Regularly directed complex linear landforms in central Europe: a large-scale disperse or zone distribution, and indication of associated landscape phenomena

The parallel linear landforms, frequent phenomena in many places on the Earth's crust surface, were systematically assessed in the area of central Europe (~3,000 km longitudinally, ~2,000 km latitudinally). In total, we estimated yet ~24,000 items. Several (>5) variously oriented large systems (networks) of such topographic features pervade fairly regularly the region.

Our study using the LiDAR or SRTM data (1) allowed to outline spatial distribution of the occurring lines, mostly by considering basic complex surface geometries or directional trends (including chaining of landforms of different types) instead of simple linear elements (valley sections, slopes, ridges) commonly applied during automatic extraction procedures. Primarily created in the Czech national conformal conic S-JTSK projection as straight features, the landforms are displayed as slightly bended curves in the WGS geographical coordinates. Usually, a general trend of some important regional fault system of Palaeozoic or Mesozoic origin served as primary direction at searching for analogous surface elements within the particular linear network in the surroundings. However, most of the linear landforms do not correspond to geological boundaries since the topographic features of all the distinguished directions are dispersed across many of regional geological units. But the elongated element clusters (zones) can accord with significant geological structures (basins, mountain ranges, or their margins) and some linear topographic features fairly correspond with current spatial limits of young sedimentary formations (covers).

(2) A plenty of other regional or local natural phenomena in the present-day landscape are closely associated with the linear landform systems. The regional features include general orientation and detailed shape of river and valley network sections (abundant deflections into the main directions), dense block segmentation of the topographic structure (separation of lower and higher surface levels) or location of concentrated surface erosion; all the main linear systems are followed by the same such expressions. Locally, smaller landforms like related saddles, cuestas, anomalously shaped meanders, river terrace risers, land slide or even cirque elements have evolved. Thus, the linear networks strongly influenced upper parts of the Earth's crust.

Besides aspects of the subject presented, a discussion on various development stages of linear landforms and related features in the deeper Earth's crust possibly including also some plate tectonics elements, as precursors of the focused surface expressions, is called for to provide proper explanation of the extensive phenomenon.