Diagenesis of siliceous particles in ODP Hole 114-699A
A number of neogenic opaline structures, not previously reported in the literature, as well as other neogenic phases are described from four Oligocene to Pliocene biosiliceous sediment samples from Hole 699A. The possible influence of microbes on the formation or the morphology of some of them is di...
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ftpangaea:oai:pangaea.de:doi:10.1594/PANGAEA.755279 2023-05-15T18:21:19+02:00 Diagenesis of siliceous particles in ODP Hole 114-699A Monty, Claude L V Westall, Francis van der Gaast, Sjierk LATITUDE: -51.542000 * LONGITUDE: -30.677000 * DATE/TIME START: 1987-03-20T10:45:00 * DATE/TIME END: 1987-03-26T15:29:00 1991-12-15 application/zip, 4 datasets https://doi.pangaea.de/10.1594/PANGAEA.755279 https://doi.org/10.1594/PANGAEA.755279 en eng PANGAEA https://doi.pangaea.de/10.1594/PANGAEA.755279 https://doi.org/10.1594/PANGAEA.755279 CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess CC-BY Supplement to: Monty, Claude L V; Westall, Francis; van der Gaast, Sjierk (1991): Diagenesis of siliceous particles in subantarctic sediments, Hole 699: possible microbial mediation. In: Ciesielski, PF; Kristoffersen, Y; et al. (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 114, 685-710, https://doi.org/10.2973/odp.proc.sr.114.121.1991 114-699A DRILL Drilling/drill rig Joides Resolution Leg114 Ocean Drilling Program ODP South Atlantic Ocean Dataset 1991 ftpangaea https://doi.org/10.1594/PANGAEA.755279 https://doi.org/10.2973/odp.proc.sr.114.121.1991 2023-01-20T07:32:00Z A number of neogenic opaline structures, not previously reported in the literature, as well as other neogenic phases are described from four Oligocene to Pliocene biosiliceous sediment samples from Hole 699A. The possible influence of microbes on the formation or the morphology of some of them is discussed. The samples, which are early Pliocene, early to middle Miocene, and late Oligocene (two) in age, were histologically fixed aboard ship upon retrieval. Investigations of the samples used SEM (with Edax/Tracor) and XRD methods. Diagenesis has affected all four samples, but the most extensive development of neoformed structures occurs in the Miocene and uppermost Oligocene samples, where microbial filaments (0.05 to 10 ?m long), microbial colonies, and siliceous microhemispheroids (0.2 to 0.7 µm diameter) were observed. The latter encrust filaments, diatoms, and detrital grains to varying degrees. Other neoformed structures include (1) flakes formed by coalesced microhemispheroids, some of which are guided by short, stubby filaments, which occur only in the Miocene and uppermost Oligocene samples, and (2) flakes characterized by smooth or microfissured surfaces, which grow on diatom frustules and in pore spaces and have a more widespread distribution. The XRD data indicate possible cristobalite formation in the Miocene and uppermost Oligocene samples; we believe that the neoformed opaline structures (encrusted filaments and microhemispheroids) may represent an early phase of opal-CT. The timing of neoformation of most of these features appears to have been fairly recent, continuing even at the time of sampling. There appears to be no direct correlation of this incipient, lower Miocene-uppermost Oligocene diagenetic layer and the pore-water chemistry profiles; a massive increase in shear strength in these sediments, however, may indicate some cementation. Smectite was identified by XRD as the most prominent clay mineral in these generally clay-poor sediments. Honeycombed minerals with filamentous edges, which ... Dataset South Atlantic Ocean PANGAEA - Data Publisher for Earth & Environmental Science ENVELOPE(-30.677000,-30.677000,-51.542000,-51.542000) |
institution |
Open Polar |
collection |
PANGAEA - Data Publisher for Earth & Environmental Science |
op_collection_id |
ftpangaea |
language |
English |
topic |
114-699A DRILL Drilling/drill rig Joides Resolution Leg114 Ocean Drilling Program ODP South Atlantic Ocean |
spellingShingle |
114-699A DRILL Drilling/drill rig Joides Resolution Leg114 Ocean Drilling Program ODP South Atlantic Ocean Monty, Claude L V Westall, Francis van der Gaast, Sjierk Diagenesis of siliceous particles in ODP Hole 114-699A |
topic_facet |
114-699A DRILL Drilling/drill rig Joides Resolution Leg114 Ocean Drilling Program ODP South Atlantic Ocean |
description |
A number of neogenic opaline structures, not previously reported in the literature, as well as other neogenic phases are described from four Oligocene to Pliocene biosiliceous sediment samples from Hole 699A. The possible influence of microbes on the formation or the morphology of some of them is discussed. The samples, which are early Pliocene, early to middle Miocene, and late Oligocene (two) in age, were histologically fixed aboard ship upon retrieval. Investigations of the samples used SEM (with Edax/Tracor) and XRD methods. Diagenesis has affected all four samples, but the most extensive development of neoformed structures occurs in the Miocene and uppermost Oligocene samples, where microbial filaments (0.05 to 10 ?m long), microbial colonies, and siliceous microhemispheroids (0.2 to 0.7 µm diameter) were observed. The latter encrust filaments, diatoms, and detrital grains to varying degrees. Other neoformed structures include (1) flakes formed by coalesced microhemispheroids, some of which are guided by short, stubby filaments, which occur only in the Miocene and uppermost Oligocene samples, and (2) flakes characterized by smooth or microfissured surfaces, which grow on diatom frustules and in pore spaces and have a more widespread distribution. The XRD data indicate possible cristobalite formation in the Miocene and uppermost Oligocene samples; we believe that the neoformed opaline structures (encrusted filaments and microhemispheroids) may represent an early phase of opal-CT. The timing of neoformation of most of these features appears to have been fairly recent, continuing even at the time of sampling. There appears to be no direct correlation of this incipient, lower Miocene-uppermost Oligocene diagenetic layer and the pore-water chemistry profiles; a massive increase in shear strength in these sediments, however, may indicate some cementation. Smectite was identified by XRD as the most prominent clay mineral in these generally clay-poor sediments. Honeycombed minerals with filamentous edges, which ... |
format |
Dataset |
author |
Monty, Claude L V Westall, Francis van der Gaast, Sjierk |
author_facet |
Monty, Claude L V Westall, Francis van der Gaast, Sjierk |
author_sort |
Monty, Claude L V |
title |
Diagenesis of siliceous particles in ODP Hole 114-699A |
title_short |
Diagenesis of siliceous particles in ODP Hole 114-699A |
title_full |
Diagenesis of siliceous particles in ODP Hole 114-699A |
title_fullStr |
Diagenesis of siliceous particles in ODP Hole 114-699A |
title_full_unstemmed |
Diagenesis of siliceous particles in ODP Hole 114-699A |
title_sort |
diagenesis of siliceous particles in odp hole 114-699a |
publisher |
PANGAEA |
publishDate |
1991 |
url |
https://doi.pangaea.de/10.1594/PANGAEA.755279 https://doi.org/10.1594/PANGAEA.755279 |
op_coverage |
LATITUDE: -51.542000 * LONGITUDE: -30.677000 * DATE/TIME START: 1987-03-20T10:45:00 * DATE/TIME END: 1987-03-26T15:29:00 |
long_lat |
ENVELOPE(-30.677000,-30.677000,-51.542000,-51.542000) |
genre |
South Atlantic Ocean |
genre_facet |
South Atlantic Ocean |
op_source |
Supplement to: Monty, Claude L V; Westall, Francis; van der Gaast, Sjierk (1991): Diagenesis of siliceous particles in subantarctic sediments, Hole 699: possible microbial mediation. In: Ciesielski, PF; Kristoffersen, Y; et al. (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 114, 685-710, https://doi.org/10.2973/odp.proc.sr.114.121.1991 |
op_relation |
https://doi.pangaea.de/10.1594/PANGAEA.755279 https://doi.org/10.1594/PANGAEA.755279 |
op_rights |
CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1594/PANGAEA.755279 https://doi.org/10.2973/odp.proc.sr.114.121.1991 |
_version_ |
1766200514668658688 |