block lava flow

geology

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June 22, 2026

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A block lava flow is a type of lava flow characterized by a surface composed of angular, polygonal fragments. These flows are typically formed by lavas of intermediate composition, such as andesite.1

Lava itself is molten rock, or magma, that emerges onto Earth's surface. Its temperature ranges from approximately 700 to 1,200 °C (1,300 to 2,200 °F). The fluidity of lava depends on its silica content; higher silica content leads

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lava
…of flow, known as a block lava flow. These resemble aa in having tops consisting largely of loose rubble, but the fragments are more regular in shape, most of them polygons with fairly smooth sides. Flows of more siliceous lava tend to be even more fragmental than block flows.
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…of flow, known as a block lava flow. These resemble aa in having tops consisting largely of loose rubble, but the fragments are more regular in shape, most of them polygons with fairly smooth sides. Flows of more siliceous lava tend to be even more fragmental than block flows.
Read More