Flashcards in Rocks and Trees Deck (47)
What factors play a significant role in chemical weathering?
Oxidation- loss of electrons
Reduction- gain of electrons when forming compound
What factors contribute to physical weathering?
What is the earths crust largely composed of?
-Oxygen (94% volume)
What group do most RFM's belong to?
Silicate RFM group - 90% of RFM's in this group
Name the 3 sources of nutrients
Primary - Derived from weathering of rock and RFM's
Secondary - Decomposition of OM
Tertiary - Internal Cycling
Define a mineral
-Definite Chemical Composition
-Possess specific physical characteristics that are unique to the mineral
What two groups are silicate RFMS broken down into?
Ferro-Magnesium Group (dark color)
-containing iron and or Mg
ex. olivine, pyroxine, hornblende, biotite
Non-Ferro-Magnesium group (light color)
-not containing iron or Mg
ex. muscovite, orthoclase feldspar, quartz, plagiocase feldspar
What are some RFM Physical Characteristics?
-Crystal form (atomic structure)
- Cleavage (how crystals separate based on planes of weakness)
-Hardness (resistance to abrasion-related to strength of atomic bonds)
-Specific Gravity (ratio between mass of mineral vs mass of equal vol. H20)
-Lustre 9metallic or non metallic)
-Optical properties (Transparent, Translucent, Opaque)
-Reaction to HCl (due to carbonate)
List the RFM Groups
-OXIDES (Oxygen plus an element Fe203)
-SULFIDES (Sulphur plus an element FeS2 - Pyrite)
CARBONATES (Co3 plus an element CaC03 - Calcite)
-SULPHATES (S04 plus an element - Gypsum)
What silicate RFM groups contribute to soil nutrients?
What is a secondary RFM
A mineral source that is produced by the decomposition of RFM's and the re-alignment of individual Si04 and Al06 molecules to form clay.
What is streak?
The color of an RFM when it is rubbed on paper
What is the source of all RFM's?
What types of rock are formed by lava?
Igneous extrusive: Basalt and lava rock ( Form on the earths surface via volcanoes/fissures)
Igneous Intrusive: Granite rock types ( Form deep within the earths crust and are exposed by upward tectonics/downward weathering)
What are the textures of intrusive/extrusive rock
Extrusive: Very fine textured, result of fast cooling on the earths surface (crystals don't have time to develop)
Intrusive: Coarse textured (visible to naked eye) because the structure develops slowly as it cools deep in the earths crust.
How are metamorphic rocks formed?
Immense heat and pressure deep in the earth.
How are sedimentary rocks formed?
Conglomerations of weathered smaller particles that solidify and fuse over time. Formed in the ocean by immense pressure which also generates heat. Tectonic uplift exposes this material.
Describe the weathering process with respect to time.
At first, physical weathering is the dominant force that breaks up large rocks into smaller fragments. When pieces are small, chemical weathering becomes more significant and fully breaks down substances to their base particles.
Where are geodes common? what are they?
Found in sedimentary rock. Mineral vapours permeate hollow, sedimentary rock and solidify into crystals.
What is the difference between Plagioclase and Orthoclase Feldspars?
Orthoclase is pink and only mildly striated and plagioclase is dark and striated
Where does most potassium come from?
Why is potassium important?
Catalyst in many reactions and helps to transport other nutrients in plants. Absorbed as an ion and gets recycled
What is a characteristic of all igneous rock?
Composed of interlocking crystals
What does batholith refer to?
Massive rock formations composed of granitic rock (coarse textured) silicates
Why is granite lighter coloured than basalt?
Because granite contains less ferro-magnesium minerals whereas basalt, being igneous extrusive would be darker due to more ferro-magnesium mineral content.
What is it called when sediments are compressed into solid rock?
What is Limestone made of?
Calcium carbonate from shellfish residue that gets deposited in the deep ocean.
What are chemical precipitates ?
When minerals precipitate out of a solution (like the sea...) and then go through lithification to become a solid mass.
What are some examples of sedimentary rock?
sandstone, limestone, shale, siltstone, breccia