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Lihtpäring otsib infot kõigilt kirjanduse andmeväljadelt: autor, aasta, pealkiri, ajakirja nimi, kogumik, abstrakt, märksõnad, doi jne.

(1) otsida saab ühe või mitme sõna järgi, tulemustes kuvatakse kirjed, kus vähemalt üks neist on olemas (nt Kaljo Kivimägi);
(2) kui lisad märksõna ette "+" märgi, siis otsitakse vaid kirjeid, kus see märksõna sisaldub (nt +Kaljo +Kivimägi);
(3) märksõna välistamiseks kasuta "-" märki (nt -Kaljo +Kivimägi);
(4) pimeotsingu tähiseks on * (nt litostrat*);
(5) kindla fraasi otsinguks ümbritse see jutumärkidega (nt "tartu riikliku ülikooli");
(6) kombineeri eelnevaid võimalusi (nt +"estonian journal of earth sciences" +Kaljo +year:[2010 TO *] annab tulemuseks kõik Dimitri Kaljo artiklid ajakirjas EJES);

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Detailsem päringuvorm valmib 2020. a teises pooles. Andmete sisestamine ja märksõnadega varustamine kestab 2020. a lõpuni ning seda finantseerib KIKi projekt "Eesti maapõue trükiste andmebaas".

Kaljo et al., 2004a

ViideKaljo, D., Hints, L., Martma, T., Nõlvak, J., Oraspõld, A., 2004: Late Ordovician carbon isotope trend in Estonia, its significance in stratigraphy and environmental analysis. Palaeogeography, Palaeoclimatology, Palaeoecology, 210, 2-4, 165-185. https://doi.org/10.1016/j.palaeo.2004.02.044
Autor(id)Kaljo, D., Hints, L., Martma, T., Nõlvak, J., Oraspõld, A.
Aasta2004
PealkiriLate Ordovician carbon isotope trend in Estonia, its significance in stratigraphy and environmental analysis
Allika tüüpartikkel ajakirjas
AjakiriPalaeogeography, Palaeoclimatology, Palaeoecology, 210, 2-4
Leheküljed165-185
Abstrakt

arbon isotope changes during most of Late Ordovician time (from the mid-Caradoc Kinnekulle K-bentonite until the beginning of the Silurian) were investigated. As the corresponding sequence of rocks is stratigraphically nearly complete in Estonia, an attempt was made to use it to elaborate the general pattern of carbon isotope changes in the Late Ordovician. Complications were caused by several local or regional hiatuses in the middle and late Caradoc and Hirnantian. A total of 385 whole rock samples were studied from eight drill cores in northern and central Estonia. The following positive carbon isotope events were observed: (1) the mid-Caradoc excursion (peak δ13C value 2.2‰) in the uppermost part of the Keila Stage, also known in Sweden; (2) the first late Caradoc excursion (1.9‰) in the lower part of the Rakvere Stage; (3) the second late Caradoc excursion (2.4‰) in the upper part of the Nabala Stage; (4) the early Ashgill excursion (2.5‰) in the lowermost part of the Pirgu Stage; (5) the widely known large Hirnantian excursion (in Estonia the peak value reaches 6.7‰) in the Porkuni Stage. The study interval comprises a long (∼10 Ma) period characterized by low-magnitude carbon isotope changes and a following brief (∼2 Ma) interval with large changes. No obvious lithological preference for hosting the positive shifts was recorded. In principle, the δ13C values exceeding the background values may occur in all types of rocks present in a sedimentary basin. Several δ13C positive excursions (values 1.5‰ to 3‰) in the Mohawkian of North America are evidence that the minor Caradoc and early Ashgill δ13C positive shifts in Baltoscandia may have counterparts in Laurentia. If correctly correlated, these shifts may have global significance. The Hirnantian excursion is usually linked to a major glacial event, even if some carbon cycling mechanisms are not completely understood. The environmental causes suggested for the earlier minor shifts range from global climatic and glacial events to very local changes in basin regime and sea level. Our study supports the primary role of climatic or climatically triggered oceanic processes.

Keelinglise
Märksõnad
Kuulub kirjanduse kogumikku
DOIhttps://doi.org/10.1016/j.palaeo.2004.02.044
Kirje ID1754
Sisestatud, muudetud2011-10-17T14:48:19Z | 2020-03-30T07:48:35Z

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