It sounds like you might be thinking of a shield volcano, which is a type of volcano with a large, broad, gently sloping shape resembling a warrior's shield. This shape is created by the effusion of very fluid lava, typically basaltic lava, which flows easily and spreads over vast areas.
Here's a breakdown of key features:
* Fluid Lava: The lava is low in silica, making it very fluid and allowing it to travel far from the vent.
* Gentle Slopes: The fluid lava spreads out, creating a broad, gently sloping cone.
* Large Size: Shield volcanoes are often very large, with some reaching heights of hundreds of meters and diameters of tens of kilometers.
* Example: Mauna Loa in Hawaii is a classic example of a shield volcano.
Cone volcanoes, on the other hand, are characterized by their steep, conical shape. They are formed by explosive eruptions that eject pyroclastic material (ash, rock fragments, etc.) which piles up around the vent.
To summarize:
* Shield volcano: Large, broad, gently sloping, formed by effusive eruptions of fluid lava.
* Cone volcano: Steep, conical, formed by explosive eruptions of pyroclastic material.
If you have any other questions about volcanoes, feel free to ask!
