『Abstract
Detailed stratigraphic studies of Jurassic deep-marine Tethyan organic-rich shales and manganoan carbonates from Austria-Germany, Italy, Greece, Hungary, and Tunisia suggest they are principally of early Toarcian, falciferum-Zone age. Carbon-isotope stratigraphy from non-carbonaceous Tethyan sections indicates a positive δ¹³C excursion in the early part of the falciferum-Zone (exaratum Subzone) suggesting accelerated extraction of organic carbon from the ocean reservoir at this time, and it is likely that most, if not all, Tethyan Jurassic black shales are confined to this interval: they can thus be used as a stratigraphic index. These facies are of exactly equivalent age to the more renowned equivalents in epicontinental northern Europe such as the Jet Rock, Schistes Cartons, and Posidonienschiefer. Epicontinental falciferum-Zone black shales are also known from weatern Canada, the Arctic Slope, Japan, Madagascar, Argentina, and possibly offshore weatern Australia. It is thus clear that synchronous deposition of these facies occurred in diverse parts of the globe ehich allows interpretation of the phenomenon as an Oceanic Anoxic Event, ehose duration is estimated as approximately half-a-million years.
detailed paleogeographic studies in the Southern Alps suggest that an oxygen-minimum model is appropriate for interpreting conditions on Tethyan continental margins. Advection of manganese in this low-oxygen layer may explain the local occurrence of carbonate ores of this element. Carbon-sulfur and iron-sulfur ratios, although showing considerable scatter, suggest that bottom waters at this time were locally euxinic, containing free hydrogen sulfide.
This Oceanic Anoxic Event was preceded by significant faunal turnover of ammonites in Tethys and accompanied by widespread extinction of benthos in northern Europe in response to the lateral spread of anoxic bottom waters during transgression. Similar changes may be recognized in other parts of the world. Other anoxic events may have taken place during the Jurassic, but documentation is as yet meager. Furthermore, models for such phenomena remain largely speculative, although upwelling and increased planktonic productivity, commencing in pre-Toarcian time, are favored for the falciferum-Zone event documented here.』

Introduction
Sratigraphic scheme for the Toarcian
Toarcian black shales in northern Europe
Age and lithology of Toarcian black shales in Tethys
Austria-Germany-Switzerland
Italy
Sicily
Yugoslavia
Greece-Albania
Czechoslovakia
Tunisia
Carbon-isotope data from Tethyan Toarcian pelagic limestones
Toarcian black shales in extra-Alpine areas
Alaska, U.S.A.
Canada
Japan
Madagascar
Australia
Argentina
Other areas
Toarcian zonation and duration of the oceanic anoxic event
Early Jurassic paleogeography of the southern Alps and deposition of black shales
Geochemical implications
Faunal change across the Pliensbachian-Toarcian boundary
Conclusions
Acknowledgments
References