with the system. The approach of Medical Geology involves the study of the materials and their reactions, transport, effects and fates. This requires a two-prong approach in understanding the respective components and the processes constituting the interactions between these.

Aspect One: Components of the Environment

One aspect involves understanding the components of the Earth System i.e. rocks, soils, waters and the atmosphere. This involves the solid or terrestrial Earth or geosphere/lithosphere, the aqueous layer or hydrosphere, the gaseous cover or atmosphere and the biosphere consists all of the living things on Earth as depicted in Fig. 8. The biosphere along with the other three spheres forms the ecosystem.




  

Theoretical Basis for Medical Geology (Part 1)

The genesis of what has evolved into Medical Geology can be traced back to the realization of the environmental factor as one of the causal factors affecting health although, according to Finkelman et al. (2001), the impacts of geologic materials on human health have been recognized for thousands of years. This developed in response to apprehension of environmental degradation arising out of anthropogenic impacts resulting from industrial technology. Silent Spring (Carson, 1962) is the earliest expression of this apprehension has come to be defined by the health and environment cause-effect framework given in Fig. 1 below by WHO (2000).

  

What is Earth Science ?

Introduction
Earth Science is the study of the Earth and its neighbors in space. It is an exciting science with many interesting and practical applications. Some Earth scientists use their knowledge of the Earth to locate and develop energy and mineral resources. Others study the impact of human activity on Earth's environment and design methods to protect the planet. Some use their knowledge about Earth processes such as volcanoes, earthquakes and hurricanes to plan communities that will not expose people to these dangerous events.

The Four Earth Sciences
Many different sciences are used to learn about the earth, however, the four basic areas of Earth science study are: geology, meteorology, oceanography and astronomy. A brief explanation of these sciences is provided below.