Answer to Question 1ANS: C
Microtektites are a type of cosmogenous sediments. They are thought to form from violent impacts of
meteors and asteroids on Earth. The impact melts part of the crust on impact, causing it to splash back
into space. The material melts again as it travels back through the atmosphere before falling back to
Earth. The result is translucent, oblong sediments made of glass particles. Information can be found in
the section Sediments May be Classified by Source.
Answer to Question 2ANS: D
Manganese nodules have yet to be commercially mined due to their low market value. As techniques
for deep-sea mining become more advance and raw material prices increase, however, the nodules'
concentration of valuable materials will almost certainly be exploited. Information can be found in the
section Marine Sediments Are Economically Important.
Answer to Question 3ANS: C
The White Cliffs of Dover are an example of the lithification of calcareous ooze. Although formations
like these are formed in the ocean, they are brought above sea level due to normal processes of plate
tectonics. Information can be found in the section Pelagic Sediments Vary in Composition and
Thickness.
Fossils are formed after an animal dies, decomposes, and is covered in sediment. Minerals in ground
The argon-argon method is useful for dating volcanic sediments.
The basalt below the hominins is dated to 1.8 million years ago, and the geomagnetic polarity of the
Ocean sediment cores preserve a record of ice sheet growth and decay
Ocean sediment cores
Melting ice is ponded behind fragile barriers of glacial sediment