how to interpret the pages of earth history. a helpful law: 1) law of superposition: in a series of...
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HOW TO INTERPRET THE PAGES OF EARTH HISTORY.
A Helpful Law:
1) Law of Superposition: In a series of sedimentary rock layers, younger rocks normally lie on top of older rocks.
HOW TO READ THE PAGES OF EARTH HISTORY.
A Helpful Laws:
1) Law of Superposition: In a series of sedimentary rock layers, younger rocks normally lie on top of older rocks.
More Helpful Laws:
2) Law of Cross cutting Relationships: Rocks or structures that cut across other structures are younger than what they cross.
More Helpful Laws:
2) Law of Cross cutting Relationships: Rocks or structures that cut across other structures are younger than what they cross.
More Helpful Laws:
3) Law of Original Horizontality: Sedimentary Rocks are normally laid down horizontally or flat, and not tilted.
More Helpful Laws:
3) Law of Original Horizontality: Sedimentary Rocks are normally laid down horizontally or flat, and not tilted.
“What are them there rocks?”
1) IGNEOUS: Rocks that were once red hot molten lava that flowed into place.
A) Two types of igneous rocks:
i) Volcanic: lava that flows over earth’s
surface and cools.
ii) Plutonic: magma that cools beneath
earth’s surface.
Plutonic
Volcanic
Plutonic
Volcanic
Plutonic
Volcanic
2) SEDIMENTARY: Rocks originally layed down in water or by the wind.
A) They are made of mega amounts, of tiny sand, silt
or clay particles.
B) They form horizontal layers called “Strata.”
C) They are uncemented at first and called “Sediments” and then later turn into rock.
2) SEDIMENTARY: Rocks originally layed down in water or by the wind.
A) They are made of mega amounts, of tiny sand, silt
or clay particles.
B) They form horizontal layers called “Strata.”
C) They are uncemented at first and called “Sediments” and then later turn into rock.
3) METAMORPHIC: Igneous or sedimentary rocks that have been heated and put under pressure until they start to melt.
A) They form three ways:
i) when shoved or buried several miles under
the earth.
ii) when hit by an asteroid.
iii) when heated by a lava flow
A. KEY WORDS:
1. Sediments - Sand, silt, clay & rocks in the bottom of a valley, river, lake, or ocean, that is uncemented.
2. Sedimentary Rock - Cemented sediments.
3. Igneous Rock - Hot melted rock known as magma that either flows over land from a volcano, or….
moves from and cools deep within the
Earth to form granite mountains.
4. Deposition - The buildup of sediments on the bottom of a basin which later may become sedimentary rock.
5. Sedimentation - Same as Deposition.
2 DEFORMATION & UPLIFT
1 DEPOSITION
3 EROSION
6. Fossilization - Burying and turning the parts of a living organism into hard, petrified remains or making an imprint of the organism in the rock.
7. Terrestrial Fossils - Fossils of organisms that lived on land.
8. Freshwater Fossils - Fossils of organisms that lived in lakes or rivers.
9. Marine Fossils - Fossils of organisms that lived in saltwater such as a lagoon, ocean or inland sea.
10. Alluvial Fans - A fan shaped deposit with boulders, rocks, and sand that forms next to a mountain.
You see these most clearly in the desert.
B. ENVIRONMENTS OF DEPOSITION:
1. Terrestrial Environments:
a) Desert - has sand dunes or alluvial fans w/ boulders.
b) Glacial - has boulders & angular rocks moved by glaciers.
c) Tropical - has tropical plant fossils.
d) If you find fossils of plants or animals that normally live on land than the deposition environment was on land (or we normally say, “it was a terrestrial environment”).
2. Freshwater Environments:
a) River or stream - has rocks, sand & silt.
b) Lake - has silt & clay.
c) Sedimentary rocks deposited in freshwater environments can have fossil organisms that lived in lakes or rivers.
3. Marine:
a) Lagoon - silt & clay w/lagoonal fossils.
b) Open ocean - limestone, coral reef and protist fossils.
c) Inland sea - has salt or other chemical deposits.
