δ[sup.13]C chemostratigraphy of the Middle and Upper Ordovician succession in the Tartu-453 drillcore, southern Estonia, and the significance of the HICE

The δ[sup.13]C isotope data from the Tartu-453 core section in southern Estonia enabled creation of a continuous Ordovician carbon isotope record, ranging from the Floian to the end of the Hirnantian. Five positive δ[sup.13]C excursions and one negative δ[sup.13]C excursion were recognized. Most of...

Full description

Saved in:
Bibliographic Details
Published in:Estonian journal of earth sciences 2014-12, Vol.63 (4), p.195
Main Authors: Bauert, Heikki, Ainsaar, Leho, Poldsaar, Kairi, Sepp, Siim
Format: Article
Language:English
Subjects:
Geology, Stratigraphic
Geophysical research
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The δ[sup.13]C isotope data from the Tartu-453 core section in southern Estonia enabled creation of a continuous Ordovician carbon isotope record, ranging from the Floian to the end of the Hirnantian. Five positive δ[sup.13]C excursions and one negative δ[sup.13]C excursion were recognized. Most of the positive excursions correspond to those defined on the Baltoscandian carbon isotope chemostratigraphic scheme, except for the Paroveja and Rakvere ICEs which are not well expressed in the Tartu-453 curve. Besides the positive δ[sup.13]C excursions, a distinctive negative δ[sup.13]C excursion, the Lower Sandbian NICE, was recorded in the Tartu-453 succession. The well-expressed HICE extends about 10 m higher than the traditional Ordovician-Silurian boundary (between the Porkuni and Juuru regional stages) into the Juuru Regional Stage, suggesting that the Ordovician-Silurian boundary is positioned significally higher than traditionally suggested for the East Baltic area. Key words: Tartu-453 drillcore, δ[sup.13]C chemostratigraphy, HICE, Ordovician-Silurian boundary.
ISSN:1736-4728
DOI:10.3176/earth.2014.18