The Siberian Trapp (Russian Сибирские траппы ) is an extensive flood basalt ( Trapp ) in Siberia. The volcanic eruptions responsible for this form one of the largest known volcanic events of earth's history and found around 250 million years ago at the Permian-Triassic boundary. The outbreaks and their consequences are brought into a causal connection with the mass extinction at the end of the Permian. Due to its expansion and its geologically relatively rapid emergence of the Siberian Trapp is an outstanding example of a large igneous province.
Extent and duration of outbreaks
As a result of the outbreak covered large amounts of basaltic lava an extended area of primeval Siberia. The still occupied by the basalt surface is about 2 million square kilometers in size, is located between 50 ° and 75 ° North and 60 ° to 120 ° East and covers the western and northern Siberian lowlands and the central Siberian Plateau and part of the Mitteljakutischen lowlands, together with the western slope of the East Siberian Uplands. Today Particularly good digestion conditions provides the Putoranagebirge. Estimates of the original area covered by the volcanic deposits amount to up to 7 million square kilometers. The maximum thickness of the Trapps is in the area of Norilsk and the rivers Maimetscha and Kotui more than 3,000 m, estimates indicate a total combined thickness of the Trapps of up to 6,500 m. The derived amount of out -carrying basalt is about one million to four million cubic kilometers.
The volcanic event took about a million years. As the center of the outbreak of numerous volcanic vents are considered near Norilsk. Some of the eruptions have produced up to 2000 km ³ of lava or more. The presence of large amounts of volcanic tuffs and pyroclastic deposits indicates that explosive eruptions occurred even before or during the onset of the flood basalts, which distributed the material as volcanic ash over wide areas. This is supported by the presence of silicon- rich igneous rocks such as rhyolite.
Causes and consequences
As the source of the Siberian Traps, a plume is seen rising from the mantle beneath the Siberian craton. This interpretation is supported by isotopic studies of helium. The scientific debate but keeps still on. Another theory suggests that the impact of a large asteroid was the cause of the Trapp volcanism.
There is no reliable evidence that the volcanic event caused the great mass extinction at the end of the Permian; the approximate temporal coincidence of the two events is, however, seen as evidence of a causal link. A current model describes that enormous releases of hydrogen chloride and carbon dioxide may have occurred before the main phase of volcanism and mass extinction may have caused.
Mineral resources of the Siberian Traps
Due to the rise of the magma it came to the deposition of nickel, copper and palladium is present in large quantities. The metal-containing rocks form extensive deposits which are mined today by the Russian mining company MMC Norilsk Nickel in the Komsomolski Mine near Norilsk.