Earth Sciences 2240F/G Lecture Notes - Lecture 12: Subduction, Radiometric Dating, Siberian Traps
16 Nov 2020
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Flood basalt or continent flood basalt or plateau basalt . Commonly in areas of large igneous prov: only happened once in human history, primary reason for 2 mass extinctions, 251 million years (95% species died, 65. 5 million years (70% species) Continental basalt flood (cfb): erupt (on land) at rifts on top of mantle plumes. Superplume: strong pulses of heat from core/mantle that generate enormous volumes of partial melt: due to reduce pressure of mantle/crust, mushrooms out through fractures. Large igneous prov: large volumes of basalt extrusive rock that from by process other than. Normal sea spreading formation due to outburst of magma flood basalt have diff trace (rare) elements and isotopes that are primitive. *igneous basalt can break through middle of plate that is generally inactive. Mantle plumes, only explanation for igneous prov. (expel huge magma, in short period) Plume reaches litho, decompress, partial melt forming hot spot: plume tracks are represented as chain of islands.
