1 ' I . I : '1I. iI NEW YORK STATE . I· GEOLOGICAL ASSOCI�ATION/ . I 58TH .l\NNUAL MEETING FIELlJ TRIP GUIDEBOOK I , ' . I ! i; ' ' I ' ' I • nct:r a. FaJJerc:k, ltlw.t4. Fro!r tketc.h by Mn . HALt. , ' CORNELL UNIVERSITY ITHACA, NEW YORK OCTOBER 10-12, 1986 I , ! I NEW YORK STATE GEOLOGICAL ASSOCIATION 58TH ANNUAL MEETING FIELD TRIP GUIDEBOOK Department of Geological Sciences and Institute for the Study of the Continents CORNELL UNIVERSITY ITHACA, NEW YORK OCTOBER 10-12, 1986 c ' ' Published by the New York State Geological Association. Additional copies available from Manfred P. Wolff, Executive Secretary, New York State Geological Association, Geology Department, Hofstra University, Hempstead, New York 11550. PREFACE AND ACKNOWLEDGMENTS It is a pleasure to welcome all of you to the 58th annual meeting of the New York State Geological Association and to Cornell University . Ithaca and the Finger Lakes region offer much to satisfy a wide range of geological interests. Field trips have been arranged to show this diversity . Topics include general geology , geomechanics , geomorphology, glacial geology , kimberlites , paleobiology, paleoenvironments , petrology of continental basement and the mantle , sedimentary petrology, strati­ graphy , structure , and tectonics . I hope the field guide proves as lastingly useful as the one from the 1959 meeting , when NYSGA last met at Cornell . I want to thank the field trip leaders and other contributors for their efforts on behalf of NYSGA . John L. Cisne , President New York State Geological Association Department of Geological Sciences and Institute for the Study of the Continents Cornell University Ithaca, New York 14853 iii i l ' ! l " [ TABLE OF CONTENTS Page PREFACE AND ACKNOWLEDGMENTS . iii GEOLOGICAL SUMMARY OF THE CAYUGA REGION by D.E. Karig and L.T. Elkins 1 SUBMARINE EROSION ON THE DYSAEROBIC SEAFLOOR: MIDDLE DEVONIAN CORRASIONAL DISCONFORMITIES IN THE CAYUGA VALLEY REGION by Gordon C. Baird and Carlton E. Brett . 23 SEDIMENTARY CYCLES AND LATERAL FACIES GRADIENTS ACROSS A MIDDLE DEVONIAN SHELF-TO-BASIN RAMP , LUDLOWVILLE FORMATION, CAYUGA BASIN by Carlton E. Brett , Gordon C. Baird and Keith B. Miller 81 THE USE OF JOINT PATTERNS FOR UNDERSTANDING THE ALLEGHANIAN OROGENY IN THE UPPE DEVONIAN APPALACHIAN BASIN, FINGER LAKES DISTRICT , NEW YORK by Terry Enge1der . 129 FACIES AND FOSSILS OF THE ONONDAGA LIMESTONE IN CENTRAL NEW YORK by Howard R. Feldman and Richard H. Lindemann . 0 0 145 STRATIGRAPHY AND PALEONTOLOGY - AROUND CAYUGA LAKE ONCE AGAIN by Thomas X. Grasso, Jonathan W. Harrington , and William T. Kirchgasser . ...167 PALEOENVIRONMENTAL ANALYSIS OF THE FIDDLERS GREEN FORMATION (LATE SILU RIAN) IN NEW YORK STATE by Richard D. Hamell and Samue l J. Ciurca, Jr . ....199 KIMBERLITES OF THE FINGER LAKES REGION by Suzanne Mahlburg Kay and Brayton P. Foster .......219 ICE READVANCE IN THE VALLEY OF FIVEMILE CREEK , STEUBEN COUNTY , NEW YORK AND THE EFFECT OF THE RESULTING DEPOSITS ON POSTGLACIAL STREAMFLOW by Allan D. Randall . 0 0 0 0 0 239 GEOMORPHOLOGY OF THE CAYUGA LAKE BASIN by Arthur L. Bloom 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 261 v � l I l ' f i. [ [ l . 1 GEOLOGICAL SUMMARY OF THE CAYUGA REGION D.E. KARIG Department of Geological Sciences 2124 Snee Hall Cornell University Ithaca, NY 14850 L.T. ELKINS Department of Earth and Planetary Sciences Massachusetts Institute of Technology Cambridge , MA 02139 INTRODUCTION No general summary of the geology in the region around Ithaca and Cornell University has appeared since that in the N.Y. Geol. Assoc . Guide ­ book of 1959 . Not only has much information been gathered since that time but also the geological emphasis has shifted. Earlier studies stress the geomorphic and paleontologic aspects of the area, whereas more recent attention has been toward the physical stratigraphy , environments of deposition and tectonic evolution of the region. In addition, geophysical studies and deep drill holes have greatly expanded our knowledge of the subsurface geology and deep crustal conditions . This chapter, therefore , is designed to synthesize the geologic information pertaining to the Cayuga region, emphasizing that material collected since 1959 , and is oriented toward physical stratigraphy , tec­ tonics and geophysics . The summary aspect of this paper precludes much detail , but extensive referencing in this and the following papers will enable the reader to pursue topics in greater depth. GEOLOGIC AND TECTONIC SETTING The Cayuga region (Fig. 1) is physiographically part of the Appalachian Plateau Province, which forms the cratonic flank of the foreland to the Alleghanian collision zone (Engelder, 1979b) . In north central Pennsyl­ vania the foreland fold and thrust belt trends nearly east west, as do the related structures on the foreland in central New York (Wedel, 1932 ; Engelder and Geiser, 1980) . This obliquity with the general northeasterly trend of the Alleghanian collision zone marks the northern flank of a large salient in the structural front , which is in part related to the distribution of the Silurian salt (Davis and Engelder , 1985) . There is , however , a similar salient in the internal part of the collision belt, wh ich suggests that initial passive margin configuration (e.g. , Rankin, 1976) and/or collision complexities were in large part responsible . The Cayuga region has lain well within a continental interior during all of Phanerozoic time, yet close enough to the continental margin to show subtle effects of more pronounced tectonic events that shaped that margin from the late Precambrian into the Mesozoic (Colton, 1970; Engelder and Geiser , 1980) . Thus the stratigraphy of this area bears witness to the formation of a passive continental margin dur ing the late Precamb rian 2 and Cambrian, the Taconic collision in the Ordovician, and the more enig­ matic Acadian event of the mid to late Devonian age (Ettensohn , 1985; Bradley , 1983) . Although younger sediments have since been eroded from the region, its structural framework is basically a result of the Alle­ gh anian collision . The sum of these processes has produced gently south­ ward tilted and thickening pile of strata (Rickard , 1973) , but within that pile are sharply varying trends reflecting earlier events . These trends , primarily in the subsurface, have been delineated by regional strati­ graphic and geophysical studies . GEOPHYSICAL STUDIES Regional gravity and magnetic data provide a primary source of informa­ tion concerning the depth and character of Precamb rian basement in south central New York . Sparse heat flow, seismologic , and electromagnetic studies give further insights into the deep crust and its behavior . A moderate number of seismic reflection profiles have been run in the Cayuga region, wh ich should clarify structural and stratigraphic relations within the sedimentary column, but none of these have been released for public use . Gravity The Bouguer gravity field in New York State (Revetta and Diment , 1971) west of the Taconic zone basically reflects the depth to and density variations of the Precambrian basement . In central New York a very gen­ eral southward decrease in the gravity field is associated with the 15 m/km southward dip of the basement surface (Hodge et al ., 1982 ; Rickard, 1973) . Superimposed on this gradient are sub-circular to more linear NNE trending anomalies . The character of the anomaly field changes markedly across a zone of steep , easterly decreasing gradients that trends NNEerly just west of Rochester (here referred to as the Clarendon-Linden grad­ ient) . To the east and including the Cayuga region, anomalies have lower amplitudes (10-15 mgal) and longer wavelengths than to the west. The eastward decrease in dens ity, smoother field, and more circular anomalies have been interpreted as reflecting less mafic Precamb rian rocks to the east, which have been intruded by both mafic and silicic plutons (Hodge et al ., 1982) . Magnetics i The total fiel� aeromagnetic map s of western New York (e.g. , Zietz and Gilbert , 1981) show a good correspondence to the gravity field (Hodge et l . al ., 1982) . Thus the magnetic field east of the Clarendon-Linden gradient is more subdued than that to the west. In both areas most magnetic highs correlate with gravity highs and are attributed to mafic intrusions or amphibolites (Hodge et al ., 1982) . Lows in both fields reflect granitic or anorthositic bodies. A larger [ � ENE- trending gravity and magnetic low south of Ithaca may imply a syenitic l to anorthositic mass in the Precambrian (Sneddon, 1983) . f l . l . 't 3 Heat Flow Heat flow measurements in New York show approximately normal values for stable continental crust (50-60 mwfm2) but the few measurements in the Cayuga region are significantly higher (65-94 mw/m2) (Hodge et al . , 1982) . In general higher heat flow is attributed to the higher radiogenic content of underlying granitic masses . Variations in temperature gradients differ from those of heat flow because thermal conductivities are a function of lithology. A compilation of temperature gradients in the upper 1 km (Hodge et al ., 1982) show east­ west trends reflecting surface lithology , but also define a N-S trending band of high gradients near 76' 40 'W longitude . Near Auburn , values rise to near 40'C/km, · which provided the basis for the drilling of 2 geothermal wells (Hickman et al ., 1985) . Seismicity Although several regions in New York show significant seismic activity (Sykes , 1978 ; Nottis, 1983) , central New York , and in particular that region east of the Clarendon- Linden gradient has been almost aseismic during historic time . This lack of seismicity correlates well with the other geophysical fields in outlining maj or subdivisions of the Precam­ brian basement in New York (Zoback and Zoback , 1980) . PHYSICAL STRATIGRAPHY AND DEPOSITIONAL SETTINGS Emphasis in previous guidebooks on the Cayuga region has been placed on the description of the exposed Middle and Upper Devonian section. Beneath these strata, however, are over 2 km of older, Cambrian to Devonian strata that overlie a much older Precambrian basement .