Are there three types of lava or four?

Answer 1

It depends on what criteria you use. If you go with the kind of flow there are four.

1. Pahoehoe (ropey lava flows)
2. A'a (jagged, more viscous flows)
3. Pillow lava (rounded lumps that form underwater)
4. Block lava (very viscous, very slow moving)

The first three are all associated with mafic lava, also called basaltic lava, which refers to a specific composition. Pillow lava is sometimes ignored as are black lava flows, which don't much resemble traditional images of lava.

In terms of composition there are also 4 basic types on a spectrum of increasing silica content and viscosity

1. Mafic (basaltic)
2. Intermediate (andesitic)
3. Intermediate-felsic (dacitic)
4. Felsic (rhyolitic)

These can be further subdivided. Another, rare kind of lava exists called carbonatite. This strange lava is composed of carbobnates rather than silicates as the others are, and is only found in one volcano: Ol Doinyo Lengai in Tanzania.

Answer 2

There are 6 different types of lava. There is Aa, Pahoehoe, Pyroclastic, Andesitic, Rhyolitic, and lastly Basaltic.

Answer 3

there are 4 different types of lava flows maybe more

Answer 4

Yes. Lava rocks are classified based on their composition and their grain structure.