Lecture Outlines PowerPoint Chapter 6 Earth Science, 12e Tarbuck/Lutgens 2009 Pearson Prentice Hall This work is protected by United States copyright laws and is provided solely for the use of instructors in teaching their courses and assessing student learning.
Dissemination or sale of any part of this work (including on the World Wide Web) will destroy the integrity of the work and is not permitted. The work and materials from it should never be made available to students except by instructors using the accompanying text in their classes. All recipients of this work are expected to abide by these restrictions and to honor the intended pedagogical purposes and the needs of other instructors who rely on these materials. Earth Science,
12e Glaciers, Deserts, and Wind Chapter 6 Glaciers: a part of two basic cycles in the Earth system Glaciers are a part of both the hydrologic
cycle and rock cycle Glacier a thick mass of ice that forms over land from the compaction and recrystallization of snow and shows evidence of past or present flow Glaciers: a part of two basic cycles in the Earth system
Types of glaciers Valley, or alpine glaciers form in mountainous areas Ice sheets, or continental glaciers Large scale e.g., Over Greenland and Antarctica Other types
Ice caps and piedmont glaciers Currently ice sheets cover Greenland and Antarctica Figure 6.2
Glaciers: a part of two basic cycles in the Earth system Movement of glacial ice Types of glacial movements Plastic flow Slipping along the ground Zone of fracture
Uppermost 50 meters Crevasses form in brittle ice Glaciers: a part of two basic cycles in the Earth system Movement of glacial ice Zone of accumulation the area where a glacier forms
Zone of wastage the area where there is a net loss due to melting The glacial budget Figure 6.7
Glaciers: a part of two basic cycles in the Earth system Glaciers erode by Plucking lifting of rock blocks Abrasion Rock flour (pulverized rock) Striations (grooves in the bedrock)
Glaciers: a part of two basic cycles in the Earth system Landforms created by glacial erosion
Glacial trough Hanging valley Cirque Arte Horn Fiord
Erosional landforms created by alpine glaciers Figure 6.10 C The Matterhorn in the Swiss Alps
Figure 6.12 Glaciers: a part of two basic cycles in the Earth system Glacial deposits Glacial drift All sediments of glacial origin
Types of glacial drift Till material that is deposited directly by ice Stratified drift sediment deposited by meltwater Glacial till is typically unstratified and unsorted
Figure 6.13 Close-up view of the boulder in the previous slide Glaciers: a part of two basic cycles in the Earth system Glacial deposits
Depositional features Moraines layers or ridges of till Types of moraines Lateral Medial End Ground
Glaciers: a part of two basic cycles in the Earth system Glacial deposits Depositional features
Outwash plain, or valley train Kettles Drumlins Eskers Kames
Glacial depositional features Figure 6.18 Kettle lakes Figure 6.18
Glaciers: a part of two basic cycles in the Earth system Glaciers of the past Ice Age Began 2 to 3 million years ago Division of geological time is called the Pleistocene epoch
Ice covered 30% of Earths land area Maximum extent of ice during the Ice Age Figure 6.22 Glaciers: a part of two basic
cycles in the Earth system Glaciers of the past Indirect effects of Ice Age glaciers
Migration of animals and plants Rebounding upward of the crust Worldwide change in sea level Climatic changes Glaciers: a part of two basic cycles in the Earth system Causes of glaciation
Successful theory must account for Cooling of Earth, as well as Short-term climatic changes Proposed possible causes Plate tectonics Continents were arranged differently Changes in oceanic circulation
Glaciers: a part of two basic cycles in the Earth system Causes of glaciation Proposed possible causes Variations in Earths orbit Milankovitch hypothesis Shape (eccentricity) of Earths orbit varies
Angle of Earths axis (obliquity) changes Axis wobbles (precession) Changes in climate over the past several hundred thousand years are closely associated with variations in Earths orbit Deserts Geologic processes in arid climates
Weathering Not as effective as in humid regions Mechanical weathering forms unaltered rock and mineral fragments Some chemical weathering does occur Clay forms Thin soil forms
Deserts Geologic processes in arid climates Role of water in arid climates Streams are dry most of the time Desert streams are said to be ephemeral Flow only during periods of rainfall Different names are used for desert streams including wash, arroyo, wadi, donga, and nullah
Deserts Geologic processes in arid climates Role of water in arid climates Desert rainfall Rain often occurs as heavy showers Causes flash floods Poorly integrated drainage
Most erosional work in a desert is done by running water A dry stream channel in the desert Figure 6.28 A
The same stream channel following heavy rainfall Figure 6.28 B Deserts Basin and Range: the evolution of a desert landscape
Uplifted crustal blocks Interior drainage into basins produces Alluvial fans and bajadas Playas and playa lakes Deserts Basin and Range: the evolution of a desert landscape
Erosion of mountain mass causes local relief to continually diminish Eventually mountains are reduced to a few large bedrock knobs called inselbergs projecting above a sediment-filled basin Landscape evolution in a mountainous desert early
Figure 6.29 A Landscape evolution in a mountainous desert middle Figure 6.29 B
Landscape evolution in a mountainous desert late Figure 6.29 C Deserts Wind erosion Deflation
Lifting of loose material Produces Blowouts Desert pavement Abrasion Formation of
desert pavement Figure 6.34 Deserts Types of wind deposits Loess Deposits of windblown silt
Extensive blanket deposits Primary sources are deserts and glacial stratified drift Deserts Types of wind deposits Sand dunes Mounds and ridges of sand formed from the winds
bed load Characteristic features Slip face the leeward slope of the dune Cross beds sloping layers of sand in the dune Formation of sand dunes Figure 6.37
Deserts Types of wind deposits Sand dunes Types of sand dunes Barchan dunes Transverse dunes Longitudinal dunes
Parabolic dunes Star dunes Sand dune types Figure 6.38 Sand dunes in the
Leveraging Adaptive Implementation Strategies to Achieve Universal Coverage of Antiretroviral Treatment in Senegal . ... Characterize the acceptability of iris scanning as a biometric follow up strategy to enhance the measurement of follow-up and retention of PLHIV receiving ART care.
CC and Women's Empowerment and Inclusion post 2015 There is a need to rebalance priorities and to accelerate both adaptation and mitigation programmes and projects in order to meet the immediate and medium term needs of women, men and children...
ISO 12207 documents the common elements in the ICT lifecycle. From initial concept through retirement. ISO 12207 consists of processes for acquiring and supplying ICT products and services. The U.S. version of the IEEE/EIA 12207 standard provides detailed information about...
Great Society Programs. Which of these programs have you heard of? (list them and describe in what context) Which programs do you think have been successful? How would you measure whether these programs were successful? How is the Great Society...
Our program makes it easy for career changers to get their initial certification If you meet the prerequisite Liberal Arts and Science requirements, pass the LAST, and complete the other admissions steps, you will be able to enroll Degrees Offered...
Ready to download the document? Go ahead and hit continue!