Galena-Bearing Pyrite Nodules in the Nelway Formation, Salmo, British Columbia

1974 ◽  
Vol 11 (4) ◽  
pp. 495-502 ◽  
Author(s):  
Joseph W. Mills
Keyword(s):  
British Columbia ◽  
Low Temperature ◽  
Host Rock ◽  
Ore Deposits ◽  
Middle Cambrian ◽  
Stratigraphic Position

Pyrite nodules composed of radiating elongate pyrite crystals and including some galena are found in the sparry dolomite matrix of a dolomite breccia within the middle Cambrian Nelway Formation, Salmo map-area, British Columbia.Similar textures, mineralogy, host rock, and stratigraphic position for the nodules and some pyritic zinc-lead ores in northeastern Washington are taken to indicate a common lineage. Favored is an hypothesis calling for the formation of solution-collapse breccias and their filling by dolomite and sulfides precipitated from low temperature solutions. Later deformation and metamorphism erased or concealed the record of these early events in many of the ore deposits.

The Pilot Knob Iron Ore Deposits in Southeast Missouri: A High-To-Low Temperature Magmatic-Hydrothermal Continuum

2021 ◽  
pp. 103973
Author(s):  
Bolorchimeg N. Tunnell ◽  
Marek Locmelis ◽  
Cheryl Seeger ◽  
Ryan Mathur ◽  
István Dunkl ◽  
...  
Keyword(s):  
Low Temperature ◽  
Iron Ore ◽  
Ore Deposits ◽  
Southeast Missouri ◽  
Iron Ore Deposits

The “evolution” of Anomalocaris and its classification in the arthropod class Dinocarida (nov.) and order Radiodonta (nov.)

1996 ◽  
Vol 70 (2) ◽  
pp. 280-293 ◽  
Author(s):  
Desmond Collins
Keyword(s):  
British Columbia ◽  
Sea Cucumber ◽  
Great Difficulty ◽  
Burgess Shale ◽  
Middle Cambrian ◽  
The Past ◽  
History Of ◽  
The Many ◽  
Life On Earth ◽  
Mistaken Identification

The remarkable “evolution” of the reconstructions of Anomalocaris, the extraordinary predator from the 515 million year old Middle Cambrian Burgess Shale of British Columbia, reflects the dramatic changes in our interpretation of early animal life on Earth over the past 100 years. Beginning in 1892 with a claw identified as the abdomen and tail of a phyllocarid crustacean, parts of Anomalocaris have been described variously as a jellyfish, a sea-cucumber, a polychaete worm, a composite of a jellyfish and sponge, or have been attached to other arthropods as appendages. Charles D. Walcott collected complete specimens of Anomalocaris nathorsti between 1911 and 1917, and a Geological Survey of Canada party collected an almost complete specimen of Anomalocaris canadensis in 1966 or 1967, but neither species was adequately described until 1985. At that time they were interpreted by Whittington and Briggs to be representatives of “a hitherto unknown phylum.”Here, using recently collected specimens, the two species are newly reconstructed and described in the genera Anomalocaris and Laggania, and interpreted to be members of an extinct arthropod class, Dinocarida, and order Radiodonta, new to science. The long history of inaccurate reconstruction and mistaken identification of Anomalocaris and Laggania exemplifies our great difficulty in visualizing and classifying, from fossil remains, the many Cambrian animals with no apparent living descendants.

Constraints on temperature–pressure conditions and fluid composition during metamorphism of the Sullivan orebody, Kimberley, British Columbia, from silicate–carbonate equilibria

1995 ◽  
Vol 32 (11) ◽  
pp. 1937-1949 ◽  
Author(s):  
Glen R. De Paoli ◽  
David R.M. Pattison
Keyword(s):  
British Columbia ◽  
Ore Deposits ◽  
Garnet Growth ◽  
Fluid Composition ◽  
Exchange Equilibrium ◽  
Low Grade ◽  
Metamorphic Temperature ◽  
Lower Temperature ◽  
Silicate Carbonate ◽  
Peak Metamorphic Temperature

The Sullivan mine, in southeastern British Columbia, is one of the world's largest sediment-hosted, massive sulphide deposits. It has undergone at least one period of metamorphism since it was deposited in mid-Proterozoic times. Mineral textures within the deposit are predominantly of metamorphic origin. A well-constrained estimate of metamorphic conditions is required to understand how the original, depositional character of the orebody has been modified by metamorphism. Metamorphic conditions were estimated using multiequilibrium thermobarometric techniques involving silicate–carbonate–fluid equilibria. Peak metamorphic temperature constrained by calibration of the garnet–biotite Fe–Mg exchange equilibrium is 450 ± 50 °C. Lower temperature estimates from some samples are interpreted to record the temperature of cessation of garnet growth prior to the attainment of peak metamorphic temperature. Peak metamorphic pressure as determined from equilibria applicable to the assemblage garnet–biotite–muscovite–chlorite–calcite–quartz–fluid is 380 ± 100 MPa. The fluid composition accompanying this pressure estimate is [Formula: see text], [Formula: see text]. This estimate is particular to one sample and may not be representative for the deposit as a whole. Metamorphic fluids at the estimated P–T conditions would not have contained significant concentrations of C–O–H–S species other than H2O and CO2. Textural evidence and temperature–pressure results from a titanite-bearing metamorphosed mafic intrusion in the deposit suggest published titanite ages near 1330 Ma in the area of the mine represent the age of the peak metamorphic event. The results of this study carry tectonic implications for the Sullivan area, and may have application to other metamorphosed ore deposits and low-grade metamorphic settings.

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