Results 171 to 180 of about 1,312 (211)

TRANSFORMATION OF ORGANIC MATTER DURING METASOMATIC ALTERATION

International Geology Review, 1989
Ye. S. Larskaya, R. G. Pankina, O. P. Chetverikova, I. V. Kucherenko, A. N. Sukhova, T. Yu. Pentina, Yu. M. Korolev   +6 more
exaly   +2 more sources

Metasomatic alterations of olivine inclusions in the Budulan mesosiderite

Petrology, 2010
Mesosiderites are thermal metamorphic breccias consisting of fragments of pyroxene-plagioclase rocks and FeNi metal. The silicate constituent of mesosiderites has a chemical and oxygen isotopic composition analogous to those of meteorites of the HED group: howardites, eucrites, and diogenites.
Lorenz, C. A., Nazarov, M. A., Brandstaetter, F., Ntaflos, Theodoros   +3 more
openaire   +1 more source

Lagrangian and Eulerian Representations of Metasomatic Alteration of Minerals

1987
Both Lagrangian and Eulerian formulations of fluid flow coupled to fluid/rock interaction provide complete descriptions of metasomatic processes based on a continuum representation of porous media. The Eulerian method is an inherently transient description of advective and diffusive/dispersive transport referred to a reference frame that is fixed with ...
Harold C Helgeson, William M Murphy, Peter C Lichtner   +2 more
exaly   +2 more sources

Evidence of multiple halogen sources in scapolites from iron oxide-copper-gold (IOCG) deposits and regional Na Cl metasomatic alteration, Norrbotten County, Sweden [PDF]

Chemical Geology, 2017
Scapolites from barren regional Na-Cl metasomatic assemblages (RM), iron oxide-copper-gold deposits (IOCG), scapolite altered metabasic rocks (IOCG-M), and from IOCG-proximal alteration/Na-skarns (IOCG-PS) from Norrbotten County in Northern Sweden have ...
Jaime Barnes, Martin Smith, Sarah A Gleeson   +2 more
exaly   +3 more sources

Chemical aspects of hydrothermal alteration with emphasis on hydrogen metasomatism

Economic Geology, 1964
The ratio of cation to hydrogen-ion concentration is used as a basis for coordinating many observed varieties of silicate rock alteration. Low ratios drive alteration from feldspar through sericite, montmorillonite, or paragonite, toward kaolinite or pyrophyllite.
J. J. Hemley, W. R. Jones
openaire   +1 more source

Metasomatic alteration of pelagic ooze on spreading ocean ridges

Marine Geology, 1982
Abstract The lithologic unit 5 at DSDP Site 251 on the western flank of the southwest branch of the Indian Ocean Ridge, in which low-temperature metasomatic grandite hydrogarnet occurs, is shown to have been a nannofossil ooze when the hydrothermal solution was introduced. Extensive recrystallization of calcite occurred subsequent to the formation of
A.J. Easton, I.E. Joslin, D.R.C. Kempe, J.M. Hancock   +3 more
exaly   +2 more sources

Mineralogical zonation and metasomatism of the alteration pipes of Cyprus sulfide deposits

Economic Geology, 1989
The stockwork mineralized lavas associated with the cupriferous pyrite deposits of Cyprus occur in the cores of concentrically zoned alteration pipes. These represent the channels of ascending hydrothermal solutions. This paper reports a detailed mineralogical and geochemical study of the Pitharokhoma alteration pipe and reconnaissance studies of other
H. G. Richards, J. R. Cann, J. Jensenius
openaire   +1 more source

Magnesium metasomatism during hydrothermal alteration of new oceanic crust

Geology, 1978
A semiquantitative calculation of the amount of Mg fixation during greenschist-facies metamorphism of a 1-km-thick section of the oceanic crust beneath mid-ocean ridge crests shows that it is of the same order of magnitude as the “excess” (unbalanced) input of this element to the ocean.
Salman Bloch, Albrecht W. Hofmann
openaire   +1 more source

Geochemical features of metasomatically altered granitic rocks in Azov region

International Geology Review, 1967
Mineralogical and chemical analyses, distribution-abundance of Li, Rb, Ta, Nb, Be, Sn, Zr and rare earths of granitoid massifs and migmatites, and other data show that the altered granitoids in the area are essentially transitions from lithionite-amazonite-biotite to biotite-albite apogranites representing early stages of the metasomatic process. --IGR
I.K. Pyatenko, A.A. Sitnin, A.F. Lavrinenko   +2 more
openaire   +1 more source

Metasomatism in Iceland: Hydrothermal Alteration and Remelting of Oceanic Crust

1987
The geochemistry of Icelandic volcanics, especially as pertains LIL-elements, RE-elements, and isotopes, has in the literature called for explanations involving heterogeneous mantle source. These explanations are shown to be incompatible with the data at hand.
S. Steinthórsson, N. Óskarsson, S. Arnórsson, E. Gunnlaugsson   +3 more
openaire   +1 more source