58 terms

Earth Science Midterm 1

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Every group of silicates is identified by
cleavage
The most important minerals for rocks are
silicates
positively charged atoms are also called
cations
negatively charged atoms are also called
anions
"cleavage" relates to
how atoms are organized within minerals
rocks are made of
minerals
Lahar
a volcanic mud flow
Mt. St Helens is what kind of volcano
explosive stratovolcano
Sill
an intrusive igneous body that is tabular and discordant to layering in adjacent rocks
Pozzolan was used to make ___
roman cement
Common detrital sedimentary rocks in order of increasing particle size are
shale, sandstone, conglomerate
'Phanerozoic' means:
visible life
The boundary at 2.5 billion years separates the ____ Eons on the Geologic time scale.
Archean and Proterozoic
What describes a mineral's response to mechanical impact (i.e., the way it breaks)?
Cleavage
What is true about rocks formed from lava at the Earth's surface?
They are extrusive rocks.They can have a fine-grained aphanitic texture.. They can have a glassy texture.
Shows the correct order (left to right) of increasing magma viscosity.
basalt, andesite, rhyolite.
Describe the fundamental concept of superposition
Any sedimentary deposit accumulates on older rock or sediment layers
Correlation
The investigative process by which geologists identify and match sedimentary strata and other rocks of the same ages in different areas
principle of fossil succession
The idea that ancient life forms succeeded each other in a definite, evolutionary pattern and that an assemblage of fossils can determine geologic ages of strata
T or F: The granite is older if the sandstone contains pebbles of the granite.
True
Mineral
naturally occurring, has specific chemical composition,
ordered internal crystal structure, and is an inorganic solid.
Low viscosity basaltic magmas generally form ___
Shield Volacanoes
Gneiss
characterized by the segregation of light- and dark-colored minerals into thin layers or bands
List the rocks in order of increasing grain size and increasing grade of metamorphism
slate, phyllite, schist, gneiss
What major change occurs during metamorphism of limestone to marble?
Calcite grains grow larger and increase in size
Migmatite
transition from high-grade metamorphic rock to igneous rock
Schist
Medium to coarse grained rock
Slate
very fine grained rock
3 Agents of metamorphism
Heat, Pressure, Fluids
3 Sedimentary Environments
Continental, Shoreline, Marine
Permeability
how well pores are connected to each other
Porosity
fraction of pores in sedimentary rock (pores often filled with water, oil, gas)
Detrital Sedimentary Rocks
Conglomerate (rounded) and Breccia (sharp, angular)
Igneous Rocks are made from
crystallization of molten rock (magma)
3 Types of Sedimentary Rocks
Detrital, Chemical, Organic
4 Factors that Control Soil Formation
Climate, Time, Plants and Animals, Topography
Acid Rain
Caused by burning of fossil fluids that product sulfur dioxide and nitrogen oxides; react with rain water to form acid
3 Types of Chemical Weathering
Dissolution, Hydrolysis, Oxidation
Erosion
Physical removal of material by mobile agents (water, ice gravity)
Weathering
general process of breakdown of rocks at Earth's surface
2 Types of tubular Intrusions
Sill (parallel to layers in country rock)
Dikes (cut across layers in country rock)
Pillow Basalts
formed by quenching of lava flow by cold ocean water
How to generate molten rock (3 ways)
increase temp, decrease pressure, add water
Igneous rocks are classified by (3 ways)
texture, types of minerals, chemical composition
Intrusive/Plutonic Rocks
rocks formed from magma at depth
Extrusive/Volcanic Rocks
rocks formed from lava at the Earth's surface
Lava
magma flowing at Earth's surface
Igneous rocks form by
cooling and solidification of magma
relative dating
A technique used to determine which of two fossils is older
absolute dating
determine actual number of years since the rock was formed
inclusions
if fragments of a rock A in a rock B implies that B is younger than A
intrusions
If rock A intrudes from B, A is younger than B
lateral continuity
If same rock bed is found in 2 distant locations, it is present between these locations
angular unconformity
rock layers deposited on top of other tilted/folded rock layers
atomic number
number of protons you see in atoms that defines a particular element
mass number
number of protons + neutrons
radioactivity
spontaneous changes in the structure of certain unstable atomic nuclei
radioactive decay types (3)
alpha (loss of 2 neutrons + 2 protons), beta (n--> p+electron) , electron capture (p+electron--->n)