Glaciers & Glaciation GLG Physical Geology Bob Leighty

These lecture notes are very similar to the ones I use in my traditional classes. You’ll find they are loaded with imagery and streamlined text that highlight the most essential terms and concepts. The notes provide a framework for learning and, by themselves, are not meant to be a comprehensive source of information. To take advantage of the global knowledge base known as the Internet, I have included numerous hyperlinks to external web sites (like the Wikipedia, USGS, NASA, etc.). Follow the links and scan them for relevant info. The information from linked web sites is meant to supplement and reinforce the lecture notes – you won’t be responsible for knowing everything contained in them. As a distance learning student, you need to explore and understand the content more independently than in a traditional class. As always, I will help guide you through this learning adventure. Remember, Dr. Bob if you have any questions about today’s lecture Leave no questions behind! Explore and have fun! These notes and web links are your primary “lecture” content in this class. Additionally, various articles are assigned each week to supplement this “lecture” information. I believe you’ll have enough information to reference without having to purchase a costly textbook.

 Fiction - There was one great Ice Age in the pastIce Age Glaciation Misconceptions Glaciers & Glaciations  Fact – There have been many Ice Ages (2 Ga, 600 Ma, 400 Ma, 3 Ma)

 Fiction – If all the ice melted, we’d all drown! Glaciation Misconceptions Glaciers & Glaciations

 Fiction – If all the ice melted, we’d all drown!  Fact – Global mean sea level would rise ~70 m (~230 ft) Glaciation Misconceptions Glaciers & Glaciations

 Fiction – North America was entirely covered by ice during the last Ice Age Glaciation Misconceptions Glaciers & Glaciations

 Fiction – North America was entirely covered by ice during the last glaciation  Fact – Not even close! Glaciation Misconceptions Glaciers & Glaciations

 A thick mass of compacted snow & ice  Flows under its own weight What is a Glacier? Glaciers & Glaciations  Forms on land (ice shelves form over water)

How Do Glaciers Form? Glaciers & Glaciations

How Do Glaciers Move? Glaciers & Glaciations

How Do Glaciers Move? Glaciers & Glaciations

Where Do Glaciers Form? Glaciers & Glaciations  Examples: Antarctica, GreenlandAntarcticaGreenland  Large ones at high latitudes (near the poles)

 Examples: Alps, Himalayas, Andes, etc.AlpsHimalayasAndes  Smaller ones in mountainous areas Where Do Glaciers Form? Glaciers & Glaciations

 On other worlds Extraterrestrial Ice Glaciers & Glaciations  Examples: Mars, EuropaMarsEuropa

Types of Glaciers Glaciers & Glaciations Alpine  Form in mountainous terrain

Types of Glaciers Glaciers & Glaciations Alpine Erosion  Caused by rock in the ice, not the ice itself

Types of Glaciers Glaciers & Glaciations Alpine Erosion  U-shaped valleys – Glacier-carved valleys U-shaped valleys

Types of Glaciers Glaciers & Glaciations Alpine Erosion  Fjords - U-shaped valleys flooded by the sea Fjords

Types of Glaciers Glaciers & Glaciations Alpine Erosion  Cirques – Bowl-shaped hollows where glaciers originate Cirques

Types of Glaciers Glaciers & Glaciations Alpine Erosion  Horns & Aretes – Peaks & ridges formed by 2 or more glaciers HornsAretes

Types of Glaciers Glaciers & Glaciations Alpine Erosion  Striations – Grooves etched into bedrock by icebound rock debris Striations >Help determine flow direction (in ancient rocks, too)

Types of Glaciers Glaciers & Glaciations Alpine Deposition  Moraine – Unconsolidated material deposited by glacial ice Moraine  Glacial till – Unsorted debris Glacial till

Types of Glaciers Glaciers & Glaciations Continental Ice Sheets  Ice covering vast land areas

Types of Glaciers Glaciers & Glaciations Continental Ice Sheets Erosion  Striations

Types of Glaciers Glaciers & Glaciations Continental Ice Sheets Deposition  Drift = Glacial till (ice-deposited) & outwash (stream-deposited)

Causes of Glaciation Glaciers & Glaciations 1) Continents collect at high latitudes (at the poles) 2) Ocean circulation patterns

3) Variations in Earth’s orbital dynamics a)orbit shape more elliptical b)changes in tilt of rotation axis c)precession of the axis Causes of Glaciation Glaciers & Glaciations

 Meteorites collect along mountain ranges as ice is sublimated off by strong winds Meteoritessublimated Antarctic Meteorites Glaciers & Glaciations

WWW Links in this Lecture > Ice Age - > Glacier - > Antarctica - > Greenland - > Alps - > Himalayas - > Andes - > Martian north polar ice cap - > Europa - > U-shaped valleys - > Fjord - > Cirque > Horn - > Arete - > Glacial striation - Glaciers & Glaciations

WWW Links in this Lecture > Moraine - > Glacial till - > Ice sheet - > Milankovitch cycles - > Antarctic meteorites - > The Antarctic Search for Meteorites - > Sublimation - Glaciers & Glaciations