Publisher © Czech Geological Survey, ISSN: 2336-5757 (online), 0514-8057 (print)
Geological setting of the Jedlka slope movement locality and its surroundings
Abstract
Another important locality of deep-seated slope movement near the Jedlka village is situated within the superficial volcanic products of the České středohoří Mts. volcanosedimentary complex. These products are subdivided into three formations by their lithology, but only two lower ones are affected by slope movement activities. This movement begins with multiple block-sliding along subvertical planes and all the rest of the slope is covered by debris accumulation down to the Ploučnice River course. The volcanics are represented by solid and argillized basanitic lavas and clayey volcaniclastics of hyaloclastic origin. These rocks form the lower Ústí Fm., together with the underlying coarse-grained products of volcanic debris flows in the western part of this area. This unit is overlain by pyroclastics of trachybasalts intercalated with thin subaerial lava flows and sheet in the upper part - the Děčín Fm. These pyroclastics were redeposited by lahars (volcanic mudflows) and washed down in a shallow lake environment in the marginal part of a composite volcano. The presence of clay material in the rocks of the Ústí Fm. is essential for the slope movement with the more solid rocks of the Děčín Fm. representing mere passive elements in this process.
