Diagenesis, Figure 1 Early marine and nonmarine cements, Mururoa Atoll, Holocene and Pleistocene reef facies. (a) Aragonite
acicular cement forming epitaxial overgrowths on aragonite scleractinian coral skeleton, thin section, scale bar: 250 mm.
(b) Botryoidal aragonite cement overgrowing a isopachous high-magnesian calcite (HMC) fibrous cement, polished slab, scale bar:
1 cm. (c) Two botryoids of aragonite cement, thin section, crossed nichols, scale bar: 250 mm. (d) HMC isopachous cement around
fragments of coral branches, this cement is overlain by geopetal infills of marine internal sediment, polished slab, scale bar: 2 cm.
(e) HMC isopachous fibrous cement followed by a thinner layer of sparitic low-magnesian calcite (LMC) cement, thin section, scale
bar: 300 mm. (f) HMC isopachous bladed palissadic cement, thin section, scale bar: 300 mm. (g) LMC karstic brown calcite cement, the
cement is affected by boring marine organisms (lower left corner of photograph) and overlain by marine bioclastic sediment,
polished slab, scale bar: 2 cm. (h) Needlelike or whisker LMC calcite cement typical of calcrete pedogenetic facies, here associated to
a characteristic alveolar texture, thin section, scale bar: 500 mm.
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DIAGENESIS