stripes
Occurrence number:
174-00-009
Country:
United States
Region:
Alaska
Location:
Longitude: -162.8, Latitude: 64.73
Carbonatite:
No
Over an area of some 260 km2 in the southeastern part of the Seward Peninsular is a swarm of northeast-trending alkaline dykes which cut Cretaceous granodiorite and syenite, and marbles which are probably of pre-Ordovician age. The dykes are generally 3-10 m thick and comprise pulaskite, pseudoleucite porphyry and foyaite. They are characterized by the presence of nepheline, alkali feldspar, abundant pseudoleucite, melanite and fluorite.
References:
MILLER, T.P. 1972. Potassium-rich alkaline intrusive rocks of western Alaska. Bulletin of the Geological Society of America, 83: 2111-28
Map:
Fig. 1_120 General distribution of alkaline rocks in western Alaska (after Miller, 1972, Fig. 1).
Location: