DUKE GEOLOGICAL LABORATORY Web: www.dukelabs.com E-Mail: [email protected] TRIPS ON THE ROCKS Guide 04: Staten Island and Vicinity, NY and NJ Trip 04: 15 April 1989; Trip 19: 29 September 1991 Figure 1 – Geological map of Staten Island, with extension of Palisades intrusive sheet northeastward onto mainland. (After Epstein and Lyttle 1987 and Okulewicz 1988.) Field Trip Notes by: Charles Merguerian and John E. Sanders © 2010 CONTENTS CONTENTS..................................................................................................................................... i INTRODUCTION .......................................................................................................................... 1 GEOLOGIC BACKGROUND....................................................................................................... 3 PHYSIOGRAPHIC SETTING................................................................................................... 3 BEDROCK UNITS..................................................................................................................... 3 Layers I and II: Pre-Newark Complex of Paleozoic- and Older Rocks.................................. 4 Geology of the Staten Island Serpentinite .............................................................................. 6 Origin of the Staten Island Serpentinite.................................................................................. 9 Contrasting Ways for Upper-mantle Material to Get Into the Continental Crust............. 14 Serpentinization and Asbestiform Mineralization ............................................................ 18 Layer V: Newark Basin-filling Strata and the Palisades Intrusive Sheet ............................ 18 Layer VI: The Coastal-plain Strata...................................................................................... 23 LAYER VII: Glacial Deposits.................................................................................................. 25 Kinds of Glacial Sediment: Till and Outwash ..................................................................... 25 Evidence For Inferring Direction of Flow of Ice.................................................................. 27 Features Eroded on Bedrock................................................................................................. 27 Features Found in Glacial Sediments ................................................................................... 28 Stratigraphic Relationships ................................................................................................... 31 Discussion of Ice-flow Evidence .......................................................................................... 37 Comparison of Pleistocene Sediments of the New York City Region With Those of Boston, Massachusetts ........................................................................................................................... 40 DRAINAGE HISTORY ............................................................................................................... 41 Times of Erosion....................................................................................................................... 42 Buried Valleys .......................................................................................................................... 42 Provenance Data ....................................................................................................................... 42 Features in Sediments Made by Currents ................................................................................. 42 Drainage Anomalies.................................................................................................................. 44 Local Examples......................................................................................................................... 47 OBJECTIVES............................................................................................................................... 50 LIST OF LOCALITIES TO BE VISITED................................................................................... 51 DRIVING DIRECTIONS AND GEOLOGIC NOTES EN ROUTE ........................................... 51 Structural Geology of New York City...................................................................................... 59 Geology of Western Queens and Southwestern Brooklyn ....................................................... 60 Synorogenic Plutonism Along Cameron's Line........................................................................ 61 Geologic Map of New York City Water Tunnel Number 3 ..................................................... 63 Brittle Faults.............................................................................................................................. 63 DESCRIPTIONS OF INDIVIDUAL LOCALITIES ("STOPS") ................................................ 70 ACKNOWLEDGEMENTS.......................................................................................................... 78 APPENDIX................................................................................................................................... 79 Table 01 ........................................................................................................................................ 82 Table 02 ........................................................................................................................................ 84 Table 03 ........................................................................................................................................ 89 Table 04 ........................................................................................................................................ 90 REFERENCES CITED................................................................................................................. 91 i DUKE GEOLOGICAL LABORATORY TRIPS ON THE ROCKS Guide 04: Geology of Staten Island and Vicinity, New York and New Jersey Trip 04: 15 April 1989 Trip 19: 29 September 1991 Trip 33: 16 October 1994 INTRODUCTION Today's field trip to Staten Island and vicinity (Figure 1, on cover) is intended to introduce the participants to the wide range of geologic features to be found southwest of Manhattan Island. Staten Island occupies a strategic position within the New York City region: nearly all the major geologic units are present. Despite this strategic position, however, bedrock exposures are scattered and scarce. Individual units can be examined easily, but the critical contact relationships among them are not visible. After the units of the bedrock had formed, Staten Island experienced a complex history of drainage development through a span of geologic time that is not well constrained and of at least three episodes of glaciation during the Quaternary. Table 1 presents a version of a geologic time chart for comparing the names of the geologic time subdivisions, such as Ordovician, Triassic, Jurassic, and Cretaceous, shown on the bedrock map, with estimates of numbers of years for their boundaries and a list of some important local geologic events. Table 2 summarizes the major local geologic units in terms of layers designated by Roman numerals. The area of our field trip is shown on the geologic map of the Newark 1/250,000-scale quadrangle (Lyttle and Epstein, 1987). Tables 3 and 4 refer to the Pleistocene formations. On Staten Island rocks from Layers II, V, and VI are all in erosional contact. That is, the rocks of Layer II, many of which formed at depths of 20 kilometers or more, were elevated, exposed at the Earth's surface and eroded. Later, they subsided once more and materials to form Layer V were deposited above them. Still later, rocks of Layer V and Layer II were tilted, elevated, and eroded. In turn, Layer V subsided and across its truncated, tilted edges, the sediments that form Layer VI were deposited (Figure 2). The rocks from each of these layers formed in totally contrasting plate-tectonic settings. The rocks of Layer II accumulated as sediments along a passive continental margin that trended E-W and was located near the Earth's Equator. These sediments were deformed and metamorphosed in a convergent-margin setting. The sediments constituting Layer V collected in the Newark Basin, in a rift-valley setting not near any plate margin. The sediments of Layer VI were deposited along the passive continental margin of eastern North America, which came into existence when the Atlantic Ocean began to open and that still prevails today. The settings of Layer VI and the early phase of the formation of Layer II are analogous. 1 Exposures- and subsurface relationships on Staten Island contribute important information about the Pleistocene history of the New York City region. (See Table 4.) Present on southwestern Staten Island is a Lower Pleistocene (Nebraskan? or Kansan?) till and outwash containing large-scale trough cross strata within which are much-decayed erratics. Enclosed within the outwash associated with a younger till is a great slab of displaced Upper Cretaceous coastal-plain strata. A paleosol, developed on one of the younger tills, forms a stratigraphic datum whose regional significance is yet to be determined. Distinctive glacial features eroded on the bedrock and/or indicator stones within the till prove that glacial ice flowed across Staten Island from two contrasting directions: NNE to SSW (youngest) and NNW to SSE (older).