Bob Leighty Mountains of the World GLG Physical Geology

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.

 Orogenic (not a dirty word): mountain-building  Orogeny: mountain-building event (e.g., Himalayan Orogeny) Orogeny  Orogenic belt: mountain belt (e.g., Himalaya) Orogenic Basics Mountains of the World

> The thicker the crust, the higher it “floats” > Crust is buoyant & “floats” on top of the mantleCrustbuoyantmantle  Isostasy = gravitational balance Isostasy > Thin crust = low elevations = sedimentary basins > Thick crust = high elevations = mountains  Elevation is related to crustal (continental or oceanic) thickness Orogenic Basics Mountains of the World

 Continental crust averages ~35 km thick Continental crust  Oceanic crust averages ~7 km thick Oceanic crust Orogenic Basics Mountains of the World

1) Thicken the crust by tectonic compression 2) Thicken the crust by magmatism Orogenic Basics Mountains of the World Ways To Make Mountains

3) Thermal uplift by magmatism Ways To Make Mountains Orogenic Basics Mountains of the World

vExtension (pull & stretch)  Erosion (off the top) Ways To Thin the Crust Orogenic Basics Mountains of the World

 Mountains can form anywhere, but mainly at tectonic plate boundariestectonic plate boundaries Mountains of the World

HimalayasHimalayas & Alps (mostly Cenozoic)Alps Continent-Continent Convergent Margins Mountains of the World AppalachiansAppalachians, Urals (mostly Paleozoic)Urals

Himalayas Continent-Continent Convergent Margins Mountains of the World

Appalachians Continent-Continent Convergent Margins Mountains of the World

Ocean-Continent Convergent Margins Mountains of the World AndesAndes, Cascades (mostly Cenozoic)Cascades Rocky Mountains Rocky Mountains (Late Mesozoic-Early Cenozoic)

Andes, Cascades Ocean-Continent Convergent Margins Mountains of the World “Continental arcs”Continental arcs

Rocky Mountains Ocean-Continent Convergent Margins Mountains of the World

AleutiansAleutians, JapanJapan (Cenozoic) Ocean-Ocean Convergent Margins Mountains of the World “Island arcs”Island arcs

Mid-Atlantic RidgeMid-Atlantic Ridge, East Pacific Rise (Cenozoic)East Pacific Rise Oceanic Divergent Margins Mountains of the World “Mid-ocean Ridges”Mid-ocean Ridges

Continental Divergent Margins Mountains of the World East Africa RiftEast Africa Rift, Basin & Range, Sierra Nevada (Cenozoic)Basin & RangeSierra Nevada “Continental Rift”Continental Rift

Basin & Range Continental Divergent Margins Mountains of the World

Sierra Nevada Continental Divergent Margins Mountains of the World

Hawaiian IslandsHawaiian Islands - Emperor Seamounts (largely Cenozoic)Emperor Seamounts Intraplate “Hotspots” Mountains of the World

WWW Links in this Lecture > Orogeny - > Isostasy - > Buoyancy - > Crust - > Mantle - > Continental crust - > Oceanic crust - > Mountains - > Tectonic plate boundaries > Appalachian Mountains - > Ural Mountains - > Himalayas - > Alps - > Andes - > Cascades - > Rocky Mountains - > Volcanic arc - Mountains of the World

WWW Links in this Lecture > Aleutian Islands - > Japanese Islands - > Mid-ocean ridge - > Mid-Atlantic ridge - > East Pacific Rise - > Continental rift - > East African Rift - > Basin and Range - > Sierra Nevada - > Hawaiian Islands - > Emperor Seamounts - Mountains of the World