2023 Mid Term Flashcards
%CF refers to:
Percentage of rocks greater than 2mm in size
What is an S6 stream?
Stream under 3m in size that is not fish bearing or a drinking water source
What are the 5 factors in soil formation?
Parent material
Time
Biota
Climate
Topography
What are the typical layers of a soil horizion?
LFH = (litter, fermentation, humus)
A = (mineral horizion of organic soil or leaching (eluviation)
B = horizion of illuviation (accumulation) materials freed up from A or LFH horizions.
C = Horizion not really effected by soil forming processes
What is an Ah horizon?
Humus enriched
What is an Ae horizon?
Leaching has occurred
What is an Ahe horizon?
Combination of humus enriched and leaching
What is a Bm horizon?
Slightly modified
What is a Bt horizon?
Clay enriched
What is a Bf horizon?
Iron enriched
What is a Bg horizon?
Mottling/gleying
What is a Bk horizon?
Calcium carbonate present?
What are the three types humus layers?
Mor, mull, moder
What is a mor and where does it form?
Forms in moist cool climates
Common under coniferus forests
Fungal mycelium is matted in F layer
Few insects, abrupt transitions between layers within LFH
What is a moder?
Forms in moderate climates
Found under both deciduous and coniferus forests
Loose mycelium, insects activity
Gradually transitions between layers within LFH
What is a mull?
Forms in warm/arid climates
Found in dry forests or grasslands
No Fungal activity, lots of insects
L and F layere very thin, no H layer
Ah layer present
What is a brunisolic soil?
Weakly developed
Little or no A horizon
Tends to be young soils
Key horizon is Bm
What is a Chernozem soil?
Typically in grasslands
What is a Chernozem soil?
Typically in grasslands
What is a gleysol?
Waterlogged soil/seasonal water table
Reduction and oxidation of iron
Key horizon is Bg
What is a podzol?
Rapid leaching
Ae horizon often present
Coarse textured in high rainfall environments
Often coastal or in mountains
Key horizon is Bf
What defines an organic soil (soil order)
Organic material greater than 40 centimeters
Found in wetlands typically
When field texturing, what are the characteristics of sand?
Feels grainy, can see individual grains
Non sticky
When field texturing, what are the characteristics of silt?
Feels gritty when dry, soapy when wet
What two types of crusts on earth are there?
Oceanic and continental
What are the differences between oceanic and continental crusts?
Continental = Thick (20 to 90km), less dense and more buoyant, composed of aluminum and silica (granitic)
Oceanic = Thin layer (5 to 10km thick), denser than continental crusts, mostly iron and magnesium (basalt)
What are the three types of plate boundaries?
Divergent, convergent, transform
What defines a divergent plate?
Convection currents and other forces pull plates apart
Occurs mainly at mid Oceanic ridges
Creates new lithosphere
Rising magma causes sea floor to diverge
What are convergent plates and the three types of them?
Occurs where two plates collide
Results in destruction of lithosphere
Results in one plate being subducted by the other
3 types are:
Oceanic-oceanic
Continental-Continental
Oceanic-continetial
What are the characteristics and differences between the three types of convergent plates?
Oceanic-oceanic =
initiates volcanic activity on ocean floor
Can create new islands
Older plates are heavier and are subducted below younger ones
Continental-Continental =
Little to no subduction occurs
Crust is forced together or onto of each other
Forms mountains
Oceanic-continential =
Ocean crusts are subducted under continental ones
Partial melting results in magma
What are transform plate boundaries?
Plates slide laterally past you
Movement can cause earthquakes
What are the two types of rock weathering?
Mechanical and chemical
What are the three types of rocks and what are they?
Igneous - formed from magma
Sedimentary- formed from surface processes
Metamorphic - formed by heat and pressure
Define how igneous rock forms.
Lava is extruded onto the landscape and cools quickly with air or water contact.
Crystals do not form; rock is fine textured like basalt and obsidian.
Define the difference between felsic and mafic rock.
Felsic = high silica content. Rich in light colored minerals (quartz and feldspar). Ie granite. Continental plates are mostly felsic
Mafic = low silica content. Rich in dark minerals (iron and magnesium). Ie basal5. Oceanic plates are mostly mafic.
Rocks can be intermediate between the two as well. Ie Diotrite.
What are the different types of intrusive structures.
Dikes
Sills
Batholiths
Stocks
Veins
What is a dike?
Magma gets injected into fractures
Forms vertical walls
Can be a few km long
Varies in chemical composition
What is a sill?
Intrusions formed when magma is interjected along Sedimentary bedding surfaces (Horizontal)
What is a batholith?
Pluton of magma greater than 100km that cools below the surface
What is a stock?
A small intrusion of magma (Small batholith)
What is a vein?
Crystallized minerals carried ban an aqueous solution/deposited by precipitation. Very narrow, in cracks or forced in rock by pressure
How are Sedimentary rocks formed?
Can be formed by weathering breaking down existing rocks
Can also be formed from organic materials (limestone, coal)
Material is moved, accumulates, and then lithifies
What is evidence of rocks being moved by water?
Rocks will be sorted, rounded.
What are the two ways sediment is turned to rock?
Compaction and cementation
How does compaction to form Sedimentary rocks occur?
Weight of an overlaying material exerts pressure
For example shale forms from clay being compacted by water
How does cementation form rocks?
Precipitation from water percolator through sediment fills open spaces and joins particles.
Calcite, silica and iron oxide are the most common cements
List some Sedimentary rocks
Limestone
Sandstone
Shale
Chert
Conglomerate
What are some of the processes involved in the formation of metamorphic rocks?
Heat: turns minerals into new forms, changes distribution of minerals.
Usually, due to magma near the surface or rock subsiding deeper around subduction zones.
Pressure: Changes physical properties (ie Sandstone to quartz)
What is foliation?
Parallel alignment of minerals in metamorphic rock due to pressure.
