GEOLEX

Summary of Citation: Black Rock

Publication:
Emerson, B.K., 1898, Description of the Holyoke quadrangle
   [Massachusetts-Connecticut]: U.S. Geological Survey Geologic
   Atlas of the United States, Holyoke folio, no. 50, 8 p.

Usage in Publication:
Black Rock diabase*

Modifications:	Geologic Province:	Dominant Lithology:
Named	New England province Hartford basin	Diabase

Summary:
Volcanic plugs parallel with Holyoke Range and 1 mi southeast of it, intrusive into Triassic and Jurassic sediments, are named Black Rock diabase. One is quartz diabase; others are similar to bedded trap rock but are fresher and form domes. Age is Triassic-Jurassic.

Summary of Citation: Black Rock

Publication:
Emerson, B.K., 1917, Geology of Massachusetts and Rhode Island:
   U.S. Geological Survey Bulletin, 597, 289 p.

Usage in Publication:
Black Rock diabase+

Modifications:	Geologic Province:	Dominant Lithology:
Abandoned	New England province Hartford basin

Summary:
Black Rock diabase is not an isolated intrusive plug as first supposed, but is a part of the Hampden diabase sheet.

Summary of Citation: Black Rock

Publication:
Balk, Robert, 1957, Geology of the Mount Holyoke quadrangle,
   Massachusetts: Geological Society of America Bulletin, v.
   68, no. 4, p. 481-504

Usage in Publication:
Black Rock diabase breccia dike

Modifications:	Geologic Province:	Dominant Lithology:
Overview Revised	New England province Hartford basin

Summary:
Black Rock diabase breccia dike in Granby tuff consists of fragments of diabase, tuff, and sedimentary rocks in diabase matrix. Cuts basal sediments above Holyoke diabase sheet.