general terms COPY Flashcards
3D QFL diagram
%mud: <5%= arenites, 5>%mud<50%=wackes, %mud>50%=mudstones QFL: %qtz: %qtz>90%=qtz arenite, 75-90%=sublithic, sub-arkosic, <75%-arkosic or lithic
A-Horizon
Zone of oxidation, leaching, organic reactions, humus, solutes, fine clay percolating. Approximately 5% rocks.
Actualism
The present processes approximate the past but it must be interpreted with a grain of salt.
Alfisols
Soils that are developped in moist, temperate climates. There is alot of insoluble cations (Fe + Al) in the alfisols. Examples include Georgia’s red clay or African soils.
Are physical, biological, and chemical weathering discrete things?
They are not. Salt crystallization is an example of both chemical and physical weathering. Root wedging and fungal breakdown are biophysical and biophysiochemical.
Arenites NEED PIC
Sandstones that are composed of distinct grains and cement with a maximum of 5% mud.
Aridsols
Soils that form in deserts. They are poorly developed, solutes are relatively static because evaporation offsets any percolation. Many evaporites and dust.
Authegenic minerals
Minerals produced at the surface. Minerals precipitated through biologic, supersaturation, oxidation, or other processes.
B-Horizon
Zone of accumulation (illuvial). Clay and solutes. Dark colors. ~80% mineral
Bed Shear Stress
tau0=SW*h*S
SW=specific weight
h=flow depth
S=slope (gradient)
This represents the shear stress a flow exerts onto a bed it is flowing over.
Bedforms
Mounds or troughs of loose sediment on a mobile bed forming @ sediment and fluid interface. They describe the relation of strata.
Bernoulli’s Principle
Derived from the conservation of energy and the principle of continuity where:
KE+PE+P(aka work)=Constant
If the path is obstructed by a grain and therefore V(flow) increases (see principle of continuity) and over a dx the PE is constant/~0 then the KE increases when traversing over the grain and therefore P (pressure) decreases. This forms hydraulic lift.
Biological Weathering
The influence of plant life of the weathering process. Examples include root wedging and bioturbation. It creates a significant part of the weathering scheme.
Biological Weathering Examples
Chelation: The Bonding of metals with organic compounds with the effect of increasing their solubility.
C-Horizon
Chunky Bedrock, regolith. 100% rock
Cataclastic Breccia
Refers to breccias formed due to land movement.
Landslide/Slump breccias form due to the tension of sliding material
Tectonic Breccias form from gouge
Collapse breccias are from cave-ins and other forms of ground failure
Chelation
Biogenic weathering through organic compounds. It forms a metal compund that increases the solubility of the metal.
Chemical Weathering
Break down of rock due to being at disequilibrium on Earth’s surface. Characterized by shifts in the chemical and/or mineralogic components of a rock.
7 Chemical Weathering Mechanisms
Carbonation because of rain being slightly acidic
Simple Solution: dissolution without precipitation
Hydrolysis: dissolution and precipitation of new minerals. Incurs a permanent composition/mineralogic shift.
REDOX: The oxidation of Mn and Fe to form hydro/oxides.
Hydration/dehydration: clays, hematite->goethite, and gypsum->anhydrite. Characterized by reversibility and impermanence.
Ion Exchange: shifting ions within clays/zeolites and solution
Chelation
Clay series
Clays constitute a significant potion of all grains in sedimentary rocks that host large metallic cations, strong, and stable structures.
illite alters to smectite (montmorillonite: expandable upon hydration)
kaolinite is a T-Oct Al-rich clay with the potential for bauxite (Al(OH)3) . It is the ultimate Alumino-silicate weathering product.
Climbing Ripples
During the de-escalation of flow ripples will stop migrating and start “mounding” Therefore downward flow will be up-dip. They form non-tangential and tabular cross-bredding.
Competence ADD FBD
The maximum particle size that a flow can move.
Determines by if the flow can exert a force that is greater than tauc
Conglomerates/Breccias:
Rocks that are primarily composed of lithic fragments over 2mm (>30%). If they are angular then it is considered a breccia. If they are more mature and rounded then they are conglomerates. Clast supported refers to if the individual clasts are touching and create the structure. Matrix supported refers to the concept of the clasts being suspended in the fine grained matrix material.
Continental Block Provenance
Typical exhumed continental material. It has a wide variety but primarily consists of quartzose, K-spar, sometimes volcanics.



