Study sets, textbooks, questions
Upgrade to remove ads
Sed Strat Exam 1
Terms in this set (84)
Most abundant rock at the earths surface, but small portion of entire earth volume.
Why are Sed Rocks important
Coal, Water, Air resevoirs
keys to climate interpretation
records continuous rock record
noting the texture, size, color, of seds to infer the environment or history
unconsolidated fragments of rocks, mineral, and debris
most abundant minerals in sedimentary rocks
from erosional products. Theres 2 types. Chemical and Biogenic
source rock has to weather
Precipitation out of solution
3 types of sediments
derived from weathered pre existing rocks (often outside basin of deposition)
grains that formed elsewhere and were transported to basin.
grains chemical precipitants in situ formed at site of deposition
Mechanical (physical) Weathering
*Increases surface area
jointing and exfoliation
solid +fluid=dissolved ions
the replacement of a cation by H+
solid mineral plus H2O = new hydrated mineral
relationship between physical and chemical weathering
physical weathering creates more surface area on the rock that allows more chemical weathering to erode rock. Chemical weathering also makes it easier for physical weathering to break rock.
When does most intense chemical weathering occur?
In hot and wet climates
When does most intense physical weathering occur?
In hot and dry climates
3 steps of erosion
disengaging particle from surrounding environment
lifting particle by agent of erosion
movement of eroded material by wind, water, or ice.
How does entrainment work?
Overcoming resistance (gravity, particle mass, ) to lift particle
what are the two types of fluid flow?
laminar and turbulent flow
no mixing between layers, stream lines do not cross, uniform flow velocity, and particles move downstream OR upstream.
mixing between layers, streamlines cross, differences in flow velocity (eddies)
Flow type is dependent on
Velocity, Viscosity of fluid, and bed roughness
Laminar flow occurs when
slow moving fluid over a smooth bed surface, or a high viscosity fluid.
turbulent flow occurs when
high velocity, rough bed surface, low viscosity flow.
what type of flow producces a high reynolds #?
How is lift created?
high velocity and low pressure produce lift.
mathematical model that predicts levels of entrainment in streams.
bed load+dissolved load+ suspended load
50% of the grains are coarser, 50% are finer.
most abundant size on histogram
describes the distribution of the weight % on a histogram
what causes deposition?
reduction in velocity
increase in resistance of particles (cohesion)
deposited in wide thin sheets
beds are mostly horizontal
create graded beds
the space between solid grains after sediment accumulation dependent on grain size, sorting, pressure surrounding, and the cement.
from fracture after lithification
the ease of flow through particles
connected pore space= more permeable
3 steps to lithification
processes that affect or change sediment after it has been deposited usually during burial.
increased T and P (not metamorphism)
pressure squeezes out water and air which leads to compaction after reduction of porosity.
mud matrix between framework grains
3 main types
3 types of cement
complete composition change
mineral dissolves and is replaced by another mineral
mineral retains chemistry but grows larger
<15% matrix (grain supported)
>15% matrix (mud supported)
clasts are the same in conglom/breccia
clasts are not the same type in conglom/breccia
clasts are rounded
clasts are angular
what mechanisms sort well?
waves and wind
what mechanisms sort poorly?
turbidity currents and high velocity rivers
what is the modality of an orthoconglomerate?
uni to bimodal
what is the modality of an paraconglomerate?
at least bimodal
rocks pointed in the direction of water flow.
what are the components of sandstones?
what are the three main types of grains in sandstones?
quartz, feldspar, and lithic fragments
what is the relationship between phi size and particle size?
phi size increases as particle size decreases
depositional environment: shallow marine/dune
coarser, poor to moderate sorting and roundness
depositional environment: alluvial fans, debris flows, and river channels.
suggests arid climate or steep topography
submature texture (up to 50% rock fragments)
found in alluvial fans around uplifted mountains, shallow marine shelf, deep sea fans.
ss >10% matrix
immature because of high matrix
mostly quartz grains
bimodal at least
DE: turbidites, marine fans
have >50% clay minerals (matrix)
Clay mineral layers consist of
tetrahedral and octahedra layers
Kaolinite (T and O sheets)
TOT-cation , TOT cation etc
2:1 clays that expand with water
clays formed by altered volcanic ash
Fe substitutes for Mg in smectite
green color, takes 1000s years to form
interlayer composed of mg2+ and fe2+ surrounded by 6 hydroxls
TOTbrucite, TOT brucite...etc
Recommended textbook explanations
Applications and Investigations in Earth Science
Dennis G. Tasa
Holt Earth Science
Arthur T. DeGaetano, Jay M. Pasachoff, Mead A. Allison
Sets with similar terms
Chapter 4 Vocabulary
chap 7 self test
Geol 314 test 1
Other sets by this creator
Econ Final All Terms
Econ Chapter 5
Chapter 4 Econ
Econ Chapter 3
Other Quizlet sets
311: lecture 1
6. Combination Vehicles
bio lab exam 2
Philosophy Final Exam