FIELD  TRIP  TO  INDIANAPOLIS,  INDIANA

 

On Saturday, 11 December 2010, the OSUN geology club took a field trip to Lehigh-Hanson’s Harding Street Quarry on the south side of Indianapolis, central Indiana, USA.  The goal was to collect coarsely-crystalline pyrite nodules derived from the Blocher Member of the lower New Albany Shale (upper Middle Devonian to Upper Devonian).  Many mineral collectors showed up from various rock & mineral societies, universities, and geologic surveys.  Despite the cold and the wind and the mud and the snow and some rain, good pyrite samples were found by all.

 


 

Mineral collectors in vehicles being led along quarry access roads to the pyrite locality.

 


 

Lehigh-Hanson’s Harding Street Quarry (above & below) in southern Indianapolis, central Indiana, USA.  Quarrying targets Middle Devonian limestones for use as aggregate, gravel, crushed rock, etc.  Material from two overlying units are dumped out of the way, as overburden - Pleistocene till and Upper Devonian black shale.  Pyrite collecting was done at the waste rock pile of black shale.

 


 

Pyrite collecting site - this is a large waste-rock pile of black shale (Blocher Member, lower New Albany Shale, upper Middle Devonian-lower Upper Devonian) at the Lehigh-Hanson Harding Street Quarry (southern Indianapolis, central Indiana, USA).  Certain horizons in the black shale are moderately pyritic, ranging from small to large nodules of various shapes to pyrite-rich laminations and pyrite-rich thin beds.  The nodules can be found within shale blocks and also weathered free from the matrix.

 Fossils observed this day include carbonized plant stem material, arthrodire placoderm fish bone fragments, and gray shale-filled burrows in black shale matrix.

 


 

Pyrite nodules in Blocher Member black shale (lower New Albany Shale, upper Middle Devonian to lower Upper Devonian) from the Lehigh-Hanson Harding Street Quarry (southern Indianapolis, central Indiana, USA).  Specimen at upper left is 4.7 cm across.  Specimen at lower right is 10.1 cm across along the base.

 


 

Coarsely-crystalline pyrite nodules derived from Blocher Member black shale (lower New Albany Shale, upper Middle Devonian to lower Upper Devonian) at the Lehigh-Hanson Harding Street Quarry (southern Indianapolis, central Indiana, USA).  The bluish color is artificial (reflectivity from the computer scanner light).  Specimen at upper left is 5.2 cm across at its widest.

 


 

Pyrite nodules from a previous collecting trip to this locality by a Columbus Rock & Mineral Society member.

 


 

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