Hydroclimatology and biogeochemistry of the Amazon: 2. Geochemical cycles - Tardy, Y; Mortatti, Jefferson; Victoria, Reynaldo Luiz; Martinelli, Luiz Antonio; Ribeiro, A.; Cerri, Carlos Clemente; Piccolo, Marisa de Cassia; Moraes, J L; Probst, J L; Andreux, F; Volkoff, B (Chemical Geology, 1993)