Announcement

Collapse
No announcement yet.

Metavolcanics of North Carolina

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Metavolcanics of North Carolina

    Metavolcanics encompass a range of metamorphosed igneous rock, most notably rhyolite.Rhyolite, (or meta-rhyolite) is formed in a volcanic environment at or near the earth's surface,usually in volcanic flows.Several varieties are found in N.C. Aphyric rhyolite is fine-grained and often exhibits flow-banding (which is most apparent when weathered).When fresh the color is a dark, almost-black, grey. Weathered examples develop a chalky patina that can be off-white to cake-batter yellow in color. Porphyritic rhyolite is notable for small inclusions or 'specs' of quartz or feldspar in a light to dark grey matrix.It's texture ranges from fine-grained to 'sugary'.Rhyolitic tuff formed not in magma flows but as ash or dust.It has a variable texture and color, ranging from fine-grained to sugary and in various shades of green to light gray in color.The Uwharrie Mountains in south-central N.C., particularly the area around Morrow Mountain, is the source of these varieties of rhyolite. This material is often identified as "silicified slate".

    Information and photo courtesy of Truett
    Last edited by gregszybala; 02-13-2016, 10:48 AM.
    Searching the fields of NW Indiana and SW Michigan
Working...
X