This page lists 56 geological features that start with P, running from “Pahoehoe” to “Pozzuoli Caldera.” The list covers lava types, volcanoes, rivers, lakes, deserts, mountains, caves, and ice fields from around the world. Whether you study earth science, plan a trip, or just enjoy learning about the planet, you can use it to find a feature quickly and see where it is.
Geological features are the natural landforms, rocks, and structures that make up Earth’s surface and the processes that shape it. Some are famous worldwide, like “Pamukkale” in Turkey, where hot springs have built white terraces that look like a frozen waterfall.
Below you’ll find the table with the feature, region, characteristics, and description for each entry.
Feature: The name of each landform, rock, or natural structure, listed alphabetically so you can scan the list and find the one you want.
Region: Where in the world you can find the feature, from a single country to wide areas, which helps you place it on a map.
Characteristics: A short summary of what makes the feature stand out, such as its shape, color, or rock type, so you can recognize it at a glance.
Description: A brief explanation of how the feature forms, what it looks like, and why it matters, giving you the key facts in a few sentences.
Geological features
| Feature | Region | Characteristics |
|---|---|---|
| Pahoehoe | Hawaii, worldwide volcanic regions | Smooth, ropy lava surface |
| Pillow Lava | Ocean floors, worldwide | Rounded, pillow-shaped masses |
| Playa | Deserts of the American Southwest, Australia, Central Asia | Flat, dry lakebed |
| Plateau | Worldwide | Elevated flat-topped land |
| Peninsula | Worldwide | Land surrounded by water on three sides |
| Pingo | Arctic Canada, Siberia, Alaska | Ice-cored mound |
| Pinnacle | Worldwide | Tall, narrow rock spire |
| Plain | Worldwide | Broad, low-relief land |
| Pothole | Rivers worldwide | Circular hollow in bedrock |
| Pyroclastic Flow | Volcanic regions worldwide | Fast, hot cloud of gas and ash |
| Pumice | Volcanic regions worldwide | Light, porous volcanic rock |
| Parasitic Cone | Volcanic regions worldwide | Small vent on a volcano’s flank |
| Pass | Mountain ranges worldwide | Low route through mountains |
| Peak | Mountain ranges worldwide | Highest point of a mountain |
| Pediment | Arid regions worldwide | Gently sloping rock surface |
| Permafrost | Arctic, Siberia, Alaska, Canada, high mountains | Permanently frozen ground |
| Piedmont | Eastern United States, Italy, Argentina | Land at the base of mountains |
| Pegmatite | Worldwide, including Brazil, Maine, Madagascar | Very coarse-grained igneous rock |
| Peridotite | Earth’s mantle, ophiolites, Oman, Newfoundland | Dense, green mantle rock |
| Phreatic Eruption | Volcanic regions worldwide | Steam-driven explosion |
| Plate Boundary | Worldwide | Edge between tectonic plates |
| Plate Tectonics | Worldwide | Moving slabs of crust |
| Plunge Pool | Below waterfalls worldwide | Deep basin at a waterfall’s base |
| Plutons | Mountain belts worldwide | Large body of cooled magma |
| Playa Lake | Great Basin, Australia, Iran | Shallow seasonal lake |
| Pocket Beach | Coastlines worldwide | Small beach between headlands |
| Point Bar | Meandering rivers worldwide | Sediment deposit on inner river bend |
| Pothole Lake | Glaciated regions, including Minnesota and Canada | Small lake in a glacial depression |
| Polje | Balkans, Dinaric Alps, Slovenia | Large flat karst basin |
| Paternoster Lakes | Glaciated mountains, including Alps and Rockies | Chain of lakes in a glacial valley |
| Peat Bog | Ireland, Scotland, Finland, Canada, Russia | Wet, spongy ground rich in plant matter |
| Petrified Forest | Arizona, Argentina, Greece, Egypt | Fossilized trees turned to stone |
| Pinnacles National Park | California, United States | Volcanic rock spires and caves |
| Pamukkale | Turkey | White travertine terraces |
| Painted Desert | Arizona, United States | Banded, colorful badlands |
| Painted Hills | Oregon, United States | Colorful striped hills |
| Pitons | Saint Lucia, Caribbean | Twin volcanic spires |
| Pico de Orizaba | Mexico | Highest volcano in North America |
| Pikes Peak | Colorado, United States | Rocky Mountain summit |
| Mount Pinatubo | Philippines | Volcano with a major 1991 eruption |
| Paricutin | Michoacan, Mexico | Cinder cone born in a cornfield |
| Pacaya | Guatemala | Active volcano |
| Popocatepetl | Central Mexico | Active stratovolcano |
| Pico Island | Azores, Portugal | Volcanic island with Portugal’s highest peak |
| Pantanal | Brazil, Bolivia, Paraguay | World’s largest tropical wetland |
| Pampas | Argentina, Uruguay, Brazil | Vast fertile grassland |
| Patagonian Ice Field | Chile, Argentina | Large temperate ice mass |
| Perito Moreno Glacier | Argentina | Advancing Patagonian glacier |
| Pamir Mountains | Tajikistan, Afghanistan, China, Kyrgyzstan | High Central Asian mountain range |
| Pyrenees | France, Spain, Andorra | Mountain range between Spain and France |
| Pennines | Northern England | Upland range of hills |
| Palisades | New Jersey and New York, United States | Tall cliffs along the Hudson River |
| Pinnacles of Nambung | Western Australia | Limestone spires in the desert |
| Puerto Princesa Underground River | Palawan, Philippines | Subterranean river cave system |
| Postojna Cave | Slovenia | Large karst cave system |
| Pozzuoli Caldera | Campania, Italy | Active volcanic depression |
Descriptions
Pahoehoe
A type of basaltic lava flow that cools into a smooth, billowy or ropy surface. It is common in Hawaii and flows slowly with a thin, glassy skin.
Pillow Lava
Lava that erupts underwater and cools quickly into rounded, pillow-like lumps. It is common along mid-ocean ridges and on the seafloor.
Playa
A flat, dry lakebed found in desert basins. It fills briefly with water after rain, then evaporates and leaves behind salts and fine clay.
Plateau
A broad area of high, relatively flat land that rises sharply above its surroundings on at least one side. The Tibetan Plateau is the largest and highest example.
Peninsula
A piece of land that juts out into a sea or lake and is surrounded by water on most sides. Florida and Iberia are well-known examples.
Pingo
A small hill with a core of ice, pushed up by freezing groundwater in permafrost regions. Some stand dozens of meters tall and eventually collapse into craters.
Pinnacle
A sharp, slender rock tower left standing after the surrounding rock has eroded away. Pinnacles often form in limestone and sandstone landscapes.
Plain
A large expanse of flat or gently rolling land with little change in elevation. Plains often form from river sediments or ancient seabeds.
Pothole
A round hole worn into riverbed rock by swirling water carrying stones and sand. Over time the spinning pebbles grind the hollow deeper.
Pyroclastic Flow
A fast-moving current of hot gas, ash and rock fragments that rushes down a volcano’s slopes. It can travel at hundreds of kilometers per hour and destroy everything in its path.
Pumice
A very light volcanic rock full of gas bubbles, light enough to float on water. It forms when frothy lava cools quickly.
Parasitic Cone
A small cone built on the side of a larger volcano, fed by the same magma system. Mount Etna has hundreds of them.
Pass
A gap or low point in a mountain range that allows travel from one side to the other. Passes have shaped trade routes and military campaigns for centuries.
Peak
The pointed summit of a mountain or hill. Peaks form through uplift, folding, volcanic activity and erosion.
Pediment
A gently sloping surface of bare rock at the foot of a desert mountain. It is formed by erosion and often covered by a thin layer of gravel.
Permafrost
Ground that stays frozen for at least two years in a row. It covers large parts of the Arctic and is thawing as the climate warms.
Piedmont
A region of foothills and gentle slopes at the base of a mountain range. The name comes from the Italian for “foot of the mountain.”
Pegmatite
An igneous rock with unusually large crystals, sometimes as long as a person. Pegmatites are an important source of lithium and gemstones.
Peridotite
A dense, olive-green rock that makes up most of the Earth’s upper mantle. It sometimes appears at the surface where slices of oceanic crust are pushed onto land.
Phreatic Eruption
A volcanic explosion caused when groundwater is suddenly heated to steam by hot rock or magma. It throws out rock and ash without fresh magma reaching the surface.
Plate Boundary
The line where two tectonic plates meet. Most earthquakes and volcanoes occur along plate boundaries.
Plate Tectonics
The theory that Earth’s outer shell is split into plates that slowly move. It explains earthquakes, volcanoes and mountain building.
Plunge Pool
A deep pool carved out at the base of a waterfall by the force of falling water. Many are popular swimming spots.
Plutons
A large mass of igneous rock that cooled slowly underground. Many plutons are only exposed after the rock above them has eroded.
Playa Lake
A shallow lake that forms in a desert basin after heavy rain and soon evaporates. It leaves behind a cracked, salty surface.
Pocket Beach
A small beach tucked between two rocky headlands. It is often sheltered from big waves and hard to reach by land.
Point Bar
A crescent of sand and gravel deposited on the inside of a river bend, where the water slows down. It builds up as the river’s channel slowly shifts outward.
Pothole Lake
A small, rounded lake that fills a hollow left behind by a melting block of glacial ice. Many dot the northern United States and Canada.
Polje
A large, flat-floored valley in limestone country with steep sides and no surface outlet. Water drains away through underground channels.
Paternoster Lakes
A string of small lakes linked by a stream in a glacial valley, resembling beads on a rosary. They form where glaciers scoured out separate basins.
Peat Bog
A wetland where dead plants build up slowly into peat because the waterlogged soil lacks oxygen. Peat bogs store huge amounts of carbon.
Petrified Forest
A landscape of fossil trees in which wood has been replaced by minerals such as quartz. Arizona’s Petrified Forest National Park is among the most famous.
Pinnacles National Park
A California park known for towering rock spires, talus caves and rock formations. They are the remains of an ancient volcano that was split by the San Andreas Fault.
Pamukkale
A hillside of white mineral terraces and warm turquoise pools created by calcium-rich hot springs. The name means “cotton castle” in Turkish.
Painted Desert
A stretch of colorful badlands with layers of red, orange, pink and lavender clay and sandstone. The colors come from iron and manganese minerals.
Painted Hills
Rolling hills in Oregon striped with bands of red, gold and black. The bands are ancient soil layers that record past climates.
Pitons
Two steep volcanic plugs that rise straight out of the Caribbean Sea. Gros Piton and Petit Piton form a UNESCO World Heritage Site.
Pico de Orizaba
A dormant stratovolcano and the third-highest peak in North America at about 18,491 feet. It is capped with a glacier and visible from far away.
Pikes Peak
A 14,115-foot peak in the Front Range of Colorado, made mostly of pink granite. Its summit is reachable by road and a cog railway.
Mount Pinatubo
A volcano in the Philippines whose 1991 eruption was among the largest of the 20th century. It sent ash high into the sky and cooled global temperatures for about a year.
Paricutin
A volcano that began erupting in a farmer’s field in 1943 and grew to over 1,000 feet in a year. It is one of the few volcanoes whose birth was watched from start to finish.
Pacaya
An active volcano near Guatemala City that has erupted almost continuously since 1965. Visitors hike its slopes to see lava glowing and even roast marshmallows on warm rocks.
Popocatepetl
An active volcano southeast of Mexico City that regularly puffs steam and ash. Its name means “smoking mountain” in the Aztec language.
Pico Island
An island in the Azores dominated by Mount Pico, which reaches 7,713 feet. Its vineyards grow in black lava rock fields.
Pantanal
A huge tropical wetland that floods seasonally and covers an area larger than many countries. It is famous for its wildlife, including jaguars.
Pampas
Flat, fertile grasslands that stretch across southern South America. Their deep soils support farming and cattle ranching.
Patagonian Ice Field
A vast ice cap in the southern Andes, the largest area of ice outside the polar regions in the Southern Hemisphere. It feeds many glaciers and lakes.
Perito Moreno Glacier
A huge glacier in Argentina that is one of the few in the world not shrinking quickly. Visitors watch giant blocks of ice break off into the lake below.
Pamir Mountains
A high mountain range where several of Asia’s great ranges meet. It is often called the “Roof of the World.”
Pyrenees
A mountain range that forms a natural border between France and Spain. It rises to over 11,000 feet at its highest point.
Pennines
A chain of hills and moors running down northern England, often called the backbone of England. It features limestone caves, gritstone edges and peat moors.
Palisades
A line of steep cliffs of dark volcanic rock along the Hudson River. They rise up to about 540 feet.
Pinnacles of Nambung
Thousands of limestone pillars rising from yellow sand in Nambung National Park. They range from low stumps to spires several meters high.
Puerto Princesa Underground River
A river that flows through a limestone cave straight into the sea. It is lined with stalactites and large chambers.
Postojna Cave
One of Europe’s best-known karst caves, with more than 15 miles of passages and halls. A small train takes visitors deep inside.
Pozzuoli Caldera
Part of the Campi Flegrei volcanic area west of Naples, where the ground has risen and fallen over centuries. It is monitored closely for signs of unrest.