( These ( ( suggest ( that ( ( the ( Lau Basin ) ) ( has ( formed ( following ( ( ( ( a ( two-stage process ) ) ( of ( arc rifting ) ) ) , ) ( followed ( by ( extension ( via ( a ( ( southward propagating ) ( oceanic ( ridge system ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT These)) (VP (VBP suggest) (SBAR (IN that) (S (NP (DT the) (NNP Lau) (NNP Basin)) (VP (VBZ has) (VP (VBN formed) (PP (VBG following) (NP (NP (DT a) (JJ two-stage) (NN process)) (PP (IN of) (NP (NN arc) (NN rifting))) (, ,) (VP (VBN followed) (PP (IN by) (NP (NP (NN extension)) (PP (IN via) (NP (DT a) (ADJP (JJ southward) (JJ propagating)) (JJ oceanic) (NN ridge) (NN system))))))))))))) (. .)))
These suggest that the Lau Basin has formed following a two-stage process of arc rifting, followed by extension via a southward propagating oceanic ridge system.
(ROOT (S (S (NP (DT This) (NN process)) (ADVP (RB usually)) (VP (VBZ takes) (NP (NP (DT the) (JJS longest) (NN amount)) (PP (IN of) (NP (NN time)))))) (: :) (S (NP (DT an) (NN ocean) (NN basin)) (VP (VBZ forms) (PP (IN between) (NP (CD two) (NNS continents))))) (. .)))
This process usually takes the longest amount of time: an ocean basin forms between two continents.