The landscape evolution of the Lausitz Block since the Palaeozoic - with special emphasis to the neovolcanic edifices in the Lausitz Volcanic Field (Eastern Germany)

The Lausitz Volcanic Field (LVF) is a part of the Cenozoic European Volcanic Province and overlay the Lausitz Block and the Zittau Mountains. Both units are part of the Central European block-faulted area, uplifted since about 100 Ma. The paper gives in the first part a review of the geological-tectonic evolution of the Lausitz Block and adjacent areas since the Cadomian consolidation at 540 Ma up to the present time. Thereafter, it could be distinguished by three uplift and two peneplain stages up to 30 Ma ago. The last (Palaeogene) peneplain stage ends with a crust extension and a continental intraplate volcanism, the topic of the present work. After this stage followed the Neogene oscillation stage up to the present time with several weaker and shorter uplifts or local subsidence, interrupted by periods of more or less tectonic quietness. The uplift increases, evidenced by sedimentological, glacial-geological and geomorphological documents for the time span between Elsterian and Saalian Glaciations between 320 ka and 250 ka. Some date imply the progress of these neotectonic activities up to the present time. The knowledge of volcanic remnants in the LVF allows a more detailed reconstruction of the pre-volcanic landscape over the whole area with implications of the landscape evolution since the volcanic time by 32-29 Ma (climax age). Therefore, in this study, three examples of monogenetic scoria cone volcanoes or volcano areas were selected and investigated. With regard to the volcanological data, the denudation of the Lausitz Block reaches up to 90 m with an uplift rate from 2 3 mm/ka for the post-volcanic time since about 30 Ma. This is very low in comparison to the calculated uplift and denudation rate for the Lausitz Block of 100 mm/ka estimated by fission track data for 85-50 Ma (Lange et al. 2008). The long-lasting denudation, the occurrence of pyroclastic remnants at several volcano structures and the partly good preservation of the volcano edifices indicate a late increase of uplifting and erosion of the Lausitz Block and the southern adjacent Zittau Mountains. The exact time for this uplift event marks the missing of basaltic pebbles in Elsterian-2 glaciofiuviatile sediment deposits and the finding of abundant scoria pebbles in Saalian-1 glaciofluvial sediments near the investigated volcanic localities. This 320 ka uplift event took place immediately after the doubly influence of the Lausitz Block by each 150-200 m thick Elsterian-1+2 ice sheets. Therefore, it is possible, that this neotectonic movement was triggered by isostatic glacier loading and unloading.