This page lists 27 geological features that start with F, running from “Fault” to “Fan”. They include mountains, valleys, volcanic vents, rivers, ice formations and rock layers found on land, in cold regions and along the coast. Students, hikers, travelers and curious readers can use the list to learn what these features are, where they form, and why they matter.
Geological features are the natural landforms and rock structures that make up the surface of the Earth. Some are very old, like the folded rock layers in the Alps. Others, like the “Fairy Chimney” spires of Cappadocia in Turkey, draw visitors from around the world.
Below you’ll find the table with the feature, region, characteristics and description for each entry.
Feature: This is the name of the landform. You can use it to quickly find the item you want or to look up more details elsewhere.
Region: This shows where in the world you can find each feature, from single sites to whole continents, so you can plan a visit or compare places.
Characteristics: This gives a short summary of the main traits of each feature, such as its shape, size or how it formed, at a glance.
Description: This explains in plain language what the feature is and how it forms, with a notable example, so you understand it without any technical background.
Geological features
| Feature | Region | Characteristics |
|---|---|---|
| Fault | Worldwide | Fracture in rock where blocks have moved |
| Fault Scarp | Worldwide | Steep step in the ground surface |
| Fault Block Mountain | Basin and Range (USA), East Africa, Germany | Tilted crustal block uplifted along faults |
| Fold | Worldwide | Bent or curved rock layers |
| Fold Mountain | Himalayas, Alps, Andes | Formed by colliding tectonic plates |
| Fjord | Norway, New Zealand, Chile, Greenland, Canada | Deep, narrow, steep-sided inlet carved by glaciers |
| Floodplain | Worldwide, especially along large rivers | Flat land beside a river that floods periodically |
| Fumarole | Iceland, Yellowstone (USA), Italy, New Zealand | Vent releasing steam and volcanic gases |
| Fissure Vent | Iceland, Hawaii, Ethiopia | Long crack from which lava erupts |
| Flood Basalt | Deccan Traps (India), Siberian Traps (Russia), Columbia River (USA) | Vast sheets of lava covering huge areas |
| Fossil Bed | Worldwide, including Wyoming and Morocco | Rock layer rich in preserved remains of ancient life |
| Foliation | Worldwide metamorphic regions | Layered texture in metamorphic rock |
| Fan Delta | Alaska, Iceland, Norway | Fan-shaped sediment deposit where a stream meets water |
| Frost Wedge | Arctic Canada, Siberia, Alaska | Ice-filled crack in frozen ground |
| Frost Heave | Cold regions worldwide | Upward swelling of soil from freezing water |
| Fairy Chimney | Cappadocia (Turkey) | Tall rock spire capped with a harder stone |
| Flatiron | Colorado (USA), Wyoming (USA), Utah (USA) | Triangular slanted rock face |
| Firn | Alps, Greenland, Antarctica | Compacted snow between snow and glacier ice |
| Frozen Waterfall | Canada, Iceland, Switzerland | Cascade frozen by winter cold |
| Fell | Northern England, Scotland, Scandinavia | High, open, rocky hill or moorland |
| Foreland Basin | Alberta (Canada), Himalayan foothills, Andes foothills | Sediment-filled depression next to a mountain belt |
| Fringing Reef | Red Sea, Caribbean, Hawaii, Pacific islands | Coral reef growing close to the shore |
| Flysch | Alps, Carpathians, Basque Coast (Spain) | Layered sediments laid down before mountains rise |
| Fluvial Terrace | River valleys worldwide | Step-like bench left by a river that has cut down |
| Fumarolic Field | Valley of Ten Thousand Smokes (Alaska), Iceland, Kamchatka | Area dotted with many steam vents |
| Fault Trough | Great Rift Valley (Africa), Rhine Graben (Germany) | Valley formed by dropped crustal block |
| Fan | Deserts and mountain fronts worldwide | Fan-shaped pile of sediment |
Descriptions
Fault
A fracture in the Earth’s crust along which rock on either side has slipped. Faults are the source of most earthquakes, and some, like the San Andreas Fault, stretch for hundreds of miles.
Fault Scarp
A cliff-like step formed when one side of a fault moves up or down relative to the other during an earthquake. Large scarps can be seen for miles across the landscape.
Fault Block Mountain
A mountain created when large blocks of crust are lifted or tilted along faults. The Sierra Nevada and the Teton Range are well-known examples.
Fold
A bend in layers of rock caused by compression deep in the Earth. Folds range from tiny wrinkles in a single outcrop to arches spanning many miles.
Fold Mountain
A mountain range built when two plates push together and crumple the crust upward. The Himalayas, Alps and Andes are all fold mountain systems.
Fjord
A long, narrow sea inlet with steep cliffs on both sides, carved by a glacier and later flooded by the ocean. Norway’s Sognefjord is more than 120 miles long.
Floodplain
The flat area next to a river that fills with water when the river overflows. Regular floods leave behind rich silt, making floodplains some of the most fertile farmland on Earth.
Fumarole
An opening in the ground, often near a volcano, that releases steam and gases such as sulfur dioxide. Fumaroles can keep venting for centuries after an eruption.
Fissure Vent
A long crack in the ground through which lava erupts, rather than a single central cone. Iceland’s Laki fissure produced one of history’s largest eruptions in 1783.
Flood Basalt
A huge outpouring of runny lava that spreads over enormous areas and builds thick layers of basalt. Some flood basalt events are linked to mass extinctions.
Fossil Bed
A layer of rock containing large numbers of fossils, often preserved by rapid burial. Famous examples include the Green River Formation in the western United States.
Foliation
A layered or banded pattern in rock that forms when heat and pressure align its minerals. It gives rocks like schist and gneiss their striped look.
Fan Delta
A wedge of sand and gravel built where a steep stream flows into a lake or the sea. It looks like a fan when seen from above.
Frost Wedge
A wedge of ice that grows in a crack in frozen soil as water freezes and expands. Over time, frost wedges can create patterned ground in polar regions.
Frost Heave
A bulge in the ground caused by ice crystals growing in the soil and pushing it upward. It is the reason roads in cold climates crack and buckle in winter.
Fairy Chimney
A tall cone of soft volcanic rock topped by a harder boulder that shields it from erosion. The most famous examples are in Cappadocia, Turkey.
Flatiron
A steep, triangle-shaped rock slab formed by tilted rock layers wearing away. The Flatirons near Boulder, Colorado, are a popular climbing spot.
Firn
Old, granular snow that has survived at least one summer and is partway to becoming glacier ice. It forms the upper layer of many glaciers.
Frozen Waterfall
A waterfall whose flowing water has frozen into columns and curtains of ice. Many are popular spots for ice climbing.
Fell
A high, bare hill or stretch of upland moor, common in northern England and Scandinavia. The Lake District’s fells attract hikers from around the world.
Foreland Basin
A low area that forms beside a rising mountain range as the crust bends under its weight. Rivers fill it with sediment eroded from the mountains.
Fringing Reef
A coral reef that grows directly along a coastline, separated from land by a narrow, shallow lagoon or none at all. It is the most common type of coral reef.
Flysch
A thick sequence of alternating sandstone and shale deposited in deep sea basins ahead of rising mountains. The Basque Coast flysch shows striking, tilted layers.
Fluvial Terrace
A flat, step-like surface on a valley side that marks a former level of the river. Terraces form when a river cuts deeper into its valley over time.
Fumarolic Field
A stretch of ground with many fumaroles venting steam and gas. Alaska’s Valley of Ten Thousand Smokes was named for its thousands of steaming vents.
Fault Trough
A long valley created when a block of crust sinks between two parallel faults. Also called a graben, it can reach huge sizes like East Africa’s Rift Valley.
Fan
A cone-shaped deposit of gravel and sand left where a stream leaves a steep mountain valley. Death Valley has some of the best-known alluvial fans.