  Correlations in quantum systems exhibit a rich phenomenology under the effect
of various sources of noise. We investigate theoretically and experimentally
the dynamics of quantum correlations and their classical counterparts in two
nuclear magnetic resonance setups, as measured by geometric quantifiers based
on trace-norm. We consider two-qubit systems prepared in Bell diagonal states,
and perform the experiments in decohering environments resulting from Bell
diagonal-preserving Markovian local noise. We then report the first observation
of environment-induced double sudden transitions in the geometric quantum
correlations, a genuinely nonclassical effect not observable in classical
correlations. The evolution of classical correlations in our physical
implementation reveals in turn the finite-time relaxation to a pointer basis
under nondissipative decoherence, which we characterize geometrically in full
analogy with predictions based on entropic measures.
