Exam 1 Flashcards
What are maps?
Something that shows the relationship between different ideas
Are maps always geological?
No, maps can also be brain maps
What is a map in relation to geology?
Maps are a 2D representation of a 3D space
What makes a good map?
It should highlight key details, while hiding less important ones
What was William Smith credited with?
Biostratigraphy
What is biostratigraphy?
Using the orientation of rocks on the surface to locate rocks in the subsurface
What are the four layers of earth?
The crust, mantle, outer core and, inner core
Which layer of the earth is a liquid?
The outer core
How do we know about the layers of earth?
Using seismology, as well as earthquakes and volcanoes – they are responsible for our knowledge of earth’s layers
What is the difference between p and s waves
P wave (Pushing and pulling) while s wave (shear waves – waving around a wand)
Between P and S waves, which cannot pass through liquids?
S waves
At what degrees are P-waves affected by shadow zones?
103 to 142 degrees
At what degrees are S-waves affected by shadow zones?
103 to 103 degrees
What is an epicentre?
The location of an earthquake
What is the composition of the crust made up of?
Oxygen and silicon
What makes up a majority of the planet?
Oxygen and iron
Why is iron more plentiful beneath the surface?
Because metal is heavy and it sinks
How did the layers of Earth form?
From bombardment, gravitational compression, and radioactive decay which causes rocks to melt
What are the composition layer? (Chemistry)
Continental crust and, the oceanic crust
What are the mechanical layers called?
The lithosphere and the asthenosphere
What are the five components of a mineral?
- Solid
- Inorganic
- Naturally occurring
- Definite with sometimes varying chemical composition
- Crystal lattice
What should we not use to identify minerals?
Colours
What are earth materials made of?
Minerals, rocks, soils, fossils
What is the difference between rocks an minerals?
Minerals are made of single crystals, while rocks are aggregate materials
What is the most common building block of minerals?
Silicate Tetrahedron
Why are covalent bonds stronger than ionic bonds?
Covalent bonds share ions
What charges do minerals have?
They are all electrically neutral
What are the physical properties of silicate determined by?
Their composition, the arrangement, and bonds of atoms on a crystal lattice
What are the 5 ways minerals are created?
Solidification, precipitation from a solution, solid-state diffusion, biomineralization, precipitation from gas
What are the three types of rocks?
Igneous, sedimentary an, metamorphic
What minerals are in granite?
Potassium and sodium feldspar, muscovite, biotite, hornblende, and quartz
What is the difference between magma and lava?
Magma only exists underneath the earth, and once it touches earth’s surface it becomes lava
Where does magma exist?
Stored in earth’s crust as molted rock (as long as it exists i the subsurface it will be magma)
When does the mantle melt?
Pressure on rock is reduced, a volatile is added to the rock, hot magma melting other rocks
What is decompression melting?
When the temperature remains the same, though pressure on a rock is reduced
What is the Liquidus?
Conditions where a rock completely melts
What is the sollidus?
Conditions where rock begins to melt
What is the difference between assimilation and contamination?
Assimilation: rocks fall into magma
Contamination: the partial melting of rocks at magma rises upwards
Where does magma come from?
Convergent boundaries, divergent boundaries, and hot spots
What are the four types of magma?
Felsic, intermediate, mafic, and ultramafic
What is felsic magma rich in?
Silica and oxygen
What is mafic magma rich in?
Magnesium, iron, and calcium
What factors control the composition of magma?
Comp of source rocks (rock which is partially melted), Crystal settling, magma mixing, assimilation and contamination
What is a discontinuous reaction?
When temperature changes, minerals break down to create new minerals
What is a continuous reaction?
The composition of plagioclase changes with temperature (More ca when hotter, more potassium when cooler)
What determines how quickly magma cools?
The depth of magma, the size and shape of magma bodies, the presence of groundwater
What do extrusive rocks look like?
Smaller crystals as they cooled quickly
What do intrusive rocks look like?
Visible crystals as they cooled slowly
What is the difference between aphanitic and phaneritic?
Aphanitic rocks have small crystals, while phaneritic rocks have large crystals
What do porphyritic rocks look like?
The have multiple crystal sizes
What are pyroclastic rocks?
Fragmented rocks
What are vesicular rocks?
Rocks with large pores or holes
What is special about felsic and mafic rocks?
They are only present in the igneous system
What determines the composition of igneous rock?
Bowen’s Reaction series
What kind of magma is produced with fewer covalent bonds between tetrahedra?
Thin, runny magma
What kind of magma is produced with more covalent bonds between tetrahedra?
Thicker, dense magma
Which volcanoes has easily flowing lava? (Low silica, low viscosity, low gas?)
Mafic lava
What are the two types of mafic lavas?
Aa – rough, fragmented lava
Pahoehoe – smooth, shiny, and ropey
Which volcanoes are the ones which erupt catastrophically?
Felsic lava
What is the difference between felsic and mafic magma?
Mafic magma erupts like a liquid, while felsic magma erupts as a solid
What are pyroclastic debris?
Things that fly out of a volcano
Where are volcanoes most likely to occur?
At divergent and convergent boundaries (and sometimes over hotspots)
What are the two types of volcanoes?
Central vent volcanoes (Stereotypical ones and large volcanic terrains (Mid-ocean ridge)
What are the different types of central vent volcanoes?
Shield volcanoes, cinder cones, stratovolcanoes, and Rhyolite Caldera complexes
What are the characteristics of shield volcanoes?
Low silica, low gas, tends not to be explosive
What are the characteristics of stratovolcanoes?
Intermediate to felsic, minerals are explosively ejected as pyroclastic fragments
What are the characteristics of Rhyolite Caldera Complexes?
Produces inverse volcanoes, withdrawal of magma causes collapse
Where do divergent boundaries mostly exist?
On the sea floor
What different parts is the mantle composed of?
The uppermost mantle, the aesthenosphere, and the mesosphere
Which part of the mantle can flow? (and which flows more)
The aesthenosphere flows the best, and the mesosphere can flow
What makes up the oceanic lithosphere?
Oceanic crust and the uppermost mantle
What is the difference between a slope and a dip?
Slope: a line perpendicular to slope and parallel to surface bedding
Dip: The slope of a dipping bed
How are the ages of rocks read on a geological map?
Older rocks appear on the bottom, while younger rocks appear on the top
What can changes in density show?
It can deflect waves, and can change the velocity of waves
How do we know the composition of earth?
Because of volcanoes and meteorites
What kind of elements float?
Lighter elements float while denser elements sink
Between the continental and oceanic crusts, which is lighter?
The continental crust
What do ocean-continent boundaries form?
Volcano arcs and mountains
What do ocean-ocean convergent boundaries form?
Isalnd arcs
What do continent-continent convergent boundaries form?
Mountains
Why are plates likely to move?
Asthenosphere is weaker, allowing the lithosphere to slip underneath — oceanic plates are denser than continental plates
What are the three types of habits on a mineral?
Euhedral, Subhedral, and Anhedral
Both diamonds and graphite are made out of pure carbon, why is one stronger than the other?
Diamonds have stronger covalent bonds in all directions
What are the seven mineral classes?
Silicates — SiO4
Native elements
Oxides — O2-
Sulfides — S2-
Sulfates — (SO4)2-
Halides — Contains halogens
Carbonates — (CO3)2-
How do can silicate tetrahedron be neutralized?
Ionic bonds with cations, covalent bonds with other tetrahedron, mix of covalent and ionic bonds
Where does lava come from?
The mantle (asthenosphere)
How can felsic minerals be identified?
They are light in colour and weight, and are magnesium and iron deficient
How can mafic materials be identified?
They are darker in colour, heavier, and are rich in both iron and magnesium
What is the composition of the mantle?
It is ultramafic
Why does felsic magma require many phases?
Because it requires many phases of crystal settling and partial melting to produce enough silica content
