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
Fluvial sandy gravels of the vineyard terrace
The level ground in the uppermost part of the zoo is covered by Quaternary fluvial sands interspersed with pebbles (sandy gravels), which are the vestiges of much more extensive deposits formed by the forerunner to what is now the Vltava River.
The evolution of the Bohemian river system was characterized by a terraced arrangement imposed by alternating periods of dominant sedimentation and erosion. This is the result of a changing climate, i.e., an alternation of cold "ice" ages with warmer "interglacial" periods.
We find ourselves at the base of the vineyard terrace. Up to around half a meter above the level of the path you can see the exposed underlying rock, but look higher up the low slope and you will see sand and gravel strewn with flawlessly rounded pebbles. These loose deposits lie about fifty meters above the level of the modern floodplain of the Vltava River, and date back to around half a million years ago. They provide evidence that the Prague Basin used to be much shallower and vaster. In addition, it did not have continuous forest cover, and the river would often change course within the basin.
Prague's borders
Prague's borders encompass ten different river terraces, which are referred to by local place names. The terrace found on the zoo grounds is called the Vineyard Terrace – it is the terrace next to which we find ourselves.
