GEOL 446Environmental Geology

PART IFOUNDATIONS OF ENVIRONMENTAL

GROLOGY

1 .Philosophy and Fundamental Concepts

2 .Earth Material and Processes

3 .Soils and Environment

Earth Materials and Processes

• Learning Objectives:• Acquire basic understanding of the geologic cycle and its

sub-cycles (tectonic, rock, hydrologic, and biogeochemical).

• Make a modest acquaintance with some of the important mineral and rock types and their environmental significance.

• Gain an appreciation of the landforms, deposits, and environmental problems resulting from wind and glacial processes.

Plate Tectonics, Earthquakes, and Active Volcanoes

Earth Materials and Processes

The Rock CycleTectonism controls the rock cycle and is important to many surficial processes and other Earth Cycles.

The Hydrologic Cycle

Units are relative to annual P on land surface100 = 119,000 km3/yr)

The Biogeochemical Cycle

• The Biogeochemical Cycle traces the movement of an element, like carbon, in the air, water, on and in the land, and as used by living organisms. This issue is of particular importance today because large amounts of carbon dioxide are produced by burning fossil fuels. Many scientists are concerned that this trapped carbon dioxide may heat the earth in a process known as the "greenhouse effect."

Carbon Cycle

Strength of Rocks

Strength of Rocks

• Rock strength is highly variable.• Many Factors:

• rock type• texture• chemical composition• internal structures• presence or absence of fluids

• Most rocks already fractured by joints and faults.• Fractured rocks are only as strong as whatever is holding the rock

together (gravity or friction). • fracture along planes of weakness• fracture along bedding planes or along foliation planes• orientation of planes of weakness is important, Why?

Table 2.1

Terms to Understand

• hydrocompaction• geologic cycle• tectonic cycle• rock cycle• hydrologic cycle• biogeochemical cycle• greenhouse effect• rock strength

• reliable strength• safety factor• stress and strain• ductile and brittle substances• elastic and plastic

deformation• proportional elastic limit• ultimate strength• rupture strength

Read Case Histories in the textbook:

Baldwin Hills Dam and St. Francis Dam