Alkaline Rocks and Carbonatites of the World

Setup during HiTech AlkCarb: an online database of alkaline rock and carbonatite occurrences

Cuttingsville

stripes

Occurrence number: 
174-00-132
Country: 
United States
Region: 
Vermont
Location: 
Longitude: -72.88, Latitude: 43.48
Carbonatite: 
No

An oval-shaped body of 2.3x1.7 km, the Cuttingsville complex intrudes Precambrian schists and gneisses of the Green Mountain anticlinorium. Four main units may be distinguished (Laurent and Pierson, 1973, p. 1246) which are from oldest to youngest: (1) hastingsite foyaite and biotite foyaite (pulaskites), (2) diorite and porphyritic diorite, (3) essexite, porphyritic essexite, plagifoyaite and sodalite foyaite and (4) quartz syenite (larvikite) and syenite. The predominantly syenitic rocks contain 80-90% perthite, but the feldspar of the diorites is labradorite. The foyaites and essexites contain nepheline and cancrinite, but sodalite is predominant in the sodalite foyaite. Quartz is present in the unit 4 syenite and in very minor amounts in the diorite. Pyroxenes vary from titanaugite in the essexites to aegirine-augite in the foyaites, hedenbergite in the syenites and pigeonite/ferroaugite in the diorites. Amphiboles are a major phase in units 1 and 2 and the porphyritic essexite of unit 3. They vary from magnesiohastingsites in the foyaites to kaersutite in the diorites. The outer contacts of the complex are not exposed but country rock xenoliths are common near the contact. Dykes are numerous within the intrusion and country rocks.

Age: 
K-Ar on biotite from foyaite gave 100 ±2 Ma and on biotite from essexite 96.4 ±2 Ma (Armstrong and Stump, 1971).
References: 

ARMSTRONG, R.L. and STUMP, E. 1971. Additional K-Ar dates, White Mountain Magma Series, New England. American Journal of Science, 270: 331-3.
LAURENT, R. and PIERSON, T.C. 1973. Petrology of alkaline rocks from Cuttingsville and the Shelburne Peninsula, Vermont. Canadian Journal of Earth Sciences, 10: 1244-56

Map: 
Fig. 1_182 Cuttingsville (after Laurent and Pierson, 1973, Fig. 2).
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith