mountain formation. how are formed convergence due to converging plates can be either...

Mountain formation Reporters:

Steffanie MahusayCris MagawayRoda Notario

How Are Formed

•Convergence due to converging plates can be either continental-oceanic convergence, oceanic-oceanic convergence or continental-continental convergence.

•deformation folding and faulting of layers

Types of mountains Volcanic mountainsFold- Block mountainsErosional mountainsFolded Mountains

Volcano-Natural vent or opening in the earth’s crust that is connect by a pipe, or conduit , to a chamber at a depth that contains magma

Volcanoes may be:• active•Extinct•Dormant

Type of eruption•Hawaiian-out pouring of fluid lava and little explosive activity.

•Peleean-violent eruption with viscous lava “ nuees ardentes ’’.

•Strombolian-moderate eruptions , small explosions and lava of average viscosity.

•Vesuvian-very explosive after a dormant period with ash/gas clouds and gas-filled lava.

•Plinian-very explosive with pyroclastics ejected in a column up to 50kg high producing thick air fall deposits

Volcanic mountains

•found in association with mid ocean ridge systems , plate tectonics , along convergent boundaries.

•also known as a composite volcano,

tall, conical volcano built up by many layers (strata) of hardened lava, tephra, pumice, and volcanic ash.

•built almost entirely of highly fluid basaltic lava, which travel farther than those erupted from more explosive volcanoes

Grand Tetons from Jackson Lake Lodge (WY)

Fault-block mountains•are formed when large areas of bedrock are widely broken up by faults creating large vertical displacements of continental crust.

Erosional mountains •formed by wind or water wearing down weak spots in land and carrying it away. Non-resistant material is washed away, whereas the stronger material remains

Rocky mountains(north America)

Folded mountaincreated when two tectonic plates come together . This causes them to rise out of the earth. These mountains are formed by compression

Fault structures•is a structure with major displacement of

rock material along a crack in a rock

Types of faults • are based on relative movement along the cracked rock and include horizontal, vertical, or a combination of movements

1. Vertical or dip slip fault •type of fault with movement along the dip of the fault--the concepts of hanging wall and footwall are important in defining the different types of vertical faults

Normal fault--hanging wall moves down in respect to footwall Reverse fault--hanging wall moves up in respect to footwall--a low angled reverse fault is called a thrust fault •Horst and graben--a wedge of land which moves up (horst) or down (graben) between 2 normal faults

2. Horizontal or strike slip fault •type fault with horizontal movement along the cracked rock--movement can be left lateral or right lateral

3.Oblique fault is a fault which has a major dip slip and strike slip component

•Slickenside- a polish and striated rock surface that results from friction along a fault plane.•Striations- means linear furrows generated from fault movement.

striation slickenslide grooves

Fault breccia, or tectonic breccia, is a breccia (a rock type consisting of

angular clasts) that was formed tectonic forces.

Fault breccia of the Keystone Thrust, Red Rock Canyon National Conservation Area, Nevada.

Fault gouge is an unconsolidated tectonite(a rock formed by tectonic forces) with a very small grain size

Salmon-colored fault gouge and associated fault separates two different rock types on the left (dark grey) and right (light grey). From the Gobi of Mongolia.

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