SUDBURY  IMPACT  CRATER  SULFIDES

 

The Sudbury Complex (Sudbury Basin) in southeastern Canada has intrigued geologists for decades, and not just due to the tremendous economic value of the area’s mineral deposits.

 

Sudbury is one of the largest preserved impact structures on Earth.  The impact occurred ~1.85 billion years ago, during the late Paleoproterozoic.  The Sudbury Impact Structure is no longer circular or subcircular in shape, however - it's been compessed into a stretched-egg shape from an ancient continental collision event.

 


 

Chalcopyrite (CuFeS2) (field of view ~4.5 cm) from the Sudbury Impact Crater in Ontario, Canada.  The specimen really does look like this - better, in fact.  This gorgeous rock comes from a massive sulfide vein hosted in Neoarchean-aged Levack Gneiss (2.64 to 2.71 billion years) from the Coleman Mine’s 153 orebody (North Range, northwest of Sudbury, southeastern Ontario, Canada).  Sulfide mineralization likely occurred during or very soon after the Sudbury impact event at 1.85 billion years (Paleoproterozoic).

 


  

Tarnished chalcopyrite (CuFeS2) & bornite (Cu5FeS4) (2.5 cm tall) from the Sudbury Impact Crater in Ontario, Canada.  This rock comes from a massive sulfide vein intruded within the Levack Gneiss Complex (Neoarchean - 2.64 to 2.71 billion years), which forms the northwestern footwall of the Sudbury Impact Crater.  Sulfide mineralization likely occurred during or very soon after the Sudbury impact event at 1.85 billion years (Paleoproterozoic).

Locality: Coleman Mine (apparently derived from the 153 Orebody, at about 1290-1460 meters depth), North Range, northwest of the city of Sudbuy, southeastern Ontario, southeastern Canada.

 


 

Pentlandite (Ni,Fe)9S8) in pyrrhotite (Fe1-xS) (above & below; 3.4 cm across) from the Sudbury Impact Structure in Ontario, Canada.  Sulfide mineralization likely occurred during or very soon after the Sudbury impact event at 1.85 billion years (Paleoproterozoic).

Bright patches at left & top-center right = pentlandite

Brassy gray-brown areas = pyrrhotite

Black = magnetite

Locality: South Mine, near Sudbury, southeastern Ontario, southeastern Canada.

 


 

Pentlandite (Ni,Fe)9S8) in pyrrhotite (Fe1-xS) (above & below; 8.35 cm across) from the Sudbury Impact Structure in Ontario, Canada.

Bright gold-colored patches = pentlandite

Brassy gray-brown areas = pyrrhotite

Dark grayish to black patches & network = magnetite

Geologic Context & Age: massive sulfide, 800 Orebody at contact of the Copper Cliff offset dike (quartz diorite) & McKim Formation deltaic metapelites (upper Elliot Group, lower Huronian Supergroup, lower Paleoproterozoic, 2.45 b.y.), sulfide mineralization was early post-Sudbury Impact, 1.85 b.y.

Locality: 800 Orebody, South Mine (Copper Cliff South Mine), near Sudbury, southeastern Ontario, southeastern Canada.

 


 

Home page