THE BUFFALO SPRINGS FORMATION AS A POTENTIAL PENNSYLVANIA SOURCE FOR ROSENDALE-STYLE NATURAL CEMENT

Before Portland cement use became dominant after 1910, “natural” cements quarried from the Rosendale and Whiteport Members of the Rondout Formation near Rosendale, New York were extensively used for construction throughout the United States. Although similar clayey and/or sandy dolomites were used across the United States, Rosendale natural cement became the market leader due to its properties and location in the densely populated Northeast. Need for repairs and upkeep of 19th century buildings and infrastructure has resulted in an increased demand for matching materials. Rosendale cement was no longer produced after the 1970s until recent resumption, and available resources are significantly more difficult to extract than before. Determining suitable substitutes for this in Pennsylvania is preferable due to transportation cost and economic benefit to the region.

The Cambrian Buffalo Springs Formation of southeastern Pennsylvania was identified by Gray et al. (1958) as 700+ feet of crystalline limestone, dolomite, and magnesian limestones with variably thick shaley, sandy, and silty beds. Stratigraphically above is the Snitz Creek Formation, a thick-bedded oolitic dolomite with shaley and sandy interbeds and localized chert. Due to recumbent folding and faulting obscured by both agriculture and development, these layers may be structurally intermixed.

Reported chemistry ranges of the Rondout members, and therefore sources of natural cement, are conservatively 45-51% CaCO₃, 17-26% MgCO₃, and 15-23% SiO₂ (after Nason, 1894). Recent assessment of historical chemistry data suggests that portions of the Buffalo Springs Formation are suitable as a natural cement due to falling within these ranges. Recent geochemical sampling of available outcrops confirms this. Preliminary data suggests that three identifiable zones of this formation have chemistry values that fall within the specifications needed for Rosendale-style natural cement: a light yellow to yellow-tan weathered dolomite with quartz ribbons that may have been veins or ductily deformed pebbles, a dark gray laminated dolomite with occasional 1 mm siliceous beds, and a medium gray, irregularly laminated dolomite with very small pyrite grains. Further geochemical analyses are being pursued to determine if other zones are also suitable.