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 https://doi.org/10.1594/PANGAEA.819840 Riech Volkher 1981 Siliceous sediments from the Nauru Basin: Diagenetic alteration of biogenic opal and authigenesis of silica and silicates book chapter In: Larson, RL; Schlanger, SO; et al. (eds.), Initial Reports of the Deep Sea Drilling Project (U.S. Govt. Printing Office) 61 https://doi.org/10.2973/dsdp.proc.61.109.1981 523-531 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. 165.0305 165.0317 7.2375 7.2417 165.03109999999998 7.239599999999999 1978-05-28T00:00:00 1978-06-09T00:00:00 -5181.0 -5177.0 not specified DSDP Deep Sea Drilling Project https://www.deepseadrilling.org/ Deep Sea Drilling Project DSDP 61-462 7.2375 165.0305 -5181.0 1978-05-28T00:00:00 Leg61 Leg61 1978-05-22T00:00:00 1978-05-22 1978-07-29T00:00:00 1978-07-29 Glomar Challenger https://www-odp.tamu.edu:443/glomar.html Larson, Roger L Larson, Roger L Schlanger, Seymour O Schlanger, Seymour O doi:10.2973/dsdp.proc.61.1981 Glomar Challenger https://www-odp.tamu.edu:443/glomar.html Drilling/drill rig DRILL 617 m 386 m 70 cores; 627.4 m cored; 0 m drilled; 61.5 % recovery 61-462A 7.2417 165.0317 -5177.0 1978-06-09T00:00:00 Leg61 Leg61 1978-05-22T00:00:00 1978-05-22 1978-07-29T00:00:00 1978-07-29 Glomar Challenger https://www-odp.tamu.edu:443/glomar.html Larson, Roger L Larson, Roger L Schlanger, Seymour O Schlanger, Seymour O doi:10.2973/dsdp.proc.61.1981 Glomar Challenger https://www-odp.tamu.edu:443/glomar.html Drilling/drill rig DRILL 1068.5 m 344 m 90 cores; 619.5 m cored; 14.5 m drilled; 55.5 % recovery 273 CC-BY-3.0 Creative Commons Attribution 3.0 Unported https://creativecommons.org/licenses/by/3.0/ - = no data, + = least abundant, ++++ = most abundant, ? = unknowns. Event label Event Event Sample code/label Sample label DSDP/ODP/IODP sample designation hdl:10013/epic.27914.d001 Riech Volkher Sample label (DSDP/ODP/IODP sample designation) Lithology/composition/facies Lithology X-ray diffraction (XRD) Optical tools & radiometric sensors X-ray diffractometers http://vocab.nerc.ac.uk/collection/L05/current/LAB26/ Riech Volkher Of silicified rock Lithology (Of silicified rock, X-ray dif...) Main Lithology Main lith X-ray diffraction (XRD) Optical tools & radiometric sensors X-ray diffractometers http://vocab.nerc.ac.uk/collection/L05/current/LAB26/ Riech Volkher Calcareous Main lith (Calcareous, X-ray diffraction...) Main Lithology Main lith X-ray diffraction (XRD) Optical tools & radiometric sensors X-ray diffractometers http://vocab.nerc.ac.uk/collection/L05/current/LAB26/ Riech Volkher Siliceous Main lith (Siliceous, X-ray diffraction ...) Quartz Qz quartz http://purl.obolibrary.org/obo/CHEBI_46727 X-ray diffraction (XRD) Optical tools & radiometric sensors X-ray diffractometers http://vocab.nerc.ac.uk/collection/L05/current/LAB26/ Riech Volkher Early Diagenetic Qz (Early Diagenetic, X-ray diffr...) - - Molar Concentration X-ray diffraction (XRD) Optical tools & radiometric sensors X-ray diffractometers http://vocab.nerc.ac.uk/collection/L05/current/LAB26/ Riech Volkher Opal-CT/quartz ratio - (Opal-CT/quartz ratio, X-ray d...) - - Molar Concentration X-ray diffraction (XRD) Optical tools & radiometric sensors X-ray diffractometers http://vocab.nerc.ac.uk/collection/L05/current/LAB26/ Riech Volkher Stage of opal-CT - quartz transformation: + = small amount of opal-CT starts to transform into quartz, ++++ = all opal-CT transformed into quartz - (Stage of opal-CT - quartz tra...) supplement citable author21499 basis12 campaign183 campaign3374922 event74899 event74900 geocode1599 geocode1600 geocode1601 geocode500000 geocode8128 inst41 license101 method10974 method12 method5059 param16431 param18423 param2834 param29333 param790 pi21499 project4 ref60558 term1073282 term2299415 term44030 term67649 topotype1