2. UPLOAD TO SLIDE SHARE ALL4
OPEN ALL OF THESE-3 AM
• aaaaaaaaaaROCKEXAM aaaaaFELSIC PAGE 58
• Answers to tell class on Monday j5 ese 11 new
• And
• Characteristics of sedimentary rocks
• And
• Agends foe first payday open this Sunday and
monday
6. 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..
7. 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.
8. 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
9. 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
10. 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.
12. Characteristics of Sedimentary rocks
• The sedimentary rocks are consolidated and
compacted by cementing elements Such as
Silica, iron compounds, Calcite, Clay Etc
13. 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
14. Characteristics of Sedimentary rocks
• Sedimentary rocks are seldom crystalline but
are Characterized by Joints perpendicular to
the bedding Planes
15. Characteristics of Sedimentary rocks
• The connecting Plane between two
consecutive beds or layers is called as bedding
Plane.
16. Types of formation in Sedimentary
rocks
• When two beds are uniform along the
bedding Plane then this type of formation is
called conformity.
24. • Sedimentation units in the rocks which are
more than One centimeter is called BEDS
25. • The upper and lower surface of the beds are
called BEDDING PLANE or BOUNDING PLANES
26. • 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
27. 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.
28. 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.
29. Permeable and Porous
• Most of the sedimentary rocks are
Permeable and Porous but few of them are
nonporous and Impermeable
31. Classification of sedimentary rocks
– ON THE BASIS OF NATURE OF SEDIMENTS
– Mechanically formed or clastic rocks
• Sandstones
• Conglomerates
• Clay rock
• Shale
• Loess
32. Classification of sedimentary rocks
– ON THE BASIS OF NATURE OF SEDIMENTS
– Chemically formed sedimentary rocks
• Gypsum
• Salt rock
33. Classification of sedimentary rocks
– ON THE BASIS OF NATURE OF SEDIMENTS
– Organically formed sedimentary rocks
• Limestone
• Dolomites
• Coals
• Peats
34. ON THE BASIS OF TRANSPORTING
AGENTS
– Argillaceous or aqueous rocks
• Marine rocks
• Lacustrine rocks
• Riverine rocks
35. ON THE BASIS OF TRANSPORTING
AGENTS
– Aeolian sedimentary rocks
• Loess
36. ON THE BASIS OF TRANSPORTING
AGENTS
– Glacial sedimentary rocks
• Till
• Moraines
38. 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. 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.
39. 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. 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.
40. 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
41. Classification of sands by grain size
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
42. •
• 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. Sandstones become red and gray
when cemented by iron oxide and in to white when the
cementing element is replaced by calcium Carbonate.
They become hard and resistant when cemented by
Silica. On an average the sandstones are generally
porous rocks.
43. •
• 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. Sandstones become red and gray
when cemented by iron oxide and in to white when the
cementing element is replaced by calcium Carbonate.
They become hard and resistant when cemented by
Silica. On an average the sandstones are generally
porous rocks.
44. •
• 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. Sandstones become red and gray
when cemented by iron oxide and in to white when the
cementing element is replaced by calcium Carbonate.
They become hard and resistant when cemented by
Silica. On an average the sandstones are generally
porous rocks.
45. • Sandstones
• On the basis of mineralogical and textural
Characteristics sandstones are classified in to
the following types
• Quartz Arenites (composed entirely of quartz
grains)
50. • Note: The English word Arsenite is derived
from Latin word Arena-meaning thereby
Sand.
51. 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.
52. • Clay rock and shale
• They are formed due to the deposition
and cementation of fine sediments.
53. • 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.
54. • 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.
55. 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.
56. 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
58. 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
59. Organically formed sedimentary rocks
• Calcium oxide (Cao) reacts with water to form
Calcium hydroxide Ca (0H) 2. This is given by
the following equation,
60. 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,
62. 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).
63. 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.
64. 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.
68. Location map of the Palisades Sill (red)
within the Newark Basin (yellow)
69. • 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
70. • 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
71. • 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.
72. • 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.
73. 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
74. 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
75. Figure 11
• 4. lastly-magma mixing-evidence suggests
some intermediate rocks did not crystalize
• So they formed when-felsic and mafic were
mixed