Individual Week 1 Review Questions

GLG/220
10/02/2013

Critical and Creative Thinking Questions

Chapter 1
3. How do you think the principle of uniformitarianism accounts for occasional catastrophic events such as meteorite impacts, huge volcanic eruptions, or great earthquakes?
The principle of uniformitarianism states the processes occurring on Earth today are very similar in manner as those throughout much of geologic times. In other words “the present is the key to the past.”(Murck, B. W., Skinner, B. J., & Mackenzie, D. (2010)). When looking at past geological events and occurrences that happened in the past with additions of new testing and technology they can predict when and if volcanic eruptions may occur, meteorite impacts and their damages, and if plate shifts will occur resulting in earthquakes. Scientists rate the earthquakes on a scale based on how damaging they are.
5. In what ways do geologic processes affect your daily life?
Daily activities including the water we drink or the tress we plant to help prevent and control soil erosion are a part of geologic processes. Earth materials and processes affect our lives through our dependence on Earth resources; through geologic hazards such as volcanic eruptions, floods and earthquakes; and through the physical properties of the natural environment (Murck, B. W., Skinner, B. J., & Mackenzie, D. (2010)). Understanding Earth’s materials is important because we depend on its resources for building, soil for agricultural needs, energy resources, the air we breathe, and water needed to sustain life. Earth’s natural resources are not all unlimited some or many need management and conservation because they are not infinite.
Chapter 2
1. When astronauts brought back rock samples from the Moon, the minerals present were mostly the same as those found on Earth. Can you think of reasons why this might be so? Would you expect minerals on Mars or Venus to be the same, or at least very similar, to those on Earth?
Like Earth Mars and Venus are relatively dense, rocky and smaller in size then other planets in the solar system. Mars and Venus are Earth’s neighboring planets each having different chemical compositions, but all has experienced volcanic activity and meteor impacts. Minerals present on the moon are also present on Earth’s surfaces due to geological processes and activities within the solar system that has taken place over many years. I expect that the same minerals would be present on both Mars and Venus due to their chemical makeup. Due to all of the meteorite collisions Earth, Venus and Mars have had a differentiation in their geospheres. Earths geosphere differentiated into three layers: a relatively thin, low-density, rocky crust; a rocky, intermediate-density mantle; and a metallic, high-density core (Murck, B. W., Skinner, B. J., & Mackenzie, D. (2010)). Venus and Mars have a difference in composition and size they to formed similar layers to that of Earth.
3. Which of the following materials are minerals, and why (or why not)? Water; beach sand; diamond; wood; vitamin pill; gold nugget; fishbone; emerald.
Water - Is not a mineral because it is a liquid not a solid.
Beach Sand – Is not a mineral itself, but contains several minerals within it such as quartz and silica (Si02) which are the primary components in beach sand.
Diamond – Is a mineral often times colorless, but some with color and are considered rare. It is also the hardest mineral with a value of 10 on Mohs Scale of Relative Hardness.
Wood – Is not a mineral its chemical composition varies, its organic, and is not crystalline in structure.
Vitamin Pill – Is not a mineral because it is man-made not naturally occurring.
Gold Nugget – Is a mineral because Gold occurs in hydrothermal veins deposited by ascending solutions; as disseminated particles through some sulfide deposits and in placer deposits (Gold Mineral Properties and Uses).
Fishbone – Is not a mineral because bones form by organic processes.
Emerald – Is a mineral a green variety of the mineral called beryl.
Chapter 3
3. How old are the rock formations in the area where you live and attend college or university? How can you find out the answer to this question?
I live and attend college in the Valley of the Sun. Many of the rock formations here are extremely old dating back nearly 2 billion years during a time period geologists called the Precambrian Period (GeoHistory). Information to answer this question can be found in news articles, biology journals, historical websites, and government and educational readings as well.
4. Choose one of the geologic periods or epochs listed in Figure 3.8 and find out all you can about it: How are rocks from that period identified? What are its most characteristic fossils? Where are the best samples of rocks from your chosen period found?
Rocks formed during the cretaceous period are identifiable in more ways than one would think. The cretaceous period occurred at the end of the Mesozoic Era. Rocks such as limestone, basaltic, clays, salts, gypsum, sandstone, conglomerates, and shale’s were found during this time period (Cretaceous Period). Sedimentary rocks hold many fossils of the predominant organisms to inhabit the planet Earth dinosaurs. Many of the rocks can be identified by the variation in their lithological character and thickness of their sequences, or by the fossils that are discovered in them. Some of the best samples of rocks from this time period can be found right here in Arizona at the Grand Canyon. There is no better place in the world to appreciate the immensity of geologic time than the Grand Canyon (Murck, B. W., Skinner, B. J., & Mackenzie, D. (2010)).

Chapter 14
1. Recall from Chapter 1 (see Table 1) that Earth and Venus are so similar in size and overall composition that they are almost “twins.” Why did these two planets evolve so differently? Why is Earth's atmosphere rich in oxygen and poor in carbon dioxide, whereas the reverse is true on Venus? What would happen to Earth's oceans if Earth were a little bit closer to the Sun?
Due to profound geological differences Earth is the only planet that is inhabitable by life. Earth has three things that Venus and Mars do not which is an atmosphere that is rich in oxygen, biosphere occupied by millions of living organisms, and a hydrosphere that consists of water in the forms of solids, liquids, and gases. Venus being closer to the sun in the solar system is much hotter deeming it uninhabitable it has no biosphere, and its hydrosphere is consists of vapors only. Earth’s temperatures are more stable in nature. The tectonic activity that has taken place on Earth provided earth with two types of crust continental and oceanic crust both of which is not the case on Venus it is only unique to Earth. Earth’s regolith is unique and different to the regolith on Venus, the moon, and other planets because it teems with life. Earth and Venus evolve in different manners. Venus was shaped primarily by the endless impacts from meteors while Earth was formed through tectonic activity.
4. What do you think might have happened to mammals if the end-of-Cretaceous extinction had not wiped out the dinosaurs?
If dinosaurs had survived the end-of-Cretaceous extinction other mammals and species would not have an ecological niche to inhabit. Fact is dinosaurs are extremely large mammals needing many resources to survive leaving fewer resources for any other species to survive on. Diversity would not have occurred for many species. Evolution of millions of species took place after the extinction of dinosaurs. Vegetation, soils, and other needed resources became plentiful for the habitation of other mammals. Dinosaurs would have still been dominant in any species had they survived that period of time.

References:
Murck, B. W., Skinner, B. J., & Mackenzie, D. (2010). Visualizing geology (2nd ed.). Hoboken, NJ: Wiley.
Gold Mineral Properties and Uses. What is gold? Retrieved From: http://geology.com/minerals/gold.shtml
GeoHistory of the Valley of the Sun and the Superstition Mountains. Retrieved From: http://www.gemland.com/geohistory.htm
Cretaceous Period. Retrieved From: http://www.britannica.com/EBchecked/topic/142729/Cretaceous-Period/69968/Types-of-Cretaceous-rocks