The Earth's Crust Flashcards
The outer layer of the earth’s crust is known as-
lithosphere
sial and sima density?
sial- 2.7, sima-3.0.
sial and sima both forms the earth crust.
what is beneath crust or lithosphere? it is rich in?
mantle.
olivian
parts of earth’s crust are immersed by oceans or seas known as-
hydrosphere
classification of rocks according to their origin and appearance-
igneous, sedimentary, metamorphic
- how igneous rock formed?
- structure?
- Do they occur in layers, do they contain fossil feuls?
- when they are said to be acid?
- when they are said to be basics?
- density n color?
- cooling and solidification of magma
- crystalline
- they do not occur in layers , they do not contain fossil feuls.
- high silica proportion
- high iron, magnesium, aluminium
- acid ign rock: less dense and light in color
basic ign rock: denser n dark in colour
- what are two main classes of igneous rock
- plutonic rocks and volcanic rocks
plutonic rocks are formed where? Do they cool and solidifies slowly or at fast pace?
they are formed in some depth of earth’s crust.
slowly
how volcanic rocks are formed? Do they solidify rapidly?
they are formed from lavas. They solidify rapidly.
Applications of igneous rocks?
road making, polished as monuments, gravestones
- how sedimentary or stratified rocks are formed?
- how they are brought?
- What is their form?
- They are formed in layers. The rocks can be coarse or fine grained , soft or hard.
- They are brought by streams, glaciers, winds or even animals.
- They are non-crystalline. They contain fossils.
which rock contain fossils?
sedimentary rocks
sedimentary rocks classification according to origin n composition?
- Mechanically formed sed rocks
- organically formed sed rocks
- chemically formed sed rocks
- Mechanically sed rocks
- Organically sed rocks
- Chemically
- They are derived from materials which are derived from other rocks. ex: sandstone.
Finer sedimentary material: clay - Formed from remains of living organism such as coral or shellfish. ex: limestones n chalk
- such rocks are precipitated chemically from solutions. Ex: gypsum/calcium sulphate, potash n nitrates.
which type of sedimentary rocks are formed from vegetative matter-swamps and forest?
Carbonaceous- organically sed rocks.
peat,lignite or coal
Metamorphic rocks are also known as?
Change rocks. Igneous n sed rocks change themselves into metamorphic under heat and pressure.
Match correctly:
- clay a.marble
- limestone b. quartzite
- sandstone c.slate
- granite d. graphite
- shale e. gneiss
- coal f.schist
- slate
- marble
- quartzite
- gneiss
- schist
- graphite
running water, rain, frost,sun,wind,glaciers and waves are the agents which constantly reshaped earth, they are the agents of -
Denudation
mountain building movement is known as-
oregenic
3 most recent oregenics are-
caledonian, hercynian, alpine
recently formed ranges-
alps, himalayas, andes,rockies
Types of mountains?
Fold mountains
Block mountains
Volcanic mountains
Residual mountains
- How the fold mountains are caused?
- where the folding caused?
- what are upfolded waves and downfolds?
- ex of great fold mountains?
- They are caused by large scale earth movement when stresses are set up in the earth’s crust.
- folding is caused along the line of weakness.
- Upfolds- anticlines, downfolds- synclines
- Himalayas, rockies, Andes, Alps
when the crest of a fold pushed too far, known as-
overfold
when the overfold is pushed further-
recumbent fold
when the upper part of the recumbant fold slides forward over the lower part along a thrust plane, forming an overthrust fold, the over-riding portion is known as ?
nappe
By which force block mountains are formed?
Tensional force
Rift valley system can be seen under which mountain type?
block mountain.
What does volcanic mountain include?
molten lava, volcanic bombs, cinders, ashes, dust and liquid mud.
Volcanic mountains are often called?
mountains of accumulation
The type of mountains that are evolved by denudation?
Residual mountain
can residual mountains may also evolve from plateux which have been dissected by rivers into hills and valleys?
yes , ex: deccan plateau
what are plateaux?
Plateaux are elevated uplands with extensive level surfaces, and are usaually sdescend steeply to the surrounding lowland.
Plateuax sometimes reffered as?
Tableland
Plateaux are subjected to-
erosional process
Types of plateaux?
Tectonic, Volcanic, Dissected
Tectonic plateux
They are formed by earth movements.
when plateau are enclosed by fold mountains , are known as-
Intermont plateaux. ex: tibetan plateau between the himalayas and the kunlun.
how volcanic plateau formed?
molten lava spread over the surface to fom successive sheets of basaltic lava, solidify to form lava plateau. ex: north western part of deccan plateau, columbia snake plateau.
How dissected plateau get formed?
Through the continuos process of weathering and erosion. Stream action and glaciation cut deep, narrow valleys in the plateaux, described as dissected p.
what are plains?
area of lowland, rises more than a few hundred feet above the sea level.
Best for population n settlement, cultivation.
ex : indo gangetic plain.
grasslands-
- russia
- north america
- argentina
- steppes
- prairies
- Pampas
Types of plain?
Structional, Depositional, Erosional plains
Structural plain?
They are formed by horizontally bedded rocks, relatively undisturbed by the crustal movements of the earth. Ex: the great plains of usa
Depositional plain?
These are formed by the depositions of materials brought by various agents of transportation.
Which type of plain is more productive?
Depositional plains
Erosional plane?
These plains are carved by agents of erosion.
