Cadastral area: Kojetín
Area: 0,2331 ha, protective zone not proclaimed
Date of the proclamation: 23.4.1997
Charakterization: Important geological locality - exposure of picrit almond-stones from the period of lower chalk.

Protective motive is geological. It concerns the conservation of one of the kinds of undersea volcanic activity in the perion of lower chalk. It originated here so-called "picrit almond-stone".


Stopping Nr. 10 - Natural monument
Picrit almond-stones by Kojetín, nature trail of Palacký
(elevation above sea level 490 m)

You did well deciding to continue in the marked route of Nature trail relating to national history and geography of František Palacký.

On the southern edge of housing Kojetín we stop in the former picrit quarry. After the stoppage of mining at the turn of the 19th and 20th century the local road leading from Kojetín to Straník diverted by quarry wall, that originally went around the whole locality eastwards. Thanks to the stoppage of mining, that didn't benefit in view of the character of mineral, typical example (stratotype) of one of kinds of undersea volcanic activity from the period of lower chalk stayed open for us.

It concerns the picrit almond-stone of so-called tephra association of volcanic minerals of Silesian unit (component part of so-called formation of Těšín - Hradiště). This few coherent mineral contains frangments of lavas of trachytického composition, thermally transformed and keratious fragments of sedimentary minerals from the surroundings, together with small material of volcanic origin and with aggregates (almonds) of minerals, as calcite and others. The mineral originated by sedimentation of still glowing fragments of lava (volcanic bombs) together with volcanic sand and dust, released during undersea explosures, and damaged sedimentary minerals from the surroundings. After the sedimentation the mineral was transformed on the one hand by seepage of solutions of volcanic origin, on the other hand by the very fact of action of sea water.

Nowadays on the walls of exposures develops natural rock plant association with crownwetch (Coronilla varia L.), fescue (Festuca rupicola), stonecrop (Sedum acre), basil thyme (Acinos arvensis) and other species.

For its extraordinary value there was proclaimed in the locality statutory protection of the category "natural monument". Walls of the quarry aren't allowed to be wilfully disturbed.