  The quantum correlations, including entanglement and discord with its
geometric measure, and classical correlation are studied for a bipartite
partition of a open or closed quantum system. It is found that the purity of
the initial state plays an important role in the dynamics of quantum and
classical correlations. In the dephasing model, the quantum correlations loss
and the classical correlation gain are instantaneously happen. While, the
purity of the initial state destroys the quantum correlations which is resulted
by the unitary interaction. Therefore, with the purity parameter, a particular
region in which there is no state have quantum correlations can be determined.
