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The Coal Creek Serpentinite is a small section of outcrop that consists of precambrian aged metamorphic rock located in the Llano Uplift area of Texas. The entire outcrop can be accessed by driving on Willow City Loop and County Road 310. The easiest way of getting to a descent outcrop is turning onto Willow City Loop off of State Road 16.
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Accessibility
The Coal Creek Serpentinite is accessible only by entering private property, so prior permission is required. The Willow City Loop, which is the main route can be accessed by the public, however signs are posted exclaiming no one can stop for anything.
Geology
The rocks that make up the Coal Creek Serpentinite Formation is PreCambrian in age (around 1 to 1.2 billion years old). A time when Texas was much like today's Gulf of Mexico, a stable sedimentary basin. The sediments that were deposited is known as the Packsaddle and Big Branch sediments; exposed now as schists and gneisses. Mountain building episodes crushed these sediments into what we see today; this particular area is known for its altered serpentine rocks.
Composition
Light to green to very dark green rocks. Varies widely in texture, and one large mass in south eastern Llano region, comprises 2.54 square miles in a mass 3.7 miles long. Potential source of magnesium, silica gel, and byproduct of nickel and chromium.