The combination of volcanic ash and clay in the sediments at these three Sites appears to play an important role in determining the evolution of sediment physical properties with burial. Anomalously high porosity was observed in the shallow section at Sites C0011 and C0012, with porosity > 60% persisting to ~ 250 mbsf at C0011 and ~ 80 mbsf at C0012 (Expedition 333 Scientists, 2012c and Expedition 333 Scientists, 2012d). Hüpers et al. (in review) proposed that the anomalously high porosity at these two Sites is caused by the abundance of pumice in the sediments, since pumice resists consolidation and has abundant microporosity. At the
p53 tumor suppressor fragment of the anomalous high porosity zone (HPZ) at Site C0011, an abrupt change in the alteration state of volcanic glass was observed in smear slides, with glass crystals assuming a pitted, partially dissolved character (Expedition 333 Scientists, 2012c). The
base of the HPZ at both Sites C0011 and C0012 was associated with other indicators of volcanic ash alteration, including local minima in porewater 87Sr/86Sr ratios (Joseph et al., 2013), as well as a rapid decrease in porewater Si concentrations (Expedition 333 Scientists, 2012c and Expedition 333 Scientists, 2012d). The presence of zeolites, most likely clinoptilolite, has been inferred below this HPZ based on X-ray diffraction (XRD) analysis and geochemical modeling (Destrigneville et al., 2013 and Hong et al., in review).
