SEDIMENTOLOGY OF THE SILURIAN RONDOUT SERIES (CEMENT SERIES), ROSENDALE, UPSTATE NEW YORK

The exposed Silurian Rondout series (RS) include SR: Silurian Rosendale member, SC: Silurian Cobleskill member and the SW: Silurian Whiteport member and are located in Rosendale, upstate New York. Two of the three members of the RS were extensively quarried and mined out for natural cement production in the past, and include Whiteport and Rosendale. These two members were mined out because of the slightly argillaceous, calcitic to dolomitic component with lesser silica content. The repetitive nature of SR due to two episodes of intense folding (Taconic and Acadian) caused vertical stacking of thick strata and enabled mining companies to excavate entire units and supply raw materials for natural cement production in Rosendale. SR limestone is also rich in MgO and CaO, and poor in silica. Overall depositional environment associated with SR and SW is indicated to be shallow marine to intertidal to supratidal based on lithofacies characteristics. The Cobleskill is a fossiliferous limestone and is well-known in the outcrop to possess a very distinct index fossil Halysites. The deconstruction of the limestone to turn into a cement requires soft materials to be broken down easily, which is why the Rosendale and Whiteport members were mined out for cement. However, the Cobleskill was left alone as a “pillar” to hold up all the mined out Rosendale and Whiteport members. In addition, Cobleskill consists of dense material that cannot be broken down easily to be used in natural cement. As observed, the Whiteport member and Rosendale member would require less heating energy for it to be reduced to its cement form.