Midterms

• Minerals - it is a naturally occurring inorganic element of compound having an orderly internal structure and characteristic chemical composition. Building blocks of rocks
• Mineralogy - Is the study of minerals
• Characteristics of Minerals:

  1. Naturally-Occurring
  2. Inorganic
  3. Homogeneous Solid
  4. Has definite chemical Composition
  5. Crystalline Shape
• Properties of Minerals:

  1. Color
  2. Streak
  3. Hardness
  4. Cleavage
  5. Luster
  6. Specific Gravity
• Color - is caused by the absorption, or lack thereof, of visible light by their crystalline structure.
• Luster - Refers to the quality of light on the surface of a rock, crystal, or mineral
• Hardness - ability to resist scratching or abrasion
• Cleavage - is the tendency of a mineral to split or cleave along the plane of weakness
• Specific Gravity - is to measure of relative density of a mineral
• Streak - is the color of powdered mineral produced hen it is dragged across an unweather surface.
• Rocks - a natural-occurring aggregate or combination of minerals and mineraloid, such as fossils and glass. The natural building block of the earth's lithosphere
• Petrology - is the scientific study of rocks
• Igneous rocks - formed from hardening and crystallization of magma or molten material that originated deep within the earth
• Two types of igneous rock:

  1. Extrusive / Volcanic rock
  2. Intrusive / Plutonic
• Extrusive - forms when magma makes it way to earth's surface as lave and then cools.
• Intrusive - it cools slowly beneath the earths surface and are created by magma.
• Sedimentary Rocks - rocks that are accumulated on earth's surface in a process called deposition
• 3 types of sedimentary rocks:

  1. Clastic
  2. Chemical
  3. Organic
• Clastic - formed from the accumulation of clasts: little pieces of broken rocks and shells
• Chimical - formed when dissolved minerals precipitate from a solution.
• Organic - rocks formed from the accumulation of animal debris
• Metamorphic rocks - forms from pre-existing rocks: methamorphic, igneous, sedimentary or other metamorphic rocks that have been altered by agents of metamorphism
• Metamorphism - transformation of one rock type into another
• two types of metamorphism:

  1. Contact
  2. Regional
• Contact - the rock minerals and textures are changed mainly by head due to contact with magma
• Regional - due to changes in pressure and temperature over large region of the crust. It may happen when rock is buried deep below the surface of the earth
• Types of Metamorphic Rocks:

  1. foliated
  2. Non-foliated
• Foliated - can be arranged in terms of increasing metamorphism, and it appeared layered or banded with compressed mineral grains.
• Non foliated - usually made up of only few mineral
• Geomorphic Processes - physical processes create and modify landforms on the surface of the earth
• Exogenic process - also called gradational process, the comprise degradation and aggradation. a CONTINUUM of process
• Exogenic process - are processes that take place at or near the earth's surface that makes the surface wear away
• Types of Exogenic Process:

  1. Weathering
  2. Erosion
  3. Mass Wasting
• Weathering - is the general term applied to the combined action of all physical and chemical processes that disintegrate and decompose rocks near the earth's surface through the elements of weathering
• Types of Weathering:

  1. Physical
  2. Chemical
  3. Biotic
• Physical Weathering - happens whenever rocks are broken up without any change in their chemical composition. Sometimes called as mechanical weathering
• Examples of Physical Weathering:

  1. Block disintegration
  2. Exfoliation
  3. Frost Action
• Block disintegration - caused by successive heating and cooling that cause the expansion and contraction of rocks
• Exfoliation - is the stripping of the outer layers of rocks due to intense heating
• Chemical Weathering - is the weakening or disintegration of rocks and the formation of new compounds or new substances caused by chemical reaction