This page lists 40 geological features that start with L, from “Lahar” to “Lut Desert”. They include volcanic landforms, lakes, caves, rock types, glacial deposits, and large deserts. Some are tiny fragments you can hold in your hand, while others cover whole regions of the planet. People use this kind of knowledge to plan safe travel, study natural hazards, understand where resources come from, and make sense of the landscapes around them.
Geological features are the natural formations and materials that make up the Earth’s surface and interior, shaped by volcanoes, water, ice, wind, and moving plates. In 1985, a lahar from the Nevado del Ruiz volcano buried the town of Armero in Colombia, showing how a single feature can change history.
Below you’ll find the table with the geological feature, region, characteristics, and description for each entry.
Geological Feature: The name of each formation, rock, or landform, listed alphabetically so you can quickly find the one you want to look up.
Region: Where in the world you can find each feature, from specific countries and mountain ranges to broad areas that span several continents.
Characteristics: A short summary of the key traits, such as size, shape, age, or how the feature formed, which helps you compare entries at a glance.
Description: A plain explanation of what each feature is, how it forms, and why it matters, with a notable example or fact when one is available.
Geological features
| Geological Feature | Region | Characteristics |
|---|---|---|
| Lahar | Volcanic regions worldwide (Indonesia, Andes, Pacific Northwest) | Volcanic mudflow, fast-moving, destructive |
| Laccolith | Henry Mountains (Utah), Black Hills (South Dakota) | Igneous intrusion, dome-shaped, flat base |
| Lagoon | Coastal regions worldwide | Shallow water, separated from sea by barrier |
| Lake | Worldwide | Inland standing water, freshwater or saline |
| Lake Baikal | Siberia, Russia | World’s deepest lake, rift origin, about 5,300 feet deep |
| Lake Natron | Tanzania | Alkaline soda lake, red-tinged, caustic |
| Lake Titicaca | Peru and Bolivia, Andes | High-altitude lake, about 12,500 feet elevation |
| Lake Vostok | Antarctica | Subglacial lake, buried under about 2.5 miles of ice |
| Lamprophyre | Worldwide, in dikes and sills | Dark igneous rock, volatile-rich, often hosts diamonds |
| Landform | Worldwide | General term, shaped by tectonic or erosional forces |
| Landslide | Mountainous and hilly regions worldwide | Downslope movement of rock and soil, often triggered by rain or quakes |
| Lapilli | Volcanic regions worldwide | Small volcanic fragments, 0.08 to 2.5 inches |
| Laterite | Tropical regions (India, West Africa, Brazil) | Iron- and aluminum-rich, red, hardens when dry |
| Lava | Volcanic regions worldwide | Molten rock at the surface, 1,300 to 2,200 degrees F |
| Lava Dome | Mount St. Helens (US), Merapi (Indonesia) | Steep-sided mound, thick viscous lava |
| Lava Field | Iceland, Hawaii, Canary Islands | Broad expanse of solidified lava flows |
| Lava Lake | Erta Ale (Ethiopia), Kilauea (Hawaii) | Persistent pool of molten lava in a crater |
| Lava Tube | Hawaii, Iceland, Canary Islands, Jeju Island | Natural tunnel, formed by flowing lava |
| Lava Plateau | Columbia River (US), Deccan (India), Iceland | Flat highland, built from repeated flood basalts |
| Levee | River floodplains worldwide (Mississippi, Yellow River) | Raised bank, natural or artificial |
| Limestone Cave | Karst regions worldwide (Mexico, Slovenia, China) | Dissolved rock, stalactites and stalagmites |
| Limestone Pavement | Yorkshire Dales (UK), The Burren (Ireland) | Flat exposed rock, cracked into blocks |
| Lithosphere | Global | Rigid outer shell, crust and upper mantle |
| Loess | China, Midwestern US, Central Europe | Wind-blown silt, fertile, yellowish |
| Longshore Drift | Sandy coastlines worldwide | Sediment transport, zigzag movement along beaches |
| Lopolith | Bushveld Complex (South Africa), Sudbury (Canada) | Igneous intrusion, saucer-shaped |
| Loch | Scotland | Glacial lake or sea inlet |
| Lode | Mining regions worldwide (Nevada, California) | Mineral vein, metal-bearing rock |
| Longitudinal Dune | Sahara, Australian Deserts, Arabian Peninsula | Long, straight sand ridge, parallel to wind |
| Lower Mantle | Deep Earth, 410 to 1,800 miles down | Dense, hot, solid but slowly flowing |
| Lagerstatte | Burgess Shale (Canada), Solnhofen (Germany) | Fossil-rich deposit, exceptional preservation |
| Lateral Moraine | Alpine and polar glaciated valleys | Ridge of debris, along glacier sides |
| Lake Superior | North America, US and Canada border | Largest Great Lake, glacier-carved |
| Lake Tanganyika | East Africa, Tanzania, DR Congo, Burundi, Zambia | Rift lake, second deepest in the world |
| Lake Malawi | Malawi, Mozambique, Tanzania | Rift lake, over 1,000 fish species |
| Lassen Peak | California, USA | Lava dome volcano, last erupted 1915 |
| Laurentide Ice Sheet | North America | Ancient ice sheet, up to 2 miles thick |
| Lena Delta | Siberia, Russia | Large Arctic river delta, permafrost |
| Lechuguilla Cave | New Mexico, USA | Deep limestone cave, over 150 miles mapped |
| Lut Desert | Iran | Hot desert, yardang formations |
Descriptions
Lahar
A fast-moving mixture of volcanic debris and water that rushes down a volcano’s slopes and river valleys. Lahars can bury entire towns, as happened at Armero, Colombia in 1985.
Laccolith
A mass of magma that pushes up overlying rock layers into a dome without reaching the surface. When erosion strips away the cover, it leaves rounded mountain peaks.
Lagoon
A shallow body of water cut off from the open sea by a sandbar, reef, or barrier island. Lagoons are often rich habitats for fish and birds.
Lake
A large body of water surrounded by land, fed by rivers, rain, or springs. Lakes form through glaciers, tectonic movement, volcanic activity, or river processes.
Lake Baikal
A rift lake in southern Siberia and the deepest lake on Earth. It holds roughly 20 percent of the world’s unfrozen fresh water and is about 25 million years old.
Lake Natron
A salty, highly alkaline lake in the East African Rift. Its red color comes from microorganisms, and it is a key breeding ground for flamingos.
Lake Titicaca
One of the highest navigable lakes in the world, set on the Andean plateau. It is the largest freshwater lake in South America by volume.
Lake Vostok
A large lake hidden beneath the Antarctic ice sheet, sealed off for millions of years. Scientists study it for clues about life in extreme isolation.
Lamprophyre
A group of dark, unusual igneous rocks rich in volatile elements. Some types, like lamproite, carry diamonds up from deep within the Earth.
Landform
Any natural feature on the Earth’s surface, such as a mountain, valley, or plain. Landforms are shaped by tectonic activity, weathering, erosion, and deposition.
Landslide
The sudden sliding of rock, earth, or debris down a slope. Heavy rain, earthquakes, and volcanic activity are common triggers.
Lapilli
Small pieces of rock and lava thrown out during volcanic eruptions. The name comes from the Italian word for “little stones.”
Laterite
A reddish soil or rock formed by intense weathering in hot, wet climates. It hardens when exposed to air and has long been used as a building material.
Lava
Molten rock that erupts from a volcano or fissure and flows across the ground. It cools into solid igneous rock such as basalt.
Lava Dome
A rounded mound formed when thick, sticky lava piles up around a volcanic vent instead of flowing away. Domes can collapse and trigger dangerous flows.
Lava Field
A wide area covered by lava flows that have cooled and hardened. Fields often look dark, rugged, and barren for decades.
Lava Lake
A large volume of molten lava sitting in a volcanic crater or pit. Only a handful of volcanoes on Earth host long-lasting lava lakes.
Lava Tube
A cave formed when the surface of a lava flow hardens while molten rock keeps flowing beneath. When the lava drains out, a hollow tunnel remains.
Lava Plateau
A broad elevated area built up by many layers of lava that spread across the landscape. The Deccan Traps in India are a famous example.
Levee
A raised ridge along a river’s edge, formed by sediment deposits during floods or built by people. Levees help keep rivers within their channels.
Limestone Cave
A cave carved out as slightly acidic water dissolves limestone over thousands of years. Many contain dripstone formations like stalactites and stalagmites.
Limestone Pavement
A flat surface of limestone broken up by deep cracks called grikes, separated by blocks known as clints. Glaciers scraped these surfaces bare thousands of years ago.
Lithosphere
The Earth’s rigid outer layer, made up of the crust and the uppermost mantle. It is broken into the tectonic plates that move over the softer layer below.
Loess
A fine, windblown sediment that forms thick, fertile soil deposits. The Loess Plateau in China holds some of the deepest deposits in the world.
Longshore Drift
The movement of sand and pebbles along a coast as waves hit the beach at an angle. It shapes spits, bars, and beaches over time.
Lopolith
A large, saucer-shaped body of intrusive igneous rock that sagged into the crust. The Bushveld Complex is the biggest known example.
Loch
The Scottish word for a lake or narrow sea inlet. Many lochs were carved by glaciers during the last ice age, including Loch Ness and Loch Lomond.
Lode
A vein of metal-bearing ore running through solid rock. The Comstock Lode in Nevada was a famous source of silver and gold.
Longitudinal Dune
A long, straight sand ridge that lines up with the prevailing wind direction. These dunes can stretch for miles across deserts.
Lower Mantle
The deepest part of the Earth’s mantle, lying below the transition zone. It makes up the largest share of the planet’s volume.
Lagerstatte
A rock deposit with exceptionally well-preserved fossils, often including soft tissues. These sites give scientists rare glimpses of ancient life.
Lateral Moraine
A ridge of rock and sediment piled up along the sides of a glacier. It remains as a visible ridge after the ice melts away.
Lake Superior
The largest of the Great Lakes by area and one of the biggest freshwater lakes in the world. It was shaped by glaciers and ancient rift activity.
Lake Tanganyika
A long, narrow lake in the East African Rift. It is the world’s second deepest lake and home to hundreds of fish species found nowhere else.
Lake Malawi
A large rift lake in southeastern Africa. It contains more fish species than any other lake, many of them colorful cichlids.
Lassen Peak
One of the world’s largest lava dome volcanoes, in northern California. Its 1914 to 1917 eruptions were the last in the Cascades before Mount St. Helens.
Laurentide Ice Sheet
A massive ice sheet that covered much of Canada and the northern US during the last ice age. Its movement carved out the Great Lakes and countless smaller lakes.
Lena Delta
One of the largest river deltas in the world, where the Lena River meets the Arctic Ocean. It is a mix of channels, islands, and frozen wetlands.
Lechuguilla Cave
A cave in Carlsbad Caverns National Park, known for rare crystal formations. Sulfuric acid, not just water, carved this extraordinary cave system.
Lut Desert
A vast desert in Iran with some of the highest recorded land surface temperatures on Earth. It features huge wind-carved ridges called kaluts.