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The end-Permian and Early Triassic sedimentary environments in the Croatian Dinarides - the example of global warming ocean and a link to calibrate events in the western Tethys
[PROJECT URL ]
Project status:
From: 2013-10-31
To: 2015-10-31
(Completed)
Type (Programme):
BILAT
Project funding:
-
International partner
Organisation Name:
Austrian Academy of Sciences c/o Institute of Earth Sciences, University of Graz
The end-Permian mass extinction and the subsequent Early Triassic experienced increase in global warming. This interval is considered as a time of crisis and profound changes in ecosystems on Earth and thus worth of thorough investigation. It is the greatest of all extinctions in the Phanerozoic. The process of progressive elimination of marine species in Permian (Aljinović et al., 2008; Isozaki & Aljinović, 2009) is punctuated by a final extinction pulse at Permian-Triassic Boundary. This pulse is generally correlated with a conspicuous depletion in 13C especially in marine carbonates (δ13Ccarb), reflecting a dramatic disturbance in the global carbon cycle (e.g. Baud et al., 1989; Richoz et al., 2010). Although palaeogeographic, climatic, and geochemical conditions as well as evolutionary state of biological systems were different from now, results from this natural experiment on the Earth system can be observed from the fossil and stratigraphic record and provide information to understand our future global warming ocean. Successive events and strong carbon and sulfur cycle disturbance have been described during the Lower Triassic and early Middle Triassic questioning the reasons of the expanded recovery time after the Permian-Triassic events (e.g.: Payne et al., 2004, Richoz 2006, Horacek et al., 2007a, b, 2009, 2010a,b; Hermann et al., 2011; Meyer et al., 2011). Although the negative carbon isotope shift at the Permian-Triassic Boundary have been well recorded in many places around the world (Luo et al., 2011 for a review), the Early Triassic and early Middle Triassic suit of disturbance had been mainly studied in Panthalassa (Horacek et al., 2009), China (e.g. Payne et al., 2004, Zuo et al., 2006; Galfetti et al., 2007) or Central Tethys (e.g. Richoz, 2006; Horacek et al., 2007a, b; Hermann et al., 2011). It will be of crucial importance to have more data from other settings to understand the reasons of the carbon cycle disturbance and the effect on the biotic recovery in ocean. The two carbon isotope curves obtained from the western Tethys in the Werfen Formation in the Dolomite (Northern Italy) (Horacek et al., 2007; 2010a) lack index fossils and calibration had to be achieved with other, better dated, sections from Central Tethys or China. Moreover the late Early Triassic and the early Middle Triassic is missing in the Werfen Formation of the Dolomites due to an erosive event during the Anisian. The matching of the δ 13Ccarb record with the ammonoid, conodont and microbial record in the Croatian Dinarides could give some clues on environmental and evolutionary conditions on the Early Triassic recovery in shallow ramp areas that are currently unknown. Was the recovery straight forward or were there several rapid starts followed by extinctions as it is recently described from deeper-water faunas (Brayard et al., 2009)? The interpretation of the δ 13Ccarb and eventually δ 34Sbarite curves will allow us to better understand the geochemical disturbance in carbon cycle at this peculiar time of life evolution and to which extent episodes of severe environmental change lead to the development of alternative ecosystems in the global ocean. Although not a perfect analogue, The Early Triassic ocean has much to teach us about the future global warming ocean.
Short description of the task performed by Croatian partner
The project is subdivided into field work and laboratory work Field work will include precise lithostratigraphic description; study of sedimentary and bedding features to recognize potential microbialitic structures, disconformity surfaces, sequence tracts and major cyclic pattern. Sections will be measure in detail with bed by bed fossils collection, samples for microfacies, conodonts and C stable isotope. The localities are Plavno and Muć (near Knin and Sinj, Dalmatia), Mrzla Vodica in Gorski Kotar Region and Velebit Mts. Laboratory work will encompass study of ammonoid, conodont and other invertebrate faunas for biofacies analysis and to be used for regional and global correlation; calculation of evolutionary rates will give information about the environmental and recovery conditions after end-Permian mass extinction. Petrography of carbonate and clastic rocks and microfacies analysis of potential microbial strucutres will give palaeoenvironmental indications of recovery phase; high-resolution δ13Ccarb curve calibrate with conodont and ammonite biostratigraphy will be produced, that will enable an exact correlation with the Werfen Formation in the Southern Alps and other sections worldwide. It will allow us to focus in the environmental factor driving the observed changes.
Ovo web sjedište koristi tehnologiju "kolačića" (eng. cookie) da bi se korisnicima prikazao dinamičan i personaliziran sadržaj, te su oni nužni za ispravan rad. Ako nastavite pregledavati ove stranice, kolačići će biti korišteni u suradnji s vašim preglednikom Weba.
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