stripes
Occurrence number:
174-00-095
Country:
United States
Region:
New Mexico
Location:
Longitude: -106, Latitude: 35
Carbonatite:
No
This syenite outcrops over an area of 3000x220 m and apparently intrudes Precambrian schists. It is a pink rock of 60% albite and orthoclase as phenocrysts and matrix, 3-5% oligoclase, much altered to clay minerals, sericite, 5-10% hematite dust, 1-2% voids after amphibole lined with magnetite, clays, sericite and fluorite; a little calcite and quartz are also present. The average K2O value of four chemical analyses was 14.2% (Loring and Armstrong, 1980, Table 1) with Na2O 2.9%.
Age:
A maximum age of 604 Ma by Rb-Sr on a whole rock sample has been calculated by Loring and Armstrong (1980, p. 345).
References:
LORING, A.K. and ARMSTRONG, D.G. 1980. Cambrian-Ordovician syenites of New Mexico, part of a regional alkalic intrusive episode. Geology, 8: 344-8
Location: