Zakázanka
Menu- Welcome to Zakázanka
- In search of bygone eons
- An example of a reverse fault and a crush zone
- Folds
- A fault separating two geological periods
- Iron ore
- Exposed boundary
- What is growing here (1)
- What is growing here (2)
- Little warm lovers
- Sun lovers
- Bedrock
- Fluvial sandy gravels of the vineyard terrace
- Local denizens of the air
- A window into Prague's geological past
- Iron ore on the zoo grounds
- The rock face bears silent witness
- Regeneration of the rocky steppe
Bedrock
The bedrock consists of folded and slightly metamorphosed sediments from the late Proterozoic (around 600 million years ago). They are the remnants of the floor of an antediluvian sea that covered this area to a depth of over 200 meters.
The layers you see at this stop show a distinctly visible syncline, i.e. a trough-like bend of the layers that is part of the fold arrangement. This folding, which was accompanied by slight metamorphism, took place towards the end of the Proterozoic (during the Cadomian Orogeny).
Na ukázkách představujeme tři základní horniny starohorních usazenin z okolí Zakázanky.
Wacke consists of sandstone
Wacke consists of sandstone. It contains more than 20 % of unstable components, and sometimes a clayey binding agent. Wackes generally have darker, grayish hues. They occur predominantly in Proterozoic rocks.
Slates
Slates were formed by compaction of the finest, mainly clayey, mud and can split into thin slabs.
Lydites
Lydites (cherts) are solid compact rocks, usually dark gray in color. They consist almost exclusively of quartz. At the zoo, they occur only in pebbles of basal conglomerate.
Siltites
Siltites are composed predominantly of dust-sized particles (0.06 - 0.004 mm), and therefore constitute a transition from slates to wackes.