The relation between temperature and silica benthic exchange rates and implications for near-seabed formation of diagenetic opal
This study calculated the dissolution rates of biogenic silica deposited on the seafloor and the silicic acid benthic flux for 22 Ocean Drilling Program sites. Simple models developed for two host sediment types—siliciclastic and carbonate—were used to explain the variability of biogenic silica diss...
Published in: | Results in Geophysical Sciences |
---|---|
Main Authors: | , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Elsevier
2020
|
Subjects: | |
Online Access: | https://doi.org/10.1016/j.ringps.2020.100002 https://doaj.org/article/d99acd13f00f4564b414e0c1939b3fae |
id |
ftdoajarticles:oai:doaj.org/article:d99acd13f00f4564b414e0c1939b3fae |
---|---|
record_format |
openpolar |
spelling |
ftdoajarticles:oai:doaj.org/article:d99acd13f00f4564b414e0c1939b3fae 2023-05-15T13:38:18+02:00 The relation between temperature and silica benthic exchange rates and implications for near-seabed formation of diagenetic opal Shahab Varkouhi Jonathan Wells 2020-12-01T00:00:00Z https://doi.org/10.1016/j.ringps.2020.100002 https://doaj.org/article/d99acd13f00f4564b414e0c1939b3fae EN eng Elsevier http://www.sciencedirect.com/science/article/pii/S266682892030002X https://doaj.org/toc/2666-8289 2666-8289 doi:10.1016/j.ringps.2020.100002 https://doaj.org/article/d99acd13f00f4564b414e0c1939b3fae Results in Geophysical Sciences, Vol 1, Iss , Pp 100002- (2020) Bottom-water temperature Biogenic silica Dissolution rate Benthic flux Ocean Drilling Program Geophysics. Cosmic physics QC801-809 Geology QE1-996.5 article 2020 ftdoajarticles https://doi.org/10.1016/j.ringps.2020.100002 2022-12-31T06:55:47Z This study calculated the dissolution rates of biogenic silica deposited on the seafloor and the silicic acid benthic flux for 22 Ocean Drilling Program sites. Simple models developed for two host sediment types—siliciclastic and carbonate—were used to explain the variability of biogenic silica dissolution and recycling under present-day low (−0.3 to 2.14 °C) bottom-water temperatures. The kinetic constants describing silicic acid release and silica saturation concentration increased systematically with increasing bottom-water temperatures. When these temperature effects were incorporated into the diagenetic models, the prediction of dissolution rates and diffusive fluxes was more robust. This demonstrates that temperature acts as a primary control that decreases the relative degree of pore-water saturation with biogenic opal while increasing the silica concentration. The correlation between the dissolution rate and benthic flux with temperature was pronounced at sites where biogenic silica is hosted in surficial sediments mostly composed of biogenic carbonates. This association is because the dissolution of carbonates provides the alkalinity necessary for both silica dissolution (also its reprecipitation as opal-CT) and clay formation; thus strongly reducing the retarding influence of clays on biogenic opal dissolution. Conversely, the silica exchange rates were modified by presence of aluminosilicates, which led to a higher burial efficiency for biogenic opal in detrital- than in carbonate-dominated benthic layers. Though model prediction of first-order silica early transformation suggests likely effects from surface temperatures (0–4 °C) on opal-CT precipitation over short geological times (< 4 Ma) near seabed in the Antarctic Site 751, the relationship between silica solubility and surface-area variability in time is a more critical control. Since silica solubility and surface area decrease with time, the < 4 Ma elapsed time aged opal-A to the point that changes in specific surface area caused minor ... Article in Journal/Newspaper Antarc* Antarctic Directory of Open Access Journals: DOAJ Articles Antarctic The Antarctic Results in Geophysical Sciences 1-4 100002 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Bottom-water temperature Biogenic silica Dissolution rate Benthic flux Ocean Drilling Program Geophysics. Cosmic physics QC801-809 Geology QE1-996.5 |
spellingShingle |
Bottom-water temperature Biogenic silica Dissolution rate Benthic flux Ocean Drilling Program Geophysics. Cosmic physics QC801-809 Geology QE1-996.5 Shahab Varkouhi Jonathan Wells The relation between temperature and silica benthic exchange rates and implications for near-seabed formation of diagenetic opal |
topic_facet |
Bottom-water temperature Biogenic silica Dissolution rate Benthic flux Ocean Drilling Program Geophysics. Cosmic physics QC801-809 Geology QE1-996.5 |
description |
This study calculated the dissolution rates of biogenic silica deposited on the seafloor and the silicic acid benthic flux for 22 Ocean Drilling Program sites. Simple models developed for two host sediment types—siliciclastic and carbonate—were used to explain the variability of biogenic silica dissolution and recycling under present-day low (−0.3 to 2.14 °C) bottom-water temperatures. The kinetic constants describing silicic acid release and silica saturation concentration increased systematically with increasing bottom-water temperatures. When these temperature effects were incorporated into the diagenetic models, the prediction of dissolution rates and diffusive fluxes was more robust. This demonstrates that temperature acts as a primary control that decreases the relative degree of pore-water saturation with biogenic opal while increasing the silica concentration. The correlation between the dissolution rate and benthic flux with temperature was pronounced at sites where biogenic silica is hosted in surficial sediments mostly composed of biogenic carbonates. This association is because the dissolution of carbonates provides the alkalinity necessary for both silica dissolution (also its reprecipitation as opal-CT) and clay formation; thus strongly reducing the retarding influence of clays on biogenic opal dissolution. Conversely, the silica exchange rates were modified by presence of aluminosilicates, which led to a higher burial efficiency for biogenic opal in detrital- than in carbonate-dominated benthic layers. Though model prediction of first-order silica early transformation suggests likely effects from surface temperatures (0–4 °C) on opal-CT precipitation over short geological times (< 4 Ma) near seabed in the Antarctic Site 751, the relationship between silica solubility and surface-area variability in time is a more critical control. Since silica solubility and surface area decrease with time, the < 4 Ma elapsed time aged opal-A to the point that changes in specific surface area caused minor ... |
format |
Article in Journal/Newspaper |
author |
Shahab Varkouhi Jonathan Wells |
author_facet |
Shahab Varkouhi Jonathan Wells |
author_sort |
Shahab Varkouhi |
title |
The relation between temperature and silica benthic exchange rates and implications for near-seabed formation of diagenetic opal |
title_short |
The relation between temperature and silica benthic exchange rates and implications for near-seabed formation of diagenetic opal |
title_full |
The relation between temperature and silica benthic exchange rates and implications for near-seabed formation of diagenetic opal |
title_fullStr |
The relation between temperature and silica benthic exchange rates and implications for near-seabed formation of diagenetic opal |
title_full_unstemmed |
The relation between temperature and silica benthic exchange rates and implications for near-seabed formation of diagenetic opal |
title_sort |
relation between temperature and silica benthic exchange rates and implications for near-seabed formation of diagenetic opal |
publisher |
Elsevier |
publishDate |
2020 |
url |
https://doi.org/10.1016/j.ringps.2020.100002 https://doaj.org/article/d99acd13f00f4564b414e0c1939b3fae |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
Results in Geophysical Sciences, Vol 1, Iss , Pp 100002- (2020) |
op_relation |
http://www.sciencedirect.com/science/article/pii/S266682892030002X https://doaj.org/toc/2666-8289 2666-8289 doi:10.1016/j.ringps.2020.100002 https://doaj.org/article/d99acd13f00f4564b414e0c1939b3fae |
op_doi |
https://doi.org/10.1016/j.ringps.2020.100002 |
container_title |
Results in Geophysical Sciences |
container_volume |
1-4 |
container_start_page |
100002 |
_version_ |
1766103504219275264 |