ABSTRACT

The reconstruction of depositional environments of the middle Allegheny sediments includes isopachous map of the Middle Kittanning-Lower Freeport interval. Thus, the amount of complete stratigraphic interval thickness controls the accuracy of the isopach map and indirectly affects environmental interpretations. This paper presents a specific solution to prediction of thickness of the Middle Kittanning-Lower Freeport interval from the thickness of enclosed channel sandstone by using the linear regression model. The application of the linear regression as a predicting equation has increased the data of complete stratigraphic sections approximately twofold.

The results of the linear regression analyses indicate that along the fluvio-lacustrine and brackish-marine facies areas, the stratigraphic interval thickness is controlled by the thickness of the enclosed channel sandstone. That is, thick Middle Kittanning-Lower Freeport interval includes thick channel sandstone. The analysis further indicates that the stratigraphic interval shows progressive thickening toward the brackish-marine facies area and thinning toward the fluvio-lacustrine facies area.

The analysis has established that the linear regression relationship between the stratigraphic interval and channel sandstone thickness does not significantly vary within and between the fluvio-lacustrine and brackish-marine facies areas. Thus, a Common Regression equation of the entire stratigraphical data along the outcrop belt was devised and used as the predicting equation. Such a device has proved to be operational in eastern Ohio and also should prove useful to other areas and rock units of fluvio-lacustrine and brackish-marine origins.