GEOLEX

Summary of Citation: Barnard

Publication:
Richardson, C.H., 1924, The terranes of Bethel, Vermont: Vermont
   State Geologist Report, no. 14, p. 77-103

Usage in Publication:
Barnard gneiss

Modifications:	Geologic Province:	Dominant Lithology:
Named	New England province	Gneiss

Summary:
Named Barnard gneiss for Barnard Township, Windsor Co., VT. Unit is an acid intrusive gneiss forming continuous outcrop for several miles in Barnard Township. Composes prominent ridge on west side of Locust Creek north of village of Barnard, but before it enters Bethel, on north, it forms prominent ridge on both sides of Locust Creek. Unit is light gray, tinged with green from presence of a little chlorite and epidote. The Barnard is of gneissoid structure and medium to coarse grained texture. The exact age is unknown, but it seems certain to be pre-Ordovician and may even be Precambrian.

Summary of Citation: Barnard

Publication:
Aleinikoff, J.N. and Karabinos, Paul, 1990, Zircon U-Pb data
   for the Moretown and Barnard Volcanic Members of the Missisquoi
   Formation and a dike cutting the Standing Pond Volcanics, IN
   Slack, J.F., ed., Summary results of the Glens Falls CUSMAP
   Project, New York, Vermont, and New Hampshire: U.S. Geological
   Survey Bulletin, 1887-D, p. D1-D10

Usage in Publication:
Barnard Volcanic Member*

Modifications:	Geologic Province:	Dominant Lithology:
Age modified Isotopic dating	New England province

Summary:
New U-Pb zircon data indicate an age of 418+/-1 Ma (Silurian) for the Barnard Volcanic Member of Missisquoi Formation. Another sample, thought to be from Barnard, yielded an Early Cambrian age; this leads to one of two possibilities: either the rock was not actually from Barnard as was thought, or the zircons were detrital or xenocrystic in origin.

Summary of Citation: Barnard

Publication:
Thompson, J.B., Jr., 1990, An introduction to the geology and
   Paleozoic history of the Glens Falls 1 degrees x 2 degrees
   quadrangle, New York, Vermont, and New Hampshire, IN Slack,
   J.F., ed., Summary results of the Glens Falls CUSMAP project,
   New York, Vermont, and New Hampshire: U.S. Geological Survey
   Bulletin, 1887-A, p. A1-A13

Usage in Publication:
Barnard Volcanic Member*

Modifications:	Geologic Province:	Dominant Lithology:
Areal limits	New England province

Summary:
In Glens Falls quad, rocks of eastern Green Mountain terrane, east of Richardson Memorial Contact (an eastward-facing unconformity or possibly a tectonic contact) include the Hoosac, Pinney Hollow, Ottauquechee, and Stowe Formations (of probable Cambrian through Early Ordovician age), Moretown Formation (probably Ordovician), and Barnard Volcanic Member of Missisquoi Formation [unclear as to its stratigraphic position or age here]. West of Richardson Memorial Contact, rocks include conglomeratic units such as Tyson Formation as used by Doll and others (1961) [no age provided, but presumably Cambrian].

Summary of Citation: Barnard

Publication:
Trzcienski, W.E., Thompson, J.B., Jr., Rosenfeld, J.L. and
   Hepburn, J.C., 1992, The Chicken Yard line/Whately fault
   debate; from Springfield, Vermont, to Whately, Massachusetts,
   IN Robinson, Peter, and Brady, J.B., eds., Guidebook for
   field trips in the Connecticut Valley region of Massachusetts
   and adjacent states; Volume 2: University of Massachusetts,
   Geology Department Contribution, no. 66, New England
   Intercollegiate Geological Conference, 84th Annual Meeting,
   Amherst, MA, October, 9-11, 1992, p. 291-304

Usage in Publication:
Barnard Gneiss

Modifications:	Geologic Province:	Dominant Lithology:
Isotopic dating	New England province

Summary:
Isotopic age on zircons from Barnard Gneiss of 524+/-4 Ma (Cambrian) reported by Aleinikoff and Karabinos (1990) has been refined to 484+/-2 Ma (Early Ordovician) by Karabinos (personal commun., 1992). Barnard underlies the Ordovician and Silurian Hawley Formation.

Summary of Citation: Barnard

Publication:
Ratcliffe, N.M., in press, Bedrock geologic map of the Cavendish
   quadrangle, Windsor County, Vermont: U.S. Geological Survey
   Geologic Quadrangle Map, GQ- __, 1 sheet, scale 1:24,000

Usage in Publication:
Barnard Gneiss*

Modifications:	Geologic Province:	Dominant Lithology:
Age modified Overview	New England province

Summary:
The Barnard Gneiss consists of layered felsic and mafic gneiss. Unit is heterogeneous consisting of light-gray, magnetite-hornblende-biotite-plagioclase-quartz granofels, hornblende fascicle schist or dark-gray to greenish-gray-weathering, biotite-hornblende-plagioclase amphibolite. Passes laterally into rusty weathering amphibolite. Overlies rusty weathering sulfidic schist of the Moretown Formation. The age of the Barnard is Ordovician and Silurian. U-Pb age on zircon from felsic, probably youngest, nearly concordant intrusive phase of Barnard yields date of 418+/-1 Ma (Aleinikoff and Karabinos, 1990), which gives an upper age of probably Late Silurian. Elsewhere, Barnard contains zircon dated as old as Middle Ordovician or even Cambrian (Aleinikoff and Karabinos, 1990). Age is most probably Ordovician to Silurian.