Oceanography 10 West Valley College

R. Lopez

Materials of the Seafloor : Minerals, Igneous Rocks, Ocean Sediment

1)      What is the four-part definition of a mineral?


2)      What does crystal form reflect as a physical property of minerals?


3)      What crystal habit characterizes the mineral quartz?


4)      What crystal habit characterizes the mineral halite?


5)      What crystal habit characterizes the mineral calcite?


6)      What crystal habit characterizes the mica minerals?


7)      The color of mineral is best uses to distinguish between ___ and ___ minerals.


8)      What is a minerals luster? What are the two primary types of luster?


9)      What is mineral cleavage and in what three ways is it characterized?


10)   What is the difference between Mohs hardness and the Knoop Hardness of minerals?


11)   What is the Mohs hardness of calcite, feldspar, quartz, talc?


12)   What is the hardness of your fingernail, a knife blade, glass plate?


13)   What mineral has striations? What mineral has exsolution lamellae?


14)   What is the origin of the word igneous? What are the two types of igneous rocks?


15)   All igneous rocks share one common characteristic. What is it?


16)   How are igneous rocks classified?


17)   What are the three primary types of igneous rock texture. What texture do plutonic rocks have? What texture do volcanic rocks have?


18)   What is the temperature range of magmas?


19)   Where do magmas originate? What are the bodies of magma that pond in the crust called?


20)  Complete the following diagram. correct rock names (basalt, granite, rhyolite, diorite, andesite, gabbro). Under texture, label whether aphanitic or phaneritic.



















21)   What is the definition of porphyritic texture? Are plutonic or volcanic rocks porphyritic?


22)   What are the four major subdivisions for ocean sediment?


23)   What is the definition of sediment?


24)   What is the difference between sediment and sedimentary rock?


25)   What is the lithification process (three steps)?


26)   What type of ocean sediment covers most of the sea floor?


27)   What does the term siliciclastic mean? Break it down into components silici and clastic.


28)   What is the source of terrigenous (Lithogenous) sediment, biogenous sediment, hydrogenous sediment, and cosogenous sediment?


29)   Terrigenous sediment is described as in terms of grain size. What are the difference between gravel, sand, and mud sizes (see Table 5-1). Recall that we group silt and clay as mud.


30)   On a diagram depicting continental shelf, slope, rise, and abyssal plane, label where turbidites, sands, mud, and both calcareous and siliceous oozes are deposited. Also label the CCD.


31)   Where is most of the terrigenous sediment deposited in the oceans?


32)   Terrigenous sediment is divided into two categories based on where it is deposited in the ocean. One is on the continental shelf, the other is on the slope, rise, and deep ocean floor. What are these two categories?


33)   What are turbidites and how are they deposited?


34)   Where are turbidites deposited, how are coarser and finer particles distributed, and what does each sequence represent?


35)   What size of terrigenous sediment makes it to the abyssal planes?


36)   Why is there very little to no sediment deposited at mid-oceanic ridges?


37)   Hydrogenous sediment is referred to as inorganic because it forms from calcareous oozes. TRUE or FALSE?


38)   Hydrogenous sediment is said to be inorganic. What is the definition of inorganic in terms of hydrogenous sediment?


39)   Evaporites (hydrogenous sediment) are chemically precipitated from evaporating water. TRUE or FALSE?


40)   What are calcareous oozes? What types of marine organisms extract CaCO3 from seawater to form their shells or skeletons?


41)   What are foraminifera and coccolithophores and what type of ooze do they form?


42)   Below 4500 meters depth, the activity of CO2 in seawater increases. Higher activities of CO2 in seawater will yield more _____________, which will cause ________________ to dissolve. What is this depth known as? _____________


43)   What are siliceous oozes?


44)   Name two marine organisms that extract silica from seawater to make their shells and hard body parts.


45)   Where are radiolarian oozes and diatom oozes deposited in the ocean?


46)   What are manganese nodules? Their rate of formation is extremely slow (about 1 to 10 millimeters per 1 million years). Why are they not completely buried by sediment (see p. 9)?