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Conodont biostratigraphy, paleoecology, and taphonomy of the Second Creek Bed and Wolcott Furnace hematite (Clinton Group) in West Central New York State

Nicholas B. Sullivan, Mark A. Kleffner, and Carlton E. Brett

Plain Language Abstract

The Second Creek Bed is a thin conglomeratic layer that can be traced for hundreds of kilometers along the Silurian outcrop belt in New York and Ontario in eastern North America. It overlies a regionally angular unconformity, and it contains numerous rip-up clasts, quartz pebbles, phosphate, and iron sulfides (i.e., pyrite). Correlation of the unit at a regional scale is problematic; different index fossils collected from this succession have yielded contradictory ages for this bed. These ages in turn are substantially different from the accepted age of the Westmoreland Ironstone, which was previously assumed to be the lateral equivalent of the Second Creek Bed in east-central New York. Furthermore, the abundant pyrite and organic matter strongly suggest anoxic, sulfidic conditions prevailed as the bed was deposited; yet its coarse sediments and position over a major unconformity suggests a high-energy environment. To address these issues, we collected samples from the Second Creek Bed at its type locality. We corroborate studies of conodonts collected from this unit at localities to the west, assigning a Pterospathodus amorphognathoides angulatus Biozone to the unit. This casts further doubt on the age suggested by other biostratigraphic indicators (i.e., graptolites). It is also inconsistent with the presumed correlation of the Second Creek Bed to the Westmoreland Ironstone. We also collected microfossils from strata underneath the unconformity; these samples yield conodonts that were tentatively assigned to the Pterospathodus eopennatus Superzone, though this finding is equivocal.

Detrital iron sulfides and reworked pyritic internal molds of mollusks were also recovered from the Second Creek Bed. We argue that these sediments, as well as limestone rip-up clasts, and phosphatic pebbles were concentrated in an erosive lag deposit that formed in a deep, low-oxygen depositional environment during a time of rapid sea-level rise and low sedimentation. This erosion and reworking was most likely driven by deep storm-waves, internal waves, and density currents that occasionally scoured the seafloor.

Resumen en Español

Precisiones sobre la edad y el medio de sedimentación en la base de la Formación Williamson (Second Creek Bed) en el centro-oeste del estado de Nueva York
Conodontos en el Second Creek Bed

El Second Creek Bed es un estrato conglomerático delgado, pero fácil de seguir, presente en la base de la Formación Williamson, tanto en el centro-oeste de Nueva York como en el sur de Ontario. La correlación de esta unidad es problemática, y los estudios bioestratigráficos previos de conodontos y graptolites arrojaron edades contradictorias. Para abordar estas cuestiones, se obtuvieron muestras de roca total del Second Creek Bed y estratos subyacentes de la localidad tipo, en el centro-oeste de Nueva York, y se procesaron para la extracción de microfósiles.

Se obtuvo una pobre asociación de conodontos de la Wolcott Furnace Hematite, que en esta localidad se encuentra directamente subyacente al Second Creek Bed, la cual ha sido asignada provisionalmente a la Superzona Pterospathodus eopennatus. Del Second Creek Bed se obtuvieron los restos de una fauna de conodontos diversa del Telychiense temprano a medio. Esta asociación se asigna a la Zona Pterospathodus amorphognathoides angulatus, aunque también presenta elementos conodontos reelaborados más antiguos. Los resultados son consistentes con los estudios cronoestratigráficos previos realizados en el oeste.

Las muestras procesadas del Second Creek Bed también proporcionaron, en gran abundancia, pequeños (500-1500 μm) moldes internos piritizados de gasterópodos, bivalvos y tentaculites. Argumentamos que estos moldes internos se produjeron durante la diagénesis temprana en sustratos de lodos anóxicos durante la sedimentación inicial del lecho y, posteriormente, fueron reelaborados y se concentraron en el fondo marino. Sin embargo, la alta concentración de pirita y materia orgánica en esta sucesión también sugiere que las condiciones anóxicas y sulfurosas prevalecieron incluso cuando la erosión estaba teniendo lugar. Por lo tanto, proponemos que el Second Creek Bed se formó como resultado de la erosión submarina y la reelaboración de clastos remanentes en ambientes profundos que fueron movilizados por las corrientes de densidad, las olas de tormenta y/o las olas no superficiales.

Palabras clave: Silúrico; Conodonto; Autigénesis Marina; Anoxia; Secuencia Estratigráfica; Clinton Group

Traducción: Enrique Peñalver

Résumé en Français

Contraintes sur l'âge et l'Environnement de Dépôt de la Base de la Formation de Williamson (Second Creek Bed) dans le Centre-Ouest de l'Etat de New York
Les conodontes de Second Creek Bed

Second Creek Bed est une strate de conglomérat mince , encore largement traçable, à la base de la Formation de Williamson dans le centre-ouest de New York et sud de l'Ontario. La corrélation de cette unité est problématique, et des études biostratigraphiques de conodontes et graptolites précédentes ont donné des âges contradictoires. Pour résoudre ces problèmes, des échantillons de rocher en vrac provenant de Seconde Creek Bed et des strates sous-jacentes ont été recueillies à partir de la localité type dans le centre-ouest de New York et traitées pour l'extraction de microfossiles.

Un assemblage de conodontes clairsemé, provisoirement attribué à la Superzone Pterospathodus eopennatus, a été récupéré à partir d'Hématite de Wolcott Furnace, directement sous la couche de Second Creek Bed à cette localité. Les restes d'une faune diverse de conodontes du début jusqu'au milieu du Télychien ont été extraites de Second Creek Bed. Cet assemblage est affecté à la Zone Pterospathodus amorphognathoides angulatus, bien que beaucoup plus d'éléments retravaillés de conodontes soient aussi présents. Ces résultats sont conformes à des études chronostratigraphiques menées précédemment à l'ouest.

Des échantillons traités de Second Creek Bed donnent aussi de petit moules internes pyritisé (500-1500 um) de gastéropodes, de bivalves, et de tentaculitids, en grande abondance. Nous soutenons que ces moules internes ont été produits au cours de la diagenèse précoce dans des sous-strates de boue anoxiques pendant le dépôt initial du lit et ensuite retravaillés et concentrées sur le fond marin. Cependant, la forte concentration de pyrite et de matière organique dans cette succession suggère également que des conditions anoxiques sulfurés prévalu en même temps que l'érosion a eu lieu. Par conséquent, nous proposons que Second Creek Bed a été formé à la suite d'érosion sous-marine et remaniement de fragments résiduels dans des environnements profonds, promues par des courants de densité, des ondes de tempête, et / ou des ondes internes.

Mots-clés: Silurien; conodontes; Marine Authigenesis; Anoxia; stratigraphie séquentielle; Groupe Clinton

Translator: Kenny J. Travouillon

Deutsche Zusammenfassung

Constraints beim Alter und Ablagerungsmilieu der basalen Williamson-Formation (Second Creek Bed) im West Central New York State

Das Second Creek Bed ist ein dünnes, jedoch weithin verfolgbares konglomeratisches Stratum an der Basis der Williamson-Formation in West-Zentral New York und im südlichen Ontario. Eine Korrelation dieser Einheit ist problematisch und vorhergehende biostratigrafische Untersuchungen von Conodonten und Graptolithen erbrachten unterschiedliche Alter. Um diese Problematik anzugehen, wurden Mengen an Gesamt-Gestein Proben aus dem Second Creek Bed und darunterliegenden Strata in der Typlokalität in West-Zentral New York gesammelt und für mikrofossile Extraktion aufbereitet. Eine sehr kleine Sammlung an Conodonten, vorläufig der Pterospathodus eopennatus Superzone zugeordnet, wurde aus dem Wolcott Furnace Hämatit, der an dieser Lokalität direkt unter dem Second Creek Bed liegt, gewonnen. Es wurden die Überreste einer diversen Conodontenfauna aus dem frühen bis mittleren Telychium aus dem Second Creek Bed entnommen. Diese Assemblage wird der Pterospathodus amorphognathoides angulatus Zone zugeteilt, auch wenn zudem noch viele ältere Elemente vorkommen. Diese Funde sind mit vorangegangenen chronostratigraphischen Untersuchungen, die im Westen durchgeführt worden waren, stimmig. Verarbeitete Proben aus dem Second Creek Bed haben weiterhin kleine (500-1500 μm), pyritisierte interne Ausgüsse von Gastropoden, Bivalven und Tentaculiten in großer Menge erbracht. Wir argumentieren, dass diese internen Ausgüsse während der frühen Diagenese in einem anoxischen Schlammsubstrat während der ursprünglichen Ablagerung des Beds entstanden sind und danach umgelagert und am Meeresboden angereichert wurden. Jedoch legen die hohe Konzentration an Pyrit und anorganischen Bestandteilen in dieser Folge nahe, dass obwohl Erosion stattfand, anoxische, sulfifische Konditionen vorherrschten. Daher schlagen wir vor dass das Second Creek Bed als Ergebnis einer submarinen Erosion entstand und durch Umarbeitung von Gesteinsfragmenten in tiefen Milieus, zurückzuführen auf Dichteströmungen, Sturmwellen und/oder interne Wellen.

Schlüsselwörter: Silur; Conodont; marine Authigenese; Anoxia; Sequenzstratigraphie; Clinton Group

Translator: Eva Gebauer

Arabic

388 arab

Translator: Ashraf M.T. Elewa

 

 

FIGURE 1. Map of the aerial extent of Silurian bedrock exposed at the surface in central and western New York State (Modified from Fisher et al., 1970). The distribution of four major lithostratigraphic divisions of the Silurian are demarcated. Monroe, Wayne, and Oneida Counties are outlined; the three localities featured in this study are indicated by dashed lines.

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FIGURE 2. A scanned polished slab of the Second Creek Bed, collected from Second Creek. The precise level of the sample is indicated on the graphic log on the left side of the figure (key to lithologies and symbols may be found on Figure 3). The numbered boxes superimposed on the scanned image indicate the fields of three magnified views. 1. Magnified image of the upper part of a limestone rip-up clast showing the partial dissolution of the carbonate with replacement by pyrite. 2. Magnified image of phosphatized brachiopods in cross section surrounded by quartz and phosphate pebbles, with small phosphate grains sheathed by thin rinds of pyrite. 3. Upper surface of limestone rip-up clast showing a small lag of pyrite grains and a bioclast (possible crinoid) replaced by pyrite. Scale bar equals 3 cm.

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FIGURE 3. Graphic logs of outcrops exposed at the three localities featured in this study (see map on Figure 1). From left to right: Tryon Park (Monroe County), Second Creek (Wayne County), and Roaring Brook (Oneida County). Lithostratigraphic terms are shown in black italics. On the right is the sequence stratigraphic interpretation of Brett et al. (1990, 1998). The correlations of this framework are highlighted by the solid shading. Conodont biozones recognized in these successions are denoted by red lines and text (data compiled from Rexroad and Richard, 1965; Kleffner, reported in Brett et al., 1990; 1998; Loydell et al., 2007; Verniers et al., 2012; this study). Note the crossing of different correlation lines between Second Creek and Roaring Brook. A key to all lithologic symbols, labels, and patterns are shown below the correlation.

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FIGURE 4. A comparison of the traditional and revised standard conodont biozonations that have been employed in the Appalachian Foreland Basin, compared to the global standard graptolite biozonation. The standard graptolite biozonation for the Telychian comes primarily from Sadler et al. (2009), Cramer et al. (2011), and Melchin et al. (2012). The modern standard conodont biozonation is based primarily on Männik (2007a) and Jeppsson (1997). The traditional standard conodont biozonation is based on the work of Walliser (1964). The correlation of these zones is derived primarily from the work of Männik (2007a), Cramer et al. (2011), and Melchin et al. (2012). The presumed age of the stratigraphic units studied herein are displayed on the right side of the figure (based on the work of Brett et al., 1998; Loydell et al., 2007; Verniers et al., 2012; this study).

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FIGURE 5. Scanning electron microscope images of selected conodonts recovered from insoluble residues of a sample of the Wolcott Furnace Hematite collected from Second Creek, Wayne County, New York (see Figure 2). 1. Aspelundia cf. A. expansa Armstrong, 1990. Posterior view of dextral Sb element, NS20110812003A. 2. Aspelundia cf. A. expansa Armstrong, 1990. Posterior view of fragmented Sa element, NS20110812003B. 3. Aspelundia cf. A. expansa Armstrong, 1990. Specimen also shows affinities toward Oulodus? australis Bischoff, 1986 or Oulodus? rectangulus sensu Bischoff, 1986. Anterior view of dextral Sb element, NS20110812003C. 4. Aspelundia cf. A. expansa Armstrong, 1990. Lateral view of Sc element, NS20110812003D. 5. Aspelundia sp. Inner lateral view of Sc element, NS20110812003E. 6. Aspelundia? sp. or Oulodus? sp. Outer lateral view of Sb element, NS20110812003F. 7.-8. Ozarkodina polinclinata estonica Männik, 1992. 7. Lateral view of fragmented Pa element, NS20110812003G. 8. Lateral view of fragmented Pa element, MK19860104A. 9. Apsidognathus tuberculatus ssp. n. 1 Männik, 2007a. Upper view of lyriform element, MK19860104B. 10. Pseudooneotodus coniformis Upper view, MK19860104C. Scale bar equals 200 μm.

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FIGURE 6. Shaded line drawings of selected conodonts recovered from insoluble residues of a sample of Wolcott Furnace Hematite collected from Second Creek, Wayne County, New York (see Figure 2). 1.-2. Ozarkodina polinclinata estonica Männik, 1992. 1. Anterior view of Sb element, NS20110812003G. 2. Posterior view of Sb element, NS20110812003G. 3.-4. Oulodus sp. or Aspelundia sp. 3. Inner lateral view of Sc element, NS20110812003H. 4. Outer lateral view of Sc element, NS20110812003H. 5. Panderodus unicostatus Branson and Mehl, 1933. Lateral view of graciliform (qg) element, NS20110812003I. 6. Panderodus unicostatus Branson and Mehl, 1933. Lateral view of arcuatiform (qa) element, NS20110812003J. Scale bar: 200 μm.

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FIGURE 7. Scanning electron microscope images of conodonts recovered from insoluble residues of a sample of the Second Creek Bed collected from Second Creek, Wayne County, New York (see Figure 2). 1. Aulacognathus kuehni Mostler, 1967. Upper view of Pa element, NS20110807005A. 2. Ozarkodina polinclinata estonica Männik, 1992. Lateral view of Pa element, NS20110807005B. 3. Ozarkodina gulletensis Aldridge, 1972. Oblique upper view of Pa element, NS20110807005E. 4. Ozarkodina cf. O. sp. n. Männik, 2007a. Lateral view of Pa element, NS20110807005D. 5. Aspelundia? sp. Lateral view of Sb element, NS20110807005I. 6. Icriodella sp. Oblique upper view of Pa element, NS20110807005F. 7. Oulodus sp. Posterior view of Sb element, NS20110807005G. 8. Oulodus? petilus Nicoll and Rexroad, 1968. Lateral view of Sc element, NS20110807005H. 9. Pterospathodus sp. Lateral view of Pb element, NS20110807005C. 10.-12. Pterospathodus amorphognathoides angulatus Männik, 1998. 10. Lateral view of Pa element, NS20110807005J. 11. Lateral view of Pb1 element, NS20110807005K. 12. Lateral view of Pb1 element, NS20110807005L. 13.-16. Distomodus staurognathoides Walliser, 1964. 13. Upper view of Pa elements, NS20110807005M. 14. Upper view of Pa elements, NS20110807005N. 15. Lateral view of Pb element, NS20110807005O. 16. Lateral view of M element, NS20110807005P. 17.-19. Panderodus unicostatus Branson and Mehl, 1933. 17. Lateral view of falciform (pf) element, NS20110807005Q. 18. Lateral view of graciliform (qg) element, NS20110807005R. 19. Oblique lateral view of graciliform (qg) element, NS20110807005S. Scale bar equals 200 μm.

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FIGURE 8. Shaded line drawings of selected conodonts recovered from insoluble residues of a sample of the Second Creek Bed collected from Second Creek, Wayne County, New York (see Figure 2). 1. Ozarkodina sp. n. Männik, 2007a. Lateral view of Pa element, NS20110807005S. 2. Apsidognahus tuberculatus ssp. n. 2 Männik, 2007a. Upper view of lyriform element, NS20110807005T. 3. Icriodella sp. Lateral view of Pa element, NS20110807005U. 4. Distomodus staurognathoides Walliser, 1964. Upper view of Pa element, NS20110807005V. 5.-6. Pterospathodus amorphognathoides angulatus Männik, 1998. 5. Lateral view of Pa element, NS20110807005W. 6. Upper view of Pa element, NS20110807005W. Scale bar equals 200 μm.

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FIGURE 9. Scanning electron microscope images of the pyritized internal molds of mollusks collected from the insoluble residues of a sample of the Second Creek Bed, collected from Second Creek, Wayne County, New York (see Figure 2). 1.-2. Gastropods. 3.-5. Bivalves. 6.-8. Tentaculitids. Scale bar equals 200 μm.

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FIGURE 10. Polished sample of the rippled conglomeratic horizon collected 70 centimeters below the base of the Westmoreland Hematite at Roaring Brook. Numbered boxes superimposed on the scanned polished slab indicate the fields of three magnified views. 1. View of quartz and phosphate pebbles surrounded by smaller, sand sized grains, many of which are composed of, or coated with a dark red mineral of unknown composition. 2. Black phosphate pebble partially coated by dark red minerals and iron sulfides. 3. Quartz and phosphate pebbles interspersed among sand sized grains of a red mineral of unknown composition. Many of which are coated by a light grey to pink minerals, also of uncertain composition. Scale bar equals 3 cm.

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FIGURE 11. Known ranges of conodont taxa recovered from the Wolcott Furnace Hematite and Second Creek Bed (modified from Männik, 2007a, b).

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author1Nicholas B. Sullivan
Department of Geology
University of Cincinnati
Cincinnati, Ohio 45221
USA
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Starting with a childhood obsession with Dinosaurs, Nicholas B. Sullivan has never wavered from a goal of studying paleontology and geology as a career. In 2010, he received a bachelor’s degree in geological sciences from the State University of New York at Geneseo, where he participated in research on the conodont biostratigraphy and depositional history of Middle Devonian strata in New York and Mongolia. In 2013 he received a master’s degree from the University of Cincinnati where he studied the depositional history and stratigraphic relationships of Silurian strata in the Appalachian Foreland Basin. Following this, he worked at the Wisconsin Geological and Natural History survey and helped establish a conodont biostratigraphy lab. He is currently teaching geology courses at Westminster College in Salt Lake City, Utah. His research interests include conodont biostratigraphy, sequence stratigraphy, the temporal and spatial controls on marine authigenesis, and Paleozoic strata in the northeastern United States.

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author2Mark A. Kleffner
Division of Geological Sciences
School of Earth Sciences
The Ohio State University at Lima
Lima, Ohio 45804
USA
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Mark Kleffner has been involved in research on Silurian conodonts and strata since his senior thesis on the Telychian/Sheinwoodian Estill Shale of northern Kentucky and southern Ohio 35 years ago. His current research interests include Ordovician/Silurian and Silurian/Devonian boundary strata and conodonts, Aeronian-Telychian strata and conodonts of the North American Midwestern Arches and Basins region (NAMBA), Salina Group of NAMBA, and development of a multitaxa- and event-based high-resolution Silurian chronostratigraphy. All of Mark’s current stratigraphic studies utilize a combination of conodont and chitinozoan biostratigraphy and 13Ccarb chemostratigraphy. He completed his PhD on Silurian chronostratigraphy and Silurian strata and conodonts of NAMBA at The Ohio State University, and following a year as a Lecturer on the Columbus campus of Ohio State, has been at the Lima campus of Ohio State, where he is the sole member of the School of Earth Sciences.

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author3Carlton E. Brett
Department of Geology
University of Cincinnati
Cincinnati, Ohio 45221-0013
USA
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Carl Brett earned his Ph.D. at the University of Michigan in 1978, and moved that same year into a faculty position at the University of Rochester. In 1998, he joined the Department of Geology at the University of Cincinnati, where he is currently Professor and Director of Undergraduate Studies. He has spent some four decades researching the paleontology and stratigraphy of the mid Paleozoic strata of eastern North America and elsewhere. He maintains strong interests in taphonomy, paleoecology, evolutionary paleobiology and sequence stratigraphy and is noted for introduction of the concepts of taphofacies, coordinated stasis, echinoderm paleoecology, and the mid Paleozoic predator revolution.

Among the highlights of his career are the receipt the Paleontological Society’s Schuchert Award; his election as a fellow of the Paleontological Society and of the Geological Society of America; his receipt in 2008 of the Digby McClaren Medal for Lifetime Achievement in Stratigraphic Paleontology; and his receipt in 2005 of an Alexander von Humboldt Research Prize. He is the 2012 recipient of the Raymond C. Moore Medal of SEPM for sustained excellence in paleontological research and 2013 recipient of the AAPG’s Grover Murray Outstanding Geological Educator award. Carl has published some 300 peer-reviewed papers, and five edited books, and has supervised more than 50 graduate students.

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