Geology 001                                                                                          West Valley College

R. Lopez                                                                                              


Study Questions: Sedimentary Rocks


1)      What are the three reasons that sedimentary rocks are particularly important?


2)      Discuss the four main processes involved in turning parental solid rock into sediments and eventually sedimentary rock.  Make a flow chart like I did in lecture


3)      What are the two kinds of weathering and give an example of each?


4)      What natural reaction occurs between water and carbon dioxide to dissolve CaCO3? What about the formation of hematite, Fe2O3?


5)      What is karst topography?



6)      Give three examples of agents that transport sediments.


7)      Name at least three continental (terrestrial) and three marine depositional environments.


8)      What is a sedimentary “fan”, and what does alluvium mean?


9)      What is an abyssal fan?


10)   Lithification commonly involves three steps, what are they?  What are three examples of cement?


11)   What are the two major groups of sedimentary rocks?


12)   What does “clastic” mean?


13)   What is textural maturity?  What is compositional maturity?  Which is more mature, compositional or textural maturity?


14)   What is sorting and what is rounding?  How do they indicate maturity of the sediment? (see your text and lab book)


15)   Define the following:



quartz sandstone,

arkose sandstone,

greywacke sandstone,






16)   What does the term “fissile” mean? And what rock does it best describe?


17)   What are the size ratings for Mud, Sand, and Gravel?


18)   What are the two subdivisions of the Biological/Chemical group (also known as the Chemical Precipitate group)?


19)   Define Limestone? What are carbonates?


20)   Cite three examples of marine organisms that extract calcium carbonate from seawater, and whose skeletons may form limestone. 


21)   Is most limestone of inorganic or biological origin?  What is calcareous ooze?


22)   What are radiolaria?  What are their hard body parts made of? What are the deposits of radiolaria on the seafloor known as? And what kind of rock do they eventually form?


23)   Chert is composed of what material?


24)   What are diatoms and what are their deposits called?


25)   What famous geological formation in California is a Diatomite?


26)   What principle do geologists use to interpret ancient depositional environments?


27)   What kinds of features in sedimentary rocks provide information on depositional environments?


28)   In a bedded sequence of sedimentary rocks, what does each bed represent in terms of depositional environments?


29)   What are cross beds and how do they form? What are ripple marks and how do they form (see pages 51-52, Fig. 2-24)?


30)   What are graded beds and how do they form? What is a Turbidite (see page 51, Fig. 2-23)?


31)   What is the principle of uniformitarianism?


32)   Deposits of Siliceous Ooze have a deposition rate of 5 cm/1000 years.  Many chert deposits can be up to 100 meters thick.  Calculate the time required to deposit 100 meters of siliceous ooze.


33)   Natural laws that govern our universe today have changed over geologic time.  True or False?


34)   Natural laws and rates of geologic processes at work today in our Universe have been constant throughout geologic time.  True or False?


35)   What are foraminifera and what type of ooze do they form on the sea floor?


36)   What is more common, biochemical or chemical limestone?


37)   What are coccolithophores and what deposit do they make?  Name the rock that they form.



38)   What are deposits of continental sediment called when deposited in the ocean?


39)   Sketch a “trailing continental margin” showing the continental shelf, slope, rise, and deep ocean (abyssal plain).  Where would you expect coral reefs, turbidites, quartz sandstones, shales, and oozes to be deposited?


40)   Sketch an active plate tectonic boundary with shelf, slope, trench, accretionary prism, deep ocean, arc-trench gap.  Know where sands, graywacke, turbidites, oozes, reefs are formed.