NO-SERVICE INFORMATION STAND (BIS)
GPS: 49°50’19.67″ N, 15°47’57.71″ E
The open-air information system for the visitors of the Iron Mountains and for geotourists in the territory of the Iron Mountains PLA and the Iron Mountains National Geopark is structured into several levels. No-service information stands (BIS) are ranked among essential elements of this system. The choice of the site for BIS location is not an arbitrary one: the site must always meet many criteria representing one of the five themes contained in the logo of the “The Iron Mountains – a geologically significant regionˮ project and the Iron Mountains Geopark.
THE SITE OF NASAVRKY HAS BEEN CHOSEN FOR THE NO-SERVICE INFORMATION STAND FOCUSED ON ABYSSAL MAGMATITES – PLUTONITES.
The site is located in the central part of the Železné hory plutonic complex – in the Nasavrky pluton. According to petrographic classification, boulders and cliffs at this site are composed of granodiorite to tonalite. Small quarries were operated to supply stone for local needs. Most of them have been flooded or backfilled. The granodiorite body is lined by minor bodies of basic differentiates having the character of metagabbro. The high plateau around Nasavrky is typically covered with a relatively thick layer of weathering products – sandy eluvia.
The area with occurrences of abyssal magmatites is extensive, stretching from Nasavrky to Skuteč and from Trhová Kamenice to Hlinsko. The age of the magmatites varies between 300 and 360 million years, falling within the Paleozoic – the Carboniferous. Granites exceeding 400 million years in age (Paleozoic – Ordovician) were encountered in the Chvaletice area.
Pilgrimage in quest of the granites can be best started at Nasavrky. One of the reasons is that the massif of abyssal magmatites was named after Nasavrky by the geologist and local patriot Dr. Jindřich Vodička.
The no-service information stand consists of a wooden structure with five panels generally expanding the theme of abyssal magmatites. These panels also refer to nine geosites in the Iron Mountains with installed information panels reporting on closely accessible phenomena related to the times of magmatite formation. Then, the arrangement of lithospheric blocks was changing, accompanied by repeated ascent of different magmas from the depth. Each magma batch produced a rock of specific mineral composition.
Blocks of rocks from the territory of the Iron Mountains are scattered around the wooden structure, totalling 21 accessible samples of granites, granodiorites, gabbros and magmatites accompanied by aplite and pegmatite dykes from 12 sites. Most of these rocks were used as starting material for the aggregate production or for the manufacture of fine masonry products such as pavement stones, funeral art and plastic art products. The blocks are mostly polished, and always provided with an information pillar. The pillars comment on the origin and composition of the rocks, and bear colour photomicrographs.
Structured information provided in the no-service information stand allows the visitors (geotourists) of the Iron Mountains to get easily orientated and make their choice among other sites.