Stratigraphy Flashcards
Landward vs seaward building of strata
Retrogradation and Progradation
Global Sea Level rise or fall due to glacial activity or sea-floor spreading
Eustasy
These horizons are considered solum or true soil.
O, A, E, and B horizons
Enumerate the different basic soil orders.
Mnemonics - Give Him A Very Moldy Soap Or U Are An Incompetent Entity
- Gelisols - “geli-“ is to freeze, Permafrost Soils
- Histosols - “histo-“ is tissue, Organic Soils
- Aridisols - “arid-“ is dry, Desert Soils
- Vertisols - “verti-“ is vertical, Swelling Clay Soils
- Mollisols - “molli-“ is soft, Humus/Grassy Soils
- Spodosols - “woody ash” leached light-colored horizon, Acid Soils
- Oxisols - “oxi-“ is oxides, strongly weathered parent material, Oxide Soils
- Ultisols - “ulti-“ is ultimate, ultimate product of long period of weathering, Low-Nutrient Soils
- Alfisols - “Al” + “Fe” is aluminum and iron-rich, High-Nutrient Soils
- Andisols - “andi-“ is black, black from volcanic material not organic, Volcanic Soils
- Inceptisols - “inception” is beginning, weakly developed, Young Soils
- Entisols - “enti-“ is entire, entire topsoil because it has no subsoil unlike Inceptisol, New Soils
Moderately weathered soils that form under boreal forests or broadleaf deciduous forests, rich in iron and aluminum. Clay particles accumulate in a subsurface layer in response to leaching in moist environments. Fertile, productive soils, because they are neither too wet nor too dry.
Alfisol
Young soils in which the parent material is volcanic ash and cinders deposited by recent volcanic activity.
Andisol
Soils that develop in dry places; insufficient water to remove soluble minerals; may have an accumulation of calcium carbonate, gypsum, or salt in subsoil; low organic content.
Aridisol
Young soils having limited development and exhibiting properties of the parent material. Productivity ranges from very high for some formed on recent river deposits to very low for those forming on shifting sand or rocky slopes.
Entisol
Young soils with little profile development that occur in regions with permafrost. Low temperatures and frozen conditions for much of the year slow soil-forming processes.
Gelisol
Organic soils with little or no climatic implications. Can be found in any climate where organic debris can accumulate to form a bog soil. Dark, partially decomposed organic material commonly referred to as
peat.
Histosol
Weakly developed young soils in which the beginning of profile development is evident. Most common in humid climates, they exist from the Arctic to the tropics. Native vegetation is most often forest.
Inceptisol
Dark, soft soils that have developed under grass vegetation, generally found in prairie areas. Humus-rich surface horizon that is rich in calcium and magnesium. Soil fertility is excellent. Also found in hardwood forests with significant earthworm activity. Climatic range is boreal or alpine to tropical. Dry seasons are normal.
Molisol
Soils that occur on old land surfaces unless parent materials were strongly weathered before they were deposited. Generally found in the tropics and subtropical regions. Rich in iron and aluminum oxides
Oxisol
Soils found only in humid regions on sandy material. Common in northern coniferous forests and cool humid forests. Beneath the dark upper horizon of weathered organic material lies a light- colored horizon of leached material, the distinctive property of this soil.
Spodosol
Soils that represent the products of long periods of weathering. Water percolating through the soil concentrates clay particles in the lower horizons (argillic horizons). Restricted to humid climates in the
temperate regions and the tropics, where the growing season is long. Abundant water and a long frost-
free period contribute to extensive leaching, hence poorer soil quality.
Ultisol
Soils containing large amounts of clay, which shrink upon drying and swell with the addition of water. Found in subhumid to arid climates, provided that adequate supplies of water are available to saturate the soil after periods of drought. Soil expansion and contraction exert stresses on human structures.
Vertisol
Shallow diagenesis, occurs shortly after burial
Eodiagenesis
Diagenesis where sedimentary rocks approach the surface due to erosion
Telodiagenesis
Cavities filled with internal sediment and sparry calcite cement
Geopetal structure
Sandy deposits that develop where overbank flooding causes a break in the channel levee
Crevasse Splay
Small islands of deposited material within the channel of braided rivers.
Eyots or Aits
The warm layer of the lake’s thermal stratification that is usually oxic
Epilimnion
The cold layer of the lake’s thermal stratification that is usually anoxic
Hypolimnion
is the boundary between epilimnion and hypolimnion which may change throughout the day
Thermocline or Metalimnion
Brackish waters have salinity of ____ grams of solute per liter of water.
5 g/L
The floor of the receiving basin immediately seaward of the base of the delta front slope
Prodelta
a layer in an ocean or other body of water in which water density increases rapidly with depth.
Pycnocline
Enumerate the 3 ventifacts
Eikanter - single face
Zweikanter - two face
Dreikanter - three face
Differentiate Homopycnal, Hyperpycnal, and Hypopycnal flow
Hypopycnal - Water surface-hugging flow of suspended sediments
Homopycnal - Uniform flow of suspended sediment in river water
Hyperpycnal - Ground-hugging flow of suspended sediments
Commonly formed due to settling of sand suspended during flood events
Graded Rhythmites
Arcuate and Cuspate deltas are dominated by
Wave-Dominated
Estuarine Delta are dominated by
Tide Dominated Delta
Bird’s foot delta are dominated by:
River Dominated Delta
What year did a certain El Niño event caused 16% of corals all over the world to be bleached
1998
Are corals that do not build reefs
Ahermatypic
A mound-like mass built up by sedimentary organisms composed exclusively of their calcareous remains and enclosed by rock of different lithology. An organic reef or non-reef limestone mound
Bioherm
Sandy or Muddy sediments deposited and/or reworked by contour currents
Contourites
Turbid body of suspended sediment that is denser than the surrounding water but not dense enough to sink rapidly
Nepheloid Flow
a sedimentary structure characterized by alternating rippled sand and discontinuous mud layers created by the deposition of mud on previously existing sand ripples.
Flaser Bedding
Is the deposit of a pyroclastic flow composed of pumiceous material that is a poorly sorted mixture of blocks, lapilli, and ash
Ignimbrites
Jokulhlaups
is a type of glacial outburst flood that is associated with glacial sedimentation
This chemical reacts with traces of iron in a carbonate to stain it blue and to differentiate between Ferroan and Non-ferroan.
Potassium ferricyanide
One species disappears leaving behind another more evolved one. The original species (ancestor) is considered to be extinct but its lineage continues.
Phyletic extinction/pseudoextinction
A mudstone that display an array of cracks that are often filled with sparry calcite.
Septarian structures
A hard layer, rich in calcium carbonate, that forms beneath the B horizon in soils of Arid region.
Caliche
Refers to minerals or sedimentary rock deposits that are formed in place, where they are found, through processes such as crystallization or precipitation.
Authigenic
What impurity causes the green color in Prasiolite quartz?
Iron
What is a relative direction of flow of a river which displays no reason for its course called?
Insequent Stream
What is a doab?
a. Alluvial track between two adjacent rivers
b. depressions between seif chains
c. plains below the hills of the northeast
d. the confluence of two rivers
Alluvial track between two adjacent rivers
The term ‘sedimentology’ was first proposed by whom and in which year?
a. C. K. Wentworth in 1922
b. A. C. Trowbridge in 1925
c. H. Wadell in 1933
d. F. J. Pettijohn in 1934
A. C. Trowbridge in 1925 (first used)
H. Wadell in 1933 (formally proposed)
Which class of sedimentary rocks forms the largest proportion in the
Earth’s crust?
a. sandstone
b. limestone
c. shale
d. conglomerate
shale
Varves are characteristic of what type of sediments?
a. fluviatile
b. glacial
c. fluvioglacial
d. lacustrine
glacial
‘Regur’ is the name of which kind of soil?
a. lateritic soil
b. black cotton soil
c. reh
d. loess
black cotton soil (This type of soil is primarily found in the Deccan plateau region of India and is known for its suitability for growing cotton)
What term is used for coarse gravel according to Greek derived terminology?
a. spherite
b. rudite
c. psephite
d. tillite
Answer: Psephite
Rudite (Latin)
A diamictite is what type of rock?
a. nonsorted or poorly-sorted rock
b. beach-side pebble accumulation
c. lithified conglomerate
d. lithified breccia
nonsorted or poorly-sorted rock
A well-consolidated, unstratified iron-rich rock composedof varying
amounts of fragments is known as?
a. tilloid
b. canga
c. laterite
d. rubble rock
Answer: Canga
- Tilloids: These are poorly sorted sedimentary rocks that consist of a mixture of various grain sizes, typically associated with glacial deposits.
- Laterite: This is a type of soil rich in iron and aluminum, formed in tropical regions through intense weathering of the underlying rock. Laterites can also form iron-rich deposits but are not specifically consolidated rocks like canga.
Rock formed of fragments of various sizes in an alluvial fan is
termed as
a. fanglomerate
b. bajada breccia
c. delta bar
d. delta cap
fanglomerate
What is gerollton?
a. an unconsolidated pebbly claystone
b. an indurated pebbly claystone
c. nonglacial conglomeratic mudstone
d. glacial conglomeratic mudstone
an unconsolidated pebbly claystone
A sandstone that consists of fine to coarse, angular to subangular
particles mainly with lithic fragments is known as?
a. arkose
b. greensand
c. greywacke
d. quartzite
greywacke
A sandstone which is principally composed of quartz and feldspar presumably derived from a granitic rock is known as?
a. feldspathic sandstone
b. arkose
c. subgreywacke
d. lithic sandstone
arkose
A well-sorted sandstone lacking well-rounded grains is known as?
a. subgreywacke
b. paraquartzite
c. orthoquartzite
d. protoquartzite
paraquartzite
What is an allochem?
a. a colourless carbonate mineral
b. calcite precipitated from solution
c. loose debris of carbonate rocks
d. discrete and organized carbonate aggregate
discrete and organized carbonate aggregate
A fine-grained arenaceous rock that underlies certain coal measures
is known as?
a. crowstone
b. galliard
c. ganister
d. silica rock
ganister
Discoidal shapes of sedimentary particles according to Zingg
classification are known by which term?
a. equant
b. oblate
c. bladed
d. prolate
Answer: b. Oblate: As mentioned, this describes discoidal shapes where the particle is flattened along one axis. These particles have a b/a ratio greater than 2/3 and a c/b ratio less than 2/3.
a. Equant: This term refers to particles that are approximately equal in all dimensions, resulting in a roughly spherical shape. In Zingg’s classification, equant particles have both b/a and c/b ratios greater than 2/3.
c. Bladed: This term refers to elongated, thin particles that resemble blades. In Zingg’s classification, bladed particles typically have both b/a and c/b ratios less than 2/3.
d. Prolate: Prolate particles are elongated along one axis, resembling rods. They have a b/a ratio less than 2/3 and a c/b ratio greater than 2/3 in Zingg’s classification.
In which type of sedimentary structure are found cosets’?
a. ripple-drift deposits
b. graded bedding
c. cross-bedding
d. ripple marks
cross-bedding
What is a septarian nodule?
a. nodule found in shale
b. having a series of radiating cracks
c. having chatter marks on surface
d. having one face smoothened by abrasion
Answer: having a series of radiating cracks
Septarian Nodule, also referred to as Dragon Stone, is a tri color concretion composed of Aragonite (the brown), Calcite, (the yellow), and Limestone (the grey)
What type of symmetry is present in an oscillatory ripple mark?
a. regular
b. sinous
c. straight
d. asymmetrical
regular
Festoon-bedding is a type of?
a. crossbedding
b. sinuous bedding
c. ripple mark
d. graded bedding
crossbedding
Limestone deposits which show crossbedding indicate which type of
sedimentation?
a. precipitate
b. clastic
c. chemical
d. evaporite
clastic
What is the name given to a sequence of beds deposited in a repetitive cycle?
rhythmite
What are chronostratigraphic units?
a. units defined by fossil content
b. units of time distinguished by rock record
c. rocks formed during a defined interval of time
d. units distinguished by Unconformities
rocks formed during a defined interval of time
What is the geochronologic equivalent of ‘Series’?
a. Age
b. Era
c. Period
d. Epoch
Epoch
The fundamental unit of lithostratigraphy, mappable at the surface or subsurface.
Formation
When did the Deccan Trap activity start?
a. end of Eocene Epoch
b. beginning of Eocene Epoch
c. beginning of Cretaceous Period
d. end of Cretaceous Period
end of Cretaceous Period
The designated exposure of a named layered stratigraphic unit or of a stratigraphic boundary that serves as the standard of reference. Is the specific strata’ sequence used for the definition and/or characterization of the stratigraphic unit or boundary being defined.
Stratotype (Type Section)
The type section of a layered stratigraphic unit that serves as the standard of reference for the definition and characterization of the unit.
Unit-stratotype
The specified sequence of strata that contains the specific point that defines a boundary between two stratigraphic units.
Boundary-stratotype.
A unit-stratotype formed by the combination of several specified intervals of strata combined to make a composite standard of reference
Composite-Stratotype
The specific geographic locality was the stratotype of a layered stratigraphic unit is situated. The name also refers to the locality where the unit was originally described and/or named. In the case of units composed of nonlayered igneous or metamorphic rocks, the _____ is the specific geographic locality where the unit was originally defined.
Type Locality
The geographic area or region that encompasses the stratotype or type locality of a stratigraphic unit or boundary.
Type Area or Type Region
In the Rule of V’s it is the only bed orientation where the “V” points downstream.
a. Beds dip upstream
b. Beds dip gently downstream
c. Beds dip steeply downstream
d. Beds dip with stream gradient
Answer: Beds dip steeply downstream
a. Beds dip upstream (V points upstream; blunter than the contour)
b. Beds dip gently downstream (V points upstream; sharper than the contour
d. Beds dip with stream gradient (No V shape)
In the Rule of V’s, what bed orientation creates V pointing upstream and parallel to the contour?
a. Beds dip upstream
b. Vertical beds
c. Horizontal beds
d. Beds dip with stream gradient
Answer: Horizontal beds
a. Beds dip upstream (V points upstream; blunter than the contour)
b. Vertical beds (No V shape)
d. Beds dip with stream gradient (No V shape)
A matrix-supported rock with > 10% of grains >2mm and original components are not organically bounded together during deposition
Floatstone
a grain-supported rock with > 10% of grains >2mm and original components are not organically bounded together during deposition
Rudstone
In situ organically-bound rock in which organisms encrust
Bindstone
in situ organically-bound rock in which organisms build a rigid framework
Framestone
