Chapter 1 Flashcards
In what way is geology different from the other sciences, such as chemistry and physics?
Geology involves integration of various different sciences (chemistry, physics, and biology for example), but also requires an understanding of the importance of billions of years of geological time.
How would some familiarity with biology be helpful to a geologist?
Paleontology is an important aspect of geology and requires an understanding of biology, including evolution, the physiology of animals and plants and ecological relationships.
List three ways in which geologists can contribute to society.
Geologists provide information to reduce the risk of harm from hazards such as earthquakes, volcanoes, and slope failures; they play a critical role in the discovery of important resources; they contribute to our understanding of life and its evolution through paleontological studies; and they play a leading role in the investigation of climate change, past and present and its implications.
Describe the lattice structure and elemental composition of the mineral halite.
Halite is composed of sodium (Na) and chlorine (Cl) with the Na+ and Cl− ions alternating with one another in all three directions within a cubic structure.
In what way is a mineral different from a rock?
A mineral has a specific chemical composition and lattice structure. Rocks are made out of minerals, and most rocks contain several different types of minerals.
What is the main component of Earth’s core?
The main component of Earth’s core is iron (Fe).
What process leads to convection in the mantle?
Transfer of heat from the core to the mantle leads to heating of lower mantle rock. When heated, the rock expands and its density is reduced. Because the mantle is plastic, this lower-density material tends to rise toward the surface, and cooler denser mantle material moves in to take its place.
How does mantle convection contribute to plate tectonics?
Mantle convection creates the traction that can force plates to move around on the surface.
What are some of the processes that take place at a divergent plate boundary?
Hot mantle rock moving toward the surface partially melts because the pressure is reduced. The magma produced moves upward into cracks in the crust and is extruded onto the sea floor.
Dinosaurs first appear in the geological record in rocks at 225 Ma and then disappear at 65 Ma. For what proportion (%) of geological time did dinosaurs exist?
215 − 65 = 150 Ma. Since the age of the Earth is 4570 Ma, this represents 150 ÷ 4,570 = 0.033 or 3.3% of geological time.
If a typical rate for the accumulation of sediments is 1 mm/year, what thickness (metres) of sedimentary rock could accumulate over a period of 30 million years?
At 1 mm/y, 30,000,000 mm would accumulate over that 30 million years. This is equivalent to 30,000 metres or 30 kilometres. Few sequences of sedimentary rock are even close to that thickness because most sediments accumulate at much lower rates, more like 0.1 millimetre per year.
