The concentrations of the metalsCu, Pb, Mn and Zn in fra ctions geochemistry insix sediment core of the lagoon Unare, Venezuela.A procedure of sequential extraction of metalswas determined, for each fraction was usedreagents different and conditions of digestionand the concentrations of metals determinedwith spectrophotometer of Atomic Absorption.The fractionating of metals indicated an order ofdecreasing concentration as it follows: residualfraction > organic/sulfur matter > carbonates...