Abstract: Enigmatic Solution Phenomena in Salina Group (Late Silurian) in New York State

M. I. Treesh

Due to its highly soluble nature halite within the Salina Group (Late Silurian) of New York state has been subjected to three major episodes of solution. Solution-collapse breccias superjacent to many halite beds and solution channels are early solution phenomena as indicated by stratigraphic and petrographic relations.

Second generation salt beds may have resulted as follows: (1) release of water via gypsum dehydration to anhydrite during moderate burial, (2) solution of salt interbedded with, or disseminated in, the sulfate-bearing rocks, (3) upward migration of NaCl-saturated solutions into penecontemporaneous collapse zones that formed during dehydration of gypsum and salt solution, and (4) precipitation of second generation salt in the collapse zones as a result of a brine-mixing process or by cooling as the saturated solutions moved upward. Second generation halite is distinguished by inclusions of brecciated fragments of overlying lithologies and lower water-insoluble-residue content.

The third period of solution resulted from groundwater action near the outcrop belt late in the geologic history of the salt. The breccias on outcrop and those above salt as observed in cores are very similar to water-insoluble residues of Salina Group salt beds. Dissolution of the subsurface salt beds would result in a breccia of approximately the same thickness as breccias observed in outcrop. In cores the top of the highest observed salt coincides with the lowermost extent of gypsum and indicates maximum penetration of ground waters during the third period of solution. The gypsum formed as a result of the hydration of anhydrite by ground water while overlying sediments were being eroded.

AAPG Search and Discovery Article #90978©1975 GCAGS-GC Section SEPM Annual Meeting, Jackson, Mississippi