WEATHERING AND MASS WASTING

Please refer to the GETTING STARTEDmodule to learn how to maneuver through, and how to answer the lab questions, in the Google Earth () component.

KEY TERMS

You should know and understand the following terms:

Avalanche

Frost wedging

Rockslide

Carbonation

Hydrolysis

Root wedging

Chemical Weathering

Landslide

Salt crystal growth

Debris flow

Mass wasting

Soil creep

Earthflow

Mechanical (Physical)Weathering

Solifluction

Exfoliation

Mudflow

Slump

Frost heaving

Oxidation

LAB MODULE LEARNING OBJECTIVES

After successfully completing this module, you should be able to accomplish the following tasks:

· Identify erosional processes and features created by weathering and mass wasting

· Identify depositional processes and features created by weathering and mass wasting

· Examine the processes that create mass wasting landforms

· Distinguish different weathering and mass wasting types

· Calculate slope

· Interpret the topographic profile of a landscape

INTRODUCTION

This module examines weathering and mass wasting. Topics includephysical weathering, chemical weathering, and mass wasting. While these topics may appear to be disparate, you will learn how they are inherently related.The modules start with four opening topics, or vignettes, which are found in the accompanying Google Earth file. These vignettes introduce basic concepts of the weathering and mass wasting. Some of the vignettes have animations, videos, or short articles that will provide another perspective or visual explanation for the topic at hand.After reading the vignette and associated links, answer the following questions. Please note that some links might take a while to download based on your Internet speed.

Expandthe INTRODUCTION folder and then check Topic 1: Introduction.

Read Topic 1:Introduction

Question 1: According to the website, which of the following factors influence the speed of landslides? (Check all that apply).

A. Slope of ground

B. Water content

C. Volume of debris

D. Time since last landslide

Read Topic 2: Weathering

Question 2: Other than the rock material, what are the two most important factors in chemical weathering?

A. Water and slope of land

B. Debris type and water

C. Slope of land and temperature

D. Water and temperature

Read Topic 3: Mass Wasting

Question 3: What does the presence of lichen on boulders tell scientists?

A. It tells us the parent material of the debris

B. It tells us the relative time of a mass wasting event

C. It tells us what the slope of the land used to be

D. It tells us what the moisture content was at the time of the mass wasting event.

Read Topic 4: Human Interaction

Question 4: What are the characteristics of areas generally considered to be safe from landslides? (Check all that apply)

A. On flat areas away from slopes

B. On hard, non-jointed bedrock that has not moved in the past

C. At the base of minor drainage hollows

D. At the top or along the nose of ridges, set back from the tops of slopes

Collapse and uncheck the INTRODUCTIONfolder.

GLOBAL PERSPECTIVE

Figure 1.The geography of weathering (Arbogast 2nd Ed.).

Double-click and selectGLOBAL PERSPECTIVE.

Figure 1 is a graph showing the dominant type of weathering based on annual precipitation and temperature. If a location has a mean annual temperature of 20°C and receives 190cm of precipitation yearly, you can plot these values (as denoted by the star) to see this location’s dominant weathering is strong chemical.

For Questions 5 to 8, type the location information provided into the Searchtab in Google Earth and pressEnter. When you arrive at your destination, use the chart in Figure 1, in conjunction with Google Earth, to answer each question. The mean annual temperature and precipitation are provided respectively, in the parentheses.

Question 5: What is the dominant weathering In Bangkok, Thailand (28°C, 145cm)?

A. Moderate chemical

B. Strong chemical

C. Moderate chemical with frost action

D. Very slight weathering

Question 6: What is the dominant weathering in New Delhi, India (25°C, 80cm)

A. Moderate chemical

B. Strong chemical

C. Moderate chemical with frost action

D. Strong physical

Question 7: What is the dominant weathering at 19°10’21.78″N, 96° 7’59.77″W (25°C, 236cm)?

A. Moderate chemical

B. Strong chemical

C. Moderate chemical with frost action

D. Strong physical

Question 8:What is the dominant weathering at 58°18’7.00″N,134°25’11.00″W (5°C, 140cm)?

A. Moderate chemical

B. Strong chemical

C. Moderate chemical with frost action

D. Strong physical

Collapse and uncheck the GLOBAL PERSPECTIVE folder.

Weathering

Double-click WEATHERING, and then double‑click Mechanical Weathering.

Identify the dominant type of mechanical weathering at the following locations. Use the photo links in Google Earth to help you identify the type.

Double-click Feature A and then clickFeature A photo.

Question 9:Identify mechanical weathering at Feature A:

A. Frost wedging

B. Frost heaving

C. Salt-crystal growth

D. Exfoliation

Double-click Feature B and then clickFeature B photo.

Question 10:Identify mechanical weathering at Feature B:

A. Frost wedging

B. Frost heaving

C. Salt-crystal growth

D. Exfoliation

Double-click Feature C and then click Feature C photo.

Question 11:Identify mechanical weathering at Feature C:

A. Frost wedging

B. Frost heaving

C. Salt-crystal growth

D. Exfoliation

Collapse theMechanical Weathering folder.

Double-click Chemical Weathering.

Double-click Feature D and then click Feature D photo.

Question 12:Identify chemical weathering at Feature D:

A. Hydrolysis

B. Carbonation

C. Oxidation

D. Spheroidal

Double-click Feature Eand then clickFeature E photo.

Question 13:Identify chemical weathering at Feature E:

A. Hydrolysis

B. Carbonation

C. Oxidation

D. Spheroidal

Double-click Feature F and then click Feature F photo.

Question 14:Identify chemical weathering at Feature F:

A. Hydrolysis

B. Carbonation

C. Oxidation

D. Spheroidal

Collapse theChemical Weathering folder.

MASS WASTING

Expand theMASS WASTING folder.

Double-click and selectFeature G.

Select the dominant type of mass wastingat Feature G.

Question 15: Feature G: ________

A. Slump

B. Solifluction

C. Landslide

D. Rockfall

Question 16:Why did you pick the answer you did in Question 15?

A. Because the image shows material that has rotated and moved down the slope along a concave plane relative to the surface.

B. Because the image shows where freeze-thaw processes result in lobes of soil moving gradually downslope.

C. Because the image shows the result of movement of soil and bedrock down a steep slope in response to gravity,

D. Because the image shows rocks that suddenly slid down a mountainside

Double-click and selectFeature H.

Select the dominant type of mass wasting at Feature H.

Question 17: Feature H: _______

A. Slump

B. Solifluction

C. Landslide

D. Rockfall

Question 18: Why did you pick the answer you did in Question 17

A. Because the image shows material that has rotated and moved down the slope along a concave plane relative to the surface.

B. Because the image shows where freeze-thaw processes result in lobes of soil moving gradually downslope.

C. Because the image shows the result of movement of soil and bedrock down a steep slope in response to gravity,

D. Because the image shows rocks that suddenly slid down a mountainside

Double-click and selectFeature I and examine the area in September 1998. Use the historical imagery slider and advance the timeline to March 2007.

Select the dominant type of mass wasting at Feature I.

Question 19: Feature I: ______

A. Slump

B. Solifluction

C. Landslide

D. Rockfall

Question 20: Why did you pick the answer you did in Question 19?

A. Because the image shows materialthat has rotated and moved down the slope along a concave plane relative to the surface.

B. Because the image shows where freeze-thaw processes result in lobes of soil moving gradually downslope.

C. Because the image shows the result of movement of soil and bedrock down a steep slope in response to gravity,

D. Because the image shows rocks that suddenly slid down a mountainside

Double-click and select Slope 1. Right click the title Slope 1, and then select Show Elevation Profile.

Place your cursor over the elevation profile chart and compute the slope of the lines. Recall that the equation for slope is RISE/RUN and that the units must be the same when dividing (that is, both in meters).

Question 21: What is the RISE (Elevation gain) in meters?

A. 738 meters

B. 190 meters

C. 46.7 meters

D. 25.4 meters