Mather Gorge Formation - Metagraywacke

Metagraywacke, light- to medium-gray, yellowish- to red dish-brown-weathering, fine- to medium-grained, generally well-bedded, and lesser semi-pelitic schist; contains interbedded quartzose schist and some calc-silicate rock; mineral assemblages as in schist (CZms). Beds range from about 3 cm to 3 m, averaging about 20 cm; graded bedding, sole marks, and slump features are abundant. Mather Gorge is unconformable beneath Popes Head Formation, which is intruded by Occoquan Granite; includes rocks previously mapped in northern Virginia as Peters Creek Schist.
State Virginia
Name Mather Gorge Formation - Metagraywacke
Geologic age Proterozoic Z-Cambrian
Lithologic constituents
Major
Metamorphic > Metasedimentary > Metaclastic > Metasandstone > Metagraywackemetargillite, metagraywacke
Comments Western Piedmont (Northern)
References

Virginia Division of Mineral Resources, 1993, Geologic Map of Virginia: Virginia Division of Mineral Resources, scale 1:500,000.

Virginia Division of Mineral Resources, 2003, Digital Representation of the 1993 Geologic Map of Virginia, Publication 174, CD ROM (ISO-9660) contains image file, expanded explanation in pdf, and ESRI shapefiles, scale 1:500,000.

NGMDB product
Counties Fairfax - Loudoun