tchq 



NEW ENGLAND APPALACHIAN SYSTEMS 



HYDE PARK QUADRANGLE, NW VERMONT 



€chq £0 Oi 





171 



J 



MONTPELIER QUADRANGLE, NW VERMONT 



O s o ,sgo 



Om 5 i"!J"^ 5* 



Fig. 11.19. Cross sections of northwestern Vermont in Green Mountains. Hyde Park section 

 ; after Albee, 1957. Montpelier quadrangle after Cady, 1956. €ch, Camels Hump group; Cchg, 

 .albite and tremolite greenstone; Co, Ottanquechee fm.; Os, Stowe fm.; Osga, middle unit of 



CENTRAL AND EASTERN NEW ENGLAND 



Definition 



The Acadian orogeny of Late Devonian time affected much of New 

 jEngland and the Maritime Provinces, and undoubtedly spread southward 

 through the Piedmont crystalline province of the Atlantic margin. It 

 treated a mountain system that was superposed in part on the earlier 

 Taconic system. Where best known and perhaps best displayed in New 

 Hampshire, New Brunswick, and Nova Scotia, it is an irregular north- 

 south belt east of the Taconic system, but its western limit is as yet poorly 

 defined. 



The region here discussed lies east of the crest of the Green and Berk- 

 shire Mountains and includes the New England seaboard lowland, the 

 New England upland and the White Mountains in the United States and 

 Canada. See map of Fig. 11.1 and 11.2. The seaboard lowland extends 

 along the Atlantic coast as a narrow zone from Rhode Island to the 

 border of Maine and New Brunswick. 



Os consisting of greenstone and amphibolite; Om, Moretown fm.; Omsp, carbonaceous and 

 slate member; Ssm, Shaw Mountain fm.; Sn, Northfield slate; Swr, Waits River fm.; Da, 

 Adamant granite. 



Stratigraphy and Structure of Vermont 



An immensely thick section of stratified rocks exists in northwestern, 

 central, and east-central Vermont, probably reaching a thickness of 100.- 

 000 feet (White and Jahns, 1950). The strata except some lamprophyre 

 dikes are folded and metamorphosed sedimentary and volcanic rocks. A 

 number of units, members or formations of volcanic rock throughout the 

 section from Cambrian to Lower Devonian attest the eugeosynclinal 

 nature of the deposits. See correlation chart of Fig. 11.18. 



Northwestern Green Mountains 



Two quadrangles, the Hyde Park and Montpelier, have been mapped 

 by Albee (1957) and Cady (1956), and depict the structure and stratig- 

 raphy near the north end of the Green Mountains a few miles east of the 

 crest. The sections of Fig. 11.19 show the thick succession of folded beds 

 from Cambrian to Devonian. 



The axis of the Green Mountain anticlinorium trends north-northeast across 

 the northwest corner of the Hyde Park quadrangle. This anticlinorium. which 



