Bruce Yardley - Academia.edu (original) (raw)
Papers by Bruce Yardley
An Introduction to Metamorphic Petrology
Mineralogical Magazine
The Huanglongpu carbonatites are located in the north-western part of the Qinling orogenic belt i... more The Huanglongpu carbonatites are located in the north-western part of the Qinling orogenic belt in central China. Calcite carbonatite dykes at the Dashigou open pit are unusual due to their enrichment in heavy rare earth elements (HREE) relative to light rare earth elements (LREE), leading to a flat REE pattern, and in that the majority of dykes have a quartz core. They also host economic concentrations of molybdenite. The calcite carbonatite dykes show two styles of mineralogy according to the degree of hydrothermal reworking, and these are reflected in REE distribution and concentration. The REE in the little-altered calcite carbonatite occur mostly in magmatic REE minerals, mainly monazite-(Ce), and typically have ΣLREE/(HREE+Y) ratios from 9.9 to 17. In hydrothermally altered calcite carbonatites, magmatic monazite-(Ce) is partially replaced to fully replaced by HREE-enriched secondary phases and the rocks have ΣLREE/(HREE+Y) ratios from 1.1 to 3.8. The fluid responsible for hyd...
Geochemistry
Abstract The Shurab Sb-polymetallic mineralization is a subvolcanic rock-hosted epithermal deposi... more Abstract The Shurab Sb-polymetallic mineralization is a subvolcanic rock-hosted epithermal deposit and located in north Lut Block, eastern Iran. It is one of the most important deposits of the Iranian East Magmatic Assemblage (IEMA) in which numerous Middle-Cenozoic precious and base metals deposits occur. The main lithological units in the area are Paleogene subvolcanic intrusions and minor Jurassic sedimentary rocks. Mineralization occurs as veins in a series of NW-SE and E-W trending faults and fractures in the Eocene-Oligocene dacite and andesite subvolcanic rocks. Mineralization at the Shurab deposit can be subdivided into four stages: pre-ore stage, Cu-Zn-Pb ore stage, Sb-Ag ± As ore stage and post-ore stage. The total sulfide content of the veins in the area is variable, ranging from 1 to 50%, and is dominated by stibnite, chalcopyrite, galena, Fe-poor sphalerite and pyrite with minor chalcostibite, Ag-tetrahedrite and bournonite; gangue minerals are mainly quartz and calcite. Silicic, argillic, propylitic, and sericitic, are the most obvious wall rock alterations. Microthermometric measurements of primary liquid-rich fluid inclusions in quartz and sphalerite indicate that the veins were formed at temperatures between 115 and 290 °C from fluids with salinities between 0.7 and 16.2 wt% NaCl eq., suggesting an epithermal origin. The δ34S values of pyrite, chalcopyrite and galena vary between -2.5 and 0.8‰, and δ18O values of quartz range between 12.5 and 14.8‰. It is inferred that the Shurab mineralization is of epithermal origin, related to an Eocene-Oligocene magmatic geothermal system involving fluids of magmatic and meteoric origin.
Mineralogical Magazine
Multi-element crush-leach analysis of H2O-CO2 inclusion fluids from a suite of six vein samples f... more Multi-element crush-leach analysis of H2O-CO2 inclusion fluids from a suite of six vein samples from gold-quartz veins in the Brusson district demonstrates that their solute chemistry (c. 5 wt.% NaCl equivalent) is dominated by sodium chloride with lesser amounts of calcium bicarbonate, potassium chloride and sodium bicarbonate. The samples have been analysed both for gas species (CO2, H2O, N2 and H2S) and for Na, K, Li, Rb, Ca, Mg, Sr, Ba, Fe, Mn, Zn, Pb, Cu, Al, As, B, SO4 2−, F, Cl, Br and I. The fluids contain appreciable H2S (>10−3 molal), which correlates with the contents of As, CO2 and B. Concentrations of many cations remain similar irrespective of wall rock, but there is evidence of leaching of Li, and possibly I, from some wall rocks. Large variations in the K-content of the fluid may result from precipitation of sericite. The bicarbonate concentrations in the fluids, estimated from charge imbalance, are substantially less than their total CO2 content when trapped as s...
Encyclopedia of Astrobiology, 2015
Environmental Geochemistry and Health, 2001
Journal of Metamorphic Geology, 1990
Journal of Geophysical Research, 1998
… Association of Canada …, 2008
Geophysical Research Letters, 2014
Geochimica et Cosmochimica Acta, 1995
Geochimica et Cosmochimica Acta, 1996
Quartz veins hosted by late Hercynian granites and their host rocks occur across the Variscides o... more Quartz veins hosted by late Hercynian granites and their host rocks occur across the Variscides of the northern Iberian peninsula, and locally display Au-As mineralization. Four separate occurrences at Corcoesto, Tomino, Penedono, and Pino have been investigated to determine P-T-X conditions of formation and likely fluid sources. Special attention has been paid to fluid chemistry using a multidisciplinary investigation of
Economic Geology, 1995
Page 1. Economic Geology Vol. 90, 1995, pp. 1271-1287 Geochemistry of Th-U-REE Mineralizing Magma... more Page 1. Economic Geology Vol. 90, 1995, pp. 1271-1287 Geochemistry of Th-U-REE Mineralizing Magmatic Fluids, Capitan Mountains, New Mexico ANDREW R. CAMPBELL, Department of Geoscience, New Mexico Institute ...
Crustal Permeability, 2016
An Introduction to Metamorphic Petrology
Mineralogical Magazine
The Huanglongpu carbonatites are located in the north-western part of the Qinling orogenic belt i... more The Huanglongpu carbonatites are located in the north-western part of the Qinling orogenic belt in central China. Calcite carbonatite dykes at the Dashigou open pit are unusual due to their enrichment in heavy rare earth elements (HREE) relative to light rare earth elements (LREE), leading to a flat REE pattern, and in that the majority of dykes have a quartz core. They also host economic concentrations of molybdenite. The calcite carbonatite dykes show two styles of mineralogy according to the degree of hydrothermal reworking, and these are reflected in REE distribution and concentration. The REE in the little-altered calcite carbonatite occur mostly in magmatic REE minerals, mainly monazite-(Ce), and typically have ΣLREE/(HREE+Y) ratios from 9.9 to 17. In hydrothermally altered calcite carbonatites, magmatic monazite-(Ce) is partially replaced to fully replaced by HREE-enriched secondary phases and the rocks have ΣLREE/(HREE+Y) ratios from 1.1 to 3.8. The fluid responsible for hyd...
Geochemistry
Abstract The Shurab Sb-polymetallic mineralization is a subvolcanic rock-hosted epithermal deposi... more Abstract The Shurab Sb-polymetallic mineralization is a subvolcanic rock-hosted epithermal deposit and located in north Lut Block, eastern Iran. It is one of the most important deposits of the Iranian East Magmatic Assemblage (IEMA) in which numerous Middle-Cenozoic precious and base metals deposits occur. The main lithological units in the area are Paleogene subvolcanic intrusions and minor Jurassic sedimentary rocks. Mineralization occurs as veins in a series of NW-SE and E-W trending faults and fractures in the Eocene-Oligocene dacite and andesite subvolcanic rocks. Mineralization at the Shurab deposit can be subdivided into four stages: pre-ore stage, Cu-Zn-Pb ore stage, Sb-Ag ± As ore stage and post-ore stage. The total sulfide content of the veins in the area is variable, ranging from 1 to 50%, and is dominated by stibnite, chalcopyrite, galena, Fe-poor sphalerite and pyrite with minor chalcostibite, Ag-tetrahedrite and bournonite; gangue minerals are mainly quartz and calcite. Silicic, argillic, propylitic, and sericitic, are the most obvious wall rock alterations. Microthermometric measurements of primary liquid-rich fluid inclusions in quartz and sphalerite indicate that the veins were formed at temperatures between 115 and 290 °C from fluids with salinities between 0.7 and 16.2 wt% NaCl eq., suggesting an epithermal origin. The δ34S values of pyrite, chalcopyrite and galena vary between -2.5 and 0.8‰, and δ18O values of quartz range between 12.5 and 14.8‰. It is inferred that the Shurab mineralization is of epithermal origin, related to an Eocene-Oligocene magmatic geothermal system involving fluids of magmatic and meteoric origin.
Mineralogical Magazine
Multi-element crush-leach analysis of H2O-CO2 inclusion fluids from a suite of six vein samples f... more Multi-element crush-leach analysis of H2O-CO2 inclusion fluids from a suite of six vein samples from gold-quartz veins in the Brusson district demonstrates that their solute chemistry (c. 5 wt.% NaCl equivalent) is dominated by sodium chloride with lesser amounts of calcium bicarbonate, potassium chloride and sodium bicarbonate. The samples have been analysed both for gas species (CO2, H2O, N2 and H2S) and for Na, K, Li, Rb, Ca, Mg, Sr, Ba, Fe, Mn, Zn, Pb, Cu, Al, As, B, SO4 2−, F, Cl, Br and I. The fluids contain appreciable H2S (>10−3 molal), which correlates with the contents of As, CO2 and B. Concentrations of many cations remain similar irrespective of wall rock, but there is evidence of leaching of Li, and possibly I, from some wall rocks. Large variations in the K-content of the fluid may result from precipitation of sericite. The bicarbonate concentrations in the fluids, estimated from charge imbalance, are substantially less than their total CO2 content when trapped as s...
Encyclopedia of Astrobiology, 2015
Environmental Geochemistry and Health, 2001
Journal of Metamorphic Geology, 1990
Journal of Geophysical Research, 1998
… Association of Canada …, 2008
Geophysical Research Letters, 2014
Geochimica et Cosmochimica Acta, 1995
Geochimica et Cosmochimica Acta, 1996
Quartz veins hosted by late Hercynian granites and their host rocks occur across the Variscides o... more Quartz veins hosted by late Hercynian granites and their host rocks occur across the Variscides of the northern Iberian peninsula, and locally display Au-As mineralization. Four separate occurrences at Corcoesto, Tomino, Penedono, and Pino have been investigated to determine P-T-X conditions of formation and likely fluid sources. Special attention has been paid to fluid chemistry using a multidisciplinary investigation of
Economic Geology, 1995
Page 1. Economic Geology Vol. 90, 1995, pp. 1271-1287 Geochemistry of Th-U-REE Mineralizing Magma... more Page 1. Economic Geology Vol. 90, 1995, pp. 1271-1287 Geochemistry of Th-U-REE Mineralizing Magmatic Fluids, Capitan Mountains, New Mexico ANDREW R. CAMPBELL, Department of Geoscience, New Mexico Institute ...
Crustal Permeability, 2016