Early and Middle Jurassic climate changes: implications for palaeoceanography and tectonics

Christoph Korte, Stephen Hesselbo, Clemens Vinzenz Ullmann, Micha Ruhl, Nicolas Rudolph Thibault

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Abstract

The occurrence of ‘ice ages’ within the overall warm Jurassic Period has been the subject of much discussion and not a little controversy. Recently it has been suggested on the basis of occurrence of glendonites in circum-Arctic basins that cold episodes took place in the Jurassic (Price, 1999; Rogov and Zakharov, 2010). Here we present new high-resolution oxygen isotope datasets from marine calcitic fossils of different European basins that indicate strong temperature fluctuations during the Pliensbachian-Bajocian time span. The already reported cold Late Pliensbachian episode with at least three pronounced oxygen isotope ‘Ice Age’ cycles, and the subsequent well known Toarcian Oceanic Anoxic ‘supergreenhouse’ Event is followed by very warm seawater temperatures in the late Toarcian. Moreover, a very pronounced and effective cooling occurred during the latest Toarcian and early Aalenian (Early-Middle Jurassic Boundary Event) resulted in substantial expansion of Arctic climates to palaeolatitudes as low as 45° and in distinctly cooler seawater temperatures in lower latitude European seas. At least the extensive cooling at the Early-Middle Jurassic Boundary Event was most likely driven by substantial changes in oceanic current patterns which were initiated by a major tectonic uplift that prevented the transport of heat to Polar Regions.
OriginalsprogEngelsk
Artikelnummer15944-1
TidsskriftGeophysical Research Abstracts
Vol/bind16
Antal sider1
ISSN1607-7962
StatusUdgivet - 2014
BegivenhedEGU General Assembly 2014 - Vienna, Østrig
Varighed: 27 apr. 20143 maj 2014

Konference

KonferenceEGU General Assembly 2014
Land/OmrådeØstrig
ByVienna
Periode27/04/201403/05/2014

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