Chapters 1-3 Flashcards
Scientific Method order
- Observations
- Question
- Developing a hypothesis
- What are consequences if hypothesis is correct Incorrect?
- Conduct experiments
- Conclusions
Nebular Hypothesis
Solar system evolved from an enormous rotating cloud called the solar nebula and it was composed of mostly hydrogen and helium.
Nebular hypothesis continued
- About 5 billion years ago the nebula began to contract
- Assumes a flat, disk shape with the protosun (pre-Sun) at the center
- Inner planets begin to form from metallic and rocky clumps
- Larger outer planets began forming from fragments with a high percentage of ices
Hydrosphere
Ocean – the most prominent feature of the hydrosphere
- Nearly 71 percent of Earth’s surface
- About 97 percent of Earth’s water
Also includes fresh water found in streams, lakes, and glaciers, as well as that found underground
Atmosphere
- A thin, tenuous blanket of air
- One half lies below 5.6 kilometers (3.5 miles)
Biosphere
- Includes all life
- Concentrated near the surface in a zone that extends from the ocean floor upward for several kilometers into the atmosphere
Lithosphere
Rigid outer layer
System
- Closed systems are self-contained (e.g., an automobile cooling system)
- Open systems – both energy and matter flow into and out of the system (e.g., a river system)
Feedback Mechanisms
- Negative-feedback mechanisms resist change and stabilize the system
- Positive-feedback mechanisms enhance the change in the system. Push the system to an extreme.
Mineral
- Natural
- Inorganic
- Solid
- Possess an orderly internal structure of atoms
- Have a definite chemical composition
Rock
any naturally occurring solid mass of mineral or mineral-like matter
Rock-Forming Minerals
- The eight elements that compose most rock-forming minerals are oxygen (O), silicon (Si), aluminum (Al), iron (Fe), calcium (Ca), sodium (Na), potassium (K), and magnesium (Mg)
- Most abundant atoms in Earth’s crust are oxygen (46.6% by weight) and silicon (27.7% by weight)
Rock-forming silicates
Most common mineral group
Contain the silicon-oxygen tetrahedron (molecule)
- Four oxygen atoms surrounding a much smaller silicon atom
- Combines with other atoms to form the various silicate structures
Igneous Rock
Form as Magma cools and crystallizes.
Plutonic/Intrusive
Rocks formed inside the Earth.
Volcanic/Extrusive
Rocks formed on the surface.
Crystallization
Ions are arranged into orderly patterns
Crystal size is determined by the rate of cooling
- Slow rate forms large crystals
- Fast rate forms microscopic crystals
- Very fast rate forms glass
Bowen’s reaction series
the crystallization sequence of typical basaltic magma undergoing fractional crystallization.
Sedimentary Rocks
Form from sediment (weathered products)
About 75 percent of all rock outcrops on the continents
Used to reconstruct much of Earth’s history
- Clues to past environments
- Provide information about sediment transport
- Rocks often contain fossils
Detrital Rocks
Material is solid particles
Classified by particle size
Common rocks include
- Shale (most abundant)
- Sandstone
- Conglomerate
Chemical Rocks
Derived from material that was once in solution and precipitates to form sediment
- Directly precipitated as the result of physical processes, or
- Through life processes (biochemical origin)
Common sedimentary rocks
- Limestone – the most abundant chemical rock
- Microcrystalline quartz (precipitated quartz) known as chert, flint, jasper, or agate
- Evaporites such as rock salt or gypsum
- Coal
Lithification
How sedimentary rocks are produced
Processes
- Compaction
- Cementation by: Calcite, Silica, Iron Oxide.
Bedding Plane
The surface that separates each successive layer of a stratified rock from its preceding layer.
Metamorphic rocks
Changed form” rocks
Produced from preexisting
- Igneous rocks
- Sedimentary rocks
- Other metamorphic rocks
Metamorphism
Takes place where preexisting rock is subjected to temperatures and pressures unlike those in which it formed
Degrees of metamorphism
- Exhibited by rock texture and mineralogy
- Low-grade (e.g., shale becomes slate)
- High-grade (obliteration of original features)
Metamorphic Textures
Foliated texture
- Minerals are in a parallel alignment
- Minerals are perpendicular to the compressional force
Nonfoliated texture
- Contain equidimensional crystals
- Resembles a coarse-grained igneous rock
Most important ore deposits are generated from hydrothermal (hot-water) solutions
Hot
Contain metal-rich fluids
Associated with cooling magma bodies
Types of deposits include
- Vein deposits in fractures or bedding planes, and
- Disseminated deposits which are distributed throughout the rock
Rock Cycle
Magma cools and crystallizes into igneous rock.
Igneous weathers and erodes into sediments.
Those sediments lithify into sedimentary rocks
Those sedimentary rocks undergo heat and pressure into metamorphic rocks.
Rock Cycle Shortcuts
e. g., Sedimentary rock melts
e. g., Igneous rock is metamorphosed
e. g., Sedimentary rock is weathered
e. g., Metamorphic rock weathers
