Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
A sedimentological study of Cryogenian glacial-interglacial cycles recorded by the Port Askaig Tillite Formation on Islay, Scotland
Stockholm University, Faculty of Science, Department of Geological Sciences.
2018 (English)Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
Abstract [en]

An interglacial mudstone sequence from the Port Askaig Tillite Formation on Islay was analysed using an Olympus XRF detector. The resulting geochemical log was compared with an XRF dataset acquired from a Quaternary sedimentary core from the Lomonosov Ridge in the Arctic Ocean. Chemical proxies representing climatic and environmental changes were analysed in an effort to specifically identify evidence of orbital forcing in the Cryogenian Period.

The studied non-glacial rock-section from the Port Askaig Formation was interpreted as being deposited in a shallow marine setting at semitropical latitudes during an episode of global warming at some stage of the Sturtian glaciation (ca 717 – 660 Ma). The transport mechanism of glaciogenic material was by ice rafting. High hematite content was interpreted as an oxygenation event in a peritidal zone when isostatic rebound caused a sea level regression. Increasing amount of muscovite is interpreted to indicate increased weathering. Underlaying sequence of dolostone and overlaying sequence of sandstone were consistent with these interpretations. One interglacial phase is thus observed, which possibly could be attributed to Milankovitch orbital forcing.

The interpretation of the paleoclimatic setting of the studied interglacial mudstone did not provide support for the Snowball Earth hypothesis in its “hard” version. Neither did other observations such as evidence of repeating glacial-interglacial cycles and banded iron formations (BIF) appearing also within the Sturtian glaciation.

Place, publisher, year, edition, pages
2018. , p. 47
Keywords [en]
Cryogenian; Islay; Snowball Earth; Tillite
National Category
Geology
Identifiers
URN: urn:nbn:se:su:diva-157454OAI: oai:DiVA.org:su-157454DiVA, id: diva2:1220908
Supervisors
Examiners
Available from: 2018-06-19 Created: 2018-06-19 Last updated: 2018-06-19Bibliographically approved

Open Access in DiVA

fulltext(4451 kB)6 downloads
File information
File name FULLTEXT01.pdfFile size 4451 kBChecksum SHA-512
6c7bd29ceb1ca64243cb3ef99fdb80355de0465984d7c14c8651bd7f60f7a2d06438afe40000799a9ceacff20f5ef4ad61c93acdc78a894d99906e24effdd11d
Type fulltextMimetype application/pdf

By organisation
Department of Geological Sciences
Geology

Search outside of DiVA

GoogleGoogle Scholar
Total: 6 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

urn-nbn

Altmetric score

urn-nbn
Total: 14 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf