W, S & MM

This week on NS we had a report about Weathering, Soil and Mass Movement, and the other group reported about the Earth Resources. We told our classmates some important things to know about weathering and we showed them a short video for the class to not get bored.

WEATHERING

The action of the weather conditions in altering the color, texture, composition, or form of exposed objects

The physical disintegration and chemical decomposition of earth materials at or near the earth’s surface

MECHANICAL WEATHERING

        -It occurs when physical forces break rock into smaller and smaller pieces without changing the rock’s mineral composition.

3 PHYSICAL PROCESS

ž  Frost Wedging

ž  Unloading

ž  Biological Activity

1. Frost wedging

   The mechanical breakup of rock caused by the expansion of freezing water in cracks and crevices

2. Unloading

                  Reduced pressure on igneous rock causes it to expand and allows slabs of outer rock to break off in layers in a process called exfoliation.

3. Biological activity

                  The activity of organisms, including plants, burrowing animals, and humans, can also
cause mechanical weathering.

ž  CHEMICAL WEATHERING

Ø                    is the transformation of rock into one or more new compounds.

Ø  Chemical weathering changes the composition of rocks, often transforming them when water interacts with minerals to create various chemical reactions.

The reactions as follows:

CO₂ + H₂O => H₂CO₃

carbon dioxide + water => carbonic acid

Rate of Weathering

1. Rock characteristics

2. Climate

3. Differential Weathering

SOIL

Characteristics of Soil

v      Soil is part of the regolith that supports the growth of plants.

        Regolith is the layer of rock and mineral fragments that covers most of Earth’s land surface.

v  Soil Formation

The most important factors in soil formation are parent material, time, climate, organisms, and slope.

1. Parent material

ž        Residual soil —parent material is the bedrock

 Transported soil —parent material has been carried from elsewhere and deposited

2. Time - Important in all geologic processes

         The longer a soil has been forming, the thicker
         it becomes.

3. Climate - Greatest effect on soil formation

4. Organisms - Organisms influence the soil's physical and 
                  chemical properties.

5. Slope

ANGLE

 Steep slopes often have poorly developed soils.

Optimum slope is a flat-to-undulating upland surface.

ž  

Soil Types

1. Pedalfer

  Accumulation of iron oxides and aluminum-rich clays in the B horizon

  Best developed under forest vegetation

2. Pedocal

  Accumulates calcium carbonate

  Associated with drier grasslands

3. Laterite

  Hot, wet, tropical climates

  Intense chemical weathering

ž  MASS MOVEMENTS

Triggers of Mass Movements

                   Among the factors that commonly trigger mass movements are saturation of surface materials with water, oversteepening of slopes, removal of vegetation, and earthquakes.

                  The transfer of rock and soil downslope due to gravity is called mass movement.

Types of Mass Movement

1.     Rockfall

2.     Slides

3.     Slumps

4.     Flow

5.     Creep

The reporters are exempted for the quiz

Thanks to Prof Cresencio Paner some of the information and pictures in our powerpoint got from him and Wikipedia and Google J

Minerals and Rocks

I learned many things about natural science that formed the earth, It took time to create beautiful forms of rocks and minerals that we can treasure and take care of .

Minerals

There are Over 100 Elements are the basic building blocks of minerals.

Atoms

Smallest particles of matter

Have all the characteristics of an element

The nucleus is the central part of an atom and contains

•        protons, which have positive electrical charges

•        neutrons, which have neutral electrical charges

       Energy levels, or shells

•        surround the nucleus

•        contain electrons—negatively charged particles

The atomic number is the number of protons in the nucleus of an atom.

Atoms Bond when an atom’s outermost energy level does not contain the maximum number of electrons, the atom is likely to form a chemical bond with one or more atoms.

•        A compound consists of two or more elements that are chemically combined in specific proportions.

•          An ion is an atom that gains or loses electrons.

The Three Types of Chemical Bonds are Ionic bonds form between positive and negative ions, Covalent bonds form when atoms share electrons and Metallic bonds form when metal ions share electrons.

 Mineral is:

1. Naturally occurring

  2. Solid substance

 3. Orderly crystalline structure

   4. Definite chemical composition

   5. Generally considered inorganic

  Minerals Form by

        1. Crystallization from magma

        2. Precipitation

        3. Pressure and temperature

        4. Hydrothermal solutions

Mineral Groups

•        1. Silicates

•        Silicon and oxygen combine to form a structure called the silicon-oxygen tetrahedron. This silicon-oxygen tetrahedron provides the framework of every silicate mineral.

•        2. Carbonates

•        Minerals that contain the elements carbon, oxygen, and one or more other metallic elements

•        3. Oxides

•        Minerals that contain oxygen and one or more other elements, which are usually metals

  4. Sulfates and Sulfides

•        Minerals that contain the element sulfur

  5. Halides

•        Minerals that contain a halogen ion plus one or more other elements

  6. Native elements

•        Minerals that exist in relatively pure form

There are different Properties of mineral that helps us know their characteristics like:

Color

         Small amounts of different elements can give the same mineral different colors.

•            Streak

      Streak is the color of a mineral in its powdered form.

    Luster

       Luster is used to describe how light is reflected from the surface of a mineral.

  Crystal Form

      Crystal form is the visible expression
of a mineral’s internal arrangement of atoms.

    Hardness

        Hardness is a measure of the resistance of a mineral to being scratched.

        Mohs scale consists of 10 minerals arranged from 10 (hardest) to 1 (softest).

     Cleavage

         Cleavage is the tendency of a mineral to cleave, or break, along flat, even surfaces.

      Fracture

         Minerals that do not show cleavage when broken are said to fracture.

         Fracture—the uneven breakage of
a mineral

     Density

         Density is a property of all matter that
is the ratio of an object’s mass to its volume.

                 

Distinctive Properties of Minerals

         Some minerals can be recognized by other distinctive properties.

         

    Rocks

         Rocks are any solid mass of mineral or mineral-like matter occurring naturally as part of our planet.

       Types of Rocks

        1. Igneous rock is formed by the crystallization of molten magma.

        2. Sedimentary rock is formed from the weathered products of preexisting rocks that have been transported, deposited, compacted, and cemented.

        3. Metamorphic rock is formed by the alteration of pre-existing rock deep within Earth (but still in the solid state) by heat, pressure, and/or chemically active fluids.

        The Rock Cycle

         Shows the interrelationships among the three rock types (igneous, sedimentary, and metamorphic)

         Magma is molten material that forms deep beneath the Earth’s surface.

         Lava is magma that reaches the surface.

         Weathering is a process in which rocks are broken down by water, air, and living things.

         Sediment is weathered pieces of Earth elements.

       Energy That Drives the Rock Cycle

         Processes driven by heat from the Earth’s interior are responsible for forming both igneous rock and metamorphic rock.

•         Weathering and the movement of weathered materials are external processes powered by energy from the sun.

•         External processes produce sedimentary rocks.

       Formation of Igneous Rocks

        1. Intrusive igneous rocks are formed when magma hardens beneath Earth’s surface.

        2. Extrusive igneous rocks are formed when lava hardens.

        Classification of Igneous Rocks

         Igneous rocks can be classified based on their composition and texture.

          Coarse-grained texture is caused by slow cooling resulting in larger crystals.

       1. Texture

        •  Fine-grained texture is caused by rapid cooling resulting in smaller, interconnected mineral grains.

        2. Composition

       •  Granitic composition rocks are made mostly
of light-colored quartz and feldspar.

  

   Formation of Metamorphic Rocks

         Metamorphism means “to change form.”

         Most metamorphic changes occur at elevated temperatures and pressures.

        Conditions for formation are found a few kilometers below the Earth’s surface and extend into the upper mantle.

Classification of Metamorphic Rocks

 Two main categories

1. Foliated Metamorphic Rock

•        Has a banded or layered appearance

2. Nonfoliated Metamorphic Rock

               Does not have a banded texture 

We watched videos about minerals and rocks  that shows the different colors of it and there different classifications

thanks to Professor Crisencio Paner I learned so much things about nat sci :)