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A mountain is a landform that rises prominently above its surroundings, generally exhibiting steep slopes, a relatively confined summit area, and considerable local relief.

Mountains generally are understood to be larger than hills, but the term has no standardized geological meaning. Very rarely do mountains occur individually. In most cases, they are found in elongated ranges or chains.

  • Encyclopaedia Britannica

Building mountains

Yellow = continental crust (lithosphere)

thin region under the ocean (visible as the GIF progresses) = oceanic crust, also part of the lithopshere

Gray = upper mantle/lithosphere

Orange = lower mantle/asthenosphere

Himalayan mountains formation

Here we see the 6,000 kilometre-plus journey of the India landmass before its collision with Asia (Eurasian Plate) about 40 to 50 million years ago.
– Wikipedia


This GIF shows a sideways view of what happened as these landmasses collided. Observe the rock folding and forming mountains.

More here: Observe an animation of the Himalayas forming. McDougal Little.



Appalachian Mountains

A system of mountains in eastern North America. First formed roughly 480 million years ago during the Ordovician Period. They once reached elevations similar to those of the Alps and the Rocky Mountains.  Since then they have experienced natural erosion.

Northeast Appalachians Map

The United States Geological Survey (USGS) defines the Appalachian Highlands as including many regions, including the Adirondack Mountains.

Others give a similar definition, but excluding the Adirondack Mountains, as geologically it has a somewhat different origin.

An article on Building the Northern Appalachian Mountains and New England.

The Appalachian Trail

The AT is a marked hiking trail in the eastern United States extending between Springer Mountain in Georgia and Mount Katahdin in Maine. 2,200 miles (3,500 km) long.

Passes through Georgia, North Carolina, Tennessee, Virginia, West Virginia, Maryland, Pennsylvania, New Jersey, New York, Connecticut, Massachusetts, Vermont, New Hampshire, and Maine.

Maintained by trail clubs and partnerships. Managed by the National Park Service and the nonprofit Appalachian Trail Conservancy. Most of the trail is in forest or wild lands, although some portions traverse towns, roads and farms.


Extension of the Appalachians into Europe and Africa?

The mountains of the British Isles and Scandinavia turn out to be made of the same kind of rock, and formed in the same historical era. Evidence shows that in the past all of these were in fact one mountain system, torn about by the moving of the tectonic plates – continental drift.

Appalachian continents 3

Here we compare where the separate mountain ranges are today, with how they looked when they were connected in the past.

Appalachian Mt. Orogeny 1

The geographical regions of the entire east coast of the USA at one time were continuous with the western African coast.

Appalachian Mt. Orogeny 4

As the continents were separating.


Putting together a concept map of today’s lesson

Mountain building orogeny concept map

Learning Standards

2016 Massachusetts Science and Technology/Engineering Curriculum Framework

8.MS-ESS2-1. Use a model to illustrate that energy from Earth’s interior drives convection that cycles Earth’s crust, leading to melting, crystallization, weathering, and deformation of large rock formations, including generation of ocean sea floor at ridges, submergence of ocean sea floor at trenches, mountain building, and active volcanic chains.

College Board Standards for College Success: Science

ESM-PE.1.3.1 Explain and justify the topographic features typically found at each type of tectonic boundary (convergent, divergent, transform).

ESSENTIAL KNOWLEDGE Students apply, as well as engage and reason with, the following concepts in the performance expectations: Tectonic processes create distinct landforms, such as uplifted, folded, and thrusted mountains and downthrown rift valleys.

Enduring Understanding 2C: Earth’s landscapes emerge from the interactions among the atmosphere, hydrosphere, lithosphere, biosphere, cryosphere and human activity.
Benchmarks for Science Literacy, AAAS

The interior of the earth is hot. Heat flow and movement of material within the earth cause earthquakes and volcanic eruptions and create mountains and ocean basins. Gas and dust from large volcanoes can change the atmosphere. 4C/M1

There are a variety of different land forms on the earth’s surface (such as coastlines, rivers, mountains, deltas, and canyons). 4C/M8** (BSL)

The earth’s plates sit on a dense, hot, somewhat melted layer of the earth. The plates move very slowly, pressing against one another in some places and pulling apart in other places, sometimes scraping alongside each other as they do. Mountains form as two continental plates, or an ocean plate and a continental plate, press together. 4C/M12** (BSL)

There are worldwide patterns to major geological events (such as earthquakes, volcanic eruptions, and mountain building) that coincide with plate boundaries. 4C/M13** (BSL)

Earthquakes often occur along the boundaries between colliding plates, and molten rock from below creates pressure that is released by volcanic eruptions, helping to build up mountains. Under the ocean basins, molten rock may well up between separating plates to create new ocean floor. Volcanic activity along the ocean floor may form undersea mountains, which can thrust above the ocean’s surface to become islands. 4C/H5

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