Publikationsdatum:
2011-03-01
Beschreibung:
The tropical, warm, and equable climate of the Jurassic world is regularly challenged by geoscientists, especially since oxygen isotopes ({delta}18O) of fossil hardparts have been used to reconstruct the paleotemperature history of seawater. By applying the innovative "SiZer" (significant zero crossings of the derivatives) statistical approach to a newly compiled {delta}18O database for the Jurassic, we demonstrate the occurrence of major and multiscale {delta}18O changes mainly related to climate disturbances. For the first time, two long-term anomalies in {delta}18O are identified during the Toarcian and the Late Jurassic, in conjunction with intensive volcanism in large igneous provinces. These results support a strong influence of repeated volcanic pulses on the modulation of pCO2, temperatures, and polar ice cap volumes over protracted periods. At shorter time scales, 13 relatively rapid (0.5-1 m.y.) and significant warming and cooling events are identified, the causes of which include transient fluctuations in greenhouse gas concentrations related to still-debated mechanisms.
Print ISSN:
0091-7613
Digitale ISSN:
1943-2682
Thema:
Geologie und Paläontologie
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