( ( In ( carbonate minerals ) ) ( , ( ( the ( nu3 ( and ( nu4 bands ) ) ) ) ( often ( ( appear ( as ( a doublet ) ) ) . ) ) ) ) )
(ROOT (S (PP (IN In) (NP (JJ carbonate) (NNS minerals))) (, ,) (NP (DT the) (JJ nu3) (CC and) (JJ nu4) (NNS bands)) (ADVP (RB often)) (VP (VBP appear) (PP (IN as) (NP (DT a) (NN doublet)))) (. .)))
In carbonate minerals, the nu3 and nu4 bands often appear as a doublet.
(ROOT (S (NP (JJ Carbonate) (NNS minerals)) (VP (VBP are) (ADVP (RB often)) (VP (VBN found) (SBAR (WHADVP (WRB where)) (S (NP (NNS seas)) (ADVP (RB once)) (VP (VBD covered) (NP (DT the) (NN land))))))) (. .)))