( ( ( The cause ) ( of ( this ( volcanic activity ) ) ) ) ( ( was ( ( ( ( ( a ( mantle plume ) ) , ) ( a ( large ( scale ( convective system ) ) ) ) ) , ) ( ( bringing ( ( heat and ) magma ) ) ( from ( near ( ( ( the ( Earth 's ) ) core ) ( to ( the crust ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN cause)) (PP (IN of) (NP (DT this) (JJ volcanic) (NN activity)))) (VP (VBD was) (NP (NP (NP (DT a) (JJ mantle) (NN plume)) (, ,) (NP (DT a) (JJ large) (NN scale) (NN convective) (NN system)) (, ,)) (VP (VBG bringing) (NP (NN heat) (CC and) (NN magma)) (PP (IN from) (IN near) (NP (NP (NP (DT the) (NN Earth) (POS 's)) (NN core)) (PP (TO to) (NP (DT the) (NN crust)))))))) (. .)))
The cause of this volcanic activity was a mantle plume, a large scale convective system, bringing heat and magma from near the Earth's core to the crust.
(ROOT (S (NP (NNP Magma)) (VP (VBZ comes) (PP (IN toward) (NP (NP (NN earth) (POS 's)) (NN crust))) (PP (IN through) (NP (JJ mantle) (NNS plumes)))) (. .)))