Ransom Quadrangle By THOMAS M. KEHN, ERNEST E. GLICK, and WILLIAM C. CULBERTSON GEOLOGICAL SURVEY BULLETIN 1213 Description of the outcropping and subsurface strata of Devonian, Mississippian, and Pennsylvanian age and of the unconsolidated sediments of Quaternary age UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON: 1966 UNITED STATES DEPARTMENT OF THE INTERIOR STEWART L. UDALL, Secretary GEOLOGICAL SURVEY William T. Pecora, Director Library of Congress catalog-card No. GS 66-215 For sale by the Superintendent of Documents, U.S. Government Printing Office PLATE 1. Geologic map and section of the Ransom quadrangle. 2. Stratigraphic section and radiometric logs of the Richards 1 3. Composite stratigraphic section of the exposed Devonian, FIGURE 1. Map showing the Ransom quadrangle relative to the anthra- 3 2. Chart showing classification of Devonian, Mississippian, and 6 24 3. Photographs showing typical crossbedding in the Catskill 4. Diagram showing probable relation of the conglomerate ex- 5. Photograph showing ripple marks in basal part of Griswold 6. Chart showing correlation of Pennsylvanian rocks of the bitu- 31 7. Diagrammatic section of the rockfall at Bald Mountain ... ... .... 38 43 GEOLOGY OF THE RANSOM QUADRANGLE, LACKAWANNA, LUZERNE, AND WYOMING COUNTIES, PENNSYLVANIA By THOMAS M. KEHN, ERNEST E. GLICK, and WILLIAM C. CULBERTSON ABSTRACT The Ransom 72-minute quadrangle is about 56 square miles in area. Most of the quadrangle is in the Allegheny Plateau; the southeasternmost part is underlain by the Northern Anthracite field of the Valley and Ridge province. The outcropping bedrock in most of the quadrangle is the Catskill Formation of Late Devonian age. The Pocono Formation of Early Mississippian age and the Pottsville Formation and post-Pottsville rocks of Pennsylvanian age crop out in the southeastern part of the quadrangle. Eleven formations of Devonian age in the subsurface are provisionally recognized from the study of cuttings of the Richards 1 well. They range downward from the Catskill Formation of the Susquehanna Group to the Kalkberg Limestone of the Helderberg Group. The sedimentary strata studied in the Ransom quadrangle have a total stratigraphic thickness of about 12,000 feet and constitute one of the most complete sections of undeformed Devonian, Mississippian, and Pennsylvanian rock in northeastern Pennsylvania. The Lower Devonian consists of marine limestones and shales that have been assigned from the base upward to the Kalkberg Limestone, New Scotland Limestone equivalent, Becraft Limestone, and Port Ewen Limestone equivalent of the Helderberg Group; the Shriver Chert of the Oriskany Group; and the Esopus Shale. In this study the Ridgeley Sandstone of the Oriskany Group was not recognized in the well cuttings, but the uppermost beds of limestone included in the Shriver Chert may be its stratigraphic equivalent. The Middle Devonian strata consist of marine limestone, shale, and siltstone. Most limestone in the sequence is in the Onondaga Limestone, which also contains chert and bentonite. The shale and siltstone strata have been assigned to the Marcellus Shale and Mahantango Formation. Rocks of early Late Devonian age are assigned to the Trimmers Rock Formation. The lower part of the formation is a shale and siltstone sequence that was probably deposited in a marine environment. The upper part, which is a sequence of siltstone and sandstone that contains a few pyritized plant fossils, probably represents deltaic deposition. The sandstone is the oldest rock of Devonian age in which quartz granules were noted. The rocks of Late Devonian age (consisting of beds of shale, sandstone, and conglomerate of the Catskill Formation) are informally subdivided into five zones on the basis of the size of the constituent quartz sand and quartz pebbles. The two lower zones are marine and are more shaly than the three upper zones. The three upper zones are nonmarine and contain grayish-brown "red" beds. A local conglomerate that caps Bald Mountain interfingers along strike with beds of shale and conglomeratic sandstone in the upper zone of the Catskill Formation. |