Geol Exam 2

Which of the following includes the zone called the "asthenosphere"?

upper mantle

What two factors speed up rates of chemical reaction and weathering in rocks and soils?

warm temperatures; abundant moisture

Which of Earth's layers is marked at its top by the Mohorovivic discontinuity?

mantle

Which term best describes all the processes that move weathered rock materials and soil downslopes?

mass wasting

Where does Earth's magnetic field originate?

outer core

Which layer of Earth does not transmit S waves?

outer core

which layer of earth transmits P earthquake waves but not S earthquake waves?

outer core

which rock type listed below is probably closest in chemical composition to the upper mantle?

peridotite

Which of the following best describes sets of fractures in relatively fresh bedrock, such as granite, that are roughly parallel to the land surface?

sheeting fractures

which of the following are probably major components of earths inner core?

Crystalline iron and nickel

which one the following best characterizes the asthenosphere?

A zone of softened peridotite in the upper mantle

who discovered the crust mantle seismic discontinuity? in what year?

Andrija Mohorovičić, 1909

Which one of the following statements concerning Earth's magnetic field is true?

At high latitudes, the force lines intersect Earth's surface at steep angles.

which of the following rocks are closest to the average chemical composition of the oceanic crust?

Basalt and gabbro

Which of the following materials is/ are most susceptible to chemical weathering by dissolution?

Calcite

What process creates finely divided red, brown, and yellow minerals in soils?

Precipitation of iron oxides during the chemical weathering process

What causes the P- wave shadow zone?

Refraction of P waves crossing the mantle-outer core boundary

Which term describes a soil formed by weathering of the underlying bedrock?

Residual

Which of the following describes Earths magnetic field/

Earth's magnetic field is a self-generating and self-reversing dynamo in the outer core.

Which of the following statements best describes erosion?

Erosion is the process by which weathered rock and mineral particles are removed from one area and transported elsewhere.

Which of the following is an important mechanical weathering process for enlarging fractures and extending them deeper into large boulders and bedrock in temperature and arctic environments?

Frost wedging

which of the following statements concerning humus is not true?

Humus is readily leached from the B horizon in weakly acidic soil solutions.

Why is the humus layer typically thicker in a cool, temperate forest soil than in a tropical rainforest soil?

Less humus is produced in the cool, temperate forest but the rate of decay and oxidation is slower than in a tropical rainforest.

Which of the following statements concerning mechanical weathering is not true?

Mechanical weathering involves a major change in the mineral composition of the weathered material.

Which of the following best describes the process of minerals subtraction or W?

Mineral subtraction or eluviation is the removal of very fine-sized silt and clay particles from the A and E soil horizons.

From the land surface downward to the unweathered bedrock, which of the following is the correct order of the different soil horizons?

O, A, E, B, C bedrock

What is the best evidence of earth having a solidifies inner core?

P waves travel faster in the inner core than in the outer core.

Which one of the following statements concerning soil erosion is not true?

Sheet erosion, rills, and arroyos or gullies develop mainly during prolonged droughts.

Which regolith material results from frost wedging?

Talus slopes

Which structure in Earth is thought to be caused by a change in the mineral structure of olivine?

The 660-km-depth discontinuity or transition zone

What portion of an angular, fracture-bounded granitic block shows the highest rate of weathering?

The corners

During the 1930s, the United States suffered its greatest natural catastrophe. What great natural disaster affected both the farmers and the urbanites and led to the creation of the Soil Conservation Service?

The dust bowl

which of the following best characterizes how the diameter of earth's core and the nature of the outer core were discovered?

Through analysis of the P-wave and S-wave shadow zones

Which of the following is the result of convection within the mantle?

Warm rock rises as narrow pipe-like plumes.

Assume that water filling a crack in a rock undergoes cycles of freezing and melting. Which of the following statement is true?

Water expands as it freezes, causing the crack walls to be pushed apart.

What causes Earth's magnetic field?

Weak electrical currents associated with fluid motions of molten iron in the outer core causes Earth's magnetic field.

What is the upper layer of the lithosphere called?

crust

which layer of earth has the smallest volume?

crust

which layer of earth is very dense and solid and consists most likely of an iron-rich alloy?

inner core