Chemical variations within a metagabbro, N. W. Adirondack lowlands, N. Y
- State Univ., Potsdam, NY (United States). Geology Dept.
A metagabbro located in the N.W. Adirondack lowlands has been examined in order to study the chemical changes that occur from the edge of the body into the core. Samples were collected from within a mine adit starting near the contact of the country rock and going into the metagabbro for a distance of 65 feet. The country rock contains an assemblage of alkali feldspar, plagioclase, quartz, biotite, apatite and magnetite. The metagabbro contains an assemblage of plagioclase, hornblende, clinopyroxene, biotite, quartz, sphene, apatite and opaques. Chemical data show a decrease of SiO[sub 2] and K[sub 2]O from the edge of the metagabbro towards the center, and an increase in CaO, Fe[sub 2]O[sub 3], MgO, TiO[sub 2], P[sub 2]O[sub 5], Ni, V, and Cr[sub 2]O[sub 3]. The Al[sub 2]O[sub 3], and Na[sub 2]O content remain nearly constant. Hand samples stained with sodium cobaltinitrite also reflect decreasing K[sub 2]O towards the core of the body. These chemical gradations may be due to metasomatism, assimilation of country rock or true compositional zoning during crystallization of an alkali-rich gabbro.
- OSTI ID:
- 5579335
- Report Number(s):
- CONF-9303211-; CODEN: GAAPBC
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Vol. 25:2; Conference: 28. annual Geological Society of America (GSA) Northeastern Section meeting, Burlington, VT (United States), 22-24 Mar 1993; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
Similar Records
Magma mixing and mingling on Deer, Niblack, and Etolin Islands, southeastern Alaska
Origin and interaction of some alkalic and silicic plutons in the Vermilion Granitic Complex, NE Minnesota