6533b7d9fe1ef96bd126d5ce
RESEARCH PRODUCT
Cyanophyte calcification morphotypes and depositional environments (Alenquer oncolite, upper Kimmeridgian?, Portugal)
Reinhold Leinfeldersubject
Terrigenous sedimentStratigraphyPaleontologyGeologymedicine.diseaseSedimentary depositional environmentPaleontologySingle speciesPaleobotanymedicineSedimentologyBiogeosciencesGeologyCalcificationOncolitedescription
Terrigenous red siliciclastics of Upper Kimmeridgian(?) to Portlandian age around Alenguer, Portugal, comprise a narrow level of oncoid-bearing limestones. Oncoid cortices are composed of cyanophytes which appear in different calcification morphotypes according to changing physico-chemical parameters. Recent examples reveal that in most cases each calcification morphotype is related to one single species or one defined association. Hence, the characteristic calcification patterns are mostly biologically rather than abiogenetically controlled. Oncoid shapes, sizes and arrangement, on the other hand, are mainly determined by the hydraulic parameter within the depositional environment.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1985-12-01 | Facies |