Mineralogy and Diagenesis of Surface Sediments from DOMES Areas A, B, and C

Clay Sedimentology

“…Surface and core sampIes consist of fine-grained brown-chocolate sediments (e.g., Bischoff et al 1979, Hein et al 1979c). Surface and core sampIes consist of fine-grained brown-chocolate sediments (e.g., Bischoff et al 1979, Hein et al 1979c).…”

Role of Siliceous Fossil Dissolution in Downcore Variations of Grain Size and Water Content: Western Margin of Clarion-Clipperton Fracture Zone, NE Equatorial Pacific

“…Johnson (1976) reported that smectite-rich clay aggregates occurring in deep-sea sediments from the C-C zone formed within protected microenvironments in the interiors of radiolarians that dissolve concurrently with or subsequent to smectite formation. Yellow radiolarian casts were not assigned to phillipsite in some reports, but rather to Fe-rich smectite (or nontronite) aggregates (Hein et al, 1979b;Jung et al, 1998). An EDS (KEVEX, 7000) spectrum on a radiolarian cast, using a scanning electron microscope (Hitachi X-650), shows high peaks of Fe as well as Si, which supports that the cast is composed of smectite aggregates (Figure 8).…”

“…Moreover, phillipsite is indicated to be responsible for the increase in the percentage of the 6± 20 mm fraction in pale-brown and dark-brown sediment layers in the C-C zone (von Stackelberg, 1988c). Smectite aggregates are also known to grow authigenically as yellow radiolarian casts, resulting from the dissolution of biogenic debris (Hein et al, 1979b;Johnson, 1976;Jung et al, 1998). Johnson (1976) reported that smectite-rich clay aggregates occurring in deep-sea sediments from the C-C zone formed within protected microenvironments in the interiors of radiolarians that dissolve concurrently with or subsequent to smectite formation.…”

Origin and Alteration of Volcanic Ash and Pelagic Brown Clay, Deep Sea Drilling Project Leg 62, North-Central Pacific

“…The (001) smectite peaks for the bentonites are sharp and of high amplitude for both the <2-µm and <l-µm size fractions. Smectite has 0 to 17% intermixed illite layers in the <2-µm size fractions, based on the techniques of Reynolds and Hower (1970) and Perry and Hower (1970); however, it is possible that there is no intermixed illite (see Hein et al, 1979b, andSródon andHower, 1976).…”

“…The siliceous pelagic clay listed in Table 6 contains 70 to 100% clay minerals, minor feldspar, and biogenic silica (Bischoff et al, 1979;Hein et al, 1979b). The zeolitic brown clay listed in Table 6 contains abundant quartz, palygorskite, and clinoptilolite, and some smectite and mica (Couture, 1977).…”