Geology

Geological Material

• Majority of geological data comes from research on solid Earth materials
• Meteorites and other extraterrestrial natural materials are also studied
• Geologists study the mineralogical composition of rocks
• Geology determines the relative ages of rocks
• Geochemistry determines the absolute ages of rocks

Minerals

• Minerals are naturally occurring elements and compounds
• Each mineral has distinct physical properties
• Luster is the quality of light reflected from the surface of a mineral
• Color is used to identify minerals, although impurities can change color
• Streak is the color of the mark left by a mineral when scratched

Rocks

• Rocks are naturally occurring solid masses or aggregates of minerals
• Most research in geology is associated with the study of rocks
• There are three major types of rock: igneous, sedimentary, and metamorphic
• The rock cycle illustrates the relationships among these types of rock
• Organic matter is linked mainly to organic-rich sedimentary rocks

Unlithified Material

• Geologists study unlithified materials that lie above the bedrock
• This study is often known as Quaternary geology
• Superficial deposits are a type of unlithified material
• Quaternary period is the most recent period of geologic time
• Unlithified materials provide information about recent geological history

Whole-Earth Structure

• Plate tectonics is the major subtopic under whole-Earth structure
• Earth's lithosphere is separated into tectonic plates
• Plates move across the solid upper mantle called the asthenosphere
• Plate movement is coupled with mantle convection
• Plate tectonics explains geological features such as mid-ocean ridges and arcs of volcanoes and earthquakes.

Geology Data Sources