Devin Floyd, whose Center for Urban Habitats team has surveyed the QGs existing biota and planned the gardens over the past two years, has along the way found rocks that help to explain our peculiar horticultural experience. A geologist by training, he plans an exhibit of rock samples for the Visitor Center.
The sample pictured on the left—composed of magnesium plus iron silicate and calcium carbonate minerals—was found near the quarries where the soil pH is 7.5-8 (alkaline). The sample on the right is an example of ferrous silicates, with “jack rocks” or “devils dice” emerging from the matrix; it was found just east of the quarries where nutrient-poor soils with pH 4.5-6 (acid) are more typical of the Charlottesville formation. (Both areas are “ultra-mafic” formations, characterized by metamorphic rocks with very low silica content, and rich in minerals.)
As the rocks make the soil, such extreme variation in geology creates the potential for a great diversity of plants and animals—one reason we’re up to more than 580 species, and counting.
Devin’s more scientific explanation may be found in CUH’s Facebook May 19 posting: https://www.facebook.com/search/top/?q=center%20for%20urban%20habitats
In other rockin’ news, last week’s Nelson County Times article announcing the Quarry Gardens’ public opening has made the rounds of other News & Advance-associated newspapers including the Charlottesville Daily Progress and the Waynesboro News Virginian. The web version of the article is here: http://www.newsadvance.com/nelson_county_times/news/quarry-gardens-in-schuyler-open-to-public/article_ec04bcc5-ae93-5ef8-9d95-3bed491d3c86.html