Part 2 Chap 11.2 Types of mnts

Mountain Building : 

Mountain Building Types of mountains

Types of mountains : 

Types of mountains Many different forces and relationships can impact the production of mountains Examples can include Stress and strain Folding and faulting Climate, weathering, type of weathering Volcanoes and earthquakes Vegetation or lack thereof The collection of processes that produce a mountain is known as orogenesis

Types of mountains : 

Types of mountains Folding is often the most obvious sign of the forces that deform the Earth and produce mountains Thrust faulting, metamorphism, and igneous activity are also important in the process

Types of mountains : 

Types of mountains Classification of mountains Mountains are classified by the dominant processes that form them Three main types are: Folded mountains Fault-block mountains Uplifted or domed mountains

Types of mountains : 

Types of mountains Folded mountains Mountains that are formed primarily by folding The major force that creates theses are compressional forces (compressional stress) Thrust faulting Often called fold-and-thrust belts Examples include the Rockies, the Appalachians, and the Alps Reverse faulting also is a compressional force responsible the production and appearance of folded mountains

Types of mountains : 

Types of mountains Folding in the Canadian Rockies Mt. Kidd, Alberta, Canada

Types of mountains : 

Types of mountains Fault-block mountains Form as large blocks of crust are uplifted and tilted along normal faults Formed from tensional stress Consist of elongated mountain ranges Separated by valleys formed by grabens Examples include the Teton Range in WY and the Sierra Nevada in CA

Types of mountains : 

Types of mountains Horst and Graben Fault-block mountains consist of a series of horsts and grabens The tensional forces associated with normal faulting causes the crust to stretch or extend As it extends, a block called a graben, which is bound by normal faults, drops down This produces an elongated valley Graben is German for ditch or trench

Types of mountains : 

Types of mountains Horst and Graben The grabens are bordered b y uplifted structures called horsts The Basin and Range province of NV, UT, and CA is made up of elongated grabens

Types of mountains : 

Types of mountains Fault block mountains

Types of mountians : 

Types of mountians Domes and basins Domes and basins are created by upwarping and downwarping of the crust Upwarping causes causes the overlying cover of sedimentary rock to deform Mt. Rushmore is created where much upwarping has taken place in basement rock Upwarping can generate large folds

Types of mountains : 

Types of mountains Domes Circular or elongated structures created by upwarping In the Black Hills of SD the highest portion of sedimentary rock has eroded away This exposes the older igneous and metamorphic rocks at the center The oldest rocks are at the core (center) The youngest rocks are found at the sides

Types of mountains : 

Types of mountains A geological map of the Black Hills of SD Note the Dome shape of the material The oldest material is at the center

Types of mountains : 

Types of mountains Basins Circular shaped structures caused by downwarping The weight of large accumulations of sediment causes the crust to subside This leaves very gently sloping beds similar to saucers The youngest rocks are found at center The oldest rocks are found on the sides

Types of mountains : 

Types of mountains Geological map of MI Note the saucer shape of the material The youngest material is at the center