Download LITHOSPHERE

LITHOSPHERE
ROCKS
MINERALS
SOIL
Lithosphere
 The outer "solid" part of Earth.
 It has two parts, the crust and the
upper mantle.
 It is about 100 km thick.
Minerals
 To be classified as a true mineral, a
substance must be a solid and have a
crystalline structure.
 It must also be a naturally occurring,
homogeneous substance with a defined
chemical composition
 Minerals: Inorganic solids and their
composition and properties are defined
Classification of Minerals
1.
2.
3.
4.
Color
Luster
Hardness
Streak
Color
 Idiochromatic
 Allochromatic
 Idio “particular”
 Allo “other”
 Mineral in which the  Mineral in which the
color is due to some
color can vary, due to
essential constituent of
possible impurities
the stone,

Eg, Malachite (Green)
and Almandine (deep
red).


Eg, Beryl (Aquamarine
or Emarald)
Eg, Smoky Quartz or
Amethyst (Quartz)
Luster
 The way its surface reflects light.
 Minerals with a metallic luster: shiny, opaque
appearance similar to a bright chrome
 Non-metallic lusters: shiny, but somewhat
translucent or transparent lusters (glassy,
adamantine), along with dull, earthy, waxy, and
resinous lusters, are grouped as non-metallic.
Hardness
 The Mohs scale of mineral hardness
characterizes the scratch resistance of various
minerals through the ability of a harder
material to scratch a softer material.
 Created in 1812 by the German mineralogist
Friedrich Mohs
Streak
 The color of a mineral when it is powdered is called
the streak of the mineral.
 Streak can be determined for any mineral by rubbing
the mineral across the surface of a hard, unglazed
porcelain material called a streak plate.
 The streak and color of some minerals are the same.
For others, the streak may be quite different from the
color, as for example the red-brown streak of
hematite, often a gray to silver-gray mineral.
 Idiochromatic minerals will leave a bright
color
 Allochromatic will leave a white powder or
very little color
Rocks
 Heterogeneous solids composed of many
minerals.
 In general rocks are of three types, namely,
igneous, sedimentary, and metamorphic.
 Formed from volcanic eruptions
Classification
 Igneous rocks : when molten magma cools
 2 main categories: plutonic rock and volcanic.
 Plutonic or intrusive rocks result when magma
cools and crystallizes slowly within the Earth's crust
(example granite),
 Volcanic or extrusive rocks result from magma
reaching the surface as lava.
Classification
 Sedimentary rocks : by deposition of either
organic matter or chemical precipitates,
followed by compaction of the particulate
matter.
 Sedimentary rocks form at or near the Earth's
surface.
Classification
 Metamorphic rocks: by subjecting any rock type to
different temperature and pressure conditions than
those in which the original rock was formed.
 These temperatures and pressures are always higher
than those at the Earth's surface and must be
sufficiently high so as to change the original
minerals into other mineral types or else into other
forms of the same minerals (e.g. by
recrystallisation).
Soil
 Naturally occurring, loose covering on the
earth's surface.
 Made up of broken rock particles that have
been altered by chemical and environmental
conditions.
 Soil can be altered by interactions between
the lithosphere, hydrosphere, atmosphere,
and the biosphere.
Soil Horizons (Layers)
 A specific layer in the soil which measures
parallel to the soil surface and possesses
physical characteristics which differ from the
layers above and beneath.
Layers
 O- composed mainly of humus, organic layers of
plant and animal residue
 A- mixture of humus and minerals soluble in water,
support plant life
 B- composed of small particles of minerals, dense
 C- degradation of rocks, unconsolidated soil parent
material
 R- partially-weathered bedrock at the base of the
soil profile.