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Conodont biostratigraphy and sedimentary history in the upper Tremadoc at Uuga, Cape Pakri, NW Estonia

Löfgren, Anita LU ; Viira, V and Mens, K (2005) In GFF 127(Part 4). p.283-293
Abstract
The upper Tremadocian boundary beds at Cape Pakri, NW Estonia, consist of an extremely friable glauconitic sandstone, which presents a challenge to detailed biostratigraphy. A combination of sedimentological and biostratigraphical criteria has served to clarify the tempo and mode of the processes that formed the sandstone and explain its relationships to strata immediately below and above it. Apatitic conodont elements, which abound in all these sediments, are particularly well suited to tracing the geological history of the surrounding sediment, since they can be repeatedly included in the sediment, eroded and redeposited, often leaving telltale marks on the elements which are nevertheless identifiable. By separating the indigenous... (More)
The upper Tremadocian boundary beds at Cape Pakri, NW Estonia, consist of an extremely friable glauconitic sandstone, which presents a challenge to detailed biostratigraphy. A combination of sedimentological and biostratigraphical criteria has served to clarify the tempo and mode of the processes that formed the sandstone and explain its relationships to strata immediately below and above it. Apatitic conodont elements, which abound in all these sediments, are particularly well suited to tracing the geological history of the surrounding sediment, since they can be repeatedly included in the sediment, eroded and redeposited, often leaving telltale marks on the elements which are nevertheless identifiable. By separating the indigenous elements from those that had been redeposited, we could place the local upper boundary of the Tremadocian at slightly more than 1 m above the base of the c. 4 m-thick sandy deposit. We showed that the sandstone, where 58-97% of the conodont elements have been redeposited, had been formed during four successive phases of sand deposition. The entire sandstone unit belongs to the Paroistodus proteus Zone. In the sandy and clayey Varanguan beds of the Paltodus deltifer Zone that underlie the sandstone, less than 50% of the conodont elements had been redeposited. The upper part of the section consists of limestone beds belonging to the Oepikodus evae Zone, where the redeposited portion of the conodont elements decreases upwards. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
biostratigraphy, redeposition, upper Tremadocian, Estonia, conodonts
in
GFF
volume
127
issue
Part 4
pages
283 - 293
publisher
Geological Society of Sweden
external identifiers
  • wos:000235446500007
  • scopus:32944479848
ISSN
2000-0863
language
English
LU publication?
yes
id
63fab652-f26d-4f3a-bc1d-16c69035b4a4 (old id 209436)
alternative location
http://www.gff-online.se/site/article.asp?articleID=848
date added to LUP
2007-08-07 15:54:34
date last changed
2017-01-01 04:41:06
@article{63fab652-f26d-4f3a-bc1d-16c69035b4a4,
  abstract     = {The upper Tremadocian boundary beds at Cape Pakri, NW Estonia, consist of an extremely friable glauconitic sandstone, which presents a challenge to detailed biostratigraphy. A combination of sedimentological and biostratigraphical criteria has served to clarify the tempo and mode of the processes that formed the sandstone and explain its relationships to strata immediately below and above it. Apatitic conodont elements, which abound in all these sediments, are particularly well suited to tracing the geological history of the surrounding sediment, since they can be repeatedly included in the sediment, eroded and redeposited, often leaving telltale marks on the elements which are nevertheless identifiable. By separating the indigenous elements from those that had been redeposited, we could place the local upper boundary of the Tremadocian at slightly more than 1 m above the base of the c. 4 m-thick sandy deposit. We showed that the sandstone, where 58-97% of the conodont elements have been redeposited, had been formed during four successive phases of sand deposition. The entire sandstone unit belongs to the Paroistodus proteus Zone. In the sandy and clayey Varanguan beds of the Paltodus deltifer Zone that underlie the sandstone, less than 50% of the conodont elements had been redeposited. The upper part of the section consists of limestone beds belonging to the Oepikodus evae Zone, where the redeposited portion of the conodont elements decreases upwards.},
  author       = {Löfgren, Anita and Viira, V and Mens, K},
  issn         = {2000-0863},
  keyword      = {biostratigraphy,redeposition,upper Tremadocian,Estonia,conodonts},
  language     = {eng},
  number       = {Part 4},
  pages        = {283--293},
  publisher    = {Geological Society of Sweden},
  series       = {GFF},
  title        = {Conodont biostratigraphy and sedimentary history in the upper Tremadoc at Uuga, Cape Pakri, NW Estonia},
  volume       = {127},
  year         = {2005},
}