Tortonien
The Tortonien is before last subdivision of the time of the Miocène. It extends from 11,608 with 7,246 million years. It makes following the Serravallien (13,65-11,608 My).
Paleobotany
Sixteen Taxodium distichum perfectly preserved since the tortonien - one time when the continent of Europe was partially submerged by water - were found in 2007 at the bottom of an immense deep crack of 60 meters located in the brown-coal mine at open sky of Bukkabrany at 160 km in the North-East of Budapest, the capital of the Hungary. The interest of this discovery lies in the fact that these trees, old man of eight million years neither are carbonized, nor fossilized, but kept all their timber structure.
These sixteen trees located in a small perimeter of less than 100 m ², have a height of 4 with 6 meters for a diameter of 1,5 with 3 meters. Their size was to approach the 30 with 40 meters. The trunks were preserved in their original form and their matter thanks to a conservation exceptional, if not miraculous, which had with the fact that they were quickly covered by a thick gray layer of sand, itself surmounted by a fine yellow layer of sand. The gray layer of sand six meters thickness is the consequence of exceptional and sudden sandstorm. the conservation is due to the absence of Bactérie S in this gray layer of sand; original wood did not fossilize.
These trees constitute, for the scientists, an important mine of information on the flora of the tortonien and the origins of the Pannonia which at the time was immense stretch of water, called Lac Pannon, on the shores of which the Taxodium distichum thrived. Gâce with the examinations of Dendrochronologie - study of the dating of the climate changes by the study of the rings of the trees - it is possible to know in detail the climate of a small period of the tortonien being spread out between 1 000 and 1 500 years.
Several million euros was resolved by the Hungarian ministry of the Environment to ensure the safeguarding of the sixteen extraordinarily preserved trees. They should quickly be preserved in an aquarium reproducing the wet conditions of their conservation, inside Ipolytarnoc, the national park of Bükk. Subjected to the air and the sun, the trees are damaged quickly by losing their cellulose which is used as adhesive with the membranes of the cells of their wood.
See too
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