Summary: Two geometric measures for quantum discord were recently proposed by K. Modi et al. [“Unified view of quantum and classical correlations”, Phys. Rev. Lett. 104, No. 8, Article No. 080501 (2010)] and B. Dakić et al. [“Necessary and sufficient condition for nonzero quantum discord”, Phys. Rev. Lett. 105, No. 19, Article No. 190502 (2010)]. We study the similarities and differences for total quantum correlations of Bell-diagonal states using geometry-based quantum discord and the original quantum discord. We show that, under non-Markovian dephasing channels, quantum discord and one of the geometric measures remain constant for a finite amount of time, but not the other geometric measure. However, all the three measures share a common sudden change point. Our study on critical points of sudden transitions might be useful for keeping long-time total quantum correlations under decoherence.