Lecture 6 Minerals and Rocks 4 Flashcards
where do sedimentary rocks form
on or near Earths surface
what is erosion
geological process in which materials are worn away and (potentially) transported naturally by wind or water
what is weathering and what factors allow it to happen
breaking down or dissolving of rocks and minerals on Earths surface
driven by factors such as:
- water
- ice/snow
- acids
- salts
- plants
- animals
- animals
- temperature fluctuations
what are examples of sedimentary rock found on Mount Royal
- Limestone
- Shale
what do erosion and weathering do
they slowly break down mountains, boulders, and larger rocks into smaller rocks and sediment/unconsolidated materials
what are examples of unconsolidated materials
- gravel
- sand
- silt
- clay
what is dissolution and another word for it
Dissolution = chemical weathering
- a form of weathering wherein slightly acidic water (pH less than 7) slowly wears down rock
- process by which soluble rocks/minerals are dissolved/incorporated into water due to the passage of water over the rock surface, entry of water into rock fractures or entry into rock pores
what does frost do to rocks
frost causes rocks to fracture
- when rain absorbed by limestone surface freezes, it exerts pressure on the rock below, fracturing it
what does it mean for a substance to be soluble
when it can dissolve/become incorporated into a liquid such as water
is dissolution slower or faster in more or less soluble rocks/minerals
- dissolution is faster in MORE soluble rocks/minerals
- dissolution is slower in LESS soluble rocks/minerals
what does limestone consist of + what is it
calcite (mineral made up of calcium carbonate CaCO3)
- limestone is a rock
- soluble
what does dolostone consist of + what is it
dolomite [mineral made up of calcium magnesium carbonate, CaMg(CO3)2]
- dolostone is a rock
- soluble
what does gypsum consist of + what is it
calcium sulfate, CaSO4 or CaSO4.2H2O
- gypsum is rock or mineral
- soluble
what does halite consist of + what is it
sodium chloride (NaCl)
- halite is a mineral
- soluble
which is more soluble
- limestone
- gypsum
- dolostone
gypsum is more soluble than both
why does halite only exist in a certain environment + what is that environment
halite is very solvable and therefore only exists in dry environments
what does combined erosion, weathering and dissolution do
it creates raw materials for making new sedimentary rocks
what are raw materials
smaller rocks and sediment/unconsolidatd materials
- gravel
- sand
- silt
- clay
what are raw materials, new minerals and new rocks generated by
lithification
what is lithification (meaning and processes)
- from ancient Greek word “Lithos” meaning “rock”
- the making of rocks
- divided into two distinct processes:
1. Compaction
2. Cementation
What is compaction
here are the three different definition/explanations on the slides:
- as more sediments accumulate above, clasts are forces closer together
- compaction is a process that squeezes or compacts sediments
- process by which sediment/unconsolidated materials and remains of plants/animals (ex. moss, mollusk shells) become compacted/packed down by weight of sediment/unconsolidated materials piled on above them
What is compaction
here are the three different definition/explanations on the slides:
- as more sediments accumulate above, clasts are forces closer together
- compaction is a process that squeezes or compacts sediments
- process by which sediment/unconsolidated materials and remains of plants/animals (ex. moss, mollusk shells) become compacted/packed down by weight of sediment/unconsolidated materials piled on above them
what is cementation
three definitions:
- groundwater moves between the grains and leave behind mineral deposits, bonding the grains to each other
- “glue” takes place when dissolved minerals are deposited in the tiny spaces among sediments
- water moving through grains/clasts in compacted materials leaves behind mineral crystals
- mineral crystals stick/cement/bond compacted materials together
- compacting/compressing eventually results in release of any water and compacted layers of sediment becomes rock
what are clastic rocks
(e.g., conglomerate)
- rocks composed of broken pieces of other rocks bonded together
what is a clast
a fragment within clastic rocks
what is precipitation
process by which water rich in molecules that make up minerals/rocks gradually evaporates, allowing molecules to deposit and form mineral crystal/rocks
what happens in Death Valley (California) and what does it leave behind
mineral crystals form out of shallow after that flooded Death Valley, the driest location in North America
leaves behind the following minerals:
- halite (NaCl)
- calcite (CaCO3)
- gypsum (CaSO4 or CaSO4.2H2O)
- borax (Na2B4O5(OH)4.8H2O)
what are the two categories that sedimentary rocks can be classified as
- detrital sedimentary rock
- chemical sedimentary rock
what are detrital sedimentary rocks
- consist of organic and/or inorganic materials
- formed from eroded/weathered rock fragments, smaller rocks, sediments/unconsolidated materials, organic materials
- all aforementioned “ingredients are referred to as detritus, hence the name detrital sedimentary rock
what is detritus latin for
worn down
examples of detrital sedimentary rock
- conglomerate
- breccia
- sandstone
- siltstone
- shale (ie., mudstone)
what does organic detrital sedimentary rock consist of
consists of animal/plant parts (organic material) that decay in ground
what does organic detrital sedimentary rock undergo and how long does it take
over thousands or millions of years, organic material undergoes compaction and cementation (lithification), forming rock
what’s special about peat
it doesn’t undergo complete lithification
its a sedimentary material largely consisting of partially decayed vegetation/organic materials such as peat moss
- formation of peat is the first step in forming another important and controversial organic sedimentary rock
what are uses of peat
- peat harvesting in Scotland
- used for energy
- gardening
- farming
what does peat become
coal
what is coal
a sedimentary rock made up of plant matter compressed over millions of years
how does coal form
over years, with increased layers of sediment above the peat, increasing depth of burial and increased temperatures, peat is converted to lignite (one of four coal types)
what are the four coal types and how do they come about
increased time and higher temperatures can convert lignite into 3 other coal types
- lignite
- then subbituminous coal
- then bituminous coal
- and ultimately anthracite
where do we see coal
given its carbon content:
- coal is burned to generate electricity
used to manufacture steel
- coal train in canada
- coal mine in BC
what is the carbon content in each type of coal
- lignite (25-35% carbon)
- subbituminous coal (35-45% carbon)
- bituminous coal (45-86% carbon)
- anthracite (86-97% carbon)
what is steel made of
- mix of iron (Fe) and carbon (C)
- steel can contain up to approximately 2% carbon
why is coal important to the canadian economy
in 2021, canada produced 47.6 million tons (1 ton = 1000 kilograms) of coal, of which 61% was sued to manufacture steel, and 39% used to generate electricity
mining and burning of coal harmful to environment and organisms because…
** need to add
how much of canadas electricity in 2020 came from burning coal
6%
- by 2030, canada wants to phase out electricity generated using coal
what is the percentage of electricity from coal in alberta, saskatchewan, and nova scotia
alberta: 44%
saskatchewan: 43%
nova scotia: 10%
coal production percentage in canada
63% BC
21% alberta
17% saskatchewan
in 2021, canada was the 7th largest exporter of coal in the world with how many tons + where does canada export coal to
32 million tons exported
- china
- south korea
- japan
- india
what percentage of global electricity comes from coal in 2022
36%
(followed by natural gas with 22%
(3% comes from other fossil fuels
fossile fuels still produce over 60% of the worlds electricity)
