Home
Map
Browse Map
Explore away
Explore Map Collection
Check out our basemaps
Print a Map
Plus
Generate a high-quality PDF
Field Guide
Field Guide
Discover local flora, fauna, geology, and more
Local Flora & Fauna
Learn the ecology of your area
Local Geology
Learn the geologic formation at your feet
Get Started
or
Sign In
Welcome
Sign up to start exploring the one-of-a-kind Natural Atlas Topo map
Continue with Apple
Or
Sign up with Email
Already have an account?
Sign In
MAP
Topo
Waterfalls
Rock Formations
Campgrounds
Trails
Boat Launches
National Parks
State Parks
Scenic Spots
Measure
You must upgrade to measure routes
Start Free Trial
0 ft
Max
0 ft
Copyright
© Natural Atlas
| Roads, Buildings
© OSM Contributors
|
Data Sources
Topo
Ecoregions
Public Lands
...
BASEMAPS
Default Weather
Temperature
Smoke
...
WEATHER
Catoctin Formation - Metabasalt (VACAZc;0)
Geologic Formation
in
VA
,
WV
,
MD
Print Map
Generate High-Quality PDF
Lithology
Metabasalt
Geologic Age
Neoproterozoic – Cambrian (1000 Ma – 487.3 Ma ago)
Geologic Unit Label
CAZc
Grayish-green to dark-yellowish-green, fine-grained, schistose chlorite- and actinolite-bearing metabasalt, commonly associated with epidosite segregations. Mineralogy: chlorite + actinolite + albite + epidote + titanite ± quartz + magnetite. Relict clinopyroxene is common; biotite porphyroblasts occur locally in southeastern outcrop belts. Geophysical signature: The Catoctin as a whole has a strong positive magnetic signature. However, between Warrenton and Culpeper the lowest part of the Catoctin, which consists of low-titanium metabasalt and low-titanium metabasalt breccia, is non-magnetic, and displays a strong negative anomaly. Metabasalt (CZc) is by far the most widespread unit comprising 3000 feet or more of section (Gathright and others, 1977). Primary volcanic features are well preserved in many places. In the north west ern outcrop belt, these include vesicles and amygdules, sedimentary dikes, flow-top breccia, and columnar joints (Reed, 1955; Gathright, 1976; Bartholomew, 1977); relict pillow structures have been reported in Catoctin greenstones east of Buena Vista (Spencer and others, 1989). In the southeastern outcrop belt, amygdaloidal metabasalts are common, as are volcanoclastic rocks interbedded with basaltic fl ows (Rossman, 1991). Fragmental zones occur locally between individual lava fl ows; map-scale hyaloclastite pillow breccias occur at three strati raphic levels within the southeastern outcrop belt (CZcb, CZhb, CZlb; Espenshade, 1986; Kline and others, 1990).
—
USGS
Taxonomy
Classified As
Geologic Formation
Search
Search the outdoors
Map
Plans
Field Guide
Community
My Profile
My Trips
0
My Field Notes
0
Notifications
More