
Per Ahlberg
Professor

The complexity of mudstone diagenesis–some insight from the Tøyen Shale, Lower to Middle Ordovician, southern Sweden
Författare
Summary, in English
The Lower to Middle Ordovician Tøyen Shale in southern Sweden, a biostratigraphically well-dated siliciclastic mudstone unit, shows 18 distinct authigenic cements that include sulfides, carbonates, silicates, clays, and phosphates. Marcasite, sphalerite, galena, and six texturally distinct types of pyrite characterize the sulfides whereas only one type of dolomite and three different generations of calcite are observed in this unit. Quartz, phosphate, and organic matter occur as only one generation each. Authigenic clay minerals are represented by chlorite and kaolinite. The paragenetic sequence of cements is subdivided into the two pre-burial carbonates, succeeded by ten relatively early burial cements, and six late burial cements, the kaolinite being the latest of them all and potentially being of Cretaceous age. Based on textural relationships, the paragenetic sequence of alterations started with dolomite precipitation followed by calcite, and then five different generations of pyrite. All eleven other phases post-date these initial seven cements in the Tøyen Shale.
Avdelning/ar
- Berggrundsgeologi
Publiceringsår
2019
Språk
Engelska
Sidor
54-67
Publikation/Tidskrift/Serie
GFF
Volym
141
Issue
1
Dokumenttyp
Artikel i tidskrift
Förlag
Taylor & Francis
Ämne
- Geology
Nyckelord
- dolomite formation
- Lower to Middle Ordovician
- Shale diagenesis
- Tøyen Formation
Status
Published
ISBN/ISSN/Övrigt
- ISSN: 1103-5897