General Review an Chapter 1 Flashcards
to review concepts previously covered in Historical and physical geology (37 cards)
What is facies?
A body of sediment with certain characteristics indicative of a depositional environment
How much of earth’s surface is covered in sedimentary rocks?
90 percent
What is the volume of sedimentary rocks in the crust?
less than 10 percent
What are the top 3 most common rocks and what are their percentages?
Shale: 62 percent
Sandstone: 21 percent
Limestone: 13 percent
How are sedimentary rocks classified?
texture and composition
What are the basic sedimentary rock types?
Clastic rocks
Biogenic rocks
Chemical rocks
How are clastic sedimentary rocks formed?
Through the breakdown, transportation, burial, compaction and cementation of previously existing rocks
How are Biogenic sedimentary rocks formed?
Formed directly or indirectly through organic processes.
How are Biogenic rocks classified?
Classified based on chemical composition
Where are biogenic rocks commonly found?
Shallow tropical environments
How are Chemical sedimentary rocks formed?
They are inorganically precipitated from solution, with no transportation and are typically very crystalline.
What are Steno’s 3 principles of geology?
Superposition
Original horizontality
Lateral continuity
What are the types of physical weathering?
Frost
Insolation
Salt
Wetting and drying
Stress release
Exfoliation
What is frost weathering?
Repeated freezing and thawing of water particles in rocks
What is insolation weathering?
Rock surfaces are heated by the sun which creates and thermal gradient within the layers of the rocks. This leads to cracks in the rock surface.
What is wetting and drying?
Drying leads to contraction and absorption of water causes swelling and cracks.
What is stress release weathering?
Rocks deep below the surface are under pressure which is then reduces when the above layers are eroded. This leads to cracks in the rock which are parallel to the topographic surface.
What is exfoliation?
Peeling of the rock surface due to the release of pressure
What are the chemical weathering Processes?
Simple Solution
Hydrolysis
Oxidation
How does simple solution weathering work?
when a mineral dissolves into a solution completely without the precipitation of other minerals.
How does Hydrolysis work?
moving around of H atoms
How does oxidation weathering work?
loss of an electron leads to the formation of oxides or hydroxides
What is the soil formation process?
Addition to ground surface
transformation
Transfers
Removal
bioturbation of soil
How does addition to ground surface work?
Precipitation of dissolved ion of rainwater with solid particles and organic matter from surface vegetation.