NEW ENGLAND APPALACHIAN SYSTEMS 



1S1 



•COOS ANTICLINORIUM- 





A 



Ot 



BRONSON 



«*— HILL 



ANTICLINE 



Om3<C> 5 fog 5 jLD_Djf0b£?k£^^ 



Monroe Ammonoosuc Northey Hill 

 thrust thrust thrust 



9P 



MERRIMACK SYN CLI NORIUM- 



WHITE MOUNTAIN BATHOLITH 



CO , 9 £ P'q mo syj^ C 9 PV . 



Mm 



irfMWTi 



A' 



CONNECTICUT 



■*VALLEY->-«-BRONSON HILL ANTICLINE- 

 SYNCLINORIUM 



UNITY DOME "*" MT CLOUGH^ 

 PLUTON 



CARDIGAN PLUTON 



MERRIMACK SYNCLINORIUM 



B' 



big Dl gqg 



Osp D, D 5i bg PI / Jlk kqtn Pig Dl big Dl big Dl big Dl gqg 



Mn,+ h,a„ 1-1,1 1 5d 



Northey Hill 

 thrust (overturned) 



FITCHBURG PLUTON- 



B' 



949 Dl 



PAWTUCKAWAY 

 RING-DIKE COMPLEX 



■ m, nn „S0, 

 d id/ Q<W i \ 



ROCKINGHAM 



EXETER 

 PLUTON 



ANTICLINORIUM 



GREAT BAY 

 SYNCLINE 



B 



ii 



_!3 MILES 



RYE ANT. BAY OF MAINE 

 50rv .'5o"" v SOr« 



349 Dl 949 d ,d/ gg^Tx 30 /di v '\ 30 50rv .-jy^sOrv 



Fig. 11.26. Cross section of New Hampshire. After Billings, 1956. Section A-A' is across northern part of 

 state and B-B'-B" across southern part. Refer to map, Fig. 11.20. 



Hill thrust occurred. Schistosity parallel to the bedding formed during 

 the earlier stages of the folding, and fracture cleavage, essentially parallel 

 to the axial planes of the minor folds, formed during the later stages. 

 The rocks were subjected to low-grade metamorphism northwest of the 

 Ammonoosuc thrust, and to medium and high-grade alteration southeast 

 of it. The main metamorphism occurred after the Northey Hill thrust 

 and during the intrusions of the New Hampshire magma series which 

 were chiefly responsible for the medium- and high-grade metamorphism. 

 See third section in Fig. 11.27. 



Succeeding the metamorphism was the Ammonoosuc thrusting and, 

 following this, some normal faulting. Then the Moat volcanics were 

 erupted, and the plutons of the White Mountain magma series wore 

 emplaced to complete the bedrock complex. This may have occurred in 

 Mississippian time. Examine the last four diagrams of Fig. 11.27. 



Isotope Ages and the Acadian Orogeny 



It is becoming evident that die Devonian period began almost 400 

 m.y. ago, and that our previous estimates that designate this age for 



