The document provides information on various types of sedimentary rocks, including their formation processes and classification. It discusses mechanically formed sedimentary rocks such as sandstones, conglomerates, silt, shale and clay which are formed by the deposition and cementation of fragments and sediments. It also addresses chemically formed rocks like gypsum and salt rocks that are produced by dissolution of minerals in water. Finally, it covers organically formed rocks like limestone, dolomite and coal that result from the deposition and compaction of plant and animal remains.
Sedimentary Rock Characteristics and Classification
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• Characteristics of sedimentary rocks
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7. Granite is Phaneritic and
• Composed of (page 72)
• Granite is a hard, coarse-grained rock making
up most of the earth. It consists chiefly of
three minerals: quartz, alkali feldspar (which
contain alumina and silica) and plagioclase
feldspar (which contain sodium and calcium).
It also contains small amounts of minerals
such as hornblende and biotite mica.
8. What ions
• Composed of (page 72)
• 1. Feldspars AlSi3Os (M : H, Li, Ag) synthesized
by low-temperature ion exchange
• only feldspars with essentially disordered Al-Si
distributions
2. plagioclase feldspar (which contain sodium
and calcium).
10. compaction of the sediments.
• Sedimentary rocks are formed due to the
aggradations and compaction of the
sediments.
• The word sedimentary has been derived from
the Latin word which means settling down..
11. Stratified or layered rocks
• The sedimentary rocks are also Called as
Stratified or layered rocks and hence Consists
of different types of layers and strata of
various sediments. Some sedimentary rocks
do not consist of layers, ex: loess.
12. Characteristics of Sedimentary rocks
• Sedimentary rocks are formed of sediments
derived from older rocks, Plants and animal
remains thus these rocks contains fossils of
animals and plants
13. Characteristics of Sedimentary rocks
• The sedimentary rocks are widespread about
75 % of the globe consists of sedimentary
rocks and the remaining 25% by igneous and
metamorphic rocks. Nevertheless the
sedimentary constitute only 5 % of the
composition of earth’s crust
14. Characteristics of Sedimentary rocks
• The deposition of sediments takes place in a
certain sequence. The size of the Sediments
decreases from the littoral margins to the
centre of the water bodies.
16. Shoreline of a lake with nearly
unvegetated littoral zone
17. Characteristics of Sedimentary rocks
• The sedimentary rocks are consolidated and
compacted by cementing elements Such as
Silica, iron compounds, Calcite, Clay Etc
18. cement grain will not have the same
size
Mineral Chemical formula Oxide composition Abbreviation
Tricalcium silicate
(alite)
Ca3SiO5 3CaO.SiO2 C3S
Dicalcium silicate
(belite)
Ca2SiO4 2CaO.SiO2 C2S
Tricalcium aluminate Ca3Al2O4 3CaO.Al2O3 C3A
Tetracalcium
aluminoferrite
Ca4AlnFe2-nO7 4CaO.AlnFe2-nO3 C4AF
20. calcium aluminoferrite
• The calcium aluminoferrite (C4AF) forms a
continuous phase around the other mineral
crystallites, as the iron containing species act
as a fluxing agent in the rotary kiln during
cement production and are the last to solidify
around the others. Figure 1 shows a typical
cement grain.
21. Characteristics of Sedimentary rocks
• of cementing materials and the rocks are
Seldom found in their original manner because
of the lateral compressive and tensile forces
22. Characteristics of Sedimentary rocks
• Sedimentary rocks are seldom crystalline but
are Characterized by Joints perpendicular to
the bedding Planes
24. Characteristics of Sedimentary rocks
• The connecting Plane between two
consecutive beds or layers is called as bedding
Plane.
25. Types of formation in Sedimentary
rocks
• When two beds are uniform along the
bedding Plane then this type of formation is
called conformity.
26. • Non-conformity (where sedimentary rocks
succeed igneous & metamorphic rocks)
• Angular unconformity (where horizontal
sedimentary beds are deposited over the
previously folded strata)
• Disconformity (where two conformable beds are
separated by Changes in sediment type.
• Paraconfirmity ( where two sets of conformable
beds are Separated by same set of sediments)
27. two beds
• conformity.
• When two beds are uniform along the
bedding Plane then this type of formation is
called conformity.
• When two beds are not uniform then the
structure is called as Unconformity
28. Types of formation in Sedimentary
rocks
• Unconformity
• When two beds are not uniform then the
structure is called as Unconformity.
32. • Paraconfirmity ( where two sets of
conformable beds are Separated by same set
of sediments)
33. • A paraconformity is a type of unconformity in
which strata are parallel; there is little
apparent erosion and the unconformity
surface resembles a simple bedding plane. It is
also called nondepositional unconformity or
pseudoconformity.
36. • Sedimentation units in the rocks which are
more than One centimeter is called BEDS
37. • The upper and lower surface of the beds are
called BEDDING PLANE or BOUNDING PLANES
38. a bedding: BOUNDING PLANES
• In a quarry, a bedding is a term used for a
structure occurring in granite and similar
massive rocks that allows them to split in well-
defined planes horizontally or parallel to the
land surface.
39. • Sometimes the lower surface of the bed is
called SOLE. There are further sedimentary
units within a bed. The units having more than
one centimeter is called layer or Strata Where
as the units below one centimeter are Called
laminae
40. strata and Layer > 1 cm
laminae < 1 cm
• 1 cm<
• more than one centimeter is called layer
or Strata
Where as the units below one centimeter are
Called laminae < 1 cm
41. strata and laminae
• Thus several strata and laminae make up a
bed. When beds are deposited at an angle to
the depositional surface they are called cross
beds and the general phenomena of inclined
layers are called cross lamination or cross
bedding.
42. MUD CRACKS
• Soft mud or alluvial deposits by rivers develop
cracks when baked in sun and these cracks are
generally of Polygonal Shape, such cracks are
Called MUD CRACKS OR SUN CRACKS.
49. a decent oil well,
• This means 92 percent is solid rock and 8
percent is open space containing oil, gas, or
water. Eight percent is about the minimum
porosity that is required to make a decent oil
well,
52. Classification of sedimentary rocks
• ON THE BASIS OF NATURE OF SEDIMENTS
• Mechanically formed or clastic rocks
• TEETH
• Chemically formed sedimentary rocks
• SALIVA
• Organically formed sedimentary rocks
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53. Classification of sedimentary rocks
– ON THE BASIS OF NATURE OF SEDIMENTS
– Mechanically formed or clastic rocks
• Sandstones
• Conglomerates
• Clay rock
• Shale
• Loess
54. Classification of sedimentary rocks
– ON THE BASIS OF NATURE OF SEDIMENTS
– Chemically formed sedimentary rocks
• Gypsum
• Salt rock
55. Classification of sedimentary rocks
– ON THE BASIS OF NATURE OF SEDIMENTS
– Organically formed sedimentary rocks
• Limestone
• Dolomites
• Coals
• Peats
56. ON THE BASIS OF TRANSPORTING
AGENTS
– Argillaceous or aqueous rocks
• Marine rocks
• Lacustrine rocks
• Riverine rocks
57. ON THE BASIS OF TRANSPORTING
AGENTS
– Aeolian sedimentary rocks
• Loess
58. Aeolian processes
• Aeolian processes, also spelled eolian, or
æolian, pertain to wind activity in the study of
geology and weather, and specifically to the
wind's ability to shape the surface of the Earth
(or other planets). Winds may erode,
transport, and deposit materials, and are
effective agents in regions with sparse
vegetation and a large supply of
unconsolidated sediments
59. A rock sculpted by wind erosion in the
Altiplano region of Bolivia
60. Sand blowing off a crest in the Kelso
Dunes of the Mojave Desert, California
61. ON THE BASIS OF TRANSPORTING
AGENTS
– Glacial sedimentary rocks
• Till
• Moraines
66. Mechanically formed sedimentary
Rocks
• Previously formed rocks are subjected to
mechanical or physical disintegration these
are called fragmental rock materials or Clastic
materials which become the source materials
for the formation of mechanical or clastic
sedimentary rocks.
67. Mechanically formed sedimentary
Rocks-----clastic
• These materials are further broken down in
to fragments during their transportation by
the exogenous process such as wind, running
water glacier etc, some of the important
members of this group are Sandstones,
conglomerates, Silt, shale, Clay etc.
68. Clastic rocks
• Clastic rocks are composed of fragments, or
clasts, of pre-existing minerals and rock
70. Sandstones, conglomerates, Silt, shale,
Clay
• Conglomerates and Breccias
• Sandstones
• Quartz is, by far, the dominant mineral in
sandstones. Still there are other varieties. A
Quartz arenite – is nearly 100% quartz
grains. An Arkose contains abundant
feldspar. In a lithic sandstone, the grains are
mostly small rock fragments. A Wacke is a
sandstone
71. Mechanically formed sedimentary
Rocks
• Sandstones
• Sandstones are formed mostly due to the
deposition, Cementation, compaction of Sand
grains. The Sand grains are divided into five
categories on the basis of their size
72. Classification of sands by grain size
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Sand types Grain size (in mm)
Very Coarse sand 1.0 to2.0
Coarse Sand 0.5 to 1.0
Medium sand 0.25 to 0.5
Fine sand 0.125 to 0.25
Very Fine sand 0.0625 to 0.125
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• 2 cm = jelly bean
• 1 cm = popcorn
• Less than 2 mm-coffee grains
• Approx. 2 mm –0.5 mmGround coffee
74. grains are deposited in the water
•
• These grains are deposited in the water
bodies, and are aggravated and consolidated
by Cementing elements such as Silica,
Calcium, iron oxide Clay etc. The Colour of the
sandstone Varies according to the nature of
the cementing elements.
75. Sandstones
• Sandstones become red and gray when
cemented by iron oxide and in to white when
the cementing element is replaced by calcium
Carbonate.
76. Sandstones
• . They become hard and resistant when
cemented by Silica. On an average the
sandstones are generally porous rocks.
77. Sandstones
• On the basis of mineralogical and textural
Characteristics sandstones are classified in to
the following types:
• Quartz Arenites (composed entirely of quartz
grains)
82. Arsenite
• Note: The English word Arsenite is derived
from Latin word Arena-meaning thereby
Sand.
83. Stop here -3 am
• Conglomerates
• They are formed due to the consolidation
and cementing of pebbles of various Sizes
with Sands. Polished round fragments of size
with 4 mm of diameter are called Pebbles and
those with a diameter 256mm are called
boulders. Angular rock fragments are Called
breccia.
84. Clay rock and shale
• Clay rock and shale
• They are formed due to the deposition
and cementation of fine sediments.
85. Clay rock and shale
• Clay rock and shale
• . Sediment having grain size of 0.3mm to
O.4mm are called silts where as Clays are
formed When the grain size is between
0.4mm to O. 00012 mm are Cemented or
consolidated.
86. Clay rock and shale
• Clay rock and shale
• . Clay rocks are formed exclusive Kaolin
minerals and pure White in colour but they
Change to different colours because of being
mixed with impurities.
87. Chemically formed sedimentary Rocks
• When Running Water containing chemicals
come in touch with the rocks containing
Soluble materials are washed away and come
in contact with the Chemicals. The Chemical
materials are then settled down, compacted
and cemented to form Chemical sedimentary
rocks such as gypsum and salt rocks.
88. • Dissolution
• H2O + CO2 + CaCO3 --> Ca+2 + 2HCO3
-
water + carbon dioxide + calcite dissolve into
calcium ion and bicarbonate ion
89. • Oxidation (rust)
• 4Fe+2 +3O2 --> 2Fe2O3
ferrous iron + oxygen combine to form ferric
iron oxide (hematite)
• Will happen to all iron-bearing silicates to
varying degrees. Common reaction minerals
are hematite, limonite, and goethite.
90. Hydrolysis ofpotassium feldspar
• Hydrolysis
• 2KAlSi3O8 + 3H20 --> Al2Si2O5(OH)4 + 4SiO2 +
2K(OH)
potassium feldspar in acidic water hydrolyses
to kaolinite + quartz + potassium hydroxide
92. Organically formed sedimentary rocks
• The sediments derived from the
disintegration and decomposition of Plants
and animals deposit and consolidate to form
organic sedimentary rocks. The rocks are
divided in to three categories on the basis of
its carbon and lime content. They are
94. Organically formed sedimentary rocks
• Calcareous rocks are formed due to the
deposition and consolidation of sediments
derived from the remnants of animals and
plants which contain lime. Limestone is one of
the examples of the calcareous rocks.
Limestone is formed in the following Manner
95. Organically formed sedimentary rocks
• Calcium oxide (Cao) reacts with water to form
Calcium hydroxide Ca (0H) 2. This is given by
the following equation,
96. Limestone is formed in the following
Manner
• Then Calcium hydroxide reacts with Carbon
dioxide (CO2) to give Calcium carbonate
CaCo3 this is given by the following equation,
98. Limestone : calcareous rocks
•
• The calcareous rocks are collectively called
as carbonate rocks or carbonates. Calcium
carbonate (Caco3), Magnesium carbonate
(Mgco3), dolomite (CaMg (co3)2 are
important calcareous rocks. Limestone is both
thinly beaded and thickly bedded. The most
dominant minerals are calcite (Hexagonal),
Aragonite (orthorhombic).
99. Limestone : calcareous rocks
• Though Limestone are weak rocks in humid
regions they become more resistant when
exposed to dry climate, because of its uniform
or homogenous structure they are not easily
affected by differential expansion and
contraction due to temperature.
100. Limestone : calcareous rocks
• The Carbonate rocks after Chemical
weathering give birth too karst topography.
Chalks another form of Carbonate rocks are
formed due to the Precipitation of Carbonate
minerals desired from microorganisms like
foraminifera.
104. Location map of the Palisades Sill (red)
within the Newark Basin (yellow)
105. • The outcrop of the Palisades Sill is quite
recognizable for its prominent cliffs above the
Hudson River; it is easily seen from the
western portions of Manhattan
106. • The exposure is approximately 80 kilometers
(50 mi) long, most of it following the Hudson
River. It first emerges in Staten Island in New
York City.[1] The sill then crosses the state line
into New Jersey, where Hoboken, Jersey City,
Union City, Fort Lee, and Englewood Cliffs all
lie on it
107. • The sill eventually crosses back into New York,
following the Hudson River north until
reaching Haverstraw. It is at this point that the
sill makes a turn to the west, where it
disappears near Pomona. At this turn, the sill
cuts across local strata, making it a dike in that
area, not a sill.
108. • It has been proposed that the sill reemerges in
two locations in Pennsylvania (where the
outcrops are also discordant with local strata),
but this idea is not generally agreed upon, and
discussion of the Palisades Sill is usually
limited to the exposure in New York and New
Jersey.
109. Figure 11
• Separate host of granite from the mafic (Mg
and Fe)
• Suggest a origin of these zones:
• 1. partial melting-produces basalt
• 2. magnetic differentiation is best answer: it
separates early formed-denser material from
magma
110. Figure 11
• 3. also assimilation: since as magma rises-it
may add ions by melting
• As new material is incorporated –the magma
composition may change enough to enable
crystal to form –which might not ever been
otherwise able to be produced
111. Figure 11
• 4. lastly-magma mixing-evidence suggests
some intermediate rocks did not crystalize
• So they formed when-felsic and mafic were
mixed