Lab 6 Flashcards
Clastic Sedimentary Rock
Sedimentary rock that forms when physical fragments of preexisting rocks (clasts) are compacted or cemented together.
Physical Weathering
The mechanical breakdown of rocks and minerals
Chemical Weathering
The process that breaks down rock through chemical changes (which chemically decompose the rock)
Weathering
The initial break down of rocks by chemical and physical processes into sediments
Erosion
Removal of the products of weathering (sediment) by wind, water and/or gravity from their site of origin
Transportation
Long-distance movement of sediments mostly by water, but also by wind or glaciers
Burial
The process by which sediments are buried due to the deposition of later sediments
Deposition
Process by which chemical and/or physical sediment precipitate or settle out of water/wind/glaciers
Diagenesis
The physical and chemical changes occurring during the conversion of sediment to sedimentary rock (compaction and cementation) due to increased temperature and pressure. Also known as lithification
Lithification
The process that converts sediments into solid rock by compaction or cementation. Also known as diagenesis
6 steps that create sedimentary rocks (in order)
Weathering
Erosion
Transportation
Deposition
Burial
Lithification (diagnesis)
Chemical Sedimentary Rocks
Sedimentary rock consisting of material that was precipitated from water by either inorganic or organic means
Evaporite
A sedimentary rock formed of material precipitated from solution as water evaporates
Biological Sedimentary Rocks
A sedimentary rock that forms from the remains of organisms
(Bio)chemical Sedimentary Rocks
Sedimentary rock formed in one of two ways
1. Dissolved minerals precipitate out of water (when the water becomes over-saturated in a specific mineral)
2. Sedimentary rock formed from sediments derived from biological processes
Limestone
(Bio)chemical sedimentary rock, composed mainly of calcium carbonate or dolomite, the most common biochemical sedimentary rock. Reacts with HCl (hydrochloric acid).
Coal
A combustible black or dark brown sedimentary rock consisting mainly of carbonized plant matter, found mainly in underground deposits and widely used as fuel.
What happens to physical clasts as they are transported?
Two things happen to physical sediments as they are transported.
1. They change shape due to abrasion (they become smaller and more rounded)
2. They become well-sorted.
Three types of sedimentary environments are
Continental (terrestrial)
Shoreline (transitional)
Marine
Sedimentary Environments
Place where a sedimentary rock is formed, really what it means is where the sediments are deposited, then buried, and finally lithified
Where does limestone form?
Reef environments (far out on the continental shelf in tropical areas)
Where does sandstone form?
On the beach
Where does mudstone form?
Abyssal place
Where do the evaporites gypsum and halite form?
In a desert lake environment where there is lots of evaporation
Which weathers faster, quartz or feldspar?
Quartz is very resistant to weathering, feldspar is not. Feldspar weather faster
Where does conglomerate form?
Conglomerates form in mountain steam or at the base of cliff along a seashore
How do we recognize sea level rise transgression) in the rock record?
As sea level rises, deeper water sediments are deposited on top of shallow water sediments. In the rock record we would see finer grained sedimentary rocks (deep water sediments) deposited on top of coarser sediments (shallow water sediments).
How do we recognize regression (sea level fall) in the rock record
As sea level falls, shallow water sediments are deposited on top of deep water sediments. In the rock record we would see coarser grained sedimentary rocks (shallow water sediments) deposited on top of finer sediments (deep water sediments).
What type of sedimentary rock react with acid?
Carbonates (example: limestone)
Examples of clastic sedimentary rocks
Conglomerate
Breccia
Sandstone
Siltstone
Mudstone
Shale
Examples of (bio)chemical sedimentary rocks
Limestone
Fossiliferous limestone
Coquina
Chalk
Chert
Where does coal form?
Swamps
Where do we find volcanoes?
Convergent boundaries, hot spots and drivgent boundaries
Basalt is formed at
Divergent boundaries are hot spots
Andesite is formed at
Subduction zones and hot spots
Rhyolite is formed at
Subduction zones and hot spots are
How do we identift different lava flows on Mars and the Moon
Using satellite imagery, we look for flow margins, differences in colors and textures, differences in the number of impact craters
An area on the moon with greater number of impact craters would be _____ than an area with fewer impact craters
older
Why do we not use impact craters to identify flows on Earth?
Due to weathering, plate tectonic processes, vegetation and the large amounts of ocean, impact craters are mostly hidden, destroyed or nonexistant
How do we identify different lava flow on Earth?
- Differences in color and texture
- Flow margins
- Differences in vegetation
- Chemical analysis of the different flows
Shield volcan
A low, flat, gently sloping volcano built from many flows of fluid, low-viscosity basaltic lava
What type of magma is the most common in the universe
Basaltic
Volcanic Hazards
Natural hazards associated with eruptions. Volcanic hazards include:
Lava flows
Lahars
Pyroclastic flows
Ash falls
Landslides
Tsunami
Volcanic Gases
Projectiles
Lava Flow
The spread of lava as it pouts out of a vent
Lahar
A destructive mudflow or debris flow on the slopes of a volcano. Typically contains rock, soil, vegetation and water. and flow down river valleys like fast moving rivers
Pyroclastic flow
Pyroclastic flow is a density driven current formed when an eruption column collapses on itself causing hot ash, lava fragments and gasses to flow rapidly down the flanks of a volcano
Ashfall
Volcanic ash that has fallen through the air from an eruption cloud
Volcanic rockslides
Loose soil, rock, vegetation, volcanic debris slide downhill along the flanks of a volcano
Volcanic gases
Vapor and aerosols that exit a volcano, some of which are dangerous
Volcanic Projectiles
large particles hurled from a volcano
What volcanic hazard is associated with Mount Rainer
Lahar
Metamorphic Rock
A type of rock that forms from an existing rock that is changed by heat, pressure, or chemical reactions (due to the presence of fluids)