The University of Southampton
University of Southampton Institutional Repository

Production of calcareous nannofossil ooze for sedimentological experiments

Production of calcareous nannofossil ooze for sedimentological experiments
Production of calcareous nannofossil ooze for sedimentological experiments
The notion of fine-grained pelagic carbonates as uniform, monotonous sequences of sediments settled in a quiescent environment has been challenged over the past few decades. Fine-grained pelagic carbonates can undergo substantial reworking after their first deposition, as illustrated by an abundance of sedimentary structures, such as drifts, moats, sediment waves, and channels documented in the Upper Cretaceous Chalk Group of NW Europe. Despite chalk being a major hydrocarbon reservoir rock of the North Sea, surprisingly little is known about the physical behavior of the pelagic carbonate sediment from which the chalk formed—calcareous nannofossil ooze. This poses a serious challenge to the understanding of the depositional system and the properties of facies distribution. Experimental tests, such as those performed in laboratory flumes, are necessary to provide empirical data on this subject. However, the use of modern calcareous nannofossil ooze as an analogue for Cretaceous ooze is associated with a number of disadvantages such as generally higher noncarbonate content and smaller coccolith size of modern oozes. Here, we document a preparation method for the production of calcareous nannofossil ooze for the purpose of physical experiments, based on disaggregation of Upper Cretaceous chalk through repeated freezing and thawing. We further document the textural characteristics of the ooze compared to the original chalk, based on quantitative backscatter scanning electron image analysis, laser diffraction granulometry, and smear slides. The Upper Cretaceous chalk chosen for disaggregation is highly friable due to delicate contact cement and has a low noncarbonate content (< 2 wt %), a high porosity, friability, and good nannofossil and microfossil preservation. These characteristics allowed an effective disaggregation of the chalk matrix into its basic nannofossil and microfossil components, which show good preservation through the disaggregation process. Textural analysis of chalk used for disaggregation and the produced ooze shows no significant differences between the two, thus validating the use of the freeze–thaw method for production of experimental ooze to model the basic depositional behavior of Cretaceous chalk.
1527-1404
1228-1237
Buls, Toms
3bcc11a2-65a1-4763-a2d8-eaad3fca005e
Anderskouv, Kresten
d73bf3d7-49d9-4e21-bcd7-faa74c7c164f
Fabricius, Ida L.
ce07fe46-b401-4274-b32f-e7e4bd32e067
Friend, Patrick L.
d7561ac5-6a95-4d99-96c4-3e00e3c06ac8
Thompson, Charlotte E.L.
2a304aa6-761e-4d99-b227-cedb67129bfb
Stemmerik, Lars
5d086c91-48fe-4f0f-8ea6-70160838eee0
Buls, Toms
3bcc11a2-65a1-4763-a2d8-eaad3fca005e
Anderskouv, Kresten
d73bf3d7-49d9-4e21-bcd7-faa74c7c164f
Fabricius, Ida L.
ce07fe46-b401-4274-b32f-e7e4bd32e067
Friend, Patrick L.
d7561ac5-6a95-4d99-96c4-3e00e3c06ac8
Thompson, Charlotte E.L.
2a304aa6-761e-4d99-b227-cedb67129bfb
Stemmerik, Lars
5d086c91-48fe-4f0f-8ea6-70160838eee0

Buls, Toms, Anderskouv, Kresten, Fabricius, Ida L., Friend, Patrick L., Thompson, Charlotte E.L. and Stemmerik, Lars (2015) Production of calcareous nannofossil ooze for sedimentological experiments. Journal of Sedimentary Research, 85 (10), 1228-1237. (doi:10.2110/jsr.2015.80).

Record type: Article

Abstract

The notion of fine-grained pelagic carbonates as uniform, monotonous sequences of sediments settled in a quiescent environment has been challenged over the past few decades. Fine-grained pelagic carbonates can undergo substantial reworking after their first deposition, as illustrated by an abundance of sedimentary structures, such as drifts, moats, sediment waves, and channels documented in the Upper Cretaceous Chalk Group of NW Europe. Despite chalk being a major hydrocarbon reservoir rock of the North Sea, surprisingly little is known about the physical behavior of the pelagic carbonate sediment from which the chalk formed—calcareous nannofossil ooze. This poses a serious challenge to the understanding of the depositional system and the properties of facies distribution. Experimental tests, such as those performed in laboratory flumes, are necessary to provide empirical data on this subject. However, the use of modern calcareous nannofossil ooze as an analogue for Cretaceous ooze is associated with a number of disadvantages such as generally higher noncarbonate content and smaller coccolith size of modern oozes. Here, we document a preparation method for the production of calcareous nannofossil ooze for the purpose of physical experiments, based on disaggregation of Upper Cretaceous chalk through repeated freezing and thawing. We further document the textural characteristics of the ooze compared to the original chalk, based on quantitative backscatter scanning electron image analysis, laser diffraction granulometry, and smear slides. The Upper Cretaceous chalk chosen for disaggregation is highly friable due to delicate contact cement and has a low noncarbonate content (< 2 wt %), a high porosity, friability, and good nannofossil and microfossil preservation. These characteristics allowed an effective disaggregation of the chalk matrix into its basic nannofossil and microfossil components, which show good preservation through the disaggregation process. Textural analysis of chalk used for disaggregation and the produced ooze shows no significant differences between the two, thus validating the use of the freeze–thaw method for production of experimental ooze to model the basic depositional behavior of Cretaceous chalk.

Full text not available from this repository.

More information

e-pub ahead of print date: 14 October 2015
Published date: October 2015
Organisations: Geology & Geophysics

Identifiers

Local EPrints ID: 384942
URI: https://eprints.soton.ac.uk/id/eprint/384942
ISSN: 1527-1404
PURE UUID: dbea686e-b213-4769-8c73-e8baeac3795f

Catalogue record

Date deposited: 09 Dec 2015 16:48
Last modified: 15 Jul 2019 20:54

Export record

Altmetrics

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of https://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×