Sedimentary Petrology Flashcards
(160 cards)
1
Q
It is a branch of study concerned with the composition, characteristics and origins of sedimentary rocks
A
Sedimentary Petrology
2
Q
these are particles that have been mechanically transported by water, wind or ice or chemically precipitated from solution or secreted by organisms and deposited in loose layers on the Earth’s surface
A
Sediment
3
Q
Originates and is transported as solid particles from both mechanical and chemical weathering
A
Detrital Material
or
Clastic Material
4
Q
these are produced largely by chemical weathering
A
Soluble Material
5
Q
rocks that formed at low temperature and pressure, found at or near the Earth’s surface
A
Sedimentary Rocks
6
Q
these are formed from cemented sediment grains that are fragmented of pre-existing rocks
A
Detrital or Clastic Sedimentary Rocks
7
Q
These are deposited by precipitation of minerals from solution
A
Chemical Sedimentary Rocks
8
Q
these are formed by the accumulation of the remains of organisms
A
Organic Sedimentary Rock
9
Q
The physical breakdown and chemical alteration of rocks at or near the Earth’s surface
A
Weathering
10
Q
disintegrated rock particles are transported from the source or parent rock to its site of deposition
A
Transportation
11
Q
occurs when the transported material settles or comes to rest as the medium of transport loses energy and can no longer transport its load
A
Deposition
12
Q
as material precipitates from water tthat percolates through the sediment, open spaces are filled and particles are joined together into a solid mass
A
Cementation
13
Q
the weight of the overlying material compresses more deeply buried sediment
A
Compaction
14
Q
complex process whereby freshly deposited loose grains of sediment are converted into rock
A
Lithification
15
Q
a collective term for all changes that take place in texture, composition, and other physical properties after sediments are deposited
A
Diagenesis
16
Q
a grade scale for classifying the diameters of sediments.
A
Udden-Wentworth Scale or Wentworth Scale
17
Q
Particles with
a. <1/256mm
b. 1/256 - 1/16mm
c. 1/16 - 2 mm
d. >2 mm
A
Clay
Silt
Sand
Gravel
18
Q
Particle with the grain diameter of
a. 2 - 1 mm
b. 1/4 - 1/8 mm
c. 32 mm
d. 1/64 - 1/128mm
A
Very Coarse Sand
Fine Sand
Cobble
Fine Silt
19
Q
consolidated gravel; composed of well-rounded pebbles
A
Conglomerate
20
Q
term used if most of the clasts are between 64mm and 256mm in diameter of rock
A
Cobble Conglomerate
21
Q
mixture of rounded and angular clasts
A
Breccio-Conglomerate
22
Q
clasts that are angular in shape
A
Breccia
23
Q
a gravelstone with a mud-supported matric, commonly deposited from glaciers, sediment gravity flows, particularly debris flows.
A
Diamictite
24
Q
All clasts have the same material
A
Monomictic
25
composed of clasts of the same material as the matrix and is formed as a result of reworking of lithified sediment soon after deposition
Intraformational Conglomerate
26
rocks with equally spaced fracture planes in all directions, which will form spherical clasts when the edges are rounded off
Cubic (Equant)
27
rock that is clast-supported; A conglomerate in which all clasts are in contact with other clasts
Orthoconglomerate
28
used where there are just two or three clasts types present
Oligomictic
29
a matrix-supported texturel; A conglomerate in which most clasts are not in contact
Paraconglomerate
30
conglomerate that contains clasts of many different lithologies
Polymictic
31
a conglomerate in which clasts are exotic. Clasts are derived from a distant source
Extraformational Conglomerate
32
bedrock lithologies that break up into slabs form clasts with one axis shorter than the other
Oblate (Discoid)
33
when a discoid clasts are moved into a flow of water, these are preferentially oriented and may stack up in a form called ____________
Imbrication
34
those which are less susceptible to physical and chemical breakdown have a higher chance of being preserved as a clast in a conglomerate
Resistant Lithologies
35
clasts are less common, forming mainly from metamorphic rocks with a strong linear fabric
Rod-Shaped (Prolate)
36
grains that form within the depositional environment, they are pieces of plant or animal, but there are some which are formed by chemical reactions
Biogenic Particle
37
grains in the size of 1/16 - 2mm
Sand
38
Components of sand and sandstone
```
Detrital Minerals
Authigenic Materials
Matrix
Lithic Fragments
Biogenic Particles
```
39
Minerals that grow as crystals
Authigenic Materials
40
a rock if the amount of matrix is >15%
Arenite
41
a method whereby a thin section on a petrographic microscope is examined by stepping across thin sections at equal intervals
Point Counting
42
is defined as the grain suze of material between 4 and 62 microns in diameter
Silt
43
are group pf phyllosilicate minerals that are main constituents if clay-sized particles
Clay Minerals
44
general term for any indurated sediment made up of silt and/or clay
Mudrock
45
If the rock has
a. ≥2/3 clay
b. ≥2/3 silt
c. >1/3 silt + >1/3 clay
Claystone
Siltstone
Mudstone
46
strong tendency to break in one direction, parallel to bedding
Fissility
47
applied to any mudrock that shows fissility
Shale
48
is a textural term to define the finest grade of clastic sedimentary particles
Clay
49
most common mineral seen in silt deposits
Quartz
50
these are the deposist from strong, persistent winds that carry silt-sized dust thousands of kilometers
Loess Deposit
51
most common member of the Kandite Group
Kaolinite
52
a product of more moderate temperature conditions in soils with neutraal to alkaline pH
Montmorillonite
53
swelling or expanding clay
Montmorillonite
54
generally formed in soil profiles in warm, humid environments where acidic waters intensely leach bedrock lithologies such as granite
Kaolinite
55
a clay mineral with two patterns of layering
Kandite group
56
most common clay mineral in sediments
form in soils in temperate areas where leaching is limited
illite
57
forms in soils in arid climate with moderate leaching
fairly acidic groundwater conditions
Chlorite
58
an equipment that scans the surface of the sample which features micro imaging technique
Scanning Electron Microscope (SEM)
59
cohesive properties of clay minerals in suspension tend to form small aggregates of individual particles, it is called as ________
Flocculation
60
fragments that make up a sedimentary rock are called
Clasts
61
the distribution of clast sizes present
Sorting
62
During sediment transport, sharp edges tend to be chipped off first, the abrasion smoothens the surface of the clast
Clast Roundness
63
a relatively quick and easy method of semi-quantitatively determining the mineral composition of fine-grained sediment
X-Ray Diffractometer
64
is an inherited feature, that is, it depends on the shapes of the fragments which formed during weathering
Sphericity
65
describing individual clasts, the dimensions can be considered in terms of closeness to sphere
Clast Sphericity
66
tendency to break in a certain direction or show a strong alignment of elongate clasts
Fabric
67
quantitative assessment of the percentages of different grain sizes in clastic sediments and sedimentary rocks is called
Granulometric Analysis
68
is laid over the loose material or on a surface of conglomerate and each clast measured within its area
Quadrant
69
indicator of whether the grain-size histogram is symmetrical or is skewed to a higher percentage of coarser or finer material
Skewness
70
the extent to which the material has changed when compared with the starting material of the bedrock it was derived from
Maturity
71
a measure of the proportion of resistant or stable minerals present in the sediment
Compositional Maturity
72
there has been one cycle of erosion, transport and deposition
First Cycle
73
general term for solid sedimentary particles regardless of origin
Clastic or Detrital
74
Used for clastic sediment that is transported as solid particle across Earth's surface
Epiclastic
75
used for clastic particles or organic origin such as shell fragments transported by waves or currents
Bioclastic
76
_____ refers to redeposited material
Second Cycle
77
the texture of sediment or sedimentary rock can be used to indicate information about the erosion, transport, and depositional history.
Textural Maturity
78
used for clastic particles produced initially by volcanic processes
Volcaniclastic
79
used for clastic particles composed of silicate minerals
Siliclastic
80
% of Mg in
a. Low Mg Calcite
b. High Mg Calcite
a. <4%
| b. 11-19%
81
large group of organisms that have a fossil record back to the Cambrian and commonly have calcareous hard parts
Molluscs
82
have a distinctive layered shell structure consisting of two or three layers of calcite, or aragonite, or both
Bivalve Molluscs
83
shelly organisms with two shells and hence superficially similar to bivalves
Brachiopods
84
have a calcite or aragonite layered structure and are distinctive for their coiled form
Gastropods
85
layered shell structure and in common with most other molluscs, this is a feature that may be recognizable in fragments of shell under the microscope
Cephalopods
86
cephalopods that had a cigar-shaped guard of radial, fibrous calcite
Belemnites
87
hard body parts out of whole low-magnesium calcite crystals
Echinoids
88
they reconstruct their body parts out of whole calcite crystals, with discs that make up the stem or a ______ forming sizeable accumulations in Carboniferous sediments
Crinoids
89
small, single-celled marine organisms that range from a few tens of microns in diameter to tens of millimeters across
Foraminifera
90
largest calcium carbonate biogenic structure
Cnidaria (Corals_)
91
have a symbiotic relationship with algae that require clear, warm, shallow marine waters.
Hermatypic Corals
92
do not have algae and can exist in colder, deeper water
ahermatypic Corals
93
Single-celled protozoans are seen mainly as encrusting organisms today but in the past they formed large colonies
Bryozoa
94
they are an important source of biogenic carbonate and are important contributors of fine-grained sediment in carbonate environment through much of the geologic record
Algae & Microbial Organisms
95
known as the coralline algae
Red Algae (Photophyta)
96
have calcified stems and branches, often segmented that contribute fine rods and grains of calcium carbonate to the sediment when the organism dies
Green Algae (Chlorophyta)
97
they are extremely important contributors to marine sediments in parts of the stratigraphic record
Yellow Algae (Nanoplankton)
98
these organisms are not classified separately to algae
Cyanobacteria
99
the algal mats formed by these organisms
Microbial/Bacterial Mats
100
the filaments an sticky surfaces of the cyanobacteria act as traps for fine-grained carbonate and as the structure grows it forms layered, flat or domes structures called ___
Stromatolites
101
cyanobacterial communities that have an irregular rather than layered form
Thrombolites
102
they are irregular concentric structures mm to cm across formed of layers bound by cyanobacteria found as clasts within carbonate sediments
Oncoids
103
spherical bodies of CaCO3 less than 2mm
Ooids
104
concentrically layered carbonate particles over 2mm across,
Pisoids
105
commonly fecal pellets of marine organisms, mostly particles less than a mm across
Peloids
106
fragments of CaCO3 material that has been partly lithified and then broken up and reworked to form a clast which is incorporated into the sediment
Interclasts
107
are fine-grained siliceous sedimentary rocks made up of silt-sized interlocking quartz crystals
Cherts
108
it is considered carbonaceous if it contains a proportion of organic materials
___% for mudrock
___% limestone
___% sandstone
>2% mudrock
>0.2% limestone
>0.05% sandstone
109
long-term preservation of dead vegetation is favoured by the wet, anaerobic conditions of mires, bogs, and swamps
Peat
110
if >2/3 of a rock is solid organic matter if may be called ____
economic ___ have less than ___% non-organic, noncombustible material
Coal
10%
111
bright, shiny black coal that usually breaks cubically and mostly consists of woody tissues
Vitrain
112
black or grey in color, dull and rough coal that usually contains a lot of spore and detrital plant material
Durain
113
black, fibrous with a silky luster, friable and soft coal that represents fossil charcoal
Fusain
114
banded, layered coal that consists of alternations of other 3 types
Clarain
115
microscopic examination of these lithotypes reveals that a number of different particle types can be recognized
macerals
116
origin of which is mainly cell walls of woody tissue and leaves
Vitrinite
117
mainly comes from spores, cuticles and resins
Liptinite
118
burnt, oxidized or degraded plant material
Inertinite
119
mudrocks that contain a high proportion of organic material that can be driven off as a liquid or gas by heating
Oil Shales
120
are clastic sediments that are saturated with HC and they are the exposed equivalents of subsurface of oil reservoirs
Tar Sands
| Oil Sands
121
% Marine Evaporites
a. CaCO3
b. CaSO4
c. NaCl
d. KCl
a. 0.3%
b. 3.5%
c. 78
d. 18%
122
Sequence of Precipitation of marine Evaporites
CaCO3
CaSO4
NaCl
KCl and MgCl
123
precipitated from seawater once evaporation has concentrated the water to __% of its original volume
a. 19%
b. 9.5%
a. Calcium Sulphate
| b. Halite
124
an important source of industrial potash and is interpreted as the product of of extreme evaporation of marine water
Sylvite
125
rocks with concentrations of phosphate (5-35% P2O5) are called ____
Phosphorites
126
Phosphorites are composed of _____, which is Fluorapatite
Francolite
127
Sedimentary rocks that contain at least 15% Iron ore referred to as
Ironstone
or
Iron Formation
128
are black to dark brown in color and range from a few mm to many cm across as _____ or as extensive laminated crusts on hard substrates
Nodules
129
method for representing a series of beds of sedimentary or sedimentary rocks
Sedimentary Logs
130
features that give the direction of flow
Unidirectional Indicator
131
structures that provide information about the axis of the current but do no differentiate between upstream and downstream directions
Flow Axis Indicator
132
information about the source of sediment
Provenance
133
used to determine the average chemical composition of large continental areas
Mud and Mudrock Analysis
134
sum of the characteristics of a sedimentary unit
Facies
135
confined to the physical and chemical characteristics of a rock
Lithofacies
136
Observation concentrate on the fauna and flora present
biofacies
137
focuses on trace fossils
Trace Fossils
138
temporal and spatial relationships between depositional facies as observed in the present day and recorded in sedimentary rocks
Walther's law
139
provides a framework of understanding the processes that lead to the formation of mountains as well as providing for how all the main morphological features of the crust have been formed throughout most of earth history
Plate Tectonic Theory
140
is a consequence of the movement of any body travelling towards or away from the poles over the surface of a rotating sphere
Coriolis Force
141
is an important stage in the transformation of bedrock and regolith into detritus available for transport and deposition
Soil Formation
142
a coherent mass of bedrock moving downslope without significantly breaking
Landslide
143
with significant breaking of the bedrock accumulates as a chaotic mass at the bass of slope
Rock Fall
144
Regolith is lubricated with water as it moves down the slope, almost imperceptible
Soil Creep
145
intermediate between landslides and soil creep, instantaneous events like landslides but has plastic material due to water saturation forms an internallt deformed masss
Slumping
146
laminar flow, similar to a slump but with more water involved
Debris Flow
147
weathered detritus in mountain areas that accumulated near the bottom of the slope
Scree
148
initial erosion by water on hillsides, unconfined surface run-off down a slope following rain
Sheet Wasg
149
The result of atmospheric differences that are partly due to global distribution and local variations in pressure complex shifting patterns
Wind
150
is most effective on land surfaces with sparse vegetation
Wind Erosion
151
occurs by frictional action of block of materials in ice on the bedrock
Abrasion
152
occurs when glaciers flow over an obstacle
Plucking
153
lowering of land surface by a combination of weathering and erosion
denudation
154
change in the height of the ground over the sea
Relief
155
essential to all chemical processes
Water
156
presence of acids enhances hydrolysis and dissolved oxidizing agents facilitate oxidation reactions
Water Chemistry
157
high discharge in streams but dense vegetation reduces soil erosion even on steep slopes
High Rainfall
158
effectively protects the bedrock and overlying regolith from rain impact and overland water flow; stabilizes mountain slopes; bind fine detritus into soil protecting it from wind
Dense Vegetation Cover
159
Removal of mass from an uplifted bedrock
Isostatic Uplift
160
an orographic effect resulting to a sharp climatic division across a mountain range
Thermochronology
