Metasiltstone is the most commonly found rock at the Meadow Creek South trail. It can be differentiated from nearby metasandstone by its much finer-grained texture. Metasiltstone and metasandstone are part of a group of rocks called metasedimentary rocks, which originated as sedimentary rocks like shale, sandstone, and siltstone before being transformed by heat and/or pressure into their current form. As a group, metasedimentary rocks are one of the most common groups of rocks underlying the Virginia Piedmont. Metasedimentary rocks are typically rich in quartz and iron and therefore create soils which are usually lower in important plant nutrients like calcium and magnesium. Many species of plants are well adapted to these conditions, like white pine (Pinus strobus), pinxter azalea (Rhododendon periclymenoides), lowbush blueberry (Vaccinium pallidum) and mountain-laurel (Kalmia latifolia). Can you spot any of these along the trail?
Bibliography & Definitions
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1 King, Hobart M. “Sandstone: Sedimentary Rock – Pictures, Definition & More.” Geology.com, 2019, geology.com/rocks/sandstone.shtml.
2 —. “Siltstone: A Sedimentary Rock Made up of Silt-Size Particles.” Geology.com, geology.com/rocks/siltstone.shtml#google_vignette.
8 —. “What Are Metamorphic Rocks? | U.S. Geological Survey.” Www.usgs.gov, www.usgs.gov/faqs/what-are-metamorphic-rocks.
Definitions:
Metamorphic: a rock which was originally a different type, but was transformed by natural processes like pressure or extreme heat.8
Sedimentary: a rock which was formed by the concretion of sediment particles (sand, silt, mud, clay) in place, or through mineral deposition. Often, the layers of sediment are visible, such as in sandstone.6
Siltstone: a sedimentary rock composed of silt particles (larger than clay, smaller than sand).2,5
Sandstone: a sedimentary rock composed of sand-sized particles (1/16-2 mm).1,4
