Robertson River Igneous Suite - Battle Mountain Alkali Feldspar Granite - felsite

Light-gray to gray, fine-grained to aphanitic, equigranular to sparsely porphyritic (mesoperthite phenocrysts) felsite composed of alkali feldspar, quartz, and rare plagioclase with minor biotite, aegirine, fluorite, and basnäsite; locally displays flow banding, miarolitic cavities containing quartz, and probable lithophysae; intrudes associated alkali feldspar granite; dated at 704±4 Ma (U-Pb zircon; Tollo and Aleinikoff, in press).
State Virginia
Name Robertson River Igneous Suite - Battle Mountain Alkali Feldspar Granite - felsite
Geologic age Proterozoic Z
Lithologic constituents
Major
Igneous > Volcanic > Felsic-volcanic
Comments Blue Ridge Basement Complex, Late Proterozoic Igneous
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 Culpeper - Rappahannock