Results 171 to 180 of about 6,037 (231)

Zussmanite in ferruginous metasediments from Southern Central Chile

Mineralogical Magazine, 1998
AbstractZussmanite KFe13[AlSi17O42](OH)14, a modulated 2:1 layer silicate, has so far been found only in iron-rich metasediments from Laytonville, California (Agrell et al.), 1965). A new occurrence is reported here from Punta Nihue north of Valdivia, Chile, in banded stilpnomelane-schists.
H.-J. Massonne, F. Hervé, O. Medenbach, V. Muñoz, A. P. Willner   +4 more
openaire   +1 more source

Apatite as a tracer of the source, chemistry and evolution of ore-forming fluids: The case of the Olserum-Djupedal REE-phosphate mineralisation, SE Sweden

Geochimica et Cosmochimica Acta, 2019
This study explores the suitability of apatite as a tracer of the source(s), chemistry, and evolution of ore-forming hydrothermal fluids. This is tested by analysing the halogen (F, Cl, Br, and I), stable Cl isotopic, and trace element compositions of ...
S. Andersson, T. Wagner, E. Jonsson, T. Fusswinkel, M. Whitehouse   +4 more
semanticscholar   +1 more source

Paleozoic Metasediments in the Northern Ruby Mountains, Nevada

Geological Society of America Bulletin, 1971
New evidence indicates that high-grade regionally metamorphosed marble and quartzite in the northern Ruby Mountains are Paleozoic strata. Correlation is based on a match of the lithologic sequence to strata of Cambrian to Devonian age in nearby areas; particularly diagnostic is a brown dolomite at the base of the Cambrian carbonate sequence.
openaire   +1 more source

The Jutogh Group of Metasediments of the Himachal Himalaya: Its Lithostratigraphy

Journal Geological Society of India, 1988
Abstract The Jutogh Group of the Himachal Himalaya is divisible into eleven formations based on normal order of superposition, lithological association, lateral persistence and systematic mapping. This study helps greatly in reconstructing the sedimentary history, structural evolution and promoting better inter-regional correlation.
S. V. Srikantia, O. N. Bhargava
openaire   +1 more source

The metasediments of Bunbeg (County Donegal), and their relationship to the surrounding granite

Proceedings of the Geologists' Association, 1955
Abstract A detailed description is given of the petrology of a large relic of Dalradian metasediment which is completely enclosed within the Donegal Granite at Bunbeg. Particular attention is paid to the contact relations of the granite and metamorphic rocks, and evidence for metasomatism and a complex two-way diffusion is deduced.
openaire   +1 more source

Petrochemical evidence on the probable origin of ferriferous metasediments in western Bushmanland

Mineralium Deposita, 1986
The mineralized Proterozoic metasediments of Bushmanland are characterized by the presence of ferriferous rocks. This includes banded and unbanded iron formations and various types of gossans. These units are not laterally extensive and occur in different stratigraphic levels.
Willem A. van der Westhuizen, Dawid Strydom, Aylva E. Schoch, Eric A. W. Tordiffe, Gerhard J. Beukes   +4 more
openaire   +1 more source

Lithologic and stratigraphic setting of zinc mineralization in Grenville metasediments, Quebec

Mineralium Deposita, 1980
For many years, high-grade metamorphism and multiphase deformation have discouraged mineral exploration in the Grenville terrain of the Canadian Shield. However, detailed studies of known zinc occurrences in the Grenville Supergroup metasediments of Quebec now reveal that mineralization is stratigraphically controlled and consistently limited to ...
M. Gauthier, A.C. Brown
openaire   +1 more source

Textural and chemical evidence bearing on sulfide-silicate reactions in metasediments

Mineralium Deposita, 1972
Two textural relationships between pyrrhotite and ferromagnesian silicates were found to occur in a metamorphosed sandy pelite at the staurolite grade of metamorphism. (1) Increased grain size of silicates at the pyrrhotite-silicate boundary; (2) Oriented intergrowths of pyrrhotite in large grains of chlorite and biotite. Both textures were interpreted
W.J. Mallio, M.A. Gheith
openaire   +1 more source

Significance of high-grade metasediments from the Neoproterozoic basement of Eritrea

Precambrian Research, 1997
Abstract High grade orthogneiss, amphibolitic dykes and paraschist to migmatites were studied in the Red Sea Lowlands of eastern Eritrea. Chemical data and a mineral assemblage of kyanite, staurolite, almandine garnet, biotite and quartz indicate that the schists were formed by metamorphism of pelitic metasediments derived by subaerial weathering ...
Michael Beyth, Robert J. Stern, Alan Matthews   +2 more
openaire   +1 more source

Quartz-spessartine metasediments (coticules) and their protoliths in North Wales

Geological Magazine, 1989
AbstractThin beds and small pods of quartz-spessartine metasediments (coticules) occur in pelites of the Gamlan Formation (Cambrian) of the Harlech Dome. The original microfabric of these sediments has been largely destroyed by recrystallization under low greenschist facies conditions. The quartz-spessartine pods occur throughout the pelites and appear
openaire   +1 more source