Stratigraphic Analysis Of The Binnewater Sandstone: An Episodic Perspective

Abstract

Application of the Hypothesis of Punctuated Aggradational Cycles to the stratigraphic analysis of the Binnewater Sandstone in southeast­ern New York reveals that the formation was deposited as a sequence of PACs (thin shallowing-upward cycles) in response to a series of six small-scale transgressive episodes. Each successive transgression ex­tended farther to the northeast resulting in an onlapping sequence which is conformable with the High Falls Formation to the southwest and unconformable with the Ordovician Normanskill Formation to the northeast. Within the study area the Binnewater Sandstone sequence is unconforma­bly overlain by the Rondout Formation. At each locality the Binnewater Sandstone consists of PACs repres­enting nearshore, shallow subtidal to high intertidal elastic paleo­environments. These PACs are laterally traceable and can be correlated amongst localities. To the southwest at High Falls the sequence consists of six PACs; to the northeast at South Wilbur the sequence is much thinner because only the third and fourth PACs in the sequence were deposited and preserved. That is, deposition did not begin in the northeast until the area was inundated by the third transgressive event. Then, following deposition of PACs 4, 5 and 6, the sequence was differentially truncated by erosion which eliminated PACs 5 and 6 at Wilbur. Following erosion of the Binnewater sequence the resulting erosional surface was flooded throughout the area by the first Rondout trangressive event indicating the near horizontality of this surface. These detailed strat­igraphic relationships of the Binnewater Sandstone between High Falls and Wilbur can be explained either by differential subsidence of a few meters accompanied by a minor sea-level fall or by differential uplift of a few meters causing greater erosion to the northeast.