/* DATA DESCRIPTION: Citation: Riech, Volkher (1981): (Table 1) Characteristics of silicified sediments at DSDP Site 61-462 according to host-rock lithology, opal-CT-to-quartz ratio, and the origin of the quartz phase [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.819840, Supplement to: Riech, V (1981): Siliceous sediments from the Nauru Basin: Diagenetic alteration of biogenic opal and authigenesis of silica and silicates. In: Larson, RL; Schlanger, SO; et al. (eds.), Initial Reports of the Deep Sea Drilling Project (U.S. Govt. Printing Office), 61, 523-531, https://doi.org/10.2973/dsdp.proc.61.109.1981 Abstract: This study deals with the mineralogical variability of siliceous and zeolitic sediments, porcellanites, and cherts at small intervals in the continuously cored sequence of Deep Sea Drilling Project Site 462. Skeletal opal is preserved down to a maximum burial depth of 390 meters (middle Eocene). Below this level, the tests are totally dissolved or replaced and filled by opal-CT, quartz, clinoptilolite, and calcite. Etching of opaline tests does not increase continously with deeper burial. Opal solution accompanied by a conspicuous formation of authigenic clinoptilolite has a local maximum in Core 16 (150 m). A causal relationship with the lower Miocene hiatus at this level is highly probable. Oligocene to Cenomanian sediments represent an intermediate stage of silica diagenesis: the opal-CT/quartz ratios of the silicified rocks are frequently greater than 1, and quartz filling pores or replacing foraminifer tests is more widespread than quartz which converted from an opal-CT precursor. As at other sites, there is a marked discontinuity of the transitions from biogenic opal via opal-CT to quartz with increasing depth of burial. Layers with unaltered opal-A alternate with porcellanite beds; the intensity of the opal-CT-to-quartz transformation changes very rapidly from horizon to horizon and obviously is not correlated with lithologic parameters. The silica for authigenic clinoptilolite was derived from biogenic opal and decaying volcanic components. Project(s): Deep Sea Drilling Project (DSDP) (URI: https://www.deepseadrilling.org/) Coverage: MEDIAN LATITUDE: 7.239600 * MEDIAN LONGITUDE: 165.031100 * SOUTH-BOUND LATITUDE: 7.237500 * WEST-BOUND LONGITUDE: 165.030500 * NORTH-BOUND LATITUDE: 7.241700 * EAST-BOUND LONGITUDE: 165.031700 DATE/TIME START: 1978-05-28T00:00:00 * DATE/TIME END: 1978-06-09T00:00:00 MINIMUM ELEVATION: -5181.0 m * MAXIMUM ELEVATION: -5177.0 m Event(s): 61-462 * LATITUDE: 7.237500 * LONGITUDE: 165.030500 * DATE/TIME: 1978-05-28T00:00:00 * ELEVATION: -5181.0 m * PENETRATION: 617 m * RECOVERY: 386 m * CAMPAIGN: Leg61 * BASIS: Glomar Challenger (URI: https://www-odp.tamu.edu:443/glomar.html) * METHOD/DEVICE: Drilling/drill rig (DRILL) * COMMENT: 70 cores; 627.4 m cored; 0 m drilled; 61.5 % recovery 61-462A * LATITUDE: 7.241700 * LONGITUDE: 165.031700 * DATE/TIME: 1978-06-09T00:00:00 * ELEVATION: -5177.0 m * PENETRATION: 1068.5 m * RECOVERY: 344 m * CAMPAIGN: Leg61 * BASIS: Glomar Challenger (URI: https://www-odp.tamu.edu:443/glomar.html) * METHOD/DEVICE: Drilling/drill rig (DRILL) * COMMENT: 90 cores; 619.5 m cored; 14.5 m drilled; 55.5 % recovery Comment: - = no data, + = least abundant, ++++ = most abundant, ? = unknowns. Parameter(s): Event label (Event) Sample code/label (Sample label) * PI: Riech, Volkher * METHOD/DEVICE: DSDP/ODP/IODP sample designation (URI: hdl:10013/epic.27914.d001) Lithology/composition/facies (Lithology) * PI: Riech, Volkher * METHOD/DEVICE: X-ray diffraction (XRD) * COMMENT: Of silicified rock Main Lithology (Main lith) * PI: Riech, Volkher * METHOD/DEVICE: X-ray diffraction (XRD) * COMMENT: Calcareous Main Lithology (Main lith) * PI: Riech, Volkher * METHOD/DEVICE: X-ray diffraction (XRD) * COMMENT: Siliceous Quartz (Qz) * PI: Riech, Volkher * METHOD/DEVICE: X-ray diffraction (XRD) * COMMENT: Early Diagenetic - (-) * PI: Riech, Volkher * METHOD/DEVICE: X-ray diffraction (XRD) * COMMENT: Opal-CT/quartz ratio - (-) * PI: Riech, Volkher * METHOD/DEVICE: X-ray diffraction (XRD) * COMMENT: Stage of opal-CT - quartz transformation: + = small amount of opal-CT starts to transform into quartz, ++++ = all opal-CT transformed into quartz License: Creative Commons Attribution 3.0 Unported (CC-BY-3.0) (URI: https://creativecommons.org/licenses/by/3.0/) Size: 273 data points */ Event Sample label (DSDP/ODP/IODP sample designation) Lithology (Of silicified rock, X-ray dif...) Main lith (Calcareous, X-ray diffraction...) Main lith (Siliceous, X-ray diffraction ...) Qz (Early Diagenetic, X-ray diffr...) - (Opal-CT/quartz ratio, X-ray d...) - (Stage of opal-CT - quartz tra...) 61-462 61-462-32-2,64-66 Radiolarian porecellanite - + + + + - Infinity - 61-462A 61-462A-H1-CC Calcareous porcellanite + + + + + + >>1 - 61-462 61-462-34-CC Radiolarian porcellanite - + + + + + >>1 - 61-462 61-462-40-CC Opal-CT-bearing quartzose chert + + + + - + + + <1 ? 61-462A 61-462A-H2-1,40-43 Porcellanite with quartzose patches + + + + + + >1 + + 61-462A 61-462A-H2-1,55-60(1) Porcellaneous radiolarian claystone - + + + + - >>1 - 61-462A 61-462A-H2-1,55-60(2) Calcareous quartz-bearing porcellanite + + + + + + + >1 ? 61-462A 61-462A-H2-1,79-83 Radiolarian porcellanite - + + + + - >>1 - 61-462A 61-462A-H2-1,131-135 Foraminiferal arenite with quartzose patches + + + + - + + + <1 + 61-462 61-462-42-1,1-4 Foraminiferal limestone with opal-CT- and quartz-bearing layers + + + + - + + 1 - 61-462 61-462-42-1,8-10 Calcarenite, partly replaced and cemented by opal-CT and quartz + + + + - + + + <1 + 61-462 61-462-42-1,24-27 Foraminifer-nannofossil limestone impregnated by opal-CT + + + + - + + <1 - 61-462 61-462-42-1,42-44 Quartzose chert + + + + - + + 0 + + + + 61-462 61-462-42-1,51-54 Foraminifer-nannofossil limestone impregnated by opal-CT + + + + + + + >1 - 61-462 61-462-43-1,13-15 Foraminifer-nannofossil limestone impregnated by opal-CT + + + + + + + >1 - 61-462 61-462-43-1,39-41 Calcareous porcellanite + + + + + + >1 - 61-462A 61-462A-3-1.24 Quartzose chert + + + + - + + 0 + + + + 61-462 61-462-3-1,23-25 Radiolarian porcellanite with quartz-replaced sponge spicules - + + + + + + >1 - 61-462A 61-462A-3-1,37-39 Foraminiferal arenite with opal-CT and quartz + + + + + + + + 1 + 61-462 61-462-44-1,2-4 Foraminiferal limestone impregnated by opal-CT + + + + - + + >1 - 61-462 61-462-4-1,21-23 Foraminiferal limestone with opal-CT and quartz + + + + + + + 1 - 61-462 61-462-44-1,29-32 Quartzose chert + + + + - + + + 0 + + + + 61-462 61-462-44-1,44 Opal-CT-bearing limestone + + + + + ? >>1 - 61-462 61-462-44-1,66-67 Quartzose chert + + + + - ? 0 + + + + 61-462A 61-462A-4-1,2-5 Radiolarian porcellanite - + + + + + + >1 - 61-462A 61-462A-4-1,32-36 Quartzose chert + + + + - + + + 0 + + + + 61-462A 61-462A-4-1,44-48 Opal-CT-bearing quartzose chert + + + + - + + + <1 + + + 61-462A 61-462A-4-1,62-64 Marly porcellanite + + + + + + >1 - 61-462A 61-462A-4-1,72-74 Marly porcellanite + + + + + + >1 - 61-462 61-462-45-1,7-10 Opal-CT-bearing quartzose chert + + + + - + + + <1 + 61-462 61-462-47-CC(1) Quartz-bearing porcellanite + + + + + >1 + 61-462 61-462-47-CC(2) Quartzose chert + + + + - + + + 0 + + + + 61-462A 61-462A-7-1,5-7 Quartz-rich porcellanite + + + + + + 1 + + 61-462A 61-462A-7-1,39 Porcellaneous limestone + + + + - >>1 - 61-462A 61-462A-7-1,127-129 Porcellaneous foraminifer-nannofossil limestone + + + + + + + >1 + 61-462A 61-462A-9-1,90 Zeolitic radiolarian claystone with opal-CT - + + + + - Infinity - 61-462A 61-462A-12-1,31-35 Zeolitic radiolarian claystone with opal-CT - + + + + - Infinity - 61-462 61-462-59-1,13-15 Radiolarian porcellanite - + + + + + + >1 + 61-462A 61-462A-14-1,120 Quartzose chert, rich in radiolarians and goethite (above basalt sill) - + + + + + 0 + + + +