Q&A Hero

Q: Which of the following is correct? A) The age of the sea floor is the same in most areas of the ocean. B) The age of the sea floor does not follow a discernable pattern. C) The age of the sea floor increases with increasing distance from a mid-ocean ridge. D) The age of the sea floor increases with increasing distance from a trench. E) The oldest sea floor material is several billion years in age.

Q: Ocean floor subducts under continents because A) the ocean floor has a lower density and therefore sinks more easily. B) the ocean floor is made of felsic minerals and is heavier than continental material. C) the ocean floor is made of mafic material and is therefore more dense than continental material. D) the weight of the continents is so great that they push the ocean floor material downward.

Q: How does the ocean floor preserve evidence of past magnetic reversals. A) Magnetic particles in basalt orient with the magnetic field in force at the time the oceanic lava cooled and hardened. B) Isotopic analysis of ocean core sediments help determine sea floor age and this can be used to infer past magnetism. C) The ocean floor is uniformly old, preserving the Earth's 4.6 billion history. D) Mantle hot spots are always oriented to the magnetic field.

Q: At which of the following locations does subduction occur? A) along collision zones between two continents B) at sea floor spreading zones C) above mantle hot spots D) along collision zones between continental and oceanic plates

Q: Along ________ new ocean floor is formed by upwelling flows of magma, whereas along ________ old oceanic crust is destroyed. A) subduction zones; mid-ocean ridges B) archipelagos; oceanic trenches C) mid-ocean ridges; subduction zones D) oceanic trenches; archipelagos

Q: At which of the following locations is new ocean crust being formed? A) oceanic rift zones B) along collision zones between two continents C) along collision zones between two oceanic plates D) in oceanic trenches

Q: Which of the following are located along the midocean ridges? A) volcanoes B) outcrops of granite C) old oceanic sediments D) evaporite deposits

Q: Which of the following is the fuel for continental drift and plate tectonics? A) nuclear fusion B) radioactive decay C) solar energy D) chemical reactions in Earth's core

Q: Pangaea is currently dated at A) 4.6 billion years ago. B) about half the timespan of Earth's existence. C) 225 to 200 million years ago. D) 65 million years ago. E) the beginning of the Holocene.

Q: Which of the following is not supporting evidence of plate tectonics? A) similar rock assemblages on the east coast of South America and West Coast of Africa B) the "jigsaw puzzle" shape of the continents C) lack of oceanic ridges that would indicate sea floor spreading D) the fossil and climatic record

Q: Which of the following is correct regarding Alfred Wegener's theory of continental drift? A) It was immediately adopted because of his geological background. B) Although he provided a mechanism for continental drift, he could not find evidence of it. C) He was the first to propose that the continents moved. D) He believed that 225 million years ago all the continents were joined together to form Pangaea.

Q: ________ is the theory that describes the motion of the Earth's lithosphere. A) Plate tectonics B) Sea floor spreading C) Pangaea D) Metamorphism

Q: Which of the following is correct regarding continental drift? A) It occurred about two billion years ago, but no longer occurs today. B) The term "continental drift" is now called plate tectonics. C) It does not occur because the crust is brittle. D) It is an old theory that has been essentially disproven.

Q: Earth's crust is roughly made up of A) mantle and core material. B) at least 14 plates capable of movement. C) strong, unbroken material. D) a brittle material that does not move.

Q: Sedimentary rocks are more a product of the ________ system whereas metamorphic and igneous rocks are more a product of the ________ system. A) tectonic; rock B) endogenic; exogenic C) exogenic; endogenic D) intrusive; extrusive

Q: Limestone is a type of ________ rock that forms when ________. A) igneous; magma cools B) igneous; lava cools C) sedimentary; calcium carbonate precipitates, or organic material containing calcium carbonate accumulates in a water environment D) sedimentary; broken fragments of rock are deposited in a water environment and are then cemented together.

Q: The ________ drives the endogenic processes of the rock cycle. A) atmospheric circulation B) rock cycle C) hydrologic cycle D) tectonic cycle

Q: The ________ drives the exogenic processes of the rock cycle. A) atmospheric circulation B) rock cycle C) hydrologic cycle D) tectonic cycle

Q: The continuous alteration of Earth materials from one rock type to another is known as the A) geologic cycle. B) rock cycle. C) hydrologic cycle. D) tectonic cycle.

Q: Metamorphism that occurs over broad areas when the pressure and associated heat of of overlaying rocks or other tectonic forces cause the rocks to undergo deformation is known as A) contact metamorphism. B) regional metamorphism. C) intrusive metamorphism. D) extrusive metamorphism.

Q: The occurrence of contact metamorphism would be direct evidence for A) cementation of sedimentary rock. B) the local intrusion of magma. C) regional plate collision. D) lithification of clastics.

Q: Metamorphism that occurs when rocks are exposed to the pressure and extreme temperature associated with intruding magma is known as A) contact metamorphism. B) regional metamorphism. C) intrusive metamorphism. D) extrusive metamorphism.

Q: What steps can you take to help reduce climate change?

Q: Describe the functioning of a general circulation model. What are some of the predictions for the 21st Century based on GCMs?

Q: What is radiative forcing? List gases and aerosols that have positive or negative radiative forcing. What is the primary source of each.

Q: Describe the properties, current atmospheric concentrations, and sources the primary greenhouse gases contributing to climate change?

Q: What is some of the evidence establishing that climate change is currently occurring?

Q: What are some examples of positive and negative climate feedback loops?

Q: Based on climate reconstructions, there is ample evidence that climates have fluctuated throughout Earth's long history. Describe some of the mechanisms of this climate fluctuations.

Q: What methods do scientists use to reconstruct both long-term and shorter term climate histories?

Q: The average individual is helpless to do anything about climate change.

Q: Delaying action on climate change may be dangerous and more costly in the long run.

Q: Though the U.S. is a signatory to the Kyoto Protocol, the U.S. Congress never ratified it.

Q: Vulnerability to sea level rise is not uniformly distributed across the world.

Q: Sea level is rising more quickly on the east coast of the United States than on the west coast.

Q: GCMs are used to predict specific temperatures in the near and long-term future.

Q: According to climate simulations using GCMs, natural climate forcing, alone, cannot account for the increases in global temperature trends.

Q: While GCMs are useful for visualization the complex global oceanic-atmosphere circulation, they have had little utility in the study of climate change.

Q: Natural climate forcing is greater than anthropogenic climate forcing.

Q: Halogenated gases are purely anthropogenic and have no natural sources.

Q: Methane(CH4) has a higher global warming potential than carbon dioxide (CO2).

Q: The United States leads the world in per capita carbon dioxide (CO2) emissions.

Q: The United States leads the world in total carbon dioxide (CO2) emissions.

Q: Currently, atmospheric methane(CH4) concentrations are increasing at a rate faster than carbon dioxide (CO2).

Q: Methane(CH4) is the second most prevalent anthropogenic greenhouse gas.

Q: Carbon dioxide (CO2)has a longer residence time in the atmosphere than methane (CH4).

Q: Carbon dioxide (CO2) residence time in the atmosphere is 7 to 10 years.

Q: Water vapor (H2O) has a longer residence time in the atmosphere than carbon dioxide (CO2).

Q: All greenhouse gases contribute equally to global climate change.

Q: The current data indicate that the record high global temperatures of the past two decades correspond to record high atmospheric CO2.

Q: A definitive link between climate change and extreme weather events has been established.

Q: There has been a decrease in multi-year ice., that is, sea ice that survives through two or more summers.

Q: Ice shelves and icebergs are an example of sea ice.

Q: Sea surface temperatures increased at an average annual rate of 0.07 C (0.13 F) from 1901 to 2012.

Q: According to the Intergovernmental Panel on Climate Change (IPCC), warming of the climate system is unequivocal.

Q: Over the last two decades, the Antarctic ice sheet has lost mass. However, the Greenland ice sheet has actually gained mass due to increased winter precipitation.

Q: Thawing of tundra due to warming temperatures results in more carbon released from tundra soils than is absorbed.

Q: The world's highest rates of deforestation (based on the Deforestation Index), a significant factor in global warming, is occurring in Brazil.

Q: Some climate feedback loops, such as CO2 weathering feedback, occur over very long time scales.

Q: Clouds can create both positive and negative feedback loops in relationship to warming climates.

Q: Carbon dioxide (CO2) is the most abundant natural greenhouse gas.

Q: Increased atmospheric CO2 may lead to plants in some regions of the world producing more leaves.

Q: As ocean temperatures increase, the ability of oceans to dissolve CO2 is diminished.

Q: The Earth's axial tilt varies from 21.5 to 24.5 during a 41,000 year period.

Q: The Earth's elliptical orbit around the sun (eccentricity) is mostly constant, only changing negligibly over a 100,000 year period.

Q: Milankovitch cycles are currently accepted as a causal factor for long-term climatic fluctuations.

Q: Recent temperature increases correspond to a period of increased sunspot activity.

Q: The Earth's climate cycles between warmer and colder periods.

Q: A lower 18O /16O ratio in ocean core sediments is indicative of warmer temperatures, whereas a lower 18O /16O ratio in ice cores is indicative of cooler temperatures.

Q: The Younger Dryas, the Medieval Climate Anomaly, and the Little Ice Age demonstrate that climates naturally fluctuate.

Q: The last glacial maximum (LGM) refers to the duration of the last period of glaciation.

Q: Speleothems, like trees, have growth rings whose size and property reflect the conditions under which they formed.

Q: The use of tree rings to study past climates is known as dendroclimatology.

Q: The annual growth ring added by tree species is known as a varve.

Q: Ice core analysis shows a close correlation between atmospheric methane (CH4) and carbon dioxide (CO2) concentrations and temperatures.

Q: Over the span of the last 5 million years, climate reconstructions show a series of cooler and warmer periods.

Q: The Paleocene-Eocene Thermal Maximum (PETM) is characterized by some of the coolest temperatures in the Earth's history.

Q: Ice cores provide a longer, but less detailed climate record than ocean sediment cores.

Q: The exoskeletons of marine microorganisms provide a valuable clue of past climatic conditions.

Q: Both the 16O and 18O oxygen isotopes occur in water molecules and can be used for isotopic analysis to reconstruct past climates.