WEATHERING AND SEDIMENTARY ROCKS Flashcards
The figure shows several different magnified samples of sediments. Which of the samples displays the BEST sorting?
D (evenly spaced out)
Which of the four main classes of sedimentary rock forms by the precipitation of minerals directly from water, without help from living organisms?
Chemical
The transformation of loose sediment into solid rock is a process called
lithification
Which type of weathering is responsible for changing the composition of the rock?
chemical weathering
A very fine-grained clastic sedimentary rock is called a
shale
Coral reefs that are preserved as sedimentary rocks are classified as
limestones
Reactions of iron-bearing minerals with Earth’s atmosphere result in a type of chemical weathering called
oxidation
More mature sediments are typically
further from their source and better sorted.
There are four main forces of weathering. Which one is responsible for the greatest amount of erosion?
water
Which chemical reaction breaks down feldspars into clay minerals?
Hydrolysis
What type of environment likely created the bedding structure shown?
Desert with migrating dunes
In the environment shown, the waves sort the beach sediments. What type of clastic sedimentary rock is most likely to form in this environment? (looks like a beach)
Sandstone
What type of clastic sedimentary rock will form in the environment shown?
Conglomerate
Layers of sedimentary rocks are called
beds
Coal is an example of which type of sedimentary rock?
organic
The breakdown of exposed rock into small fragments and dissolved ions is termed
weathering
Large layers of cross-bedded sand can be indicative of a __________ environment.
desert
Which of the following processes involves the creation of ions in solution?
weathering
Cementation of sediments occurs when minerals __________ the spaces between sediment grains.
precipitate in
Consult the figure below. Here, distinct internal laminations are inclined at an angle to the boundary of the main sedimentary layers. This is termed __________ bedding.
cross
The process by which solid material is ground away by glaciers, rivers, wind, or waves is called
erosion
If a geologist found preserved polygonal cracks in a sedimentary rock, he or she could conclude that the environment in which they formed
was once covered in wet mud.
Lithification, the process by which sediments are turned into sedimentary rocks, includes
compaction and cementation.
What type of sediment is typically found in lake bottoms?
clay/mud
A fine-grained clastic sedimentary rock that splits into thin sheets is
shale
A well-sorted sandstone with asymmetric ripples was MOST likely deposited as sand by a(n)
river (far from source).
Lithification occurs
in the shallow subsurface.
Precipitation of gypsum caused by evaporation of seawater produces which kind of sedimentary rock?
chemical
Which of the following does NOT reflect transport distance?
type of cement
Clastic sedimentary rocks are primarily classified on the basis of
grain size.
Cemented shells of marine organisms form which kind of sedimentary rock?
biochemical
Thick accumulations of sediments and fossils in the deep ocean tend to be __________-sized because of the low amounts of energy.
clay
If water is the primary transport mechanism for a given sediment, the grain size MOST closely indicates the
velocity of the water at the moment the sediment settled to the bottom.
Geologists call individual layers of sedimentary rocks __________, whereas several of them together are called __________.
beds; strata
Coal and oil shale are considered __________ sedimentary rocks.
organic
