James Craft

James Craft

MS - SUNY - Binghamton
Study of flat-pebble conglomerate beds, esp. temporal and spatial variations in HCS, tidal dunes, and channel deposits.

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12
Publications
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Introduction
Ongoing study of Upper Devonian/Missisippian strata in NY with emphasis on flat-pebble conglomerate beds (e.g. Salamanca Conglomerate and related beds) has correlated the Salamanca (coastal deltaic/tidal deposits) over a wide area. The presence of hummocky cross-strata (HCS) of unusual coarseness (coarse sand to 30 mm pebbles) and scale (~ 1-3 m to > 10 m) suggests strong storms (hurricanes). Variations in these deposits over space and time is of particular interest.

Publications

Publications (12)
Article
Describes centimetre- to decimetre-thick, sheetlike to lenticular beds of sandstone and siltstone interbedded with mudstone. Unidirectional current-scour marks and tool marks occur on the basal erosion surfaces of the sandstones: their internal structures are hummocky cross strata of various styles, planar laminae, and wave-ripple cross-laminae. Th...
Conference Paper
Full-text available
Pebbly hummocky cross-stratification is described and interpreted (HCS coarser than fine sand is uncommon in the rock record). Paleohydraulic estimates of large-scale forms (largest hummock wavelengths > 7 meters; largest pebbles > 5 cm) suggest large waves, strong combined flows, and energetic storms/hurricanes, in particular, at the top of the se...
Presentation
Full-text available
The final stages of the Devonian Period is recorded in the hills of Allegany State Park and surrounding area (NY/PA contain the most complete and accessible Upper Devonian stratigraphy on Earth). Extensive outcrops are uncommon on the well forested hillsides with the exception of the escarpment/ block-forming Salamanca Conglomerate: ● House-sized b...
Article
Full-text available
The orthoquartzitic Salamanca conglomerate evidently records a high-energy Upper Devonian seacoast, with at least meso-tidal range, as indicated by a sand-pebble beach, a flood-dominated delta prograding over marine wave-rippled fine sands, large-scale and coarse-grained HCS, and a sub-aqueous large-scale dune field formed by strong flood tides. Mo...
Research
Full-text available
Hourglass Rock City - "Hummocky" Conglomerate As part of a regional study to locate, correlate, and log conglomerate layers with remote sensing and ground truthing, a potential rock city and other "blocky" outcrops were noticed on 1-meter DEM images in the S.W. corner of Allegany State Park near the NY/PA border. Dubbed "Hourglass" based on its D...
Article
Full-text available
The orthoquartzitic Salamanca conglomerate records a high-energy Upper Devonian seacoast, with at least meso-tidal range, as indicated by a pebbly shoreface and beach, a tide-dominated delta prograding over marine wave-rippled fine sands, and a sub-aqueous large-scale (4m-6m foresets) dune field formed by strong flood tides. Most of the sequence re...
Article
Full-text available
A multi-year study of Odonate occurrences was conducted at a pond in western New York State. Dragonflies and damselflies comprise one of the most distinctive and intriguing groups in the animal kingdom. Classified under the Order Odonata (from Greek, “toothed ones” for serrated jaws), “Odes”, as they’re affectionately known, are carnivorous insects...
Research
Full-text available
Article
Typescript. Thesis (M.A.)--State University of New York at Binghamton, 1985. Includes bibliographical references (leaves 98-121).

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Projects

Projects (3)
Project
Understand the spatial and temporal distribution and depositional conditions of coarse-grained HCS in the late Devonian-early Mississippian "Catskill Sea". Preliminary work suggests a more energetic wave climate and less tidal influence with time (as inferred from outcrops of the Devonian Salamanca and the "Hourglass" (Miss.) conglomerates).
Project
Document the sedimentary processes and depositional environments of a prograding late Devonian high-energy (coarse quartz sand w/abundant, well-rounded, discoidal quartz pebbles) shoreline. The Salamanca Conglomerate is composed of a 2-10 meter thick coarsening-upward sequence of apparent shoreface, foreshore/beach, tidal bar/sandwave (cross-bedding up to 6m thick), and tidal/fluvial channel deposits. It forms an extensive escarpment with large joint-separated blocks ("rock cities" where concentrated) on/near hilltops as first noted and superbly described by James Hall (1843). Investigate paleohydraulic conditions; entrainment/transport thresholds for pebbles of various size (0.5 - 10 cm) suggest currents well in excess of 1m/sec. Prepared an article for the fall 2017 NYSGA meeting in Alfred, NY. Ongoing work on regional correlation and unit description of the Salamanca and other conglomerates. Use of 1m-DEM/GIS over a 2000 km2 area is facilitating the search and correlation of disparate outcrops and indicating structural complications in certain areas.