These coherent lumps of hot, fluid lava are called spatter . When they land, they can be hot and fluid enough to fuse together to form an aggregate called agglutinate , or agglutinated spatter . Spatter commonly builds up as banks along the fissure sides to produce spatter ramparts . Curtain of Fire Curtain of Fire Spatter Ramparts When fissures cease to erupt, the remaining magma residing in the fissure will cool and crystallize into an igneous rock intrusion. The resulting rock structure is called a dike .
Dikes are tabular in shape, and they cut discordantly across adjacent rock layers.
In areas of ancient volcanism, dikes are often delineated as resistant walls standing above more easily eroded rock types. Massive fissure eruptions in the geological past have generated extraordinarily voluminous lava flows that form large continental flood basalt provinces . Individual provinces can cover hundreds of square kilometers, with average thicknesses of one kilometer. These flood-basalt eruptions are rare in the geologic record. They generate h uge volumes of basalt over a very short time intervals, typically in only 1-2 million years.