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
In search of bygone eons
This rocky slope, at the foot of which you find yourself, allows you to gaze deep into the geological past of our planet. To look at the exposed rocks is to go back in time, to a period around 600 million years ago, when this part of the Earth's crust lay in the southern hemisphere, forming the bed of a Proterozoic sea. Go ahead and wend your way up the slope to discover the rich variety of our primordial past, along with a smorgasbord of intriguing geological phenomena.
Before we begin in earnest, let us make the acquaintance of the three most important stretches of geological history that fundamentally reshaped the bedrock of the Troja basin, including even the Zakázanka Path itself.
Cadomian Orogeny
During the Protherozoic Era, the area around us was an antediluvian seabed. Sometime around 550 million years ago, a period of fierce mountain-building activity broke up the sandy and clayey sediments, partly changing the structure of the minerals. This process bears the scientific name of Cadomian Orogeny.
The sea returneth
One hundred million years later, already during the Paleozoic Era, more precisely in the geological period known as the Ordovician, the area currently occupied by Prague was reclaimed by the sea. On the seafloor, clays, sands, and other sediments amassed, which, over a period of 100 million years, grew to a thickness of up to 3 km. From this period we already have a number of extant imprints of various animals, of which the best known are the trilobites.
Variscan Orogeny
Well before the Paleozoic Era came to an end – in the geological period known as the Carboniferous (350 to 300 million years ago) – the evolution of the Bohemian Massif was brought to its culmination by another mountain-building process: the Variscan Orogeny. This process, however, did not have much of an impact on the Prague Basin itself, which is why such a wealth of fossils has survived here.
