Figure 4    Rock varnish record of the Holocene wet events (WH1-WH12) in the drylands of western USA and its possible correlation with the deep sea sediment record of the Holocene millennial-scale cooling events in the subpolar North Atlantic region. The Holocene cooling events identified by Bond et al. (1997, 1999) are labeled with LIA and 1-8 on the deep sea record, and the dashed lines represent our proposed correlation of wet/cold phases between the two climate records. WH = wet event in Holocene, WP = wet event in Pleistocene, LIA = Little Ice Age, and YD = Younger Dryas.