AINSAAR, LEHO, MEIDLA, TÕNU, MARTMA, TÕNU (1999) Evidence for a widespread carbon isotopic event associated with late Middle Ordovician sedimentological and faunal changes in Estonia. Geological Magazine, 136 (1) 49-62 doi:10.1017/s001675689900223x

Reference Type | Journal (article/letter/editorial) | ||
---|---|---|---|
Title | Evidence for a widespread carbon isotopic event associated with late Middle Ordovician sedimentological and faunal changes in Estonia | ||
Journal | Geological Magazine | ||
Authors | AINSAAR, LEHO | Author | |
MEIDLA, TÕNU | Author | ||
MARTMA, TÕNU | Author | ||
Year | 1999 (January) | Volume | 136 |
Issue | 1 | ||
Publisher | Cambridge University Press (CUP) | ||
DOI | doi:10.1017/s001675689900223xSearch in ResearchGate | ||
Generate Citation Formats | |||
Mindat Ref. ID | 257958 | Long-form Identifier | mindat:1:5:257958:4 |
GUID | 0 | ||
Full Reference | AINSAAR, LEHO, MEIDLA, TÕNU, MARTMA, TÕNU (1999) Evidence for a widespread carbon isotopic event associated with late Middle Ordovician sedimentological and faunal changes in Estonia. Geological Magazine, 136 (1) 49-62 doi:10.1017/s001675689900223x | ||
Plain Text | AINSAAR, LEHO, MEIDLA, TÕNU, MARTMA, TÕNU (1999) Evidence for a widespread carbon isotopic event associated with late Middle Ordovician sedimentological and faunal changes in Estonia. Geological Magazine, 136 (1) 49-62 doi:10.1017/s001675689900223x | ||
In | (1999, January) Geological Magazine Vol. 136 (1) Cambridge University Press (CUP) | ||
Abstract/Notes | An episode of remarkable biotic, climatic, sea-level and facies changes took place during the late Viruan (Caradoc) epoch in the Baltoscandian area. We studied the carbon isotopic composition of carbonate sediments from this period. Data on the stable carbon isotopic composition of whole-rock carbonates from three south Estonian core sections, together with those on ostracode, distribution are presented. In two core sections, a positive δ13C shift of 2 ‰ was revealed in the upper part of the Keila Stage (mid-Caradoc). The comparison of isotope and ostracode data in the sections suggested the occurrence of a gap of late Keilan age in the marginal area of the basin equivalent to the North Estonian Confacies Belt. The beginning of the excursion approximately coincided with climatic and sea-level changes in the shallow shelf area. The peak of the late Keilan excursion preceded the biotic crises and maximum black shale accumulation in the Baltoscandian palaeobasin. An approximately synchronous carbon isotopic event has been reported from North America, referring to a possible global oceanographic event in the Caradoc epoch. Although the positive carbon isotopic excursion and related environmental events of the late Keilan age have some unique features, they show more similarities to the end-Ordovician and Silurian events, characterized by oceanic change from stratified state to thermohaline circulation state, than to warm anoxic events related to eustatic sea-level rise. |
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