Early Cambrian biogeography and the diversification center of Cambrian bioradiation in the Palasian Ocean

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The Cambrian Bioradiation represents one of the major biotic revolutions in Earth history. This event may have been triggered by the tectonic evolution of Earth and the breakup of a supercontinent at the beginning of Cambrian. However, the existing palaeogeogeographic reconstructions are contradictionary and detailed investigations on the palaeobiogeography of the earliest Cambrian are lacking. The proposed project aims at the investigation of the early Cambrian palaeobiogeography by the study of small skeletal faunas (SSFs) of the Dzabkhan and Tuva-Mongolia micro-continents (both Mongolia) of the Central Asian Orogeny Belt (CAOB). Biostatistical analyses shall reveal palaeobiogeographic pattern, endemism and faunal provinces of the specific groups of SSFs for the different stages of early Cambrian. To achieve this a database on the temporal and spatial distribution of SSFs in the Cambrian Palasian Ocean will be set up, which will be complemented by literature data of global SSF occurrences. Key to the proposed project is to evaluate the published palaeogeographic reconstructions of major palaeocontinents for the earliest Cambrian, discuss potential ocean currents and faunal dispersion routes and rates as well as the extent of endemism in the early Cambrian. Conclusions shall be drawn if geographic speciation played a major role during the Cambrian Bioradiation Event and if the Mongolian micro-continents were part of a tropical archipelago, which served as hotspot for developing biodiversity during the Cambrian bioradiation. To further support the palaeobiogeographic analysis and evaluation of palaeogeography it is aimed to investigate the provenances of some specific Cambrian sandstones from the Mongolian micro-continents by using combined U-Pb age dating and Lu-Hf isotope analyses on detrital zircon grains.